AcoSail/kernel_optimize_test
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Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull locking fixes from Ingo Molnar:
 "Two fixes:

   - a file locks fix (missing critical section, bug introduced in this
     merge window)

   - an x86 down_write() stack frame annotation"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking, fs/locks: Add missing file_sem locks
  locking/rwsem/x86: Add stack frame dependency for ____down_write()
This commit is contained in:
Linus Torvalds 2016-10-18 09:04:17 -07:00
commit e0ed1c22d4
2 changed files with 10 additions and 2 deletions
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6
arch/x86/include/asm/rwsem.h
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@ -103,8 +103,10 @@ static inline bool __down_read_trylock(struct rw_semaphore *sem)
({ \ ({ \
long tmp; \ long tmp; \
struct rw_semaphore* ret; \ struct rw_semaphore* ret; \
register void *__sp asm(_ASM_SP); \
\
asm volatile("# beginning down_write\n\t" \ asm volatile("# beginning down_write\n\t" \
LOCK_PREFIX " xadd %1,(%3)\n\t" \ LOCK_PREFIX " xadd %1,(%4)\n\t" \
/* adds 0xffff0001, returns the old value */ \ /* adds 0xffff0001, returns the old value */ \
" test " __ASM_SEL(%w1,%k1) "," __ASM_SEL(%w1,%k1) "\n\t" \ " test " __ASM_SEL(%w1,%k1) "," __ASM_SEL(%w1,%k1) "\n\t" \
/* was the active mask 0 before? */\ /* was the active mask 0 before? */\
@ -112,7 +114,7 @@ static inline bool __down_read_trylock(struct rw_semaphore *sem)
" call " slow_path "\n" \ " call " slow_path "\n" \
"1:\n" \ "1:\n" \
"# ending down_write" \ "# ending down_write" \
: "+m" (sem->count), "=d" (tmp), "=a" (ret) \ : "+m" (sem->count), "=d" (tmp), "=a" (ret), "+r" (__sp) \
: "a" (sem), "1" (RWSEM_ACTIVE_WRITE_BIAS) \ : "a" (sem), "1" (RWSEM_ACTIVE_WRITE_BIAS) \
: "memory", "cc"); \ : "memory", "cc"); \
ret; \ ret; \

6
fs/locks.c
View File

@ -1609,6 +1609,7 @@ int fcntl_getlease(struct file *filp)
ctx = smp_load_acquire(&inode->i_flctx); ctx = smp_load_acquire(&inode->i_flctx);
if (ctx && !list_empty_careful(&ctx->flc_lease)) { if (ctx && !list_empty_careful(&ctx->flc_lease)) {
percpu_down_read_preempt_disable(&file_rwsem);
spin_lock(&ctx->flc_lock); spin_lock(&ctx->flc_lock);
time_out_leases(inode, &dispose); time_out_leases(inode, &dispose);
list_for_each_entry(fl, &ctx->flc_lease, fl_list) { list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
@ -1618,6 +1619,8 @@ int fcntl_getlease(struct file *filp)
break; break;
} }
spin_unlock(&ctx->flc_lock); spin_unlock(&ctx->flc_lock);
percpu_up_read_preempt_enable(&file_rwsem);
locks_dispose_list(&dispose); locks_dispose_list(&dispose);
} }
return type; return type;
@ -2529,11 +2532,14 @@ locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
if (list_empty(&ctx->flc_lease)) if (list_empty(&ctx->flc_lease))
return; return;
percpu_down_read_preempt_disable(&file_rwsem);
spin_lock(&ctx->flc_lock); spin_lock(&ctx->flc_lock);
list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
if (filp == fl->fl_file) if (filp == fl->fl_file)
lease_modify(fl, F_UNLCK, &dispose); lease_modify(fl, F_UNLCK, &dispose);
spin_unlock(&ctx->flc_lock); spin_unlock(&ctx->flc_lock);
percpu_up_read_preempt_enable(&file_rwsem);
locks_dispose_list(&dispose); locks_dispose_list(&dispose);
} }