CREDITS | 2 Documentation/Configure.help | 11 ++++ Documentation/preempt-locking.txt | 104 ++++++++++++++++++++++++++++++++++++++ MAINTAINERS | 8 ++ arch/arm/config.in | 1 arch/arm/kernel/entry-armv.S | 40 ++++++++++++++ arch/arm/tools/getconstants.c | 6 ++ arch/i386/config.in | 8 ++ arch/i386/kernel/entry.S | 32 ++++++++++- arch/i386/kernel/i387.c | 3 + arch/i386/kernel/smp.c | 30 +++++++++- arch/i386/kernel/traps.c | 2 arch/i386/lib/dec_and_lock.c | 1 arch/mips/config-shared.in | 1 arch/mips/kernel/i8259.c | 1 arch/mips/kernel/irq.c | 29 ++++++++++ arch/mips/kernel/time.c | 25 +++++++++ arch/mips/mm/extable.c | 1 arch/ppc/config.in | 2 arch/ppc/kernel/entry.S | 35 ++++++++++++ arch/ppc/kernel/irq.c | 28 ++++++++++ arch/ppc/kernel/mk_defs.c | 3 + arch/ppc/kernel/setup.c | 14 +++++ arch/ppc/lib/dec_and_lock.c | 1 arch/sh/config.in | 1 arch/sh/kernel/entry.S | 104 +++++++++++++++++++++++++++++++++++--- arch/sh/kernel/irq.c | 17 ++++++ drivers/ieee1394/csr.c | 1 drivers/sound/sound_core.c | 1 fs/adfs/map.c | 1 fs/exec.c | 2 fs/fat/cache.c | 1 fs/lockd/svc.c | 1 fs/nls/nls_base.c | 1 include/asm-arm/dma.h | 1 include/asm-arm/hardirq.h | 1 include/asm-arm/pgalloc.h | 8 ++ include/asm-arm/smplock.h | 11 ++++ include/asm-arm/softirq.h | 8 +- include/asm-arm/system.h | 7 ++ include/asm-i386/hardirq.h | 14 +++-- include/asm-i386/highmem.h | 7 ++ include/asm-i386/hw_irq.h | 19 +++++- include/asm-i386/i387.h | 3 - include/asm-i386/pgalloc.h | 12 ++++ include/asm-i386/smplock.h | 14 +++++ include/asm-i386/softirq.h | 8 +- include/asm-i386/spinlock.h | 18 +++--- include/asm-i386/system.h | 7 ++ include/asm-mips/smplock.h | 15 +++++ include/asm-mips/softirq.h | 6 ++ include/asm-mips/system.h | 14 +++++ include/asm-ppc/dma.h | 1 include/asm-ppc/hardirq.h | 1 include/asm-ppc/highmem.h | 6 +- include/asm-ppc/hw_irq.h | 6 ++ include/asm-ppc/mmu_context.h | 4 + include/asm-ppc/pgalloc.h | 9 +++ include/asm-ppc/smplock.h | 14 +++++ include/asm-ppc/softirq.h | 10 +++ include/asm-sh/hardirq.h | 2 include/asm-sh/smplock.h | 85 ++++++++++++++++++++++++++++--- include/asm-sh/softirq.h | 3 + include/asm-sh/system.h | 15 +++++ include/linux/brlock.h | 10 +-- include/linux/dcache.h | 56 +++++++++++--------- include/linux/fs_struct.h | 13 +++- include/linux/mm.h | 2 include/linux/sched.h | 12 ++++ include/linux/smp.h | 2 include/linux/smp_lock.h | 2 include/linux/spinlock.h | 89 +++++++++++++++++++++++++++++--- include/linux/tqueue.h | 31 ++++++----- kernel/exit.c | 7 ++ kernel/fork.c | 7 ++ kernel/ksyms.c | 3 + kernel/sched.c | 56 ++++++++++++++++++-- lib/dec_and_lock.c | 1 mm/slab.c | 3 - net/core/dev.c | 2 net/core/skbuff.c | 29 +++++----- net/socket.c | 2 net/sunrpc/pmap_clnt.c | 1 net/sunrpc/sched.c | 1 84 files changed, 1042 insertions(+), 134 deletions(-) diff -urN linux-2.4.20-ac1/arch/arm/config.in linux/arch/arm/config.in --- linux-2.4.20-ac1/arch/arm/config.in 2002-12-11 02:48:48.000000000 -0500 +++ linux/arch/arm/config.in 2002-12-11 02:51:40.000000000 -0500 @@ -552,6 +552,7 @@ if [ "$CONFIG_ISDN" != "n" ]; then source drivers/isdn/Config.in fi +dep_bool 'Preemptible Kernel' CONFIG_PREEMPT $CONFIG_CPU_32 endmenu # diff -urN linux-2.4.20-ac1/arch/arm/kernel/entry-armv.S linux/arch/arm/kernel/entry-armv.S --- linux-2.4.20-ac1/arch/arm/kernel/entry-armv.S 2002-08-02 20:39:42.000000000 -0400 +++ linux/arch/arm/kernel/entry-armv.S 2002-12-11 02:51:40.000000000 -0500 @@ -697,6 +697,12 @@ add r4, sp, #S_SP mov r6, lr stmia r4, {r5, r6, r7, r8, r9} @ save sp_SVC, lr_SVC, pc, cpsr, old_ro +#ifdef CONFIG_PREEMPT + get_current_task r9 + ldr r8, [r9, #TSK_PREEMPT] + add r8, r8, #1 + str r8, [r9, #TSK_PREEMPT] +#endif 1: get_irqnr_and_base r0, r6, r5, lr movne r1, sp @ @@ -704,6 +710,25 @@ @ adrsvc ne, lr, 1b bne do_IRQ +#ifdef CONFIG_PREEMPT +2: ldr r8, [r9, #TSK_PREEMPT] + subs r8, r8, #1 + bne 3f + ldr r7, [r9, #TSK_NEED_RESCHED] + teq r7, #0 + beq 3f + ldr r6, .LCirqstat + ldr r0, [r6, #IRQSTAT_BH_COUNT] + teq r0, #0 + bne 3f + mov r0, #MODE_SVC + msr cpsr_c, r0 @ enable interrupts + bl SYMBOL_NAME(preempt_schedule) + mov r0, #I_BIT | MODE_SVC + msr cpsr_c, r0 @ disable interrupts + b 2b +3: str r8, [r9, #TSK_PREEMPT] +#endif ldr r0, [sp, #S_PSR] @ irqs are already disabled msr spsr, r0 ldmia sp, {r0 - pc}^ @ load r0 - pc, cpsr @@ -761,6 +786,9 @@ .LCprocfns: .word SYMBOL_NAME(processor) #endif .LCfp: .word SYMBOL_NAME(fp_enter) +#ifdef CONFIG_PREEMPT +.LCirqstat: .word SYMBOL_NAME(irq_stat) +#endif irq_prio_table @@ -801,6 +829,12 @@ stmdb r8, {sp, lr}^ alignment_trap r4, r7, __temp_irq zero_fp + get_current_task tsk +#ifdef CONFIG_PREEMPT + ldr r0, [tsk, #TSK_PREEMPT] + add r0, r0, #1 + str r0, [tsk, #TSK_PREEMPT] +#endif 1: get_irqnr_and_base r0, r6, r5, lr movne r1, sp adrsvc ne, lr, 1b @@ -808,8 +842,12 @@ @ routine called with r0 = irq number, r1 = struct pt_regs * @ bne do_IRQ +#ifdef CONFIG_PREEMPT + ldr r0, [tsk, #TSK_PREEMPT] + sub r0, r0, #1 + str r0, [tsk, #TSK_PREEMPT] +#endif mov why, #0 - get_current_task tsk b ret_to_user .align 5 diff -urN linux-2.4.20-ac1/arch/arm/tools/getconstants.c linux/arch/arm/tools/getconstants.c --- linux-2.4.20-ac1/arch/arm/tools/getconstants.c 2001-10-11 12:04:57.000000000 -0400 +++ linux/arch/arm/tools/getconstants.c 2002-12-11 02:51:40.000000000 -0500 @@ -13,6 +13,7 @@ #include #include +#include /* * Make sure that the compiler and target are compatible. @@ -39,6 +40,11 @@ DEFN("TSS_SAVE", OFF_TSK(thread.save)); DEFN("TSS_FPESAVE", OFF_TSK(thread.fpstate.soft.save)); +#ifdef CONFIG_PREEMPT +DEFN("TSK_PREEMPT", OFF_TSK(preempt_count)); +DEFN("IRQSTAT_BH_COUNT", (unsigned long)&(((irq_cpustat_t *)0)->__local_bh_count)); +#endif + #ifdef CONFIG_CPU_32 DEFN("TSS_DOMAIN", OFF_TSK(thread.domain)); diff -urN linux-2.4.20-ac1/arch/i386/config.in linux/arch/i386/config.in --- linux-2.4.20-ac1/arch/i386/config.in 2002-12-11 02:48:48.000000000 -0500 +++ linux/arch/i386/config.in 2002-12-11 02:51:40.000000000 -0500 @@ -220,6 +220,7 @@ bool 'Math emulation' CONFIG_MATH_EMULATION bool 'MTRR (Memory Type Range Register) support' CONFIG_MTRR bool 'Symmetric multi-processing support' CONFIG_SMP +bool 'Preemptible Kernel' CONFIG_PREEMPT if [ "$CONFIG_SMP" != "y" ]; then bool 'Local APIC support on uniprocessors' CONFIG_X86_UP_APIC dep_bool 'IO-APIC support on uniprocessors' CONFIG_X86_UP_IOAPIC $CONFIG_X86_UP_APIC @@ -234,9 +235,12 @@ dep_bool 'Summit Architecture support' CONFIG_SUMMIT $CONFIG_MULTIQUAD fi -if [ "$CONFIG_SMP" = "y" -a "$CONFIG_X86_CMPXCHG" = "y" ]; then - define_bool CONFIG_HAVE_DEC_LOCK y +if [ "$CONFIG_SMP" = "y" -o "$CONFIG_PREEMPT" = "y" ]; then + if [ "$CONFIG_X86_CMPXCHG" = "y" ]; then + define_bool CONFIG_HAVE_DEC_LOCK y + fi fi + endmenu mainmenu_option next_comment diff -urN linux-2.4.20-ac1/arch/i386/kernel/entry.S linux/arch/i386/kernel/entry.S --- linux-2.4.20-ac1/arch/i386/kernel/entry.S 2002-12-11 02:48:48.000000000 -0500 +++ linux/arch/i386/kernel/entry.S 2002-12-11 02:51:40.000000000 -0500 @@ -73,7 +73,7 @@ * these are offsets into the task-struct. */ state = 0 -flags = 4 +preempt_count = 4 sigpending = 8 addr_limit = 12 exec_domain = 16 @@ -184,7 +184,7 @@ ENTRY(ret_from_fork) -#if CONFIG_SMP +#if CONFIG_SMP || CONFIG_PREEMPT pushl %ebx call SYMBOL_NAME(schedule_tail) addl $4, %esp @@ -257,12 +257,31 @@ ALIGN ENTRY(ret_from_intr) GET_CURRENT(%ebx) +#ifdef CONFIG_PREEMPT + decl preempt_count(%ebx) ret_from_exception: + cli +#else +ret_from_exception: +#endif movl EFLAGS(%esp),%eax # mix EFLAGS and CS movb CS(%esp),%al testl $(VM_MASK | 3),%eax # return to VM86 mode or non-supervisor? jne ret_from_sys_call +#ifdef CONFIG_PREEMPT + cmpl $0,preempt_count(%ebx) + jnz restore_all + cmpl $0,need_resched(%ebx) + jz restore_all + testl $IF_MASK,EFLAGS(%esp) # Ints off (execption path) ? + jz restore_all + incl preempt_count(%ebx) + sti + call SYMBOL_NAME(preempt_schedule) + jmp ret_from_intr +#else jmp restore_all +#endif ALIGN reschedule: @@ -299,6 +318,9 @@ GET_CURRENT(%ebx) call *%edi addl $8,%esp +#ifdef CONFIG_PREEMPT + cli +#endif jmp ret_from_exception ENTRY(coprocessor_error) @@ -318,12 +340,18 @@ movl %cr0,%eax testl $0x4,%eax # EM (math emulation bit) jne device_not_available_emulate +#ifdef CONFIG_PREEMPT + cli +#endif call SYMBOL_NAME(math_state_restore) jmp ret_from_exception device_not_available_emulate: pushl $0 # temporary storage for ORIG_EIP call SYMBOL_NAME(math_emulate) addl $4,%esp +#ifdef CONFIG_PREEMPT + cli +#endif jmp ret_from_exception ENTRY(debug) diff -urN linux-2.4.20-ac1/arch/i386/kernel/i387.c linux/arch/i386/kernel/i387.c --- linux-2.4.20-ac1/arch/i386/kernel/i387.c 2002-12-11 02:48:48.000000000 -0500 +++ linux/arch/i386/kernel/i387.c 2002-12-11 02:51:40.000000000 -0500 @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -89,6 +90,8 @@ { struct task_struct *tsk = current; + preempt_disable(); + if (tsk->flags & PF_USEDFPU) { __save_init_fpu(tsk); return; diff -urN linux-2.4.20-ac1/arch/i386/kernel/smp.c linux/arch/i386/kernel/smp.c --- linux-2.4.20-ac1/arch/i386/kernel/smp.c 2002-12-11 02:48:48.000000000 -0500 +++ linux/arch/i386/kernel/smp.c 2002-12-11 02:51:40.000000000 -0500 @@ -359,10 +359,13 @@ asmlinkage void smp_invalidate_interrupt (void) { - unsigned long cpu = smp_processor_id(); + unsigned long cpu; + + preempt_disable(); + cpu = smp_processor_id(); if (!test_bit(cpu, &flush_cpumask)) - return; + goto out; /* * This was a BUG() but until someone can quote me the * line from the intel manual that guarantees an IPI to @@ -383,6 +386,9 @@ } ack_APIC_irq(); clear_bit(cpu, &flush_cpumask); + +out: + preempt_enable(); } static void flush_tlb_others (unsigned long cpumask, struct mm_struct *mm, @@ -432,16 +438,23 @@ void flush_tlb_current_task(void) { struct mm_struct *mm = current->mm; - unsigned long cpu_mask = mm->cpu_vm_mask & ~(1 << smp_processor_id()); + unsigned