Prev: [PATCH 2/6] futex: add futex_q static initializer
Next: [BUG] x86info fails on 2.6.34 ?
From: Darren Hart on 5 Apr 2010 16:30
Signed-off-by: Darren Hart <dvhltc(a)us.ibm.com>
---
kernel/futex.c | 24 +++++++++++++++++++++---
1 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index c33ac2a..af61dcd 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2385,6 +2385,7 @@ out:
/**
* trylock_futex_adaptive() - Try to acquire the futex lock in a busy loop
* @uaddr: the futex user address
+ * @timeout: absolute timeout or NULL if none
*
* Try to acquire a futex lock in a loop until the owner changes or the owner
* is descheduled. To lock the futex, set the value to the current TID.
@@ -2394,10 +2395,11 @@ out:
* 1 - Futex lock acquired
* <0 - On error
*/
-static int trylock_futex_adaptive(u32 __user *uaddr)
+static int trylock_futex_adaptive(u32 __user *uaddr, ktime_t *timeout)
{
int ret = 0;
u32 curval;
+ ktime_t now;

for (;;) {
struct thread_info *owner;
@@ -2433,6 +2435,22 @@ static int trylock_futex_adaptive(u32 __user *uaddr)
if (need_resched())
break;

+ if (timeout) {
+ now = ktime_get();
+/* FIXME: consider creating ktime_less_than(lhs, rhs) */
+#if (BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)
+ if (timeout->tv64 < now.tv64)
+ break;
+#else
+ if (timeout->sec < now.sec ||
+ (timeout->sec == now.sec &&
+ timeout->nsec < now.nsec)) {
+ ret = -ETIMEDOUT;
+ break;
+ }
+#endif
+ }
+
cpu_relax();
}
return ret;
@@ -2480,7 +2498,7 @@ retry:
#ifdef CONFIG_SMP
if (flags & FLAGS_ADAPTIVE) {
preempt_disable();
- ret = trylock_futex_adaptive(uaddr);
+ ret = trylock_futex_adaptive(uaddr, time);
preempt_enable();

/* We got the lock. */
@@ -2489,7 +2507,7 @@ retry:
goto out;
}

- /* We encountered an error, -EFAULT most likely. */
+ /* We encountered an error, -EFAULT or -ETIMEDOUT */
if (ret)
goto out;
}
--
1.6.3.3

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Prev: [PATCH 2/6] futex: add futex_q static initializer
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