From: Manfred Spraul <manfred@colorfullife.com>
The attached patch removes sem_revalidate and replaces it with
ipc_rcu_getref() calls followed by ipc_lock_by_ptr().
Signed-Off-By: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/ipc/sem.c | 75 +++++++++++++++++++++++++++++++++---------------------
1 files changed, 46 insertions(+), 29 deletions(-)
diff -puN ipc/sem.c~ipc-2-3-remove-sem_revalidate ipc/sem.c
--- 25/ipc/sem.c~ipc-2-3-remove-sem_revalidate 2004-07-03 13:09:19.440415120 -0700
+++ 25-akpm/ipc/sem.c 2004-07-03 13:09:19.445414360 -0700
@@ -241,25 +241,6 @@ asmlinkage long sys_semget (key_t key, i
return err;
}
-/* doesn't acquire the sem_lock on error! */
-static int sem_revalidate(int semid, struct sem_array* sma, int nsems, short flg)
-{
- struct sem_array* smanew;
-
- smanew = sem_lock(semid);
- if(smanew==NULL)
- return -EIDRM;
- if(smanew != sma || sem_checkid(sma,semid) || sma->sem_nsems != nsems) {
- sem_unlock(smanew);
- return -EIDRM;
- }
-
- if (flg && ipcperms(&sma->sem_perm, flg)) {
- sem_unlock(smanew);
- return -EACCES;
- }
- return 0;
-}
/* Manage the doubly linked list sma->sem_pending as a FIFO:
* insert new queue elements at the tail sma->sem_pending_last.
*/
@@ -614,13 +595,24 @@ static int semctl_main(int semid, int se
int i;
if(nsems > SEMMSL_FAST) {
+ ipc_rcu_getref(sma);
sem_unlock(sma);
+
sem_io = ipc_alloc(sizeof(ushort)*nsems);
- if(sem_io == NULL)
+ if(sem_io == NULL) {
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ sem_unlock(sma);
return -ENOMEM;
- err = sem_revalidate(semid, sma, nsems, S_IRUGO);
- if(err)
+ }
+
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ if (sma->sem_perm.deleted) {
+ sem_unlock(sma);
+ err = -EIDRM;
goto out_free;
+ }
}
for (i = 0; i < sma->sem_nsems; i++)
@@ -636,28 +628,43 @@ static int semctl_main(int semid, int se
int i;
struct sem_undo *un;
+ ipc_rcu_getref(sma);
sem_unlock(sma);
if(nsems > SEMMSL_FAST) {
sem_io = ipc_alloc(sizeof(ushort)*nsems);
- if(sem_io == NULL)
+ if(sem_io == NULL) {
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ sem_unlock(sma);
return -ENOMEM;
+ }
}
if (copy_from_user (sem_io, arg.array, nsems*sizeof(ushort))) {
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ sem_unlock(sma);
err = -EFAULT;
goto out_free;
}
for (i = 0; i < nsems; i++) {
if (sem_io[i] > SEMVMX) {
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ sem_unlock(sma);
err = -ERANGE;
goto out_free;
}
}
- err = sem_revalidate(semid, sma, nsems, S_IWUGO);
- if(err)
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ if (sma->sem_perm.deleted) {
+ sem_unlock(sma);
+ err = -EIDRM;
goto out_free;
+ }
for (i = 0; i < nsems; i++)
sma->sem_base[i].semval = sem_io[i];
@@ -977,11 +984,16 @@ static struct sem_undo *find_undo(int se
goto out;
}
nsems = sma->sem_nsems;
+ ipc_rcu_getref(sma);
sem_unlock(sma);
new = (struct sem_undo *) kmalloc(sizeof(struct sem_undo) + sizeof(short)*nsems, GFP_KERNEL);
- if (!new)
+ if (!new) {
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ sem_unlock(sma);
return ERR_PTR(-ENOMEM);
+ }
memset(new, 0, sizeof(struct sem_undo) + sizeof(short)*nsems);
new->semadj = (short *) &new[1];
new->semid = semid;
@@ -991,13 +1003,18 @@ static struct sem_undo *find_undo(int se
if (un) {
unlock_semundo();
kfree(new);
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ sem_unlock(sma);
goto out;
}
- error = sem_revalidate(semid, sma, nsems, 0);
- if (error) {
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ if (sma->sem_perm.deleted) {
+ sem_unlock(sma);
unlock_semundo();
kfree(new);
- un = ERR_PTR(error);
+ un = ERR_PTR(-EIDRM);
goto out;
}
new->proc_next = ulp->proc_list;
_