long cpu_mask; + + preempt_disable(); + cpu_mask = mm->cpu_vm_mask & ~(1UL << smp_processor_id()); local_flush_tlb(); if (cpu_mask) flush_tlb_others(cpu_mask, mm, FLUSH_ALL); + preempt_enable(); } void flush_tlb_mm (struct mm_struct * mm) { - unsigned long cpu_mask = mm->cpu_vm_mask & ~(1 << smp_processor_id()); + unsigned long cpu_mask; + + preempt_disable(); + cpu_mask = mm->cpu_vm_mask & ~(1UL << smp_processor_id()); if (current->active_mm == mm) { if (current->mm) @@ -451,12 +464,17 @@ } if (cpu_mask) flush_tlb_others(cpu_mask, mm, FLUSH_ALL); + + preempt_enable(); } void flush_tlb_page(struct vm_area_struct * vma, unsigned long va) { struct mm_struct *mm = vma->vm_mm; - unsigned long cpu_mask = mm->cpu_vm_mask & ~(1 << smp_processor_id()); + unsigned long cpu_mask; + + preempt_disable(); + cpu_mask = mm->cpu_vm_mask & ~(1UL << smp_processor_id()); if (current->active_mm == mm) { if(current->mm) @@ -467,6 +485,8 @@ if (cpu_mask) flush_tlb_others(cpu_mask, mm, va); + + preempt_enable(); } static inline void do_flush_tlb_all_local(void) diff -urN linux-2.4.20-ac1/arch/i386/kernel/traps.c linux/arch/i386/kernel/traps.c --- linux-2.4.20-ac1/arch/i386/kernel/traps.c 2002-12-11 02:48:48.000000000 -0500 +++ linux/arch/i386/kernel/traps.c 2002-12-11 02:51:40.000000000 -0500 @@ -765,6 +765,8 @@ * * Careful.. There are problems with IBM-designed IRQ13 behaviour. * Don't touch unless you *really* know how it works. + * + * Must be called with kernel preemption disabled. */ asmlinkage void math_state_restore(struct pt_regs regs) { diff -urN linux-2.4.20-ac1/arch/i386/lib/dec_and_lock.c linux/arch/i386/lib/dec_and_lock.c --- linux-2.4.20-ac1/arch/i386/lib/dec_and_lock.c 2000-07-07 21:20:16.000000000 -0400 +++ linux/arch/i386/lib/dec_and_lock.c 2002-12-11 02:51:40.000000000 -0500 @@ -8,6 +8,7 @@ */ #include +#include #include int atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock) diff -urN linux-2.4.20-ac1/arch/mips/config-shared.in linux/arch/mips/config-shared.in --- linux-2.4.20-ac1/arch/mips/config-shared.in 2002-11-28 18:53:09.000000000 -0500 +++ linux/arch/mips/config-shared.in 2002-12-11 02:51:40.000000000 -0500 @@ -615,6 +615,7 @@ define_bool CONFIG_HOTPLUG_PCI n fi +dep_bool 'Preemptible Kernel' CONFIG_PREEMPT $CONFIG_NEW_IRQ bool 'System V IPC' CONFIG_SYSVIPC bool 'BSD Process Accounting' CONFIG_BSD_PROCESS_ACCT bool 'Sysctl support' CONFIG_SYSCTL diff -urN linux-2.4.20-ac1/arch/mips/kernel/i8259.c linux/arch/mips/kernel/i8259.c --- linux-2.4.20-ac1/arch/mips/kernel/i8259.c 2002-11-28 18:53:10.000000000 -0500 +++ linux/arch/mips/kernel/i8259.c 2002-12-11 02:51:40.000000000 -0500 @@ -8,6 +8,7 @@ * Copyright (C) 1992 Linus Torvalds * Copyright (C) 1994 - 2000 Ralf Baechle */ +#include #include #include #include diff -urN linux-2.4.20-ac1/arch/mips/kernel/irq.c linux/arch/mips/kernel/irq.c --- linux-2.4.20-ac1/arch/mips/kernel/irq.c 2002-11-28 18:53:10.000000000 -0500 +++ linux/arch/mips/kernel/irq.c 2002-12-11 02:51:40.000000000 -0500 @@ -8,6 +8,8 @@ * Copyright (C) 1992 Linus Torvalds * Copyright (C) 1994 - 2000 Ralf Baechle */ + +#include #include #include #include @@ -19,11 +21,13 @@ #include #include #include -#include +#include +#include #include #include #include +#include /* * Controller mappings for all interrupt sources: @@ -429,6 +433,8 @@ struct irqaction * action; unsigned int status; + preempt_disable(); + kstat.irqs[cpu][irq]++; spin_lock(&desc->lock); desc->handler->ack(irq); @@ -490,6 +496,27 @@ if (softirq_pending(cpu)) do_softirq(); + +#if defined(CONFIG_PREEMPT) + while (--current->preempt_count == 0) { + db_assert(intr_off()); + db_assert(!in_interrupt()); + + if (current->need_resched == 0) { + break; + } + + current->preempt_count ++; + __sti(); + if (user_mode(regs)) { + schedule(); + } else { + preempt_schedule(); + } + __cli(); + } +#endif + return 1; } diff -urN linux-2.4.20-ac1/arch/mips/kernel/time.c linux/arch/mips/kernel/time.c --- linux-2.4.20-ac1/arch/mips/kernel/time.c 2002-11-28 18:53:10.000000000 -0500 +++ linux/arch/mips/kernel/time.c 2002-12-11 02:51:40.000000000 -0500 @@ -413,6 +413,9 @@ { int cpu = smp_processor_id(); + preempt_disable(); + preempt_lock_start(-99); + irq_enter(cpu, irq); kstat.irqs[cpu][irq]++; @@ -421,8 +424,30 @@ irq_exit(cpu, irq); + preempt_lock_stop(); + if (softirq_pending(cpu)) do_softirq(); + +#if defined(CONFIG_PREEMPT) + while (--current->preempt_count == 0) { + db_assert(intr_off()); + db_assert(!in_interrupt()); + + if (current->need_resched == 0) { + break; + } + + current->preempt_count ++; + __sti(); + if (user_mode(regs)) { + schedule(); + } else { + preempt_schedule(); + } + __cli(); + } +#endif } asmlinkage void ll_local_timer_interrupt(int irq, struct pt_regs *regs) diff -urN linux-2.4.20-ac1/arch/mips/mm/extable.c linux/arch/mips/mm/extable.c --- linux-2.4.20-ac1/arch/mips/mm/extable.c 2002-11-28 18:53:10.000000000 -0500 +++ linux/arch/mips/mm/extable.c 2002-12-11 02:51:40.000000000 -0500 @@ -3,6 +3,7 @@ */ #include #include +#include #include #include diff -urN linux-2.4.20-ac1/arch/ppc/config.in linux/arch/ppc/config.in --- linux-2.4.20-ac1/arch/ppc/config.in 2002-11-28 18:53:11.000000000 -0500 +++ linux/arch/ppc/config.in 2002-12-11 02:51:40.000000000 -0500 @@ -112,6 +112,8 @@ bool ' Distribute interrupts on all CPUs by default' CONFIG_IRQ_ALL_CPUS fi +bool 'Preemptible kernel support' CONFIG_PREEMPT + if [ "$CONFIG_6xx" = "y" -a "$CONFIG_8260" = "n" ];then bool 'AltiVec Support' CONFIG_ALTIVEC bool 'Thermal Management Support' CONFIG_TAU diff -urN linux-2.4.20-ac1/arch/ppc/kernel/entry.S linux/arch/ppc/kernel/entry.S --- linux-2.4.20-ac1/arch/ppc/kernel/entry.S 2002-12-11 02:48:48.000000000 -0500 +++ linux/arch/ppc/kernel/entry.S 2002-12-11 02:51:40.000000000 -0500 @@ -280,6 +280,41 @@ */ cmpi 0,r3,0 beq restore +#ifdef CONFIG_PREEMPT + lwz r3,PREEMPT_COUNT(r2) + cmpi 0,r3,1 + bge ret_from_except + lwz r5,_MSR(r1) + andi. r5,r5,MSR_PR + bne do_signal_ret + lwz r5,NEED_RESCHED(r2) + cmpi 0,r5,0 + beq ret_from_except + lis r3,irq_stat@h + ori r3,r3,irq_stat@l + lwz r5,4(r3) + lwz r3,8(r3) + add r3,r3,r5 + cmpi 0,r3,0 + bne ret_from_except + lwz r3,PREEMPT_COUNT(r2) + addi r3,r3,1 + stw r3,PREEMPT_COUNT(r2) + mfmsr r0 + ori r0,r0,MSR_EE + mtmsr r0 + sync + bl preempt_schedule + mfmsr r0 + rlwinm r0,r0,0,17,15 + mtmsr r0 + sync + lwz r3,PREEMPT_COUNT(r2) + subi r3,r3,1 + stw r3,PREEMPT_COUNT(r2) + li r3,1 + b ret_from_intercept +#endif /* CONFIG_PREEMPT */ .globl ret_from_except ret_from_except: lwz r3,_MSR(r1) /* Returning to user mode? */ diff -urN linux-2.4.20-ac1/arch/ppc/kernel/irq.c linux/arch/ppc/kernel/irq.c --- linux-2.4.20-ac1/arch/ppc/kernel/irq.c 2002-11-28 18:53:11.000000000 -0500 +++ linux/arch/ppc/kernel/irq.c 2002-12-11 02:51:40.000000000 -0500 @@ -556,6 +556,34 @@ return 1; /* lets ret_from_int know we can do checks */ } +#ifdef CONFIG_PREEMPT +int +preempt_intercept(struct pt_regs *regs) +{ + int ret; + + preempt_disable(); + + switch(regs->trap) { + case 0x500: + ret = do_IRQ(regs); + break; +#ifndef CONFIG_4xx + case 0x900: +#else + case 0x1000: +#endif + ret = timer_interrupt(regs); + break; + default: + BUG(); + } + + preempt_enable(); + return ret; +} +#endif /* CONFIG_PREEMPT */ + unsigned long probe_irq_on (void) { return 0; diff -urN linux-2.4.20-ac1/arch/ppc/kernel/mk_defs.c linux/arch/ppc/kernel/mk_defs.c --- linux-2.4.20-ac1/arch/ppc/kernel/mk_defs.c 2002-12-11 02:48:48.000000000 -0500 +++ linux/arch/ppc/kernel/mk_defs.c 2002-12-11 02:51:40.000000000 -0500 @@ -41,6 +41,9 @@ DEFINE(SIGPENDING, offsetof(struct task_struct, sigpending)); DEFINE(THREAD, offsetof(struct task_struct, thread)); DEFINE(MM, offsetof(struct task_struct, mm)); +#ifdef CONFIG_PREEMPT + DEFINE(PREEMPT_COUNT, offsetof(struct task_struct, preempt_count)); +#endif DEFINE(ACTIVE_MM, offsetof(struct task_struct, active_mm)); DEFINE(TASK_STRUCT_SIZE, sizeof(struct task_struct)); DEFINE(KSP, offsetof(struct thread_struct, ksp)); diff -urN linux-2.4.20-ac1/arch/ppc/kernel/setup.c linux/arch/ppc/kernel/setup.c --- linux-2.4.20-ac1/arch/ppc/kernel/setup.c 2002-12-11 02:48:48.000000000 -0500 +++ linux/arch/ppc/kernel/setup.c 2002-12-11 02:51:40.000000000 -0500 @@ -498,6 +498,20 @@ strcpy(cmd_line, CONFIG_CMDLINE); #endif /* CONFIG_CMDLINE */ +#ifdef CONFIG_PREEMPT + /* Override the irq routines for external & timer interrupts here, + * as the MMU has only been minimally setup at this point and + * there are no protections on page zero. + */ + { + extern int preempt_intercept(struct pt_regs *); + + do_IRQ_intercept = (unsigned long) &preempt_intercept; + timer_interrupt_intercept = (unsigned long) &preempt_intercept; + + } +#endif /* CONFIG_PREEMPT */ + platform_init(r3, r4, r5, r6, r7); if (ppc_md.progress) diff -urN linux-2.4.20-ac1/arch/ppc/lib/dec_and_lock.c linux/arch/ppc/lib/dec_and_lock.c --- linux-2.4.20-ac1/arch/ppc/lib/dec_and_lock.c 2001-11-16 13:10:08.000000000 -0500 +++ linux/arch/ppc/lib/dec_and_lock.c 2002-12-11 02:51:40.000000000 -0500 @@ -1,4 +1,5 @@ #include +#include #include #include #include diff -urN linux-2.4.20-ac1/arch/sh/config.in linux/arch/sh/config.in --- linux-2.4.20-ac1/arch/sh/config.in 2002-11-28 18:53:11.000000000 -0500 +++ linux/arch/sh/config.in 2002-12-11 02:51:40.000000000 -0500 @@ -124,6 +124,7 @@ hex 'Physical memory start address' CONFIG_MEMORY_START 08000000 hex 'Physical memory size' CONFIG_MEMORY_SIZE 00400000 fi +bool 'Preemptible Kernel' CONFIG_PREEMPT endmenu if [ "$CONFIG_SH_HP690" = "y" ]; then diff -urN linux-2.4.20-ac1/arch/sh/kernel/entry.S linux/arch/sh/kernel/entry.S --- linux-2.4.20-ac1/arch/sh/kernel/entry.S 2002-08-02 20:39:43.000000000 -0400 +++ linux/arch/sh/kernel/entry.S 2002-12-11 02:51:40.000000000 -0500 @@ -60,10 +60,18 @@ /* * These are offsets into the task-struct. */ -flags = 4 +preempt_count = 