... serves a bit better to clarify between blocking
and non-blocking code paths.
Signed-off-by: Davidlohr Bueso <dbu...@suse.de>
---
kernel/futex.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c
index c4a182f..153eb22 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2268,8 +2268,11 @@ static long futex_wait_restart(struct restart_block
*restart)
/*
* Userspace tried a 0 -> TID atomic transition of the futex value
* and failed. The kernel side here does the whole locking operation:
- * if there are waiters then it will block, it does PI, etc. (Due to
- * races the kernel might see a 0 value of the futex too.)
+ * if there are waiters then it will block as a consequence of relying
+ * on rt-mutexes, it does PI, etc. (Due to races the kernel might see
+ * a 0 value of the futex too.).
+ *
+ * Also serves as futex trylock_pi()'ing, and due semantics.
*/
static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
ktime_t *time, int trylock)
@@ -2300,6 +2303,10 @@ retry_private:
ret = futex_lock_pi_atomic(uaddr, hb, &q.key, &q.pi_state, current, 0);
if (unlikely(ret)) {
+ /*
+ * Atomic work succeeded and we got the lock,
+ * or failed. Either way, we do _not_ block.
+ */
switch (ret) {
case 1:
/* We got the lock. */
--
2.1.4
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