Commit-ID: 767f509ca11269c2bcd92e3972a93096f2173ac0 Gitweb: http://git.kernel.org/tip/767f509ca11269c2bcd92e3972a93096f2173ac0 Author: Davidlohr Bueso <[email protected]> AuthorDate: Mon, 29 Jun 2015 23:26:01 -0700 Committer: Thomas Gleixner <[email protected]> CommitDate: Mon, 20 Jul 2015 11:45:45 +0200
futex: Enhance comments in futex_lock_pi() for blocking paths ... serves a bit better to clarify between blocking and non-blocking code paths. Signed-off-by: Davidlohr Bueso <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Darren Hart <[email protected]> Cc: Davidlohr Bueso <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Thomas Gleixner <[email protected]> --- 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. */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