4 sigpending = 8 need_resched = 20 tsk_ptrace = 24 +flags = 84 + +/* + * These offsets are into irq_stat. + * (Find irq_cpustat_t in asm-sh/hardirq.h) + */ +local_irq_count = 8 +local_bh_count = 12 PT_TRACESYS = 0x00000002 PF_USEDFPU = 0x00100000 @@ -143,7 +151,7 @@ mov.l __INV_IMASK, r11; \ stc sr, r10; \ and r11, r10; \ - stc k_g_imask, r11; \ + stc k_g_imask, r11; \ or r11, r10; \ ldc r10, sr @@ -304,8 +312,8 @@ mov.l @(tsk_ptrace,r0), r0 ! Is current PTRACE_SYSCALL'd? mov #PT_TRACESYS, r1 tst r1, r0 - bt ret_from_syscall - bra syscall_ret_trace + bf syscall_ret_trace + bra ret_from_syscall nop .align 2 @@ -505,8 +513,6 @@ .long syscall_ret_trace __syscall_ret: .long syscall_ret -__INV_IMASK: - .long 0xffffff0f ! ~(IMASK) .align 2 @@ -518,7 +524,84 @@ .align 2 1: .long SYMBOL_NAME(schedule) +#ifdef CONFIG_PREEMPT + ! + ! Returning from interrupt during kernel mode: check if + ! preempt_schedule should be called. If need_resched flag + ! is set, preempt_count is zero, and we're not currently + ! in an interrupt handler (local irq or bottom half) then + ! call preempt_schedule. + ! + ! Increment preempt_count to prevent a nested interrupt + ! from reentering preempt_schedule, then decrement after + ! and drop through to regular interrupt return which will + ! jump back and check again in case such an interrupt did + ! come in (and didn't preempt due to preempt_count). + ! + ! NOTE: because we just checked that preempt_count was + ! zero before getting to the call, can't we use immediate + ! values (1 and 0) rather than inc/dec? Also, rather than + ! drop through to ret_from_irq, we already know this thread + ! is kernel mode, can't we go direct to ret_from_kirq? In + ! fact, with proper interrupt nesting and so forth could + ! the loop simply be on the need_resched w/o checking the + ! other stuff again? Optimize later... + ! + .align 2 +ret_from_kirq: + ! Nonzero preempt_count prevents scheduling + stc k_current, r1 + mov.l @(preempt_count,r1), r0 + cmp/eq #0, r0 + bf restore_all + ! Zero need_resched prevents scheduling + mov.l @(need_resched,r1), r0 + cmp/eq #0, r0 + bt restore_all + ! If in_interrupt(), don't schedule + mov.l __irq_stat, r1 + mov.l @(local_irq_count,r1), r0 + mov.l @(local_bh_count,r1), r1 + or r1, r0 + cmp/eq #0, r0 + bf restore_all + ! Allow scheduling using preempt_schedule + ! Adjust preempt_count and SR as needed. + stc k_current, r1 + mov.l @(preempt_count,r1), r0 ! Could replace this ... + add #1, r0 ! ... and this w/mov #1? + mov.l r0, @(preempt_count,r1) + STI() + mov.l __preempt_schedule, r0 + jsr @r0 + nop + /* CLI */ + stc sr, r0 + or #0xf0, r0 + ldc r0, sr + ! + stc k_current, r1 + mov.l @(preempt_count,r1), r0 ! Could replace this ... + add #-1, r0 ! ... and this w/mov #0? + mov.l r0, @(preempt_count,r1) + ! Maybe should bra ret_from_kirq, or loop over need_resched? + ! For now, fall through to ret_from_irq again... +#endif /* CONFIG_PREEMPT */ + ret_from_irq: + mov #OFF_SR, r0 + mov.l @(r0,r15), r0 ! get status register + shll r0 + shll r0 ! kernel space? +#ifndef CONFIG_PREEMPT + bt restore_all ! Yes, it's from kernel, go back soon +#else /* CONFIG_PREEMPT */ + bt ret_from_kirq ! From kernel: maybe preempt_schedule +#endif /* CONFIG_PREEMPT */ + ! + bra ret_from_syscall + nop + ret_from_exception: mov #OFF_SR, r0 mov.l @(r0,r15), r0 ! get status register @@ -564,6 +647,13 @@ .long SYMBOL_NAME(do_signal) __irq_stat: .long SYMBOL_NAME(irq_stat) +#ifdef CONFIG_PREEMPT +__preempt_schedule: + .long SYMBOL_NAME(preempt_schedule) +#endif /* CONFIG_PREEMPT */ +__INV_IMASK: + .long 0xffffff0f ! ~(IMASK) + .align 2 restore_all: @@ -679,7 +769,7 @@ __fpu_prepare_fd: .long SYMBOL_NAME(fpu_prepare_fd) __init_task_flags: - .long SYMBOL_NAME(init_task_union)+4 + .long SYMBOL_NAME(init_task_union)+flags __PF_USEDFPU: .long PF_USEDFPU #endif diff -urN linux-2.4.20-ac1/arch/sh/kernel/irq.c linux/arch/sh/kernel/irq.c --- linux-2.4.20-ac1/arch/sh/kernel/irq.c 2001-09-08 15:29:09.000000000 -0400 +++ linux/arch/sh/kernel/irq.c 2002-12-11 02:51:40.000000000 -0500 @@ -229,6 +229,14 @@ struct irqaction * action; unsigned int status; + /* + * At this point we're now about to actually call handlers, + * and interrupts might get reenabled during them... bump + * preempt_count to prevent any preemption while the handler + * called here is pending... + */ + preempt_disable(); + /* Get IRQ number */ asm volatile("stc r2_bank, %0\n\t" "shlr2 %0\n\t" @@ -298,8 +306,17 @@ desc->handler->end(irq); spin_unlock(&desc->lock); + if (softirq_pending(cpu)) do_softirq(); + + /* + * We're done with the handlers, interrupts should be + * currently disabled; decrement preempt_count now so + * as we return preemption may be allowed... + */ + preempt_enable_no_resched(); + return 1; } diff -urN linux-2.4.20-ac1/CREDITS linux/CREDITS --- linux-2.4.20-ac1/CREDITS 2002-12-11 02:48:48.000000000 -0500 +++ linux/CREDITS 2002-12-11 02:51:40.000000000 -0500 @@ -1001,8 +1001,8 @@ N: Nigel Gamble E: nigel@nrg.org -E: nigel@sgi.com D: Interrupt-driven printer driver +D: Preemptible kernel S: 120 Alley Way S: Mountain View, California 94040 S: USA diff -urN linux-2.4.20-ac1/Documentation/Configure.help linux/Documentation/Configure.help --- linux-2.4.20-ac1/Documentation/Configure.help 2002-12-11 02:48:48.000000000 -0500 +++ linux/Documentation/Configure.help 2002-12-11 02:51:40.000000000 -0500 @@ -263,6 +263,17 @@ If you have a system with several CPUs, you do not need to say Y here: the local APIC will be used automatically. +Preemptible Kernel +CONFIG_PREEMPT + This option reduces the latency of the kernel when reacting to + real-time or interactive events by allowing a low priority process to + be preempted even if it is in kernel mode executing a system call. + This allows applications to run more reliably even when the system is + under load. + + Say Y here if you are building a kernel for a desktop, embedded + real-time system. Say N if you are unsure. + Kernel math emulation CONFIG_MATH_EMULATION Linux can emulate a math coprocessor (used for floating point diff -urN linux-2.4.20-ac1/Documentation/preempt-locking.txt linux/Documentation/preempt-locking.txt --- linux-2.4.20-ac1/Documentation/preempt-locking.txt 1969-12-31 19:00:00.000000000 -0500 +++ linux/Documentation/preempt-locking.txt 2002-12-11 02:51:40.000000000 -0500 @@ -0,0 +1,104 @@ + Proper Locking Under a Preemptible Kernel: + Keeping Kernel Code Preempt-Safe + Robert Love + Last Updated: 22 Jan 2002 + + +INTRODUCTION + + +A preemptible kernel creates new locking issues. The issues are the same as +those under SMP: concurrency and reentrancy. Thankfully, the Linux preemptible +kernel model leverages existing SMP locking mechanisms. Thus, the kernel +requires explicit additional locking for very few additional situations. + +This document is for all kernel hackers. Developing code in the kernel +requires protecting these situations. + + +RULE #1: Per-CPU data structures need explicit protection + + +Two similar problems arise. An example code snippet: + + struct this_needs_locking tux[NR_CPUS]; + tux[smp_processor_id()] = some_value; + /* task is preempted here... */ + something = tux[smp_processor_id()]; + +First, since the data is per-CPU, it may not have explicit SMP locking, but +require it otherwise. Second, when a preempted task is finally rescheduled, +the previous value of smp_processor_id may not equal the current. You must +protect these situations by disabling preemption around them. + + +RULE #2: CPU state must be protected. + + +Under preemption, the state of the CPU must be protected. This is arch- +dependent, but includes CPU structures and state not preserved over a context +switch. For example, on x86, entering and exiting FPU mode is now a critical +section that must occur while preemption is disabled. Think what would happen +if the kernel is executing a floating-point instruction and is then preempted. +Remember, the kernel does not save FPU state except for user tasks. Therefore, +upon preemption, the FPU registers will be sold to the lowest bidder. Thus, +preemption must be disabled around such regions. + +Note, some FPU functions are already explicitly preempt safe. For example, +kernel_fpu_begin and kernel_fpu_end will disable and enable preemption. +However, math_state_restore must be called with preemption disabled. + + +RULE #3: Lock acquire and release must be performed by same task + + +A lock acquired in one task must be released by the same task. This +means you can't do oddball things like acquire a lock and go off to +play while another task releases it. If you want to do something +like this, acquire and release the task in the same code path and +have the caller wait on an event by the other task. + + +SOLUTION + + +Data protection under preemption is achieved by disabling preemption for the +duration of the critical region. + +preempt_enable() decrement the preempt counter +preempt_disable() increment the preempt counter +preempt_enable_no_resched() decrement, but do not immediately preempt +preempt_get_count() return the preempt counter + +The functions are nestable. In other words, you can call preempt_disable +n-times in a code path, and preemption will not be reenabled until the n-th +call to preempt_enable. The preempt statements define to nothing if +preemption is not enabled. + +Note that you do not need to explicitly prevent preemption if you are holding +any locks or interrupts are disabled, since preemption is implicitly disabled +in those cases. + +Example: + + cpucache_t *cc; /* this is per-CPU */ + preempt_disable(); + cc = cc_data(searchp); + if (cc && cc->avail) { + __free_block(searchp, cc_entry(cc), cc->avail); + cc->avail = 0; + } + preempt_enable(); + return 0; + +Notice how the preemption statements must encompass every reference of the +critical variables. Another example: + + int buf[NR_CPUS]; + set_cpu_val(buf); + if (buf[smp_processor_id()] == -1) printf(KERN_INFO "wee!