ipc,msg: introduce msgctl_nolock

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / ipc / sem.c

diff --git a/ipc/sem.c b/ipc/sem.c
index 70480a3aa69891b6ebc6c998e2202c3197a443ec..b4b892b5c5f8d6124c478ae10c0dcdce94b56358 100644 (file)
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -246,7 +246,7 @@ static inline int sem_lock(struct sem_array *sma, struct sembuf *sops,
                 * their critical section while the array lock is held.
                 */
  lock_array:
-               spin_lock(&sma->sem_perm.lock);
+               ipc_lock_object(&sma->sem_perm);
                for (i = 0; i < sma->sem_nsems; i++) {
                        struct sem *sem = sma->sem_base + i;
                        spin_unlock_wait(&sem->lock);
@@ -259,7 +259,7 @@ static inline int sem_lock(struct sem_array *sma, struct sembuf *sops,
 static inline void sem_unlock(struct sem_array *sma, int locknum)
 {
        if (locknum == -1) {
-               spin_unlock(&sma->sem_perm.lock);
+               ipc_unlock_object(&sma->sem_perm);
        } else {
                struct sem *sem = sma->sem_base + locknum;
                spin_unlock(&sem->lock);
@@ -872,7 +872,7 @@ static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
        int i;
 
        /* Free the existing undo structures for this semaphore set.  */
-       assert_spin_locked(&sma->sem_perm.lock);
+       ipc_assert_locked_object(&sma->sem_perm);
        list_for_each_entry_safe(un, tu, &sma->list_id, list_id) {
                list_del(&un->list_id);
                spin_lock(&un->ulp->lock);
@@ -1070,7 +1070,7 @@ static int semctl_setval(struct ipc_namespace *ns, int semid, int semnum,
 
        curr = &sma->sem_base[semnum];
 
-       assert_spin_locked(&sma->sem_perm.lock);
+       ipc_assert_locked_object(&sma->sem_perm);
        list_for_each_entry(un, &sma->list_id, list_id)
                un->semadj[semnum] = 0;
 
@@ -1199,7 +1199,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
                for (i = 0; i < nsems; i++)
                        sma->sem_base[i].semval = sem_io[i];
 
-               assert_spin_locked(&sma->sem_perm.lock);
+               ipc_assert_locked_object(&sma->sem_perm);
                list_for_each_entry(un, &sma->list_id, list_id) {
                        for (i = 0; i < nsems; i++)
                                un->semadj[i] = 0;
@@ -1289,39 +1289,44 @@ static int semctl_down(struct ipc_namespace *ns, int semid,
                        return -EFAULT;
        }
 
+       down_write(&sem_ids(ns).rw_mutex);
+       rcu_read_lock();
+
        ipcp = ipcctl_pre_down_nolock(ns, &sem_ids(ns), semid, cmd,
                                      &semid64.sem_perm, 0);
-       if (IS_ERR(ipcp))
-               return PTR_ERR(ipcp);
+       if (IS_ERR(ipcp)) {
+               err = PTR_ERR(ipcp);
+               /* the ipc lock is not held upon failure */
+               goto out_unlock1;
+       }
 
        sma = container_of(ipcp, struct sem_array, sem_perm);
 
        err = security_sem_semctl(sma, cmd);
-       if (err) {
-               rcu_read_unlock();
-               goto out_up;
-       }
+       if (err)
+               goto out_unlock1;
 
-       switch(cmd){
+       switch (cmd) {
        case IPC_RMID:
                sem_lock(sma, NULL, -1);
+               /* freeary unlocks the ipc object and rcu */
                freeary(ns, ipcp);
                goto out_up;
        case IPC_SET:
                sem_lock(sma, NULL, -1);
                err = ipc_update_perm(&semid64.sem_perm, ipcp);
                if (err)
-                       goto out_unlock;
+                       goto out_unlock0;
                sma->sem_ctime = get_seconds();
                break;
        default:
-               rcu_read_unlock();
                err = -EINVAL;
-               goto out_up;
+               goto out_unlock1;
        }
 
-out_unlock:
+out_unlock0:
        sem_unlock(sma, -1);
+out_unlock1:
        rcu_read_unlock();
 out_up:
        up_write(&sem_ids(ns).rw_mutex);
@@ -1496,7 +1501,7 @@ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid)
        new->semid = semid;
        assert_spin_locked(&ulp->lock);
        list_add_rcu(&new->list_proc, &ulp->list_proc);
-       assert_spin_locked(&sma->sem_perm.lock);
+       ipc_assert_locked_object(&sma->sem_perm);
        list_add(&new->list_id, &sma->list_id);
        un = new;
 
@@ -1833,7 +1838,7 @@ void exit_sem(struct task_struct *tsk)
                }
 
                /* remove un from the linked lists */
-               assert_spin_locked(&sma->sem_perm.lock);
+               ipc_assert_locked_object(&sma->sem_perm);
                list_del(&un->list_id);
 
                spin_lock(&ulp->lock);