diff options
| -rw-r--r-- | ipc/shm.c | 29 | ||||
| -rw-r--r-- | ipc/util.c | 36 | ||||
| -rw-r--r-- | ipc/util.h | 1 |
3 files changed, 23 insertions, 43 deletions
diff --git a/ipc/shm.c b/ipc/shm.c index a413ddf74dac..4c7ae625d996 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -180,16 +180,33 @@ static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace */ static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id) { - struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id); + struct kern_ipc_perm *ipcp; + + rcu_read_lock(); + ipcp = ipc_obtain_object_idr(&shm_ids(ns), id); + if (IS_ERR(ipcp)) + goto err; + ipc_lock_object(ipcp); + /* + * ipc_rmid() may have already freed the ID while ipc_lock_object() + * was spinning: here verify that the structure is still valid. + * Upon races with RMID, return -EIDRM, thus indicating that + * the ID points to a removed identifier. + */ + if (ipc_valid_object(ipcp)) { + /* return a locked ipc object upon success */ + return container_of(ipcp, struct shmid_kernel, shm_perm); + } + + ipc_unlock_object(ipcp); +err: + rcu_read_unlock(); /* * Callers of shm_lock() must validate the status of the returned ipc - * object pointer (as returned by ipc_lock()), and error out as - * appropriate. + * object pointer and error out as appropriate. */ - if (IS_ERR(ipcp)) - return (void *)ipcp; - return container_of(ipcp, struct shmid_kernel, shm_perm); + return (void *)ipcp; } static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp) diff --git a/ipc/util.c b/ipc/util.c index dcb437095cbd..bd1863b6ed39 100644 --- a/ipc/util.c +++ b/ipc/util.c @@ -589,42 +589,6 @@ struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id) } /** - * ipc_lock - lock an ipc structure without rwsem held - * @ids: ipc identifier set - * @id: ipc id to look for - * - * Look for an id in the ipc ids idr and lock the associated ipc object. - * - * The ipc object is locked on successful exit. - */ -struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) -{ - struct kern_ipc_perm *out; - - rcu_read_lock(); - out = ipc_obtain_object_idr(ids, id); - if (IS_ERR(out)) - goto err; - - spin_lock(&out->lock); - - /* - * ipc_rmid() may have already freed the ID while ipc_lock() - * was spinning: here verify that the structure is still valid. - * Upon races with RMID, return -EIDRM, thus indicating that - * the ID points to a removed identifier. - */ - if (ipc_valid_object(out)) - return out; - - spin_unlock(&out->lock); - out = ERR_PTR(-EIDRM); -err: - rcu_read_unlock(); - return out; -} - -/** * ipc_obtain_object_check * @ids: ipc identifier set * @id: ipc id to look for diff --git a/ipc/util.h b/ipc/util.h index fcf81425ae98..e3c47b21db93 100644 --- a/ipc/util.h +++ b/ipc/util.h @@ -142,7 +142,6 @@ int ipc_rcu_getref(struct kern_ipc_perm *ptr); void ipc_rcu_putref(struct kern_ipc_perm *ptr, void (*func)(struct rcu_head *head)); -struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int); struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id); void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out); |