\n"); + spin_lock(&buf_lock); + /* ... */ + +This code is not preempt-safe, but see how easily we can fix it by simply +moving the spin_lock up two lines. diff -urN linux-2.4.20-ac1/drivers/ieee1394/csr.c linux/drivers/ieee1394/csr.c --- linux-2.4.20-ac1/drivers/ieee1394/csr.c 2002-11-28 18:53:13.000000000 -0500 +++ linux/drivers/ieee1394/csr.c 2002-12-11 02:51:40.000000000 -0500 @@ -10,6 +10,7 @@ */ #include +#include #include "ieee1394_types.h" #include "hosts.h" diff -urN linux-2.4.20-ac1/drivers/sound/sound_core.c linux/drivers/sound/sound_core.c --- linux-2.4.20-ac1/drivers/sound/sound_core.c 2001-09-30 15:26:08.000000000 -0400 +++ linux/drivers/sound/sound_core.c 2002-12-11 02:51:40.000000000 -0500 @@ -37,6 +37,7 @@ #include #include #include +#include #include #include #include diff -urN linux-2.4.20-ac1/fs/adfs/map.c linux/fs/adfs/map.c --- linux-2.4.20-ac1/fs/adfs/map.c 2001-10-25 16:53:53.000000000 -0400 +++ linux/fs/adfs/map.c 2002-12-11 02:51:40.000000000 -0500 @@ -12,6 +12,7 @@ #include #include #include +#include #include "adfs.h" diff -urN linux-2.4.20-ac1/fs/exec.c linux/fs/exec.c --- linux-2.4.20-ac1/fs/exec.c 2002-12-11 02:48:52.000000000 -0500 +++ linux/fs/exec.c 2002-12-11 02:51:40.000000000 -0500 @@ -451,8 +451,8 @@ active_mm = current->active_mm; current->mm = mm; current->active_mm = mm; - task_unlock(current); activate_mm(active_mm, mm); + task_unlock(current); mm_release(); if (old_mm) { if (active_mm != old_mm) BUG(); diff -urN linux-2.4.20-ac1/fs/fat/cache.c linux/fs/fat/cache.c --- linux-2.4.20-ac1/fs/fat/cache.c 2001-10-12 16:48:42.000000000 -0400 +++ linux/fs/fat/cache.c 2002-12-11 02:51:40.000000000 -0500 @@ -14,6 +14,7 @@ #include #include #include +#include #if 0 # define PRINTK(x) printk x diff -urN linux-2.4.20-ac1/fs/lockd/svc.c linux/fs/lockd/svc.c --- linux-2.4.20-ac1/fs/lockd/svc.c 2001-10-21 13:32:33.000000000 -0400 +++ linux/fs/lockd/svc.c 2002-12-11 02:51:40.000000000 -0500 @@ -203,6 +203,7 @@ rpciod_down(); /* Release module */ + unlock_kernel(); MOD_DEC_USE_COUNT; } diff -urN linux-2.4.20-ac1/fs/nls/nls_base.c linux/fs/nls/nls_base.c --- linux-2.4.20-ac1/fs/nls/nls_base.c 2002-08-02 20:39:45.000000000 -0400 +++ linux/fs/nls/nls_base.c 2002-12-11 02:51:40.000000000 -0500 @@ -18,6 +18,7 @@ #ifdef CONFIG_KMOD #include #endif +#include #include static struct nls_table *tables; diff -urN linux-2.4.20-ac1/include/asm-arm/dma.h linux/include/asm-arm/dma.h --- linux-2.4.20-ac1/include/asm-arm/dma.h 2001-08-12 14:14:00.000000000 -0400 +++ linux/include/asm-arm/dma.h 2002-12-11 02:51:40.000000000 -0500 @@ -5,6 +5,7 @@ #include #include +#include #include #include #include diff -urN linux-2.4.20-ac1/include/asm-arm/hardirq.h linux/include/asm-arm/hardirq.h --- linux-2.4.20-ac1/include/asm-arm/hardirq.h 2001-10-11 12:04:57.000000000 -0400 +++ linux/include/asm-arm/hardirq.h 2002-12-11 02:51:40.000000000 -0500 @@ -34,6 +34,7 @@ #define irq_exit(cpu,irq) (local_irq_count(cpu)--) #define synchronize_irq() do { } while (0) +#define release_irqlock(cpu) do { } while (0) #else #error SMP not supported diff -urN linux-2.4.20-ac1/include/asm-arm/pgalloc.h linux/include/asm-arm/pgalloc.h --- linux-2.4.20-ac1/include/asm-arm/pgalloc.h 2001-08-12 14:14:00.000000000 -0400 +++ linux/include/asm-arm/pgalloc.h 2002-12-11 02:51:40.000000000 -0500 @@ -57,40 +57,48 @@ { unsigned long *ret; + preempt_disable(); if ((ret = pgd_quicklist) != NULL) { pgd_quicklist = (unsigned long *)__pgd_next(ret); ret[1] = ret[2]; clean_dcache_entry(ret + 1); pgtable_cache_size--; } + preempt_enable(); return (pgd_t *)ret; } static inline void free_pgd_fast(pgd_t *pgd) { + preempt_disable(); __pgd_next(pgd) = (unsigned long) pgd_quicklist; pgd_quicklist = (unsigned long *) pgd; pgtable_cache_size++; + preempt_enable(); } static inline pte_t *pte_alloc_one_fast(struct mm_struct *mm, unsigned long address) { unsigned long *ret; + preempt_disable(); if((ret = pte_quicklist) != NULL) { pte_quicklist = (unsigned long *)__pte_next(ret); ret[0] = 0; clean_dcache_entry(ret); pgtable_cache_size--; } + preempt_enable(); return (pte_t *)ret; } static inline void free_pte_fast(pte_t *pte) { + preempt_disable(); __pte_next(pte) = (unsigned long) pte_quicklist; pte_quicklist = (unsigned long *) pte; pgtable_cache_size++; + preempt_enable(); } #else /* CONFIG_NO_PGT_CACHE */ diff -urN linux-2.4.20-ac1/include/asm-arm/smplock.h linux/include/asm-arm/smplock.h --- linux-2.4.20-ac1/include/asm-arm/smplock.h 2001-08-12 14:14:00.000000000 -0400 +++ linux/include/asm-arm/smplock.h 2002-12-11 02:51:40.000000000 -0500 @@ -3,12 +3,17 @@ * * Default SMP lock implementation */ +#include #include #include extern spinlock_t kernel_flag; +#ifdef CONFIG_PREEMPT +#define kernel_locked() preempt_get_count() +#else #define kernel_locked() spin_is_locked(&kernel_flag) +#endif /* * Release global kernel lock and global interrupt lock @@ -40,8 +45,14 @@ */ static inline void lock_kernel(void) { +#ifdef CONFIG_PREEMPT + if (current->lock_depth == -1) + spin_lock(&kernel_flag); + ++current->lock_depth; +#else if (!++current->lock_depth) spin_lock(&kernel_flag); +#endif } static inline void unlock_kernel(void) diff -urN linux-2.4.20-ac1/include/asm-arm/softirq.h linux/include/asm-arm/softirq.h --- linux-2.4.20-ac1/include/asm-arm/softirq.h 2001-09-08 15:02:31.000000000 -0400 +++ linux/include/asm-arm/softirq.h 2002-12-11 02:51:40.000000000 -0500 @@ -5,20 +5,22 @@ #include #define __cpu_bh_enable(cpu) \ - do { barrier(); local_bh_count(cpu)--; } while (0) + do { barrier(); local_bh_count(cpu)--; preempt_enable(); } while (0) #define cpu_bh_disable(cpu) \ - do { local_bh_count(cpu)++; barrier(); } while (0) + do { preempt_disable(); local_bh_count(cpu)++; barrier(); } while (0) #define local_bh_disable() cpu_bh_disable(smp_processor_id()) #define __local_bh_enable() __cpu_bh_enable(smp_processor_id()) #define in_softirq() (local_bh_count(smp_processor_id()) != 0) -#define local_bh_enable() \ +#define _local_bh_enable() \ do { \ unsigned int *ptr = &local_bh_count(smp_processor_id()); \ if (!--*ptr && ptr[-2]) \ __asm__("bl%? __do_softirq": : : "lr");/* out of line */\ } while (0) +#define local_bh_enable() do { _local_bh_enable(); preempt_enable(); } while (0) + #endif /* __ASM_SOFTIRQ_H */ diff -urN linux-2.4.20-ac1/include/asm-arm/system.h linux/include/asm-arm/system.h --- linux-2.4.20-ac1/include/asm-arm/system.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/asm-arm/system.h 2002-12-11 02:51:40.000000000 -0500 @@ -63,6 +63,13 @@ #define local_irq_disable() __cli() #define local_irq_enable() __sti() +#define irqs_disabled() \ +({ \ + unsigned long cpsr_val; \ + asm ("mrs %0, cpsr" : "=r" (cpsr_val)); \ + cpsr_val & 128; \ +}) + #ifdef CONFIG_SMP #error SMP not supported diff -urN linux-2.4.20-ac1/include/asm-i386/hardirq.h linux/include/asm-i386/hardirq.h --- linux-2.4.20-ac1/include/asm-i386/hardirq.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/asm-i386/hardirq.h 2002-12-11 02:51:40.000000000 -0500 @@ -23,12 +23,16 @@ /* * Are we in an interrupt context? Either doing bottom half - * or hardware interrupt processing? + * or hardware interrupt processing? Note the preempt check, + * this is both a bugfix and an optimization. If we are + * preemptible, we cannot be in an interrupt. */ -#define in_interrupt() ({ int __cpu = smp_processor_id(); \ - (local_irq_count(__cpu) + local_bh_count(__cpu) != 0); }) +#define in_interrupt() (preempt_is_disabled() && \ + ({unsigned long __cpu = smp_processor_id(); \ + (local_irq_count(__cpu) + local_bh_count(__cpu) != 0); })) -#define in_irq() (local_irq_count(smp_processor_id()) != 0) +#define in_irq() (preempt_is_disabled() && \ + (local_irq_count(smp_processor_id()) != 0)) #ifndef CONFIG_SMP @@ -40,6 +44,8 @@ #define synchronize_irq() barrier() +#define release_irqlock(cpu) do { } while (0) + #else #include diff -urN linux-2.4.20-ac1/include/asm-i386/highmem.h linux/include/asm-i386/highmem.h --- linux-2.4.20-ac1/include/asm-i386/highmem.h 2002-08-02 20:39:45.000000000 -0400 +++ linux/include/asm-i386/highmem.h 2002-12-11 02:51:40.000000000 -0500 @@ -88,6 +88,7 @@ enum fixed_addresses idx; unsigned long vaddr; + preempt_disable(); if (page < highmem_start_page) return page_address(page); @@ -109,8 +110,10 @@ unsigned long vaddr = (unsigned long) kvaddr; enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id(); - if (vaddr < FIXADDR_START) // FIXME + if (vaddr < FIXADDR_START) { // FIXME + preempt_enable(); return; + } if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx)) out_of_line_bug(); @@ -122,6 +125,8 @@ pte_clear(kmap_pte-idx); __flush_tlb_one(vaddr); #endif + + preempt_enable(); } #endif /* __KERNEL__ */ diff -urN linux-2.4.20-ac1/include/asm-i386/hw_irq.h linux/include/asm-i386/hw_irq.h --- linux-2.4.20-ac1/include/asm-i386/hw_irq.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/asm-i386/hw_irq.h 2002-12-11 02:51:40.000000000 -0500 @@ -97,6 +97,18 @@ #define __STR(x) #x #define STR(x) __STR(x) +#define GET_CURRENT \ + "movl %esp, %ebx\n\t" \ + "andl $-8192, %ebx\n\t" + +#ifdef CONFIG_PREEMPT +#define BUMP_LOCK_COUNT \ + GET_CURRENT \ + "incl 4(%ebx)\n\t" +#else +#define BUMP_LOCK_COUNT +#endif + #define SAVE_ALL \ "cld\n\t" \ "pushl %es\n\t" \ @@ -110,15 +122,12 @@ "pushl %ebx\n\t" \ "movl $" STR(__KERNEL_DS) ",%edx\n\t" \ "movl %edx,%ds\n\t" \ - "movl %edx,%es\n\t" + "movl %edx,%es\n\t" \ + BUMP_LOCK_COUNT #define IRQ_NAME2(nr) nr##_interrupt(void) #define IRQ_NAME(nr) IRQ_NAME2(IRQ##nr) -#define GET_CURRENT \ - "movl %esp, %ebx\n\t" \ - "andl $-8192, %ebx\n\t" - /* * SMP has a few special interrupts for IPI messages */ diff -urN linux-2.4.20-ac1/include/asm-i386/i387.h linux/include/asm-i386/i387.h --- linux-2.4.20-ac1/include/asm-i386/i387.h 2002-08-02 20:39:45.000000000 -0400 +++ linux/include/asm-i386/i387.h 2002-12-11 02:51:40.000000000 -0500 @@ -12,6 +12,7 @@ #define __ASM_I386_I387_H #include +#include #include #include #include @@ -24,7 +25,7 @@ extern void restore_fpu( struct task_struct *tsk ); extern void kernel_fpu_begin(void); -#define kernel_fpu_end() stts() +#define kernel_fpu_end() do { stts(); preempt_enable(); } while(0) #define unlazy_fpu( tsk ) do { \ diff -urN linux-2.4.20-ac1/include/asm-i386/pgalloc.h linux/include/asm-i386/pgalloc.h --- linux-2.4.20-ac1/include/asm-i386/pgalloc.