ring-buffer: Do not poll non allocated cpu buffers

[platform/adaptation/renesas_rcar/renesas_kernel.git] / ipc / sem.c

diff --git a/ipc/sem.c b/ipc/sem.c
index 1f8f01a..a7e40ed 100644 (file)
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -269,6 +269,8 @@ static inline void sem_unlock(struct sem_array *sma, int locknum)
 /*
  * sem_lock_(check_) routines are called in the paths where the rw_mutex
  * is not held.
+ *
+ * The caller holds the RCU read lock.
  */
 static inline struct sem_array *sem_obtain_lock(struct ipc_namespace *ns,
                        int id, struct sembuf *sops, int nsops, int *locknum)
@@ -276,12 +278,9 @@ static inline struct sem_array *sem_obtain_lock(struct ipc_namespace *ns,
        struct kern_ipc_perm *ipcp;
        struct sem_array *sma;
 
-       rcu_read_lock();
        ipcp = ipc_obtain_object(&sem_ids(ns), id);
-       if (IS_ERR(ipcp)) {
-               sma = ERR_CAST(ipcp);
-               goto err;
-       }
+       if (IS_ERR(ipcp))
+               return ERR_CAST(ipcp);
 
        sma = container_of(ipcp, struct sem_array, sem_perm);
        *locknum = sem_lock(sma, sops, nsops);
@@ -293,10 +292,7 @@ static inline struct sem_array *sem_obtain_lock(struct ipc_namespace *ns,
                return container_of(ipcp, struct sem_array, sem_perm);
 
        sem_unlock(sma, *locknum);
-       sma = ERR_PTR(-EINVAL);
-err:
-       rcu_read_unlock();
-       return sma;
+       return ERR_PTR(-EINVAL);
 }
 
 static inline struct sem_array *sem_obtain_object(struct ipc_namespace *ns, int id)
@@ -800,6 +796,13 @@ static int count_semncnt (struct sem_array * sma, ushort semnum)
        struct sem_queue * q;
 
        semncnt = 0;
+       list_for_each_entry(q, &sma->sem_base[semnum].sem_pending, list) {
+               struct sembuf * sops = q->sops;
+               BUG_ON(sops->sem_num != semnum);
+               if ((sops->sem_op < 0) && !(sops->sem_flg & IPC_NOWAIT))
+                       semncnt++;
+       }
+
        list_for_each_entry(q, &sma->sem_pending, list) {
                struct sembuf * sops = q->sops;
                int nsops = q->nsops;
@@ -819,6 +822,13 @@ static int count_semzcnt (struct sem_array * sma, ushort semnum)
        struct sem_queue * q;
 
        semzcnt = 0;
+       list_for_each_entry(q, &sma->sem_base[semnum].sem_pending, list) {
+               struct sembuf * sops = q->sops;
+               BUG_ON(sops->sem_num != semnum);
+               if ((sops->sem_op == 0) && !(sops->sem_flg & IPC_NOWAIT))
+                       semzcnt++;
+       }
+
        list_for_each_entry(q, &sma->sem_pending, list) {
                struct sembuf * sops = q->sops;
                int nsops = q->nsops;
@@ -952,8 +962,8 @@ static int semctl_nolock(struct ipc_namespace *ns, int semid,
 
                memset(&tbuf, 0, sizeof(tbuf));
 
+               rcu_read_lock();
                if (cmd == SEM_STAT) {
-                       rcu_read_lock();
                        sma = sem_obtain_object(ns, semid);
                        if (IS_ERR(sma)) {
                                err = PTR_ERR(sma);
@@ -961,7 +971,6 @@ static int semctl_nolock(struct ipc_namespace *ns, int semid,
                        }
                        id = sma->sem_perm.id;
                } else {
-                       rcu_read_lock();
                        sma = sem_obtain_object_check(ns, semid);
                        if (IS_ERR(sma)) {
                                err = PTR_ERR(sma);
@@ -1081,17 +1090,12 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
        nsems = sma->sem_nsems;
 
        err = -EACCES;
-       if (ipcperms(ns, &sma->sem_perm,
-                       cmd == SETALL ? S_IWUGO : S_IRUGO)) {
-               rcu_read_unlock();
-               goto out_wakeup;
-       }
+       if (ipcperms(ns, &sma->sem_perm, cmd == SETALL ? S_IWUGO : S_IRUGO))
+               goto out_rcu_wakeup;
 
        err = security_sem_semctl(sma, cmd);
-       if (err) {
-               rcu_read_unlock();
-               goto out_wakeup;
-       }
+       if (err)
+               goto out_rcu_wakeup;
 
        err = -EACCES;
        switch (cmd) {
@@ -1192,10 +1196,8 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
        /* GETVAL, GETPID, GETNCTN, GETZCNT: fall-through */
        }
        err = -EINVAL;
-       if (semnum < 0 || semnum >= nsems) {
-               rcu_read_unlock();
-               goto out_wakeup;
-       }
+       if (semnum < 0 || semnum >= nsems)
+               goto out_rcu_wakeup;
 
        sem_lock(sma, NULL, -1);
        curr = &sma->sem_base[semnum];
@@ -1217,8 +1219,8 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
 
 out_unlock:
        sem_unlock(sma, -1);
+out_rcu_wakeup:
        rcu_read_unlock();
-out_wakeup:
        wake_up_sem_queue_do(&tasks);
 out_free:
        if(sem_io != fast_sem_io)
@@ -1589,22 +1591,16 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
        }
 
        error = -EFBIG;
-       if (max >= sma->sem_nsems) {
-               rcu_read_unlock();
-               goto out_wakeup;
-       }
+       if (max >= sma->sem_nsems)
+               goto out_rcu_wakeup;
 
        error = -EACCES;
-       if (ipcperms(ns, &sma->sem_perm, alter ? S_IWUGO : S_IRUGO)) {
-               rcu_read_unlock();
-               goto out_wakeup;
-       }
+       if (ipcperms(ns, &sma->sem_perm, alter ? S_IWUGO : S_IRUGO))
+               goto out_rcu_wakeup;
 
        error = security_sem_semop(sma, sops, nsops, alter);
-       if (error) {
-               rcu_read_unlock();
-               goto out_wakeup;
-       }
+       if (error)
+               goto out_rcu_wakeup;
 
        /*
         * semid identifiers are not unique - find_alloc_undo may have
@@ -1680,6 +1676,7 @@ sleep_again:
                goto out_free;
        }
 
+       rcu_read_lock();
        sma = sem_obtain_lock(ns, semid, sops, nsops, &locknum);
 
        /*
@@ -1691,6 +1688,7 @@ sleep_again:
         * Array removed? If yes, leave without sem_unlock().
         */
        if (IS_ERR(sma)) {
+               rcu_read_unlock();
                goto out_free;
        }
 
@@ -1720,8 +1718,8 @@ sleep_again:
 
 out_unlock_free:
        sem_unlock(sma, locknum);
+out_rcu_wakeup:
        rcu_read_unlock();
-out_wakeup:
        wake_up_sem_queue_do(&tasks);
 out_free:
        if(sops != fast_sops)