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authorMatthew Wilcox <matthew@wil.cx>2008-03-14 20:43:13 +0300
committerMatthew Wilcox <willy@linux.intel.com>2008-04-17 18:42:46 +0400
commitf1241c87a16c4fe9f4f51d6ed3589f031c505e8d (patch)
tree2e0ee0f2b864c89eda9067bda0d8a98596e022e7 /include/linux/semaphore.h
parentf06d96865861c3dd01520f47e2e61c899db1631f (diff)
downloadlinux-f1241c87a16c4fe9f4f51d6ed3589f031c505e8d.tar.xz
Add down_timeout and change ACPI to use it
ACPI currently emulates a timeout for semaphores with calls to down_trylock and sleep. This produces horrible behaviour in terms of fairness and excessive wakeups. Now that we have a unified semaphore implementation, adding a real down_trylock is almost trivial. Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Diffstat (limited to 'include/linux/semaphore.h')
-rw-r--r--include/linux/semaphore.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/semaphore.h b/include/linux/semaphore.h
index 88f2a28cc0f1..a107aebd9148 100644
--- a/include/linux/semaphore.h
+++ b/include/linux/semaphore.h
@@ -75,6 +75,12 @@ extern int __must_check down_killable(struct semaphore *sem);
extern int __must_check down_trylock(struct semaphore *sem);
/*
+ * As down(), except this function will return -ETIME if it fails to
+ * acquire the semaphore within the specified number of jiffies.
+ */
+extern int __must_check down_timeout(struct semaphore *sem, long jiffies);
+
+/*
* Release the semaphore. Unlike mutexes, up() may be called from any
* context and even by tasks which have never called down().
*/