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/asm-i386/pgalloc.h 2002-12-11 02:51:40.000000000 -0500 @@ -75,20 +75,26 @@ { unsigned long *ret; + preempt_disable(); if ((ret = pgd_quicklist) != NULL) { pgd_quicklist = (unsigned long *)(*ret); ret[0] = 0; pgtable_cache_size--; - } else + preempt_enable(); + } else { + preempt_enable(); ret = (unsigned long *)get_pgd_slow(); + } return (pgd_t *)ret; } static inline void free_pgd_fast(pgd_t *pgd) { + preempt_disable(); *(unsigned long *)pgd = (unsigned long) pgd_quicklist; pgd_quicklist = (unsigned long *) pgd; pgtable_cache_size++; + preempt_enable(); } static inline void free_pgd_slow(pgd_t *pgd) @@ -119,19 +125,23 @@ { unsigned long *ret; + preempt_disable(); if ((ret = (unsigned long *)pte_quicklist) != NULL) { pte_quicklist = (unsigned long *)(*ret); ret[0] = ret[1]; pgtable_cache_size--; } + preempt_enable(); return (pte_t *)ret; } static inline void pte_free_fast(pte_t *pte) { + preempt_disable(); *(unsigned long *)pte = (unsigned long) pte_quicklist; pte_quicklist = (unsigned long *) pte; pgtable_cache_size++; + preempt_enable(); } static __inline__ void pte_free_slow(pte_t *pte) diff -urN linux-2.4.20-ac1/include/asm-i386/smplock.h linux/include/asm-i386/smplock.h --- linux-2.4.20-ac1/include/asm-i386/smplock.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/asm-i386/smplock.h 2002-12-11 02:51:40.000000000 -0500 @@ -14,7 +14,15 @@ extern spinlock_cacheline_t kernel_flag_cacheline; #define kernel_flag kernel_flag_cacheline.lock +#ifdef CONFIG_SMP #define kernel_locked() spin_is_locked(&kernel_flag) +#else +#ifdef CONFIG_PREEMPT +#define kernel_locked() preempt_get_count() +#else +#define kernel_locked() 1 +#endif +#endif /* * Release global kernel lock and global interrupt lock @@ -46,6 +54,11 @@ */ static __inline__ void lock_kernel(void) { +#ifdef CONFIG_PREEMPT + if (current->lock_depth == -1) + spin_lock(&kernel_flag); + ++current->lock_depth; +#else #if 1 if (!++current->lock_depth) spin_lock(&kernel_flag); @@ -58,6 +71,7 @@ :"=m" (__dummy_lock(&kernel_flag)), "=m" (current->lock_depth)); #endif +#endif } static __inline__ void unlock_kernel(void) diff -urN linux-2.4.20-ac1/include/asm-i386/softirq.h linux/include/asm-i386/softirq.h --- linux-2.4.20-ac1/include/asm-i386/softirq.h 2002-08-02 20:39:45.000000000 -0400 +++ linux/include/asm-i386/softirq.h 2002-12-11 02:51:40.000000000 -0500 @@ -5,9 +5,9 @@ #include #define __cpu_bh_enable(cpu) \ - do { barrier(); local_bh_count(cpu)--; } while (0) + do { barrier(); local_bh_count(cpu)--; preempt_enable(); } while (0) #define cpu_bh_disable(cpu) \ - do { local_bh_count(cpu)++; barrier(); } while (0) + do { preempt_disable(); local_bh_count(cpu)++; barrier(); } while (0) #define local_bh_disable() cpu_bh_disable(smp_processor_id()) #define __local_bh_enable() __cpu_bh_enable(smp_processor_id()) @@ -22,7 +22,7 @@ * If you change the offsets in irq_stat then you have to * update this code as well. */ -#define local_bh_enable() \ +#define _local_bh_enable() \ do { \ unsigned int *ptr = &local_bh_count(smp_processor_id()); \ \ @@ -45,4 +45,6 @@ /* no registers clobbered */ ); \ } while (0) +#define local_bh_enable() do { _local_bh_enable(); preempt_enable(); } while (0) + #endif /* __ASM_SOFTIRQ_H */ diff -urN linux-2.4.20-ac1/include/asm-i386/spinlock.h linux/include/asm-i386/spinlock.h --- linux-2.4.20-ac1/include/asm-i386/spinlock.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/asm-i386/spinlock.h 2002-12-11 02:51:40.000000000 -0500 @@ -77,7 +77,7 @@ :"=m" (lock->lock) : : "memory" -static inline void spin_unlock(spinlock_t *lock) +static inline void _raw_spin_unlock(spinlock_t *lock) { #if SPINLOCK_DEBUG if (lock->magic != SPINLOCK_MAGIC) @@ -97,7 +97,7 @@ :"=q" (oldval), "=m" (lock->lock) \ :"0" (oldval) : "memory" -static inline void spin_unlock(spinlock_t *lock) +static inline void _raw_spin_unlock(spinlock_t *lock) { char oldval = 1; #if SPINLOCK_DEBUG @@ -113,7 +113,7 @@ #endif -static inline int spin_trylock(spinlock_t *lock) +static inline int _raw_spin_trylock(spinlock_t *lock) { char oldval; __asm__ __volatile__( @@ -123,7 +123,7 @@ return oldval > 0; } -static inline void spin_lock(spinlock_t *lock) +static inline void _raw_spin_lock(spinlock_t *lock) { #if SPINLOCK_DEBUG __label__ here; @@ -179,7 +179,7 @@ */ /* the spinlock helpers are in arch/i386/kernel/semaphore.c */ -static inline void read_lock(rwlock_t *rw) +static inline void _raw_read_lock(rwlock_t *rw) { #if SPINLOCK_DEBUG if (rw->magic != RWLOCK_MAGIC) @@ -188,7 +188,7 @@ __build_read_lock(rw, "__read_lock_failed"); } -static inline void write_lock(rwlock_t *rw) +static inline void _raw_write_lock(rwlock_t *rw) { #if SPINLOCK_DEBUG if (rw->magic != RWLOCK_MAGIC) @@ -197,10 +197,10 @@ __build_write_lock(rw, "__write_lock_failed"); } -#define read_unlock(rw) asm volatile("lock ; incl %0" :"=m" ((rw)->lock) : : "memory") -#define write_unlock(rw) asm volatile("lock ; addl $" RW_LOCK_BIAS_STR ",%0":"=m" ((rw)->lock) : : "memory") +#define _raw_read_unlock(rw) asm volatile("lock ; incl %0" :"=m" ((rw)->lock) : : "memory") +#define _raw_write_unlock(rw) asm volatile("lock ; addl $" RW_LOCK_BIAS_STR ",%0":"=m" ((rw)->lock) : : "memory") -static inline int write_trylock(rwlock_t *lock) +static inline int _raw_write_trylock(rwlock_t *lock) { atomic_t *count = (atomic_t *)lock; if (atomic_sub_and_test(RW_LOCK_BIAS, count)) diff -urN linux-2.4.20-ac1/include/asm-i386/system.h linux/include/asm-i386/system.h --- linux-2.4.20-ac1/include/asm-i386/system.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/asm-i386/system.h 2002-12-11 02:51:40.000000000 -0500 @@ -319,6 +319,13 @@ /* used in the idle loop; sti takes one instruction cycle to complete */ #define safe_halt() __asm__ __volatile__("sti; hlt": : :"memory") +#define irqs_disabled() \ +({ \ + unsigned long flags; \ + __save_flags(flags); \ + !(flags & (1<<9)); \ +}) + #define __save_and_cli(x) do { __save_flags(x); __cli(); } while(0); #define __save_and_sti(x) do { __save_flags(x); __sti(); } while(0); diff -urN linux-2.4.20-ac1/include/asm-mips/smplock.h linux/include/asm-mips/smplock.h --- linux-2.4.20-ac1/include/asm-mips/smplock.h 2002-08-02 20:39:45.000000000 -0400 +++ linux/include/asm-mips/smplock.h 2002-12-11 02:51:40.000000000 -0500 @@ -5,12 +5,21 @@ * * Default SMP lock implementation */ +#include #include #include extern spinlock_t kernel_flag; +#ifdef CONFIG_SMP #define kernel_locked() spin_is_locked(&kernel_flag) +#else +#ifdef CONFIG_PREEMPT +#define kernel_locked() preempt_get_count() +#else +#define kernel_locked() 1 +#endif +#endif /* * Release global kernel lock and global interrupt lock @@ -42,8 +51,14 @@ */ extern __inline__ void lock_kernel(void) { +#ifdef CONFIG_PREEMPT + if (current->lock_depth == -1) + spin_lock(&kernel_flag); + ++current->lock_depth; +#else if (!++current->lock_depth) spin_lock(&kernel_flag); +#endif } extern __inline__ void unlock_kernel(void) diff -urN linux-2.4.20-ac1/include/asm-mips/softirq.h linux/include/asm-mips/softirq.h --- linux-2.4.20-ac1/include/asm-mips/softirq.h 2002-11-28 18:53:15.000000000 -0500 +++ linux/include/asm-mips/softirq.h 2002-12-11 02:51:40.000000000 -0500 @@ -10,11 +10,15 @@ #ifndef _ASM_SOFTIRQ_H #define _ASM_SOFTIRQ_H +#include +#include + #include #include static inline void cpu_bh_disable(int cpu) { + preempt_disable(); local_bh_count(cpu)++; barrier(); } @@ -23,6 +27,7 @@ { barrier(); local_bh_count(cpu)--; + preempt_enable(); } @@ -36,6 +41,7 @@ cpu = smp_processor_id(); \ if (!--local_bh_count(cpu) && softirq_pending(cpu)) \ do_softirq(); \ + preempt_enable(); \ } while (0) #define in_softirq() (local_bh_count(smp_processor_id()) != 0) diff -urN linux-2.4.20-ac1/include/asm-mips/system.h linux/include/asm-mips/system.h --- linux-2.4.20-ac1/include/asm-mips/system.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/asm-mips/system.h 2002-12-11 02:51:40.000000000 -0500 @@ -327,4 +327,18 @@ #define die_if_kernel(msg, regs) \ __die_if_kernel(msg, regs, __FILE__ ":", __FUNCTION__, __LINE__) +static inline int intr_on(void) +{ + unsigned long flags; + save_flags(flags); + return flags & 1; +} + +static inline int intr_off(void) +{ + return ! intr_on(); +} + +#define irqs_disabled() intr_off() + #endif /* _ASM_SYSTEM_H */ diff -urN linux-2.4.20-ac1/include/asm-ppc/dma.h linux/include/asm-ppc/dma.h --- linux-2.4.20-ac1/include/asm-ppc/dma.h 2001-05-21 18:02:06.000000000 -0400 +++ linux/include/asm-ppc/dma.h 2002-12-11 02:51:40.000000000 -0500 @@ -14,6 +14,7 @@ #include #include #include +#include #include /* diff -urN linux-2.4.20-ac1/include/asm-ppc/hardirq.h linux/include/asm-ppc/hardirq.h --- linux-2.4.20-ac1/include/asm-ppc/hardirq.h 2002-11-28 18:53:15.000000000 -0500 +++ linux/include/asm-ppc/hardirq.h 2002-12-11 02:51:40.000000000 -0500 @@ -48,6 +48,7 @@ #define hardirq_exit(cpu) (local_irq_count(cpu)--) #define synchronize_irq() do { } while (0) +#define release_irqlock(cpu) do { } while (0) #else /* CONFIG_SMP */ diff -urN linux-2.4.20-ac1/include/asm-ppc/highmem.h linux/include/asm-ppc/highmem.h --- linux-2.4.20-ac1/include/asm-ppc/highmem.h 2001-07-02 17:34:57.000000000 -0400 +++ linux/include/asm-ppc/highmem.h 2002-12-11 02:51:40.000000000 -0500 @@ -84,6 +84,7 @@ unsigned int idx; unsigned long vaddr; + preempt_disable(); if (page < highmem_start_page) return page_address(page); @@ -105,8 +106,10 @@ unsigned long vaddr = (unsigned long) kvaddr; unsigned int idx = type + KM_TYPE_NR*smp_processor_id(); - if (vaddr < KMAP_FIX_BEGIN) // FIXME + if (vaddr < KMAP_FIX_BEGIN) { // FIXME + preempt_enable(); return; + } if (vaddr != KMAP_FIX_BEGIN + idx * PAGE_SIZE) BUG(); @@ -118,6 +121,7 @@ pte_clear(kmap_pte+idx); flush_tlb_page(0, vaddr); #endif + preempt_enable(); } #endif /* __KERNEL__ */ diff -urN linux-2.4.20-ac1/include/asm-ppc/hw_irq.h linux/include/asm-ppc/hw_irq.h --- linux-2.4.20-ac1/include/asm-ppc/hw_irq.