[PATCH 09/09] This patch removes the ipc_lock_down() routines: they used to call idr_find() locklessly (given that the ipc ids lock was already held), so they are not needed anymore. Signed-off-by: Nadia Derbey --- ipc/shm.c | 21 +++------------------ ipc/util.c | 52 +--------------------------------------------------- ipc/util.h | 6 ------ 3 files changed, 4 insertions(+), 75 deletions(-) Index: linux-2.6.25-mm1/ipc/util.c =================================================================== --- linux-2.6.25-mm1.orig/ipc/util.c 2008-05-07 09:56:20.000000000 +0200 +++ linux-2.6.25-mm1/ipc/util.c 2008-05-07 09:58:32.000000000 +0200 @@ -716,56 +716,6 @@ struct kern_ipc_perm *ipc_lock(struct ip return out; } -/** - * ipc_lock_down - Lock an ipc structure with rw_sem 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 exit. - * - * This is the routine that should be called when the rw_mutex is already - * held, i.e. idr tree protected. - */ - -struct kern_ipc_perm *ipc_lock_down(struct ipc_ids *ids, int id) -{ - struct kern_ipc_perm *out; - int lid = ipcid_to_idx(id); - - rcu_read_lock(); - out = idr_find(&ids->ipcs_idr, lid); - if (out == NULL) { - rcu_read_unlock(); - return ERR_PTR(-EINVAL); - } - - spin_lock(&out->lock); - - /* - * No need to verify that the structure is still valid since the - * rw_mutex is held. - */ - return out; -} - -struct kern_ipc_perm *ipc_lock_check_down(struct ipc_ids *ids, int id) -{ - struct kern_ipc_perm *out; - - out = ipc_lock_down(ids, id); - if (IS_ERR(out)) - return out; - - if (ipc_checkid(out, id)) { - ipc_unlock(out); - return ERR_PTR(-EIDRM); - } - - return out; -} - struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id) { struct kern_ipc_perm *out; @@ -837,7 +787,7 @@ struct kern_ipc_perm *ipcctl_pre_down(st int err; down_write(&ids->rw_mutex); - ipcp = ipc_lock_check_down(ids, id); + ipcp = ipc_lock_check(ids, id); if (IS_ERR(ipcp)) { err = PTR_ERR(ipcp); goto out_up; Index: linux-2.6.25-mm1/ipc/util.h =================================================================== --- linux-2.6.25-mm1.orig/ipc/util.h 2008-05-06 17:15:10.000000000 +0200 +++ linux-2.6.25-mm1/ipc/util.h 2008-05-07 09:59:31.000000000 +0200 @@ -102,11 +102,6 @@ void* ipc_rcu_alloc(int size); void ipc_rcu_getref(void *ptr); void ipc_rcu_putref(void *ptr); -/* - * ipc_lock_down: called with rw_mutex held - * ipc_lock: called without that lock held - */ -struct kern_ipc_perm *ipc_lock_down(struct ipc_ids *, int); struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int); void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out); @@ -155,7 +150,6 @@ static inline void ipc_unlock(struct ker rcu_read_unlock(); } -struct kern_ipc_perm *ipc_lock_check_down(struct ipc_ids *ids, int id); struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id); int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, struct ipc_ops *ops, struct ipc_params *params); Index: linux-2.6.25-mm1/ipc/shm.c =================================================================== --- linux-2.6.25-mm1.orig/ipc/shm.c 2008-05-06 17:15:10.000000000 +0200 +++ linux-2.6.25-mm1/ipc/shm.c 2008-05-07 10:01:05.000000000 +0200 @@ -112,23 +112,8 @@ void __init shm_init (void) } /* - * shm_lock_(check_)down routines are called in the paths where the rw_mutex - * is held to protect access to the idr tree. - */ -static inline struct shmid_kernel *shm_lock_down(struct ipc_namespace *ns, - int id) -{ - struct kern_ipc_perm *ipcp = ipc_lock_down(&shm_ids(ns), id); - - if (IS_ERR(ipcp)) - return (struct shmid_kernel *)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 held. + * is not necessarily held. */ static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id) { @@ -211,7 +196,7 @@ static void shm_close(struct vm_area_str down_write(&shm_ids(ns).rw_mutex); /* remove from the list of attaches of the shm segment */ - shp = shm_lock_down(ns, sfd->id); + shp = shm_lock(ns, sfd->id); BUG_ON(IS_ERR(shp)); shp->shm_lprid = task_tgid_vnr(current); shp->shm_dtim = get_seconds(); @@ -933,7 +918,7 @@ invalid: out_nattch: down_write(&shm_ids(ns).rw_mutex); - shp = shm_lock_down(ns, shmid); + shp = shm_lock(ns, shmid); BUG_ON(IS_ERR(shp)); shp->shm_nattch--; if(shp->shm_nattch == 0 && -- -- 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/