[PATCH] spinlock consolidation
This patch (written by me and also containing many suggestions of Arjan van de Ven) does a major cleanup of the spinlock code. It does the following things: - consolidates and enhances the spinlock/rwlock debugging code - simplifies the asm/spinlock.h files - encapsulates the raw spinlock type and moves generic spinlock features (such as ->break_lock) into the generic code. - cleans up the spinlock code hierarchy to get rid of the spaghetti. Most notably there's now only a single variant of the debugging code, located in lib/spinlock_debug.c. (previously we had one SMP debugging variant per architecture, plus a separate generic one for UP builds) Also, i've enhanced the rwlock debugging facility, it will now track write-owners. There is new spinlock-owner/CPU-tracking on SMP builds too. All locks have lockup detection now, which will work for both soft and hard spin/rwlock lockups. The arch-level include files now only contain the minimally necessary subset of the spinlock code - all the rest that can be generalized now lives in the generic headers: include/asm-i386/spinlock_types.h | 16 include/asm-x86_64/spinlock_types.h | 16 I have also split up the various spinlock variants into separate files, making it easier to see which does what. The new layout is: SMP | UP ----------------------------|----------------------------------- asm/spinlock_types_smp.h | linux/spinlock_types_up.h linux/spinlock_types.h | linux/spinlock_types.h asm/spinlock_smp.h | linux/spinlock_up.h linux/spinlock_api_smp.h | linux/spinlock_api_up.h linux/spinlock.h | linux/spinlock.h /* * here's the role of the various spinlock/rwlock related include files: * * on SMP builds: * * asm/spinlock_types.h: contains the raw_spinlock_t/raw_rwlock_t and the * initializers * * linux/spinlock_types.h: * defines the generic type and initializers * * asm/spinlock.h: contains the __raw_spin_*()/etc. lowlevel * implementations, mostly inline assembly code * * (also included on UP-debug builds:) * * linux/spinlock_api_smp.h: * contains the prototypes for the _spin_*() APIs. * * linux/spinlock.h: builds the final spin_*() APIs. * * on UP builds: * * linux/spinlock_type_up.h: * contains the generic, simplified UP spinlock type. * (which is an empty structure on non-debug builds) * * linux/spinlock_types.h: * defines the generic type and initializers * * linux/spinlock_up.h: * contains the __raw_spin_*()/etc. version of UP * builds. (which are NOPs on non-debug, non-preempt * builds) * * (included on UP-non-debug builds:) * * linux/spinlock_api_up.h: * builds the _spin_*() APIs. * * linux/spinlock.h: builds the final spin_*() APIs. */ All SMP and UP architectures are converted by this patch. arm, i386, ia64, ppc, ppc64, s390/s390x, x64 was build-tested via crosscompilers. m32r, mips, sh, sparc, have not been tested yet, but should be mostly fine. From: Grant Grundler <grundler@parisc-linux.org> Booted and lightly tested on a500-44 (64-bit, SMP kernel, dual CPU). Builds 32-bit SMP kernel (not booted or tested). I did not try to build non-SMP kernels. That should be trivial to fix up later if necessary. I converted bit ops atomic_hash lock to raw_spinlock_t. Doing so avoids some ugly nesting of linux/*.h and asm/*.h files. Those particular locks are well tested and contained entirely inside arch specific code. I do NOT expect any new issues to arise with them. If someone does ever need to use debug/metrics with them, then they will need to unravel this hairball between spinlocks, atomic ops, and bit ops that exist only because parisc has exactly one atomic instruction: LDCW (load and clear word). From: "Luck, Tony" <tony.luck@intel.com> ia64 fix Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjanv@infradead.org> Signed-off-by: Grant Grundler <grundler@parisc-linux.org> Cc: Matthew Wilcox <willy@debian.org> Signed-off-by: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Mikael Pettersson <mikpe@csd.uu.se> Signed-off-by: Benoit Boissinot <benoit.boissinot@ens-lyon.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Ingo Molnar
committed by
Linus Torvalds
Linus Torvalds
parent
4327edf6b8
commit
fb1c8f93d8
@@ -185,15 +185,6 @@ EXPORT_SYMBOL(smp_num_cpus);
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EXPORT_SYMBOL(smp_call_function);
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EXPORT_SYMBOL(smp_call_function_on_cpu);
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EXPORT_SYMBOL(_atomic_dec_and_lock);
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#ifdef CONFIG_DEBUG_SPINLOCK
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EXPORT_SYMBOL(_raw_spin_unlock);
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EXPORT_SYMBOL(debug_spin_lock);
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EXPORT_SYMBOL(debug_spin_trylock);
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#endif
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#ifdef CONFIG_DEBUG_RWLOCK
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EXPORT_SYMBOL(_raw_write_lock);
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EXPORT_SYMBOL(_raw_read_lock);
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#endif
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EXPORT_SYMBOL(cpu_present_mask);
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#endif /* CONFIG_SMP */
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@@ -989,175 +989,3 @@ flush_icache_user_range(struct vm_area_struct *vma, struct page *page,
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preempt_enable();
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}
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#ifdef CONFIG_DEBUG_SPINLOCK
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void
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_raw_spin_unlock(spinlock_t * lock)
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{
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mb();
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lock->lock = 0;
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lock->on_cpu = -1;
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lock->previous = NULL;
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lock->task = NULL;
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lock->base_file = "none";
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lock->line_no = 0;
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}
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void
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debug_spin_lock(spinlock_t * lock, const char *base_file, int line_no)
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{
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long tmp;
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long stuck;
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void *inline_pc = __builtin_return_address(0);
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unsigned long started = jiffies;
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int printed = 0;
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int cpu = smp_processor_id();
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stuck = 1L << 30;
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try_again:
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/* Use sub-sections to put the actual loop at the end
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of this object file's text section so as to perfect
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branch prediction. */
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__asm__ __volatile__(
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"1: ldl_l %0,%1\n"
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" subq %2,1,%2\n"
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" blbs %0,2f\n"
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" or %0,1,%0\n"
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" stl_c %0,%1\n"
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" beq %0,3f\n"
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"4: mb\n"
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".subsection 2\n"
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"2: ldl %0,%1\n"
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" subq %2,1,%2\n"
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"3: blt %2,4b\n"
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" blbs %0,2b\n"
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" br 1b\n"
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".previous"
