Messages in this thread Patch in this message | | | Date | Mon, 30 Mar 2009 15:40:50 -0700 | From | Darren Hart <> | Subject | Re: [tip PATCH v6 6/8] RFC: futex: Add FUTEX_HAS_TIMEOUT flag to restart.futex.flags |
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Eric Dumazet wrote:
Hi Eric,
Thanks for the prompt review...
> Darren Hart a écrit :
>> - t.tv64 = restart->futex.time; >> + if (restart->futex.flags | FLAGS_HAS_TIMEOUT) { > > You probably meant : > > if (restart->futex.flags & FLAGS_HAS_TIMEOUT)
Gah! You are correct. Corrected patch below.
RFC: futex: Add FUTEX_HAS_TIMEOUT flag to restart.futex.flags
From: Darren Hart <dvhltc@us.ibm.com>
Currently restart is only used if there is a timeout. The requeue_pi functionality requires restarting to futex_lock_pi() on signal after wakeup in futex_wait_requeue_pi() regardless of if there was a timeout or not. Using 0 for the timeout value is confusing as that could indicate an expired timer. The flag makes this explicit.
Changelog: V7pre: -Corrected FLAGS_HAS_TIMEOUT flag detection logic per Eric Dumazet V6: - Initial version
Signed-off-by: Darren Hart <dvhltc@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sripathi Kodi <sripathik@in.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: John Stultz <johnstul@us.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Dinakar Guniguntala <dino@in.ibm.com> Cc: Ulrich Drepper <drepper@redhat.com> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jakub Jelinek <jakub@redhat.com> ---
kernel/futex.c | 12 ++++++++---- 1 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c index dd05803..07e314c 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1254,6 +1254,7 @@ handle_fault: */ #define FLAGS_SHARED 0x01 #define FLAGS_CLOCKRT 0x02 +#define FLAGS_HAS_TIMEOUT 0x04 static long futex_wait_restart(struct restart_block *restart); @@ -1493,7 +1494,7 @@ retry_private: restart->futex.val = val; restart->futex.time = abs_time->tv64; restart->futex.bitset = bitset; - restart->futex.flags = 0; + restart->futex.flags = FLAGS_HAS_TIMEOUT; if (fshared) restart->futex.flags |= FLAGS_SHARED; @@ -1517,13 +1518,16 @@ static long futex_wait_restart(struct restart_block *restart) { u32 __user *uaddr = (u32 __user *)restart->futex.uaddr; int fshared = 0; - ktime_t t; + ktime_t t, *tp = NULL; - t.tv64 = restart->futex.time; + if (restart->futex.flags & FLAGS_HAS_TIMEOUT) { + t.tv64 = restart->futex.time; + tp = &t; + } restart->fn = do_no_restart_syscall; if (restart->futex.flags & FLAGS_SHARED) fshared = 1; - return (long)futex_wait(uaddr, fshared, restart->futex.val, &t, + return (long)futex_wait(uaddr, fshared, restart->futex.val, tp, restart->futex.bitset, restart->futex.flags & FLAGS_CLOCKRT); } -- Darren Hart IBM Linux Technology Center Real-Time Linux Team -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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