From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx194.postini.com [74.125.245.194]) by kanga.kvack.org (Postfix) with SMTP id 3BFD76B0034 for ; Tue, 18 Jun 2013 21:18:49 -0400 (EDT) From: Davidlohr Bueso Subject: [PATCH 01/11] ipc,shm: introduce lockless functions to obtain the ipc object Date: Tue, 18 Jun 2013 18:18:26 -0700 Message-Id: <1371604716-3439-2-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 Add shm_obtain_object() and shm_obtain_object_check(), which will allow us to get the ipc object without acquiring the lock. Just as with other forms of ipc, these functions are basically wrappers around ipc_obtain_object*(). Signed-off-by: Davidlohr Bueso --- ipc/shm.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/ipc/shm.c b/ipc/shm.c index c6b4ad5..216ae72 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -124,6 +124,26 @@ void __init shm_init (void) IPC_SHM_IDS, sysvipc_shm_proc_show); } +static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id) +{ + struct kern_ipc_perm *ipcp = ipc_obtain_object(&shm_ids(ns), id); + + if (IS_ERR(ipcp)) + return ERR_CAST(ipcp); + + return container_of(ipcp, struct shmid_kernel, shm_perm); +} + +static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id) +{ + struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id); + + if (IS_ERR(ipcp)) + return ERR_CAST(ipcp); + + return container_of(ipcp, struct shmid_kernel, shm_perm); +} + /* * shm_lock_(check_) routines are called in the paths where the rw_mutex * is not necessarily held. -- 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