Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933996Ab3FSBSy (ORCPT ); Tue, 18 Jun 2013 21:18:54 -0400 Received: from g4t0017.houston.hp.com ([15.201.24.20]:48274 "EHLO g4t0017.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932644Ab3FSBSw (ORCPT ); Tue, 18 Jun 2013 21:18:52 -0400 From: Davidlohr Bueso To: akpm@linux-foundation.org, riel@redhat.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Davidlohr Bueso Subject: [PATCH 04/11] ipc,shm: introduce shmctl_nolock Date: Tue, 18 Jun 2013 18:18:29 -0700 Message-Id: <1371604716-3439-5-git-send-email-davidlohr.bueso@hp.com> X-Mailer: git-send-email 1.7.11.7 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: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2870 Lines: 111 Similar to semctl and msgctl, when calling msgctl, the *_INFO and *_STAT commands can be performed without acquiring the ipc object. Add a shmctl_nolock() function and move the logic of *_INFO and *_STAT out of msgctl(). Since we are just moving functionality, this change still takes the lock and it will be properly lockless in the next patch. Signed-off-by: Davidlohr Bueso --- ipc/shm.c | 57 +++++++++++++++++++++++++++++++++++++++------------------ 1 file changed, 39 insertions(+), 18 deletions(-) diff --git a/ipc/shm.c b/ipc/shm.c index 22cffd7..3e12398 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -820,29 +820,24 @@ out_up: return err; } -SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) +static int shmctl_nolock(struct ipc_namespace *ns, int shmid, + int cmd, int version, void __user *buf) { + int err; struct shmid_kernel *shp; - int err, version; - struct ipc_namespace *ns; - if (cmd < 0 || shmid < 0) { - err = -EINVAL; - goto out; + /* preliminary security checks for *_INFO */ + if (cmd == IPC_INFO || cmd == SHM_INFO) { + err = security_shm_shmctl(NULL, cmd); + if (err) + return err; } - version = ipc_parse_version(&cmd); - ns = current->nsproxy->ipc_ns; - - switch (cmd) { /* replace with proc interface ? */ + switch (cmd) { case IPC_INFO: { struct shminfo64 shminfo; - err = security_shm_shmctl(NULL, cmd); - if (err) - return err; - memset(&shminfo, 0, sizeof(shminfo)); shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni; shminfo.shmmax = ns->shm_ctlmax; @@ -864,10 +859,6 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) { struct shm_info shm_info; - err = security_shm_shmctl(NULL, cmd); - if (err) - return err; - memset(&shm_info, 0, sizeof(shm_info)); down_read(&shm_ids(ns).rw_mutex); shm_info.used_ids = shm_ids(ns).in_use; @@ -928,6 +919,36 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) err = result; goto out; } + default: + return -EINVAL; + } + +out_unlock: + shm_unlock(shp); +out: + return err; +} + +SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) +{ + struct shmid_kernel *shp; + int err, version; + struct ipc_namespace *ns; + + if (cmd < 0 || shmid < 0) { + err = -EINVAL; + goto out; + } + + version = ipc_parse_version(&cmd); + ns = current->nsproxy->ipc_ns; + + switch (cmd) { + case IPC_INFO: + case SHM_INFO: + case SHM_STAT: + case IPC_STAT: + return shmctl_nolock(ns, shmid, cmd, version, buf); case SHM_LOCK: case SHM_UNLOCK: { -- 1.7.11.7 -- 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/