From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx134.postini.com [74.125.245.134]) by kanga.kvack.org (Postfix) with SMTP id 57FF96B0037 for ; Tue, 18 Jun 2013 21:18:50 -0400 (EDT) From: Davidlohr Bueso Subject: [PATCH 02/11] ipc,shm: shorten critical region in shmctl_down Date: Tue, 18 Jun 2013 18:18:27 -0700 Message-Id: <1371604716-3439-3-git-send-email-davidlohr.bueso@hp.com> In-Reply-To: <1371604716-3439-1-git-send-email-davidlohr.bueso@hp.com> References: <1371604716-3439-1-git-send-email-davidlohr.bueso@hp.com> Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, riel@redhat.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Davidlohr Bueso Instead of holding the ipc lock for the entire function, use the ipcctl_pre_down_nolock and only acquire the lock for specific commands: RMID and SET. Signed-off-by: Davidlohr Bueso --- ipc/shm.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/ipc/shm.c b/ipc/shm.c index 216ae72..22cffd7 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -780,11 +780,10 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd, down_write(&shm_ids(ns).rw_mutex); rcu_read_lock(); - ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd, - &shmid64.shm_perm, 0); + ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd, + &shmid64.shm_perm, 0); if (IS_ERR(ipcp)) { err = PTR_ERR(ipcp); - /* the ipc lock is not held upon failure */ goto out_unlock1; } @@ -792,14 +791,16 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd, err = security_shm_shmctl(shp, cmd); if (err) - goto out_unlock0; + goto out_unlock1; switch (cmd) { case IPC_RMID: + ipc_lock_object(&shp->shm_perm); /* do_shm_rmid unlocks the ipc object and rcu */ do_shm_rmid(ns, ipcp); goto out_up; case IPC_SET: + ipc_lock_object(&shp->shm_perm); err = ipc_update_perm(&shmid64.shm_perm, ipcp); if (err) goto out_unlock0; @@ -807,6 +808,7 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd, break; default: err = -EINVAL; + goto out_unlock1; } out_unlock0: -- 1.7.11.7 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org