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/asm-ppc/hw_irq.h 2002-12-11 02:51:40.000000000 -0500 @@ -13,6 +13,12 @@ extern int timer_interrupt(struct pt_regs *); extern void ppc_irq_dispatch_handler(struct pt_regs *regs, int irq); +#define mfmsr() ({unsigned int rval; \ + asm volatile("mfmsr %0" : "=r" (rval)); rval;}) +#define mtmsr(v) asm volatile("mtmsr %0" : : "r" (v)) + +#define irqs_disabled() ((mfmsr() & MSR_EE) == 0) + extern void __sti(void); extern void __cli(void); extern void __restore_flags(unsigned long); diff -urN linux-2.4.20-ac1/include/asm-ppc/mmu_context.h linux/include/asm-ppc/mmu_context.h --- linux-2.4.20-ac1/include/asm-ppc/mmu_context.h 2001-10-02 12:12:44.000000000 -0400 +++ linux/include/asm-ppc/mmu_context.h 2002-12-11 02:51:40.000000000 -0500 @@ -158,6 +158,10 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk, int cpu) { +#ifdef CONFIG_PREEMPT + if (preempt_get_count() == 0) + BUG(); +#endif tsk->thread.pgdir = next->pgd; get_mmu_context(next); set_context(next->context, next->pgd); diff -urN linux-2.4.20-ac1/include/asm-ppc/pgalloc.h linux/include/asm-ppc/pgalloc.h --- linux-2.4.20-ac1/include/asm-ppc/pgalloc.h 2001-05-21 18:02:06.000000000 -0400 +++ linux/include/asm-ppc/pgalloc.h 2002-12-11 02:51:40.000000000 -0500 @@ -68,20 +68,25 @@ { unsigned long *ret; + preempt_disable(); if ((ret = pgd_quicklist) != NULL) { pgd_quicklist = (unsigned long *)(*ret); ret[0] = 0; pgtable_cache_size--; + preempt_enable(); } else + preempt_enable(); ret = (unsigned long *)get_pgd_slow(); return (pgd_t *)ret; } extern __inline__ void free_pgd_fast(pgd_t *pgd) { + preempt_disable(); *(unsigned long **)pgd = pgd_quicklist; pgd_quicklist = (unsigned long *) pgd; pgtable_cache_size++; + preempt_enable(); } extern __inline__ void free_pgd_slow(pgd_t *pgd) @@ -120,19 +125,23 @@ { unsigned long *ret; + preempt_disable(); if ((ret = pte_quicklist) != NULL) { pte_quicklist = (unsigned long *)(*ret); ret[0] = 0; pgtable_cache_size--; } + preempt_enable(); return (pte_t *)ret; } extern __inline__ void pte_free_fast(pte_t *pte) { + preempt_disable(); *(unsigned long **)pte = pte_quicklist; pte_quicklist = (unsigned long *) pte; pgtable_cache_size++; + preempt_enable(); } extern __inline__ void pte_free_slow(pte_t *pte) diff -urN linux-2.4.20-ac1/include/asm-ppc/smplock.h linux/include/asm-ppc/smplock.h --- linux-2.4.20-ac1/include/asm-ppc/smplock.h 2001-11-02 20:43:54.000000000 -0500 +++ linux/include/asm-ppc/smplock.h 2002-12-11 02:51:40.000000000 -0500 @@ -15,7 +15,15 @@ extern spinlock_t kernel_flag; +#ifdef CONFIG_SMP #define kernel_locked() spin_is_locked(&kernel_flag) +#else +#ifdef CONFIG_PREEMPT +#define kernel_locked() preempt_get_count() +#else +#define kernel_locked() 1 +#endif +#endif /* * Release global kernel lock and global interrupt lock @@ -47,8 +55,14 @@ */ static __inline__ void lock_kernel(void) { +#ifdef CONFIG_PREEMPT + if (current->lock_depth == -1) + spin_lock(&kernel_flag); + ++current->lock_depth; +#else if (!++current->lock_depth) spin_lock(&kernel_flag); +#endif } static __inline__ void unlock_kernel(void) diff -urN linux-2.4.20-ac1/include/asm-ppc/softirq.h linux/include/asm-ppc/softirq.h --- linux-2.4.20-ac1/include/asm-ppc/softirq.h 2001-09-08 15:02:31.000000000 -0400 +++ linux/include/asm-ppc/softirq.h 2002-12-11 02:51:40.000000000 -0500 @@ -10,6 +10,7 @@ #define local_bh_disable() \ do { \ + preempt_disable(); \ local_bh_count(smp_processor_id())++; \ barrier(); \ } while (0) @@ -18,9 +19,10 @@ do { \ barrier(); \ local_bh_count(smp_processor_id())--; \ + preempt_enable(); \ } while (0) -#define local_bh_enable() \ +#define _local_bh_enable() \ do { \ if (!--local_bh_count(smp_processor_id()) \ && softirq_pending(smp_processor_id())) { \ @@ -28,6 +30,12 @@ } \ } while (0) +#define local_bh_enable() \ +do { \ + _local_bh_enable(); \ + preempt_enable(); \ +} while (0) + #define in_softirq() (local_bh_count(smp_processor_id()) != 0) #endif /* __ASM_SOFTIRQ_H */ diff -urN linux-2.4.20-ac1/include/asm-sh/hardirq.h linux/include/asm-sh/hardirq.h --- linux-2.4.20-ac1/include/asm-sh/hardirq.h 2001-09-08 15:29:09.000000000 -0400 +++ linux/include/asm-sh/hardirq.h 2002-12-11 02:51:40.000000000 -0500 @@ -34,6 +34,8 @@ #define synchronize_irq() barrier() +#define release_irqlock(cpu) do { } while (0) + #else #error Super-H SMP is not available diff -urN linux-2.4.20-ac1/include/asm-sh/smplock.h linux/include/asm-sh/smplock.h --- linux-2.4.20-ac1/include/asm-sh/smplock.h 2001-09-08 15:29:09.000000000 -0400 +++ linux/include/asm-sh/smplock.h 2002-12-11 02:51:40.000000000 -0500 @@ -9,15 +9,88 @@ #include -#ifndef CONFIG_SMP - +#if !defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT) +/* + * Should never happen, since linux/smp_lock.h catches this case; + * but in case this file is included directly with neither SMP nor + * PREEMPT configuration, provide same dummys as linux/smp_lock.h + */ #define lock_kernel() do { } while(0) #define unlock_kernel() do { } while(0) -#define release_kernel_lock(task, cpu, depth) ((depth) = 1) -#define reacquire_kernel_lock(task, cpu, depth) do { } while(0) +#define release_kernel_lock(task, cpu) do { } while(0) +#define reacquire_kernel_lock(task) do { } while(0) +#define kernel_locked() 1 + +#else /* CONFIG_SMP || CONFIG_PREEMPT */ + +#if CONFIG_SMP +#error "We do not support SMP on SH yet" +#endif +/* + * Default SMP lock implementation (i.e. the i386 version) + */ + +#include +#include + +extern spinlock_t kernel_flag; +#define lock_bkl() spin_lock(&kernel_flag) +#define unlock_bkl() spin_unlock(&kernel_flag) +#ifdef CONFIG_SMP +#define kernel_locked() spin_is_locked(&kernel_flag) +#elif CONFIG_PREEMPT +#define kernel_locked() preempt_get_count() +#else /* neither */ +#define kernel_locked() 1 +#endif + +/* + * Release global kernel lock and global interrupt lock + */ +#define release_kernel_lock(task, cpu) \ +do { \ + if (task->lock_depth >= 0) \ + spin_unlock(&kernel_flag); \ + release_irqlock(cpu); \ + __sti(); \ +} while (0) + +/* + * Re-acquire the kernel lock + */ +#define reacquire_kernel_lock(task) \ +do { \ + if (task->lock_depth >= 0) \ + spin_lock(&kernel_flag); \ +} while (0) + +/* + * Getting the big kernel lock. + * + * This cannot happen asynchronously, + * so we only need to worry about other + * CPU's. + */ +static __inline__ void lock_kernel(void) +{ +#ifdef CONFIG_PREEMPT + if (current->lock_depth == -1) + spin_lock(&kernel_flag); + ++current->lock_depth; #else -#error "We do not support SMP on SH" -#endif /* CONFIG_SMP */ + if (!++current->lock_depth) + spin_lock(&kernel_flag); +#endif +} + +static __inline__ void unlock_kernel(void) +{ + if (current->lock_depth < 0) + BUG(); + if (--current->lock_depth < 0) + spin_unlock(&kernel_flag); +} +#endif /* CONFIG_SMP || CONFIG_PREEMPT */ #endif /* __ASM_SH_SMPLOCK_H */ diff -urN linux-2.4.20-ac1/include/asm-sh/softirq.h linux/include/asm-sh/softirq.h --- linux-2.4.20-ac1/include/asm-sh/softirq.h 2001-09-08 15:29:09.000000000 -0400 +++ linux/include/asm-sh/softirq.h 2002-12-11 02:51:40.000000000 -0500 @@ -6,6 +6,7 @@ #define local_bh_disable() \ do { \ + preempt_disable(); \ local_bh_count(smp_processor_id())++; \ barrier(); \ } while (0) @@ -14,6 +15,7 @@ do { \ barrier(); \ local_bh_count(smp_processor_id())--; \ + preempt_enable(); \ } while (0) #define local_bh_enable() \ @@ -23,6 +25,7 @@ && softirq_pending(smp_processor_id())) { \ do_softirq(); \ } \ + preempt_enable(); \ } while (0) #define in_softirq() (local_bh_count(smp_processor_id()) != 0) diff -urN linux-2.4.20-ac1/include/asm-sh/system.h linux/include/asm-sh/system.h --- linux-2.4.20-ac1/include/asm-sh/system.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/asm-sh/system.h 2002-12-11 02:51:40.000000000 -0500 @@ -289,4 +289,17 @@ void disable_hlt(void); void enable_hlt(void); -#endif +/* + * irqs_disabled - are interrupts disabled? + */ +static inline int irqs_disabled(void) +{ + unsigned long flags; + + __save_flags(flags); + if (flags & 0x000000f0) + return 1; + return 0; +} + +#endif /* __ASM_SH_SYSTEM_H */ diff -urN linux-2.4.20-ac1/include/linux/brlock.h linux/include/linux/brlock.h --- linux-2.4.20-ac1/include/linux/brlock.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/linux/brlock.h 2002-12-11 02:51:40.000000000 -0500 @@ -173,11 +173,11 @@ } #else -# define br_read_lock(idx) ((void)(idx)) -# define br_read_unlock(idx) ((void)(idx)) -# define br_write_lock(idx) ((void)(idx)) -# define br_write_unlock(idx) ((void)(idx)) -#endif +# define br_read_lock(idx) ({ (void)(idx); preempt_disable(); }) +# define br_read_unlock(idx) ({ (void)(idx); preempt_enable(); }) +# define br_write_lock(idx) ({ (void)(idx); preempt_disable(); }) +# define br_write_unlock(idx) ({ (void)(idx); preempt_enable(); }) +#endif /* CONFIG_SMP */ /* * Now enumerate all of the possible sw/hw IRQ protected diff -urN linux-2.4.20-ac1/include/linux/dcache.h linux/include/linux/dcache.h --- linux-2.4.20-ac1/include/linux/dcache.