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| author |   Russell King <rmk+kernel@arm.linux.org.uk> | 2015-07-07 12:35:33 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-07-07 12:35:33 +0100 |
| commit | 06be5eefe1192eb8ce8d07497f67595b6bfe9741 (patch) | |
| tree | 80f1987d4970f8079681f8be0c135cafc8d6329a /arch/tile/include/asm/spinlock_32.h | |
| parent | ARM: fix lockdep unannotated irqs-off warning (diff) | |
| parent | ARM: avoid unwanted GCC memset()/memcpy() optimisations for IO variants (diff) | |
| download | linux-dev-06be5eefe1192eb8ce8d07497f67595b6bfe9741.tar.xz linux-dev-06be5eefe1192eb8ce8d07497f67595b6bfe9741.zip | |
Merge branches 'fixes' and 'ioremap' into for-linus
Diffstat (limited to 'arch/tile/include/asm/spinlock_32.h')
| -rw-r--r-- | arch/tile/include/asm/spinlock_32.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/tile/include/asm/spinlock_32.h b/arch/tile/include/asm/spinlock_32.h index c0a77b38d39a..b14b1ba5bf9c 100644 --- a/arch/tile/include/asm/spinlock_32.h +++ b/arch/tile/include/asm/spinlock_32.h @@ -41,8 +41,12 @@ static inline int arch_spin_is_locked(arch_spinlock_t *lock) * to claim the lock is held, since it will be momentarily * if not already. There's no need to wait for a "valid" * lock->next_ticket to become available. + * Use READ_ONCE() to ensure that calling this in a loop is OK. */ - return lock->next_ticket != lock->current_ticket; + int curr = READ_ONCE(lock->current_ticket); + int next = READ_ONCE(lock->next_ticket); + + return next != curr; } void arch_spin_lock(arch_spinlock_t *lock); |