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authorMark Brown <broonie@linaro.org>2013-12-31 12:59:55 +0000
committerMark Brown <broonie@linaro.org>2013-12-31 12:59:55 +0000
commit68066bb378a0504439e046cdb55d88362eb6379d (patch)
tree0b60f72ddf7108a63dd4db617b42e07fbae5346d /drivers/tty/tty_ldsem.c
parent43f627ac9de42607b2cdcc7a41f2bcc82187e06a (diff)
parent802eee95bde72fd0cd0f3a5b2098375a487d1eda (diff)
Merge tag 'v3.13-rc6' into spi-dw
To resolve trivial overlaps with fixes. Linux 3.13-rc6
Diffstat (limited to 'drivers/tty/tty_ldsem.c')
-rw-r--r--drivers/tty/tty_ldsem.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/tty/tty_ldsem.c b/drivers/tty/tty_ldsem.c
index 22fad8ad5ac..d8a55e87877 100644
--- a/drivers/tty/tty_ldsem.c
+++ b/drivers/tty/tty_ldsem.c
@@ -86,11 +86,21 @@ static inline long ldsem_atomic_update(long delta, struct ld_semaphore *sem)
return atomic_long_add_return(delta, (atomic_long_t *)&sem->count);
}
+/*
+ * ldsem_cmpxchg() updates @*old with the last-known sem->count value.
+ * Returns 1 if count was successfully changed; @*old will have @new value.
+ * Returns 0 if count was not changed; @*old will have most recent sem->count
+ */
static inline int ldsem_cmpxchg(long *old, long new, struct ld_semaphore *sem)
{
- long tmp = *old;
- *old = atomic_long_cmpxchg(&sem->count, *old, new);
- return *old == tmp;
+ long tmp = atomic_long_cmpxchg(&sem->count, *old, new);
+ if (tmp == *old) {
+ *old = new;
+ return 1;
+ } else {
+ *old = tmp;
+ return 0;
+ }
}
/*