diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-08-12 12:46:37 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-08-12 12:46:37 -0700 |
| commit | 1f8083c640bf08aab8762a9e10326ce767c66492 (patch) | |
| tree | ccac514a6fd67bca75767af3a9670a2cab7837bd /include | |
| parent | 25db69188e0369a8c4ac53f71e935a8b6e22e117 (diff) | |
| parent | c2ace36b884de9330c4149064ae8d212d2e0d9ee (diff) | |
Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Ingo Molnar:
"Misc fixes: lockstat fix, futex fix on !MMU systems, big endian fix
for qrwlocks and a race fix for pvqspinlocks"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/pvqspinlock: Fix a bug in qstat_read()
locking/pvqspinlock: Fix double hash race
locking/qrwlock: Fix write unlock bug on big endian systems
futex: Assume all mappings are private on !MMU systems
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-generic/qrwlock.h | 27 |
1 files changed, 25 insertions, 2 deletions
diff --git a/include/asm-generic/qrwlock.h b/include/asm-generic/qrwlock.h index 54a8e65e18b6..7d026bf27713 100644 --- a/include/asm-generic/qrwlock.h +++ b/include/asm-generic/qrwlock.h @@ -25,7 +25,20 @@ #include <asm-generic/qrwlock_types.h> /* - * Writer states & reader shift and bias + * Writer states & reader shift and bias. + * + * | +0 | +1 | +2 | +3 | + * ----+----+----+----+----+ + * LE | 78 | 56 | 34 | 12 | 0x12345678 + * ----+----+----+----+----+ + * | wr | rd | + * +----+----+----+----+ + * + * ----+----+----+----+----+ + * BE | 12 | 34 | 56 | 78 | 0x12345678 + * ----+----+----+----+----+ + * | rd | wr | + * +----+----+----+----+ */ #define _QW_WAITING 1 /* A writer is waiting */ #define _QW_LOCKED 0xff /* A writer holds the lock */ @@ -134,12 +147,22 @@ static inline void queued_read_unlock(struct qrwlock *lock) } /** + * __qrwlock_write_byte - retrieve the write byte address of a queue rwlock + * @lock : Pointer to queue rwlock structure + * Return: the write byte address of a queue rwlock + */ +static inline u8 *__qrwlock_write_byte(struct qrwlock *lock) +{ + return (u8 *)lock + 3 * IS_BUILTIN(CONFIG_CPU_BIG_ENDIAN); +} + +/** * queued_write_unlock - release write lock of a queue rwlock * @lock : Pointer to queue rwlock structure */ static inline void queued_write_unlock(struct qrwlock *lock) { - smp_store_release((u8 *)&lock->cnts, 0); + smp_store_release(__qrwlock_write_byte(lock), 0); } /* |