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/linux/dcache.h 2002-12-11 02:51:40.000000000 -0500 @@ -128,31 +128,6 @@ extern spinlock_t dcache_lock; -/** - * d_drop - drop a dentry - * @dentry: dentry to drop - * - * d_drop() unhashes the entry from the parent - * dentry hashes, so that it won't be found through - * a VFS lookup any more. Note that this is different - * from deleting the dentry - d_delete will try to - * mark the dentry negative if possible, giving a - * successful _negative_ lookup, while d_drop will - * just make the cache lookup fail. - * - * d_drop() is used mainly for stuff that wants - * to invalidate a dentry for some reason (NFS - * timeouts or autofs deletes). - */ - -static __inline__ void d_drop(struct dentry * dentry) -{ - spin_lock(&dcache_lock); - list_del(&dentry->d_hash); - INIT_LIST_HEAD(&dentry->d_hash); - spin_unlock(&dcache_lock); -} - static __inline__ int dname_external(struct dentry *d) { return d->d_name.name != d->d_iname; @@ -277,3 +252,34 @@ #endif /* __KERNEL__ */ #endif /* __LINUX_DCACHE_H */ + +#if !defined(__LINUX_DCACHE_H_INLINES) && defined(_TASK_STRUCT_DEFINED) +#define __LINUX_DCACHE_H_INLINES + +#ifdef __KERNEL__ +/** + * d_drop - drop a dentry + * @dentry: dentry to drop + * + * d_drop() unhashes the entry from the parent + * dentry hashes, so that it won't be found through + * a VFS lookup any more. Note that this is different + * from deleting the dentry - d_delete will try to + * mark the dentry negative if possible, giving a + * successful _negative_ lookup, while d_drop will + * just make the cache lookup fail. + * + * d_drop() is used mainly for stuff that wants + * to invalidate a dentry for some reason (NFS + * timeouts or autofs deletes). + */ + +static __inline__ void d_drop(struct dentry * dentry) +{ + spin_lock(&dcache_lock); + list_del(&dentry->d_hash); + INIT_LIST_HEAD(&dentry->d_hash); + spin_unlock(&dcache_lock); +} +#endif +#endif diff -urN linux-2.4.20-ac1/include/linux/fs_struct.h linux/include/linux/fs_struct.h --- linux-2.4.20-ac1/include/linux/fs_struct.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/linux/fs_struct.h 2002-12-11 02:51:40.000000000 -0500 @@ -23,6 +23,15 @@ extern void exit_fs(struct task_struct *); extern void set_fs_altroot(void); +struct fs_struct *copy_fs_struct(struct fs_struct *old); +void put_fs_struct(struct fs_struct *fs); + +#endif +#endif + +#if !defined(_LINUX_FS_STRUCT_H_INLINES) && defined(_TASK_STRUCT_DEFINED) +#define _LINUX_FS_STRUCT_H_INLINES +#ifdef __KERNEL__ /* * Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values. * It can block. Requires the big lock held. @@ -68,9 +77,5 @@ mntput(old_pwdmnt); } } - -struct fs_struct *copy_fs_struct(struct fs_struct *old); -void put_fs_struct(struct fs_struct *fs); - #endif #endif diff -urN linux-2.4.20-ac1/include/linux/mm.h linux/include/linux/mm.h --- linux-2.4.20-ac1/include/linux/mm.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/linux/mm.h 2002-12-11 02:51:40.000000000 -0500 @@ -344,6 +344,7 @@ * busywait with less bus contention for a good time to * attempt to acquire the lock bit. */ + preempt_disable(); while (test_and_set_bit(PG_chainlock, &page->flags)) { while (test_bit(PG_chainlock, &page->flags)) cpu_relax(); @@ -353,6 +354,7 @@ static inline void pte_chain_unlock(struct page *page) { clear_bit(PG_chainlock, &page->flags); + preempt_enable(); } /* diff -urN linux-2.4.20-ac1/include/linux/sched.h linux/include/linux/sched.h --- linux-2.4.20-ac1/include/linux/sched.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/linux/sched.h 2002-12-11 02:51:40.000000000 -0500 @@ -91,6 +91,7 @@ #define TASK_UNINTERRUPTIBLE 2 #define TASK_ZOMBIE 4 #define TASK_STOPPED 8 +#define PREEMPT_ACTIVE 0x4000000 #define __set_task_state(tsk, state_value) \ do { (tsk)->state = (state_value); } while (0) @@ -157,6 +158,9 @@ #define MAX_SCHEDULE_TIMEOUT LONG_MAX extern signed long FASTCALL(schedule_timeout(signed long timeout)); asmlinkage void schedule(void); +#ifdef CONFIG_PREEMPT +asmlinkage void preempt_schedule(void); +#endif extern int schedule_task(struct tq_struct *task); extern void flush_scheduled_tasks(void); @@ -322,7 +326,7 @@ * offsets of these are hardcoded elsewhere - touch with care */ volatile long state; /* -1 unrunnable, 0 runnable, >0 stopped */ - unsigned long flags; /* per process flags, defined below */ + int preempt_count; /* 0 => preemptable, <0 => BUG */ int sigpending; mm_segment_t addr_limit; /* thread address space: 0-0xBFFFFFFF for user-thead @@ -348,6 +352,7 @@ unsigned long policy; unsigned long cpus_allowed; unsigned int time_slice; + unsigned long flags; task_t *next_task, *prev_task; @@ -1011,6 +1016,11 @@ #endif /* CONFIG_SMP */ +#define _TASK_STRUCT_DEFINED +#include +#include +#include + #endif /* __KERNEL__ */ #endif diff -urN linux-2.4.20-ac1/include/linux/smp.h linux/include/linux/smp.h --- linux-2.4.20-ac1/include/linux/smp.h 2002-12-11 02:48:52.000000000 -0500 +++ linux/include/linux/smp.h 2002-12-11 02:51:40.000000000 -0500 @@ -81,7 +81,9 @@ #define smp_processor_id() 0 #define hard_smp_processor_id() 0 #define smp_threads_ready 1 +#ifndef CONFIG_PREEMPT #define kernel_lock() +#endif #define cpu_logical_map(cpu) 0 #define cpu_number_map(cpu) 0 #define cpu_online(cpu) ({ BUG_ON((cpu) != 0); 1; }) diff -urN linux-2.4.20-ac1/include/linux/smp_lock.h linux/include/linux/smp_lock.h --- linux-2.4.20-ac1/include/linux/smp_lock.h 2001-11-22 14:46:27.000000000 -0500 +++ linux/include/linux/smp_lock.h 2002-12-11 02:51:40.000000000 -0500 @@ -3,7 +3,7 @@ #include -#ifndef CONFIG_SMP +#if !defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT) #define lock_kernel() do { } while(0) #define unlock_kernel() do { } while(0) diff -urN linux-2.4.20-ac1/include/linux/spinlock.h linux/include/linux/spinlock.h --- linux-2.4.20-ac1/include/linux/spinlock.h 2002-11-28 18:53:15.000000000 -0500 +++ linux/include/linux/spinlock.h 2002-12-11 02:51:40.000000000 -0500 @@ -2,6 +2,7 @@ #define __LINUX_SPINLOCK_H #include +#include /* * These are the generic versions of the spinlocks and read-write @@ -62,8 +63,10 @@ #if (DEBUG_SPINLOCKS < 1) +#ifndef CONFIG_PREEMPT #define atomic_dec_and_lock(atomic,lock) atomic_dec_and_test(atomic) #define ATOMIC_DEC_AND_LOCK +#endif /* * Your basic spinlocks, allowing only a single CPU anywhere @@ -80,11 +83,11 @@ #endif #define spin_lock_init(lock) do { } while(0) -#define spin_lock(lock) (void)(lock) /* Not "unused variable". */ +#define _raw_spin_lock(lock) (void)(lock) /* Not "unused variable". */ #define spin_is_locked(lock) (0) -#define spin_trylock(lock) ({1; }) +#define _raw_spin_trylock(lock) ({1; }) #define spin_unlock_wait(lock) do { } while(0) -#define spin_unlock(lock) do { } while(0) +#define _raw_spin_unlock(lock) do { } while(0) #elif (DEBUG_SPINLOCKS < 2) @@ -144,13 +147,85 @@ #endif #define rwlock_init(lock) do { } while(0) -#define read_lock(lock) (void)(lock) /* Not "unused variable". */ -#define read_unlock(lock) do { } while(0) -#define write_lock(lock) (void)(lock) /* Not "unused variable". */ -#define write_unlock(lock) do { } while(0) +#define _raw_read_lock(lock) (void)(lock) /* Not "unused variable". */ +#define _raw_read_unlock(lock) do { } while(0) +#define _raw_write_lock(lock) (void)(lock) /* Not "unused variable". */ +#define _raw_write_unlock(lock) do { } while(0) #endif /* !SMP */ +#ifdef CONFIG_PREEMPT + +#define preempt_get_count() (current->preempt_count) +#define preempt_is_disabled() (preempt_get_count() != 0) + +#define preempt_disable() \ +do { \ + ++current->preempt_count; \ + barrier(); \ +} while (0) + +#define preempt_enable_no_resched() \ +do { \ + --current->preempt_count; \ + barrier(); \ +} while (0) + +#define preempt_enable() \ +do { \ + --current->preempt_count; \ + barrier(); \ + if (unlikely(current->preempt_count < current->need_resched)) \ + preempt_schedule(); \ +} while (0) + +#define spin_lock(lock) \ +do { \ + preempt_disable(); \ + _raw_spin_lock(lock); \ +} while(0) + +#define spin_trylock(lock) ({preempt_disable(); _raw_spin_trylock(lock) ? \ + 1 : ({preempt_enable(); 0;});}) +#define spin_unlock(lock) \ +do { \ + _raw_spin_unlock(lock); \ + preempt_enable(); \ +} while (0) + +#define spin_unlock_no_resched(lock) \ +do { \ + _raw_spin_unlock(lock); \ + preempt_enable_no_resched(); \ +} while (0) + +#define read_lock(lock) ({preempt_disable(); _raw_read_lock(lock);}) +#define read_unlock(lock) ({_raw_read_unlock(lock); preempt_enable();}) +#define write_lock(lock) ({preempt_disable(); _raw_write_lock(lock);}) +#define write_unlock(lock) ({_raw_write_unlock(lock); preempt_enable();}) +#define write_trylock(lock) ({preempt_disable();_raw_write_trylock(lock) ? \ + 1 : ({preempt_enable(); 0;});}) + +#else + +#define preempt_get_count() (0) +#define preempt_is_disabled() (1) +#define preempt_disable() do { } while (0) +#define preempt_enable_no_resched() do {} while(0) +#define preempt_enable() do { } while (0) + +#define spin_lock(lock) _raw_spin_lock(lock) +#define spin_trylock(lock) _raw_spin_trylock(lock) +#define spin_unlock(lock) _raw_spin_unlock(lock) +#define spin_unlock_no_resched(lock) _raw_spin_unlock(lock) + +#define read_lock(lock) _raw_read_lock(lock) +#define read_unlock(lock) _raw_read_unlock(lock) +#define write_lock(lock) _raw_write_lock(lock) +#define write_unlock(lock) _raw_write_unlock(lock) +#define write_trylock(lock) _raw_write_trylock(lock) +#endif + /* "lock on reference count zero" */ #ifndef ATOMIC_DEC_AND_LOCK #include diff -urN linux-2.4.20-ac1/include/linux/tqueue.h linux/include/linux/tqueue.h --- linux-2.4.20-ac1/include/linux/tqueue.h 2001-11-22 14:46:19.000000000 -0500 +++ linux/include/linux/tqueue.h 2002-12-11 02:51:40.000000000 -0500 @@ -94,6 +94,22 @@ extern spinlock_t tqueue_lock; /* + * Call all "bottom halfs" on a given list. + */ + +extern void __run_task_queue(task_queue *list); + +static inline void