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: "=r" (tmp), "=m" (lock->lock), "=r" (stuck)
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: "m" (lock->lock), "2" (stuck) : "memory");
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if (stuck < 0) {
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printk(KERN_WARNING
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"%s:%d spinlock stuck in %s at %p(%d)"
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" owner %s at %p(%d) %s:%d\n",
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base_file, line_no,
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current->comm, inline_pc, cpu,
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lock->task->comm, lock->previous,
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lock->on_cpu, lock->base_file, lock->line_no);
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stuck = 1L << 36;
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printed = 1;
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goto try_again;
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}
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/* Exiting. Got the lock. */
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lock->on_cpu = cpu;
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lock->previous = inline_pc;
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lock->task = current;
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lock->base_file = base_file;
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lock->line_no = line_no;
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if (printed) {
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printk(KERN_WARNING
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"%s:%d spinlock grabbed in %s at %p(%d) %ld ticks\n",
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base_file, line_no, current->comm, inline_pc,
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cpu, jiffies - started);
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}
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}
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int
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debug_spin_trylock(spinlock_t * lock, const char *base_file, int line_no)
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{
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int ret;
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if ((ret = !test_and_set_bit(0, lock))) {
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lock->on_cpu = smp_processor_id();
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lock->previous = __builtin_return_address(0);
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lock->task = current;
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} else {
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lock->base_file = base_file;
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lock->line_no = line_no;
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}
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return ret;
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}
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#endif /* CONFIG_DEBUG_SPINLOCK */
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#ifdef CONFIG_DEBUG_RWLOCK
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void _raw_write_lock(rwlock_t * lock)
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{
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long regx, regy;
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int stuck_lock, stuck_reader;
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void *inline_pc = __builtin_return_address(0);
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try_again:
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stuck_lock = 1<<30;
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stuck_reader = 1<<30;
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__asm__ __volatile__(
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"1: ldl_l %1,%0\n"
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" blbs %1,6f\n"
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" blt %1,8f\n"
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" mov 1,%1\n"
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" stl_c %1,%0\n"
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" beq %1,6f\n"
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"4: mb\n"
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".subsection 2\n"
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"6: blt %3,4b # debug\n"
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" subl %3,1,%3 # debug\n"
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" ldl %1,%0\n"
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" blbs %1,6b\n"
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"8: blt %4,4b # debug\n"
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" subl %4,1,%4 # debug\n"
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" ldl %1,%0\n"
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" blt %1,8b\n"
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" br 1b\n"
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".previous"
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: "=m" (*(volatile int *)lock), "=&r" (regx), "=&r" (regy),
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"=&r" (stuck_lock), "=&r" (stuck_reader)
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: "m" (*(volatile int *)lock), "3" (stuck_lock), "4" (stuck_reader) : "memory");
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if (stuck_lock < 0) {
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printk(KERN_WARNING "write_lock stuck at %p\n", inline_pc);
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goto try_again;
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}
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if (stuck_reader < 0) {
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printk(KERN_WARNING "write_lock stuck on readers at %p\n",
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inline_pc);
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goto try_again;
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}
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}
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void _raw_read_lock(rwlock_t * lock)
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{
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long regx;
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int stuck_lock;
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void *inline_pc = __builtin_return_address(0);
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try_again:
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stuck_lock = 1<<30;
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__asm__ __volatile__(
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"1: ldl_l %1,%0;"
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" blbs %1,6f;"
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" subl %1,2,%1;"
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" stl_c %1,%0;"
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" beq %1,6f;"
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"4: mb\n"
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".subsection 2\n"
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"6: ldl %1,%0;"
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" blt %2,4b # debug\n"
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" subl %2,1,%2 # debug\n"
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" blbs %1,6b;"
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" br 1b\n"
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".previous"
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: "=m" (*(volatile int *)lock), "=&r" (regx), "=&r" (stuck_lock)
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: "m" (*(volatile int *)lock), "2" (stuck_lock) : "memory");
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if (stuck_lock < 0) {
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printk(KERN_WARNING "read_lock stuck at %p\n", inline_pc);
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goto try_again;
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}
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}
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#endif /* CONFIG_DEBUG_RWLOCK */
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