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| author | Darren Hart <dvhltc@us.ibm.com> | 2009-04-03 13:40:22 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2009-04-06 11:14:02 +0200 |
| commit | a72188d8a64ebe74722f1cf7ffac41b41ffdba21 (patch) | |
| tree | 5283404345b270bf5ca95ce8d792baacdf8cf7dc /kernel/futex.c | |
| parent | 8dac456a681bd94272ff50ecb31be6b669382c2b (diff) | |
| download | lwn-a72188d8a64ebe74722f1cf7ffac41b41ffdba21.tar.gz lwn-a72188d8a64ebe74722f1cf7ffac41b41ffdba21.zip | |
futex: add FUTEX_HAS_TIMEOUT flag to restart.futex.flags
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. While the
check is not technically needed in futex_wait_restart(), doing so
makes the code consistent with and will avoid confusion should the
need arise to restart wait without a timeout.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/futex.c')
| -rw-r--r-- | kernel/futex.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index af831fbb7fb4..6b597cf33b02 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1252,6 +1252,7 @@ handle_fault: */ #define FLAGS_SHARED 0x01 #define FLAGS_CLOCKRT 0x02 +#define FLAGS_HAS_TIMEOUT 0x04 static long futex_wait_restart(struct restart_block *restart); @@ -1486,7 +1487,7 @@ 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; @@ -1510,13 +1511,16 @@ 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); } |