Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934018Ab3FSBTA (ORCPT ); Tue, 18 Jun 2013 21:19:00 -0400 Received: from g4t0014.houston.hp.com ([15.201.24.17]:44495 "EHLO g4t0014.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932644Ab3FSBSz (ORCPT ); Tue, 18 Jun 2013 21:18:55 -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 06/11] ipc,shm: shorten critical region for shmctl Date: Tue, 18 Jun 2013 18:18:31 -0700 Message-Id: <1371604716-3439-7-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: 3301 Lines: 129 With the *_INFO, *_STAT, IPC_RMID and IPC_SET commands already optimized, deal with the remaining SHM_LOCK and SHM_UNLOCK commands. Take the shm_perm lock after doing the initial auditing and security checks. The rest of the logic remains unchanged. Signed-off-by: Davidlohr Bueso --- ipc/shm.c | 49 +++++++++++++++++++++++++------------------------ 1 file changed, 25 insertions(+), 24 deletions(-) diff --git a/ipc/shm.c b/ipc/shm.c index 43a8786..e4ac1c1 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -940,10 +940,8 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) int err, version; struct ipc_namespace *ns; - if (cmd < 0 || shmid < 0) { - err = -EINVAL; - goto out; - } + if (cmd < 0 || shmid < 0) + return -EINVAL; version = ipc_parse_version(&cmd); ns = current->nsproxy->ipc_ns; @@ -954,36 +952,40 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) case SHM_STAT: case IPC_STAT: return shmctl_nolock(ns, shmid, cmd, version, buf); + case IPC_RMID: + case IPC_SET: + return shmctl_down(ns, shmid, cmd, buf, version); case SHM_LOCK: case SHM_UNLOCK: { struct file *shm_file; - shp = shm_lock_check(ns, shmid); + rcu_read_lock(); + shp = shm_obtain_object_check(ns, shmid); if (IS_ERR(shp)) { err = PTR_ERR(shp); - goto out; + goto out_unlock1; } audit_ipc_obj(&(shp->shm_perm)); + err = security_shm_shmctl(shp, cmd); + if (err) + goto out_unlock1; + ipc_lock_object(&shp->shm_perm); if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) { kuid_t euid = current_euid(); err = -EPERM; if (!uid_eq(euid, shp->shm_perm.uid) && !uid_eq(euid, shp->shm_perm.cuid)) - goto out_unlock; + goto out_unlock0; if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) - goto out_unlock; + goto out_unlock0; } - err = security_shm_shmctl(shp, cmd); - if (err) - goto out_unlock; - shm_file = shp->shm_file; if (is_file_hugepages(shm_file)) - goto out_unlock; + goto out_unlock0; if (cmd == SHM_LOCK) { struct user_struct *user = current_user(); @@ -992,32 +994,31 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) shp->shm_perm.mode |= SHM_LOCKED; shp->mlock_user = user; } - goto out_unlock; + goto out_unlock0; } /* SHM_UNLOCK */ if (!(shp->shm_perm.mode & SHM_LOCKED)) - goto out_unlock; + goto out_unlock0; shmem_lock(shm_file, 0, shp->mlock_user); shp->shm_perm.mode &= ~SHM_LOCKED; shp->mlock_user = NULL; get_file(shm_file); - shm_unlock(shp); + ipc_unlock_object(&shp->shm_perm); + rcu_read_unlock(); shmem_unlock_mapping(shm_file->f_mapping); + fput(shm_file); - goto out; - } - case IPC_RMID: - case IPC_SET: - err = shmctl_down(ns, shmid, cmd, buf, version); return err; + } default: return -EINVAL; } -out_unlock: - shm_unlock(shp); -out: +out_unlock0: + ipc_unlock_object(&shp->shm_perm); +out_unlock1: + rcu_read_unlock(); return err; } -- 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/