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author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-07-25 19:59:08 +0300 |
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committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-07-25 19:59:08 +0300 |
commit | 931ab4a5ce2d93cb434dc7fc067a702117453b13 (patch) | |
tree | 7135ba1e9b24886af8b42f7d20297507b33f7155 /include/linux/spinlock.h | |
parent | 520eccdfe187591a51ea9ab4c1a024ae4d0f68d9 (diff) | |
download | linux-931ab4a5ce2d93cb434dc7fc067a702117453b13.tar.xz |
atomics: Revert addition of comment header to spin_unlock_wait()
There is still considerable confusion as to the semantics of
spin_unlock_wait(), but there seems to be universal agreement that
it is not that of a lock/unlock pair. This commit therefore removes
the comment added by 6016ffc3874d ("atomics: Add header comment so
spin_unlock_wait()") in order to prevent at least that flavor of
confusion.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'include/linux/spinlock.h')
-rw-r--r-- | include/linux/spinlock.h | 20 |
1 files changed, 0 insertions, 20 deletions
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h index d9510e8522d4..59248dcc6ef3 100644 --- a/include/linux/spinlock.h +++ b/include/linux/spinlock.h @@ -369,26 +369,6 @@ static __always_inline int spin_trylock_irq(spinlock_t *lock) raw_spin_trylock_irqsave(spinlock_check(lock), flags); \ }) -/** - * spin_unlock_wait - Interpose between successive critical sections - * @lock: the spinlock whose critical sections are to be interposed. - * - * Semantically this is equivalent to a spin_lock() immediately - * followed by a spin_unlock(). However, most architectures have - * more efficient implementations in which the spin_unlock_wait() - * cannot block concurrent lock acquisition, and in some cases - * where spin_unlock_wait() does not write to the lock variable. - * Nevertheless, spin_unlock_wait() can have high overhead, so if - * you feel the need to use it, please check to see if there is - * a better way to get your job done. - * - * The ordering guarantees provided by spin_unlock_wait() are: - * - * 1. All accesses preceding the spin_unlock_wait() happen before - * any accesses in later critical sections for this same lock. - * 2. All accesses following the spin_unlock_wait() happen after - * any accesses in earlier critical sections for this same lock. - */ static __always_inline void spin_unlock_wait(spinlock_t *lock) { raw_spin_unlock_wait(&lock->rlock); |