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authorIngo Molnar <mingo@kernel.org>2014-01-12 14:12:44 +0100
committerIngo Molnar <mingo@kernel.org>2014-01-12 14:12:44 +0100
commitdba861461f88c12249ac78fb877866c04f99deb3 (patch)
tree5812b143581bcc66c7c542f01ba0cb22e489b8e5 /drivers/tty/tty_ldsem.c
parent0e6601eee039893a3f6420596ae4588d90d13cbe (diff)
parent228fdc083b017eaf90e578fa86fb1ecfd5ffae87 (diff)
Merge branch 'linus' into timers/core
Pick up the latest fixes and refresh the branch. Signed-off-by: Ingo Molnar <mingo@kernel.org>
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 22fad8ad5ac2..d8a55e87877f 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;
+ }
}
/*