sched/wait: Introduce wait_on_bit_timeout()
Add a new wait_on_bit_timeout() helper, basically the same as
wait_on_bit() except that it also takes a 'timeout' parameter.
All the building blocks like bit_wait_timeout() and
out_of_line_wait_on_bit_timeout() are already in place so the
addition is rather simple.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: davem@davemloft.net
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1422616476-2917-2-git-send-email-johan.hedberg@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 37423e0..537d58e 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -990,6 +990,32 @@
}
/**
+ * wait_on_bit_timeout - wait for a bit to be cleared or a timeout elapses
+ * @word: the word being waited on, a kernel virtual address
+ * @bit: the bit of the word being waited on
+ * @mode: the task state to sleep in
+ * @timeout: timeout, in jiffies
+ *
+ * Use the standard hashed waitqueue table to wait for a bit
+ * to be cleared. This is similar to wait_on_bit(), except also takes a
+ * timeout parameter.
+ *
+ * Returned value will be zero if the bit was cleared before the
+ * @timeout elapsed, or non-zero if the @timeout elapsed or process
+ * received a signal and the mode permitted wakeup on that signal.
+ */
+static inline int
+wait_on_bit_timeout(void *word, int bit, unsigned mode, unsigned long timeout)
+{
+ might_sleep();
+ if (!test_bit(bit, word))
+ return 0;
+ return out_of_line_wait_on_bit_timeout(word, bit,
+ bit_wait_timeout,
+ mode, timeout);
+}
+
+/**
* wait_on_bit_action - wait for a bit to be cleared
* @word: the word being waited on, a kernel virtual address
* @bit: the bit of the word being waited on