diff options
| author | Darren Hart <dvhltc@us.ibm.com> | 2009-03-12 08:55:52 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-03-12 11:20:56 +0100 |
| commit | 5eb3dc62fc5986e85715041c23dcf3832812be4b (patch) | |
| tree | e8b55b84cc50841ab7f7c87afdcc3d5e419cb4e9 /kernel | |
| parent | futex: additional (get|put)_futex_key() fixes (diff) | |
| download | linux-5eb3dc62fc5986e85715041c23dcf3832812be4b.tar.xz linux-5eb3dc62fc5986e85715041c23dcf3832812be4b.zip | |
futex: add double_unlock_hb()
Impact: cleanup
The futex code uses double_lock_hb() which locks the hb->lock's
in pointer value order. There is no parallel unlock routine,
and the code unlocks them in name order, ignoring pointer value.
This patch adds double_unlock_hb() to refactor the duplicated
code segments.
Build and boot tested on a 4 way Intel x86_64 workstation.
Passes basic pthread_mutex and PI tests out of
ltp/testcases/realtime.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <20090312075552.9856.48021.stgit@Aeon>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/futex.c | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index 4000454e4d83..e149545c5cea 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -690,6 +690,19 @@ double_lock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2) } } +static inline void +double_unlock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2) +{ + if (hb1 <= hb2) { + spin_unlock(&hb2->lock); + if (hb1 < hb2) + spin_unlock(&hb1->lock); + } else { /* hb1 > hb2 */ + spin_unlock(&hb1->lock); + spin_unlock(&hb2->lock); + } +} + /* * Wake up waiters matching bitset queued on this futex (uaddr). */ @@ -767,9 +780,7 @@ retry: if (unlikely(op_ret < 0)) { u32 dummy; - spin_unlock(&hb1->lock); - if (hb1 != hb2) - spin_unlock(&hb2->lock); + double_unlock_hb(hb1, hb2); #ifndef CONFIG_MMU /* @@ -833,9 +844,7 @@ retry: ret += op_ret; } - spin_unlock(&hb1->lock); - if (hb1 != hb2) - spin_unlock(&hb2->lock); + double_unlock_hb(hb1, hb2); out_put_keys: put_futex_key(fshared, &key2); out_put_key1: @@ -876,9 +885,7 @@ retry: ret = get_futex_value_locked(&curval, uaddr1); if (unlikely(ret)) { - spin_unlock(&hb1->lock); - if (hb1 != hb2) - spin_unlock(&hb2->lock); + double_unlock_hb(hb1, hb2); put_futex_key(fshared, &key2); put_futex_key(fshared, &key1); @@ -925,9 +932,7 @@ retry: } out_unlock: - spin_unlock(&hb1->lock); - if (hb1 != hb2) - spin_unlock(&hb2->lock); + double_unlock_hb(hb1, hb2); /* drop_futex_key_refs() must be called outside the spinlocks. */ while (--drop_count >= 0) |