Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753183AbYL2SyZ (ORCPT ); Mon, 29 Dec 2008 13:54:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752513AbYL2SyB (ORCPT ); Mon, 29 Dec 2008 13:54:01 -0500 Received: from e31.co.us.ibm.com ([32.97.110.149]:33781 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752493AbYL2Sx7 (ORCPT ); Mon, 29 Dec 2008 13:53:59 -0500 From: Darren Hart Subject: [PATCH 1/2] futex: make futex_(get|put)_key() calls symmetric To: Ingo Molnar , linux-kernel@vger.kernel.org Cc: Darren Hart , Peter Zijlstra , Thomas Gleixner , Rusty Russell Date: Mon, 29 Dec 2008 10:53:56 -0800 Message-ID: <20081229185355.10342.85717.stgit@Aeon> In-Reply-To: <20081229185238.10342.75651.stgit@Aeon> References: <20081229185238.10342.75651.stgit@Aeon> User-Agent: StGIT/0.14.2 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6384 Lines: 273 Impact: cleanup This patch makes the calls to futex_get_key_refs() and futex_drop_key_refs() explicitly symmetric by only "putting" keys we successfully "got". Also cleanup a couple return points that didn't "put" after a successful "get". Build and boot tested on an x86_64 system. Signed-off-by: Darren Hart Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Rusty Russell --- kernel/futex.c | 66 ++++++++++++++++++++++++++++++-------------------------- 1 files changed, 35 insertions(+), 31 deletions(-) diff --git a/kernel/futex.c b/kernel/futex.c index b4f87ba..cf363ce 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -723,8 +723,8 @@ static int futex_wake(u32 __user *uaddr, int fshared, int nr_wake, u32 bitset) } spin_unlock(&hb->lock); -out: put_futex_key(fshared, &key); +out: return ret; } @@ -748,7 +748,7 @@ retryfull: goto out; ret = get_futex_key(uaddr2, fshared, &key2); if (unlikely(ret != 0)) - goto out; + goto out_put_key1; hb1 = hash_futex(&key1); hb2 = hash_futex(&key2); @@ -770,12 +770,12 @@ retry: * but we might get them from range checking */ ret = op_ret; - goto out; + goto out_put_keys; #endif if (unlikely(op_ret != -EFAULT)) { ret = op_ret; - goto out; + goto out_put_keys; } /* @@ -789,7 +789,7 @@ retry: ret = futex_handle_fault((unsigned long)uaddr2, attempt); if (ret) - goto out; + goto out_put_keys; goto retry; } @@ -827,10 +827,11 @@ retry: spin_unlock(&hb1->lock); if (hb1 != hb2) spin_unlock(&hb2->lock); -out: +out_put_keys: put_futex_key(fshared, &key2); +out_put_key1: put_futex_key(fshared, &key1); - +out: return ret; } @@ -847,13 +848,13 @@ static int futex_requeue(u32 __user *uaddr1, int fshared, u32 __user *uaddr2, struct futex_q *this, *next; int ret, drop_count = 0; - retry: +retry: ret = get_futex_key(uaddr1, fshared, &key1); if (unlikely(ret != 0)) goto out; ret = get_futex_key(uaddr2, fshared, &key2); if (unlikely(ret != 0)) - goto out; + goto out_put_key1; hb1 = hash_futex(&key1); hb2 = hash_futex(&key2); @@ -875,7 +876,7 @@ static int futex_requeue(u32 __user *uaddr1, int fshared, u32 __user *uaddr2, if (!ret) goto retry; - return ret; + goto out_put_keys; } if (curval != *cmpval) { ret = -EAGAIN; @@ -920,9 +921,10 @@ out_unlock: while (--drop_count >= 0) drop_futex_key_refs(&key1); -out: put_futex_key(fshared, &key2); +out_put_key1: put_futex_key(fshared, &key1); +out: return ret; } @@ -983,7 +985,7 @@ static int unqueue_me(struct futex_q *q) int ret = 0; /* In the common case we don't take the spinlock, which is nice. */ - retry: +retry: lock_ptr = q->lock_ptr; barrier(); if (lock_ptr != NULL) { @@ -1165,11 +1167,11 @@ static int futex_wait(u32 __user *uaddr, int fshared, q.pi_state = NULL; q.bitset = bitset; - retry: +retry: q.key = FUTEX_KEY_INIT; ret = get_futex_key(uaddr, fshared, &q.key); if (unlikely(ret != 0)) - goto out_release_sem; + goto out; hb = queue_lock(&q); @@ -1197,6 +1199,7 @@ static int futex_wait(u32 __user *uaddr, int fshared, if (unlikely(ret)) { queue_unlock(&q, hb); + put_futex_key(fshared, &q.key); ret = get_user(uval, uaddr); @@ -1206,7 +1209,7 @@ static int futex_wait(u32 __user *uaddr, int fshared, } ret = -EWOULDBLOCK; if (uval != val) - goto out_unlock_release_sem; + goto out_unlock_put_key; /* Only actually queue if *uaddr contained val. */ queue_me(&q, hb); @@ -1298,11 +1301,11 @@ static int futex_wait(u32 __user *uaddr, int fshared, return -ERESTART_RESTARTBLOCK; } - out_unlock_release_sem: +out_unlock_put_key: queue_unlock(&q, hb); - - out_release_sem: put_futex_key(fshared, &q.key); + +out: return ret; } @@ -1351,16 +1354,16 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared, } q.pi_state = NULL; - retry: +retry: q.key = FUTEX_KEY_INIT; ret = get_futex_key(uaddr, fshared, &q.key); if (unlikely(ret != 0)) - goto out_release_sem; + goto out; - retry_unlocked: +retry_unlocked: hb = queue_lock(&q); - retry_locked: +retry_locked: ret = lock_taken = 0; /* @@ -1381,14 +1384,14 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared, */ if (unlikely((curval & FUTEX_TID_MASK) == task_pid_vnr(current))) { ret = -EDEADLK; - goto out_unlock_release_sem; + goto out_unlock_put_key; } /* * Surprise - we got the lock. Just return to userspace: */ if (unlikely(!curval)) - goto out_unlock_release_sem; + goto out_unlock_put_key; uval = curval; @@ -1424,7 +1427,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared, * We took the lock due to owner died take over. */ if (unlikely(lock_taken)) - goto out_unlock_release_sem; + goto out_unlock_put_key; /* * We dont have the lock. Look up the PI state (or create it if @@ -1463,7 +1466,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared, goto retry_locked; } default: - goto out_unlock_release_sem; + goto out_unlock_put_key; } } @@ -1554,16 +1557,17 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared, destroy_hrtimer_on_stack(&to->timer); return ret != -EINTR ? ret : -ERESTARTNOINTR; - out_unlock_release_sem: +out_unlock_put_key: queue_unlock(&q, hb); - out_release_sem: +out_put_key: put_futex_key(fshared, &q.key); +out: if (to) destroy_hrtimer_on_stack(&to->timer); return ret; - uaddr_faulted: +uaddr_faulted: /* * We have to r/w *(int __user *)uaddr, and we have to modify it * atomically. Therefore, if we continue to fault after get_user() @@ -1576,7 +1580,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared, if (attempt++) { ret = futex_handle_fault((unsigned long)uaddr, attempt); if (ret) - goto out_release_sem; + goto out_put_key; goto retry_unlocked; } @@ -1668,9 +1672,9 @@ retry_unlocked: out_unlock: spin_unlock(&hb->lock); -out: put_futex_key(fshared, &key); +out: return ret; pi_faulted: -- 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/