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authorTakashi Iwai <tiwai@suse.de>2012-11-21 07:18:11 +0100
committerTakashi Iwai <tiwai@suse.de>2012-11-21 07:18:11 +0100
commit789e05275e90b637f2029375715e187fd8cabbf4 (patch)
treeac6f9626a60e81c8af28b11f67e09bde9e145f24 /kernel
parent2ea3c6a2c779e5a6487d2b436770232162dfbbe3 (diff)
parenta6366c519cead55ce537babce2271e3b2a1ccec9 (diff)
Merge tag 'asoc-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus
ASoC: Fixes for v3.7 The biggest batch of fixes here is the Kirkwood DMA fixes, plus a couple of other small fixes.
Diffstat (limited to 'kernel')
-rw-r--r--kernel/futex.c41
1 files changed, 22 insertions, 19 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index 3717e7b306e..20ef219bbe9 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -716,7 +716,7 @@ static int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb,
struct futex_pi_state **ps,
struct task_struct *task, int set_waiters)
{
- int lock_taken, ret, ownerdied = 0;
+ int lock_taken, ret, force_take = 0;
u32 uval, newval, curval, vpid = task_pid_vnr(task);
retry:
@@ -755,17 +755,15 @@ retry:
newval = curval | FUTEX_WAITERS;
/*
- * There are two cases, where a futex might have no owner (the
- * owner TID is 0): OWNER_DIED. We take over the futex in this
- * case. We also do an unconditional take over, when the owner
- * of the futex died.
- *
- * This is safe as we are protected by the hash bucket lock !
+ * Should we force take the futex? See below.
*/
- if (unlikely(ownerdied || !(curval & FUTEX_TID_MASK))) {
- /* Keep the OWNER_DIED bit */
+ if (unlikely(force_take)) {
+ /*
+ * Keep the OWNER_DIED and the WAITERS bit and set the
+ * new TID value.
+ */
newval = (curval & ~FUTEX_TID_MASK) | vpid;
- ownerdied = 0;
+ force_take = 0;
lock_taken = 1;
}
@@ -775,7 +773,7 @@ retry:
goto retry;
/*
- * We took the lock due to owner died take over.
+ * We took the lock due to forced take over.
*/
if (unlikely(lock_taken))
return 1;
@@ -790,20 +788,25 @@ retry:
switch (ret) {
case -ESRCH:
/*
- * No owner found for this futex. Check if the
- * OWNER_DIED bit is set to figure out whether
- * this is a robust futex or not.
+ * We failed to find an owner for this
+ * futex. So we have no pi_state to block
+ * on. This can happen in two cases:
+ *
+ * 1) The owner died
+ * 2) A stale FUTEX_WAITERS bit
+ *
+ * Re-read the futex value.
*/
if (get_futex_value_locked(&curval, uaddr))
return -EFAULT;
/*
- * We simply start over in case of a robust
- * futex. The code above will take the futex
- * and return happy.
+ * If the owner died or we have a stale
+ * WAITERS bit the owner TID in the user space
+ * futex is 0.
*/
- if (curval & FUTEX_OWNER_DIED) {
- ownerdied = 1;
+ if (!(curval & FUTEX_TID_MASK)) {
+ force_take = 1;
goto retry;
}
default: