IPC/semaphores: code factorisation
Pierre Peiffer [Tue, 29 Apr 2008 08:00:46 +0000 (01:00 -0700)]
Trivial patch which adds some small locking functions and makes use of them to
factorize some part of the code and to make it cleaner.

Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ipc/sem.c

index 08da864..1b5ae35 100644 (file)
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -180,6 +180,25 @@ static inline struct sem_array *sem_lock_check(struct ipc_namespace *ns,
        return container_of(ipcp, struct sem_array, sem_perm);
 }
 
+static inline void sem_lock_and_putref(struct sem_array *sma)
+{
+       ipc_lock_by_ptr(&sma->sem_perm);
+       ipc_rcu_putref(sma);
+}
+
+static inline void sem_getref_and_unlock(struct sem_array *sma)
+{
+       ipc_rcu_getref(sma);
+       ipc_unlock(&(sma)->sem_perm);
+}
+
+static inline void sem_putref(struct sem_array *sma)
+{
+       ipc_lock_by_ptr(&sma->sem_perm);
+       ipc_rcu_putref(sma);
+       ipc_unlock(&(sma)->sem_perm);
+}
+
 static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s)
 {
        ipc_rmid(&sem_ids(ns), &s->sem_perm);
@@ -698,19 +717,15 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
                int i;
 
                if(nsems > SEMMSL_FAST) {
-                       ipc_rcu_getref(sma);
-                       sem_unlock(sma);                        
+                       sem_getref_and_unlock(sma);
 
                        sem_io = ipc_alloc(sizeof(ushort)*nsems);
                        if(sem_io == NULL) {
-                               ipc_lock_by_ptr(&sma->sem_perm);
-                               ipc_rcu_putref(sma);
-                               sem_unlock(sma);
+                               sem_putref(sma);
                                return -ENOMEM;
                        }
 
-                       ipc_lock_by_ptr(&sma->sem_perm);
-                       ipc_rcu_putref(sma);
+                       sem_lock_and_putref(sma);
                        if (sma->sem_perm.deleted) {
                                sem_unlock(sma);
                                err = -EIDRM;
@@ -731,38 +746,30 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
                int i;
                struct sem_undo *un;
 
-               ipc_rcu_getref(sma);
-               sem_unlock(sma);
+               sem_getref_and_unlock(sma);
 
                if(nsems > SEMMSL_FAST) {
                        sem_io = ipc_alloc(sizeof(ushort)*nsems);
                        if(sem_io == NULL) {
-                               ipc_lock_by_ptr(&sma->sem_perm);
-                               ipc_rcu_putref(sma);
-                               sem_unlock(sma);
+                               sem_putref(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);
+                       sem_putref(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);
+                               sem_putref(sma);
                                err = -ERANGE;
                                goto out_free;
                        }
                }
-               ipc_lock_by_ptr(&sma->sem_perm);
-               ipc_rcu_putref(sma);
+               sem_lock_and_putref(sma);
                if (sma->sem_perm.deleted) {
                        sem_unlock(sma);
                        err = -EIDRM;
@@ -1042,14 +1049,11 @@ static struct sem_undo *find_undo(struct ipc_namespace *ns, int semid)
                return ERR_PTR(PTR_ERR(sma));
 
        nsems = sma->sem_nsems;
-       ipc_rcu_getref(sma);
-       sem_unlock(sma);
+       sem_getref_and_unlock(sma);
 
        new = kzalloc(sizeof(struct sem_undo) + sizeof(short)*nsems, GFP_KERNEL);
        if (!new) {
-               ipc_lock_by_ptr(&sma->sem_perm);
-               ipc_rcu_putref(sma);
-               sem_unlock(sma);
+               sem_putref(sma);
                return ERR_PTR(-ENOMEM);
        }
        new->semadj = (short *) &new[1];
@@ -1060,13 +1064,10 @@ static struct sem_undo *find_undo(struct ipc_namespace *ns, int semid)
        if (un) {
                spin_unlock(&ulp->lock);
                kfree(new);
-               ipc_lock_by_ptr(&sma->sem_perm);
-               ipc_rcu_putref(sma);
-               sem_unlock(sma);
+               sem_putref(sma);
                goto out;
        }
-       ipc_lock_by_ptr(&sma->sem_perm);
-       ipc_rcu_putref(sma);
+       sem_lock_and_putref(sma);
        if (sma->sem_perm.deleted) {
                sem_unlock(sma);
                spin_unlock(&ulp->lock);