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ipc: get rid of ipc_lock_down()

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Remove 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 <Nadia.Derbey@bull.net>
Acked-by: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Jim Houston <jim.houston@comcast.net>
Cc: Pierre Peiffer <peifferp@gmail.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Nadia Derbey 2008-07-25 01:48:03 -07:00 committed by Linus Torvalds
parent 983bfb7db3
commit 00c2bf85d8
3 changed files with 4 additions and 75 deletions
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21
ipc/shm.c
View file

@ -111,24 +111,9 @@ void __init shm_init (void)
IPC_SHM_IDS, sysvipc_shm_proc_show);
}
/*
* 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_struct *vma)
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();
@ -932,7 +917,7 @@ 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 &&

52
ipc/util.c
View file

@ -716,56 +716,6 @@ struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id)
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(struct ipc_ids *ids, int id, int cmd,
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;

6
ipc/util.h
View file

@ -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 kern_ipc_perm *perm)
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);