run_task_queue(task_queue *list) +{ + if (TQ_ACTIVE(*list)) + __run_task_queue(list); +} + +#endif /* _LINUX_TQUEUE_H */ + +#if !defined(_LINUX_TQUEUE_H_INLINES) && defined(_TASK_STRUCT_DEFINED) +#define _LINUX_TQUEUE_H_INLINES +/* * Queue a task on a tq. Return non-zero if it was successfully * added. */ @@ -109,17 +125,4 @@ } return ret; } - -/* - * Call all "bottom halfs" on a given list. - */ - -extern void __run_task_queue(task_queue *list); - -static inline void run_task_queue(task_queue *list) -{ - if (TQ_ACTIVE(*list)) - __run_task_queue(list); -} - -#endif /* _LINUX_TQUEUE_H */ +#endif diff -urN linux-2.4.20-ac1/kernel/exit.c linux/kernel/exit.c --- linux-2.4.20-ac1/kernel/exit.c 2002-12-11 02:48:52.000000000 -0500 +++ linux/kernel/exit.c 2002-12-11 02:51:40.000000000 -0500 @@ -359,8 +359,8 @@ /* more a memory barrier than a real lock */ task_lock(tsk); tsk->mm = NULL; - task_unlock(tsk); enter_lazy_tlb(mm, current, smp_processor_id()); + task_unlock(tsk); mmput(mm); } } @@ -481,6 +481,11 @@ tsk->flags |= PF_EXITING; del_timer_sync(&tsk->real_timer); + if (unlikely(preempt_get_count())) + printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n", + current->comm, current->pid, + preempt_get_count()); + fake_volatile: #ifdef CONFIG_BSD_PROCESS_ACCT acct_process(code); diff -urN linux-2.4.20-ac1/kernel/fork.c linux/kernel/fork.c --- linux-2.4.20-ac1/kernel/fork.c 2002-12-11 02:48:52.000000000 -0500 +++ linux/kernel/fork.c 2002-12-11 02:51:40.000000000 -0500 @@ -637,6 +637,13 @@ if (p->binfmt && p->binfmt->module) __MOD_INC_USE_COUNT(p->binfmt->module); +#ifdef CONFIG_PREEMPT + /* + * schedule_tail drops this_rq()->lock so compensate with a count + * of 1. Also, we want to start with kernel preemption disabled. + */ + p->preempt_count = 1; +#endif p->did_exec = 0; p->swappable = 0; p->state = TASK_UNINTERRUPTIBLE; diff -urN linux-2.4.20-ac1/kernel/ksyms.c linux/kernel/ksyms.c --- linux-2.4.20-ac1/kernel/ksyms.c 2002-12-11 02:48:52.000000000 -0500 +++ linux/kernel/ksyms.c 2002-12-11 02:51:40.000000000 -0500 @@ -455,6 +455,9 @@ EXPORT_SYMBOL(interruptible_sleep_on); EXPORT_SYMBOL(interruptible_sleep_on_timeout); EXPORT_SYMBOL(schedule); +#ifdef CONFIG_PREEMPT +EXPORT_SYMBOL(preempt_schedule); +#endif EXPORT_SYMBOL(schedule_timeout); EXPORT_SYMBOL(yield); EXPORT_SYMBOL(__cond_resched); diff -urN linux-2.4.20-ac1/kernel/sched.c linux/kernel/sched.c --- linux-2.4.20-ac1/kernel/sched.c 2002-12-11 02:48:52.000000000 -0500 +++ linux/kernel/sched.c 2002-12-11 02:51:40.000000000 -0500 @@ -314,11 +314,13 @@ #ifdef CONFIG_SMP int need_resched; + preempt_disable(); need_resched = p->need_resched; wmb(); set_tsk_need_resched(p); if (!need_resched && (task_cpu(p) != smp_processor_id())) smp_send_reschedule(task_cpu(p)); + preempt_enable(); #else set_tsk_need_resched(p); #endif @@ -338,17 +340,26 @@ runqueue_t *rq; repeat: + preempt_disable(); rq = task_rq(p); if (unlikely(rq->curr == p)) { cpu_relax(); + /* + * enable/disable preemption just to make this + * a preemption point - we are busy-waiting + * anyway. + */ + preempt_enable(); goto repeat; } rq = task_rq_lock(p, &flags); if (unlikely(rq->curr == p)) { task_rq_unlock(rq, &flags); + preempt_enable(); goto repeat; } task_rq_unlock(rq, &flags); + preempt_enable(); } /* @@ -479,7 +490,7 @@ * * @prev: the thread we just switched away from. */ -#if CONFIG_SMP +#if CONFIG_SMP || CONFIG_PREEMPT asmlinkage void schedule_tail(task_t *prev) { finish_arch_switch(this_rq()); @@ -903,6 +914,7 @@ BUG(); need_resched: + preempt_disable(); prev = current; rq = this_rq(); @@ -911,6 +923,13 @@ prev->sleep_timestamp = jiffies; spin_lock_irq(&rq->lock); + /* + * if entering from preempt_schedule, off a kernel preemption, + * go straight to picking the next task. + */ + if (unlikely(preempt_get_count() & PREEMPT_ACTIVE)) + goto pick_next_task; + switch (prev->state) { case TASK_INTERRUPTIBLE: if (unlikely(signal_pending(prev))) { @@ -922,9 +941,7 @@ case TASK_RUNNING: ; } -#if CONFIG_SMP pick_next_task: -#endif if (unlikely(!rq->nr_running)) { #if CONFIG_SMP load_balance(rq, 1); @@ -969,10 +986,35 @@ finish_arch_schedule(prev); reacquire_kernel_lock(current); + preempt_enable_no_resched(); if (need_resched()) goto need_resched; } +#ifdef CONFIG_PREEMPT +/* + * this is is the entry point to schedule() from in-kernel preemption. + */ +asmlinkage void preempt_schedule(void) +{ + /* + * Interrupts disabled implies no kernel preemption. Just return. + */ + if (unlikely(irqs_disabled())) + return; + +need_resched: + current->preempt_count += PREEMPT_ACTIVE; + schedule(); + current->preempt_count -= PREEMPT_ACTIVE; + + /* we can miss a preemption between schedule() and now */ + barrier(); + if (unlikely((current->need_resched))) + goto need_resched; +} +#endif /* CONFIG_PREEMPT */ + /* * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve @@ -1535,7 +1577,7 @@ list_del(¤t->run_list); list_add_tail(¤t->run_list, array->queue + current->prio); } - spin_unlock(&rq->lock); + spin_unlock_no_resched(&rq->lock); schedule(); @@ -1754,6 +1796,9 @@ double_rq_unlock(idle_rq, rq); set_tsk_need_resched(idle); __restore_flags(flags); + + /* Set the preempt count _outside_ the spinlocks! */ + idle->preempt_count = (idle->lock_depth >= 0); } extern void init_timervecs(void); @@ -1849,6 +1894,7 @@ if (!new_mask) BUG(); + preempt_disable(); rq = task_rq_lock(p, &flags); p->cpus_allowed = new_mask; /* @@ -1876,7 +1922,7 @@ down(&req.sem); out: - ; + preempt_enable(); } /* diff -urN linux-2.4.20-ac1/lib/dec_and_lock.c linux/lib/dec_and_lock.c --- linux-2.4.20-ac1/lib/dec_and_lock.c 2001-10-03 12:11:26.000000000 -0400 +++ linux/lib/dec_and_lock.c 2002-12-11 02:51:40.000000000 -0500 @@ -1,5 +1,6 @@ #include #include +#include #include /* diff -urN linux-2.4.20-ac1/MAINTAINERS linux/MAINTAINERS --- linux-2.4.20-ac1/MAINTAINERS 2002-12-11 02:48:52.000000000 -0500 +++ linux/MAINTAINERS 2002-12-11 02:51:40.000000000 -0500 @@ -1338,6 +1338,14 @@ M: mostrows@styx.uwaterloo.ca S: Maintained +PREEMPTIBLE KERNEL +P: Robert M. Love +M: rml@tech9.net +L: linux-kernel@vger.kernel.org +L: kpreempt-tech@lists.sourceforge.net +W: http://tech9.net/rml/linux +S: Supported + PROMISE DC4030 CACHING DISK CONTROLLER DRIVER P: Peter Denison M: promise@pnd-pc.demon.co.uk diff -urN linux-2.4.20-ac1/mm/slab.c linux/mm/slab.c --- linux-2.4.20-ac1/mm/slab.c 2002-11-28 18:53:15.000000000 -0500 +++ linux/mm/slab.c 2002-12-11 02:51:40.000000000 -0500 @@ -49,7 +49,8 @@ * constructors and destructors are called without any locking. * Several members in kmem_cache_t and slab_t never change, they * are accessed without any locking. - * The per-cpu arrays are never accessed from the wrong cpu, no locking. + * The per-cpu arrays are never accessed from the wrong cpu, no locking, + * and local interrupts are disabled so slab code is preempt-safe. * The non-constant members are protected with a per-cache irq spinlock. * * Further notes from the original documentation: diff -urN linux-2.4.20-ac1/net/core/dev.c linux/net/core/dev.c --- linux-2.4.20-ac1/net/core/dev.c 2002-11-28 18:53:15.000000000 -0500 +++ linux/net/core/dev.c 2002-12-11 02:51:40.000000000 -0500 @@ -1049,9 +1049,11 @@ int cpu = smp_processor_id(); if (dev->xmit_lock_owner != cpu) { + preempt_disable(); spin_unlock(&dev->queue_lock); spin_lock(&dev->xmit_lock); dev->xmit_lock_owner = cpu; + preempt_enable(); if (!netif_queue_stopped(dev)) { if (netdev_nit) diff -urN linux-2.4.20-ac1/net/core/skbuff.c linux/net/core/skbuff.c --- linux-2.4.20-ac1/net/core/skbuff.c 2002-08-02 20:39:46.000000000 -0400 +++ linux/net/core/skbuff.c 2002-12-11 02:51:40.000000000 -0500 @@ -111,33 +111,36 @@ static __inline__ struct sk_buff *skb_head_from_pool(void) { - struct sk_buff_head *list = &skb_head_pool[smp_processor_id()].list; + struct sk_buff_head *list; + struct sk_buff *skb = NULL; + unsigned long flags; - if (skb_queue_len(list)) { - struct sk_buff *skb; - unsigned long flags; + local_irq_save(flags); - local_irq_save(flags); + list = &skb_head_pool[smp_processor_id()].list; + + if (skb_queue_len(list)) skb = __skb_dequeue(list); - local_irq_restore(flags); - return skb; - } - return NULL; + + local_irq_restore(flags); + return skb; } static __inline__ void skb_head_to_pool(struct sk_buff *skb) { - struct sk_buff_head *list = &skb_head_pool[smp_processor_id()].list; + struct sk_buff_head *list; + unsigned long flags; - if (skb_queue_len(list) < sysctl_hot_list_len) { - unsigned long flags; + local_irq_save(flags); + list = &skb_head_pool[smp_processor_id()].list; - local_irq_save(flags); + if (skb_queue_len(list) < sysctl_hot_list_len) { __skb_queue_head(list, skb); local_irq_restore(flags); return; } + local_irq_restore(flags); kmem_cache_free(skbuff_head_cache, skb); } diff -urN linux-2.4.20-ac1/net/socket.c linux/net/socket.c --- linux-2.4.20-ac1/net/socket.c 2002-11-28 18:53:16.000000000 -0500 +++ linux/net/socket.c 2002-12-11 02:51:40.000000000 -0500 @@ -132,7 +132,7 @@ static struct net_proto_family *net_families[NPROTO]; -#ifdef CONFIG_SMP +#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) static atomic_t net_family_lockct = ATOMIC_INIT(0); static spinlock_t net_family_lock = SPIN_LOCK_UNLOCKED; diff -urN linux-2.4.20-ac1/net/sunrpc/pmap_clnt.c linux/net/sunrpc/pmap_clnt.c --- linux-2.4.20-ac1/net/sunrpc/pmap_clnt.c 2002-08-02 20:39:46.000000000 -0400 +++ linux/net/sunrpc/pmap_clnt.c 2002-12-11 02:51:40.000000000 -0500 @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include diff -urN linux-2.4.20-ac1/net/sunrpc/sched.c linux/net/sunrpc/sched.c --- linux-2.4.20-ac1/net/sunrpc/sched.c 2002-11-28 18:53:16.000000000 -0500 +++ linux/net/sunrpc/sched.c 2002-12-11 02:51:40.000000000 -0500 @@ -1030,6 +1030,7 @@ wake_up(assassin); dprintk("RPC: rpciod exiting\n"); + unlock_kernel(); MOD_DEC_USE_COUNT; return 0; }