Merge branch 'akpm-current/current'

[karo-tx-linux.git] / drivers / block / nbd.c

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 214de17d0659f54f21e2b3034a46d690f821a063..93b3f99b6865fe721f7124412553cadf3c328e7a 100644 (file)
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -60,6 +60,7 @@ struct nbd_device {
        bool disconnect; /* a disconnect has been requested by user */
 
        struct timer_list timeout_timer;
+       spinlock_t tasks_lock;
        struct task_struct *task_recv;
        struct task_struct *task_send;
 
@@ -140,21 +141,23 @@ static void sock_shutdown(struct nbd_device *nbd)
 static void nbd_xmit_timeout(unsigned long arg)
 {
        struct nbd_device *nbd = (struct nbd_device *)arg;
-       struct task_struct *task;
+       unsigned long flags;
 
        if (list_empty(&nbd->queue_head))
                return;
 
        nbd->disconnect = true;
 
-       task = READ_ONCE(nbd->task_recv);
-       if (task)
-               force_sig(SIGKILL, task);
+       spin_lock_irqsave(&nbd->tasks_lock, flags);
+
+       if (nbd->task_recv)
+               force_sig(SIGKILL, nbd->task_recv);
 
-       task = READ_ONCE(nbd->task_send);
-       if (task)
+       if (nbd->task_send)
                force_sig(SIGKILL, nbd->task_send);
 
+       spin_unlock_irqrestore(&nbd->tasks_lock, flags);
+
        dev_err(nbd_to_dev(nbd), "Connection timed out, killed receiver and sender, shutting down connection\n");
 }
 
@@ -403,17 +406,24 @@ static int nbd_thread_recv(struct nbd_device *nbd)
 {
        struct request *req;
        int ret;
+       unsigned long flags;
 
        BUG_ON(nbd->magic != NBD_MAGIC);
 
        sk_set_memalloc(nbd->sock->sk);
 
+       spin_lock_irqsave(&nbd->tasks_lock, flags);
        nbd->task_recv = current;
+       spin_unlock_irqrestore(&nbd->tasks_lock, flags);
 
        ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
        if (ret) {
                dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
+
+               spin_lock_irqsave(&nbd->tasks_lock, flags);
                nbd->task_recv = NULL;
+               spin_unlock_irqrestore(&nbd->tasks_lock, flags);
+
                return ret;
        }
 
@@ -429,7 +439,9 @@ static int nbd_thread_recv(struct nbd_device *nbd)
 
        device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
 
+       spin_lock_irqsave(&nbd->tasks_lock, flags);
        nbd->task_recv = NULL;
+       spin_unlock_irqrestore(&nbd->tasks_lock, flags);
 
        if (signal_pending(current)) {
                ret = kernel_dequeue_signal(NULL);
@@ -532,8 +544,11 @@ static int nbd_thread_send(void *data)
 {
        struct nbd_device *nbd = data;
        struct request *req;
+       unsigned long flags;
 
+       spin_lock_irqsave(&nbd->tasks_lock, flags);
        nbd->task_send = current;
+       spin_unlock_irqrestore(&nbd->tasks_lock, flags);
 
        set_user_nice(current, MIN_NICE);
        while (!kthread_should_stop() || !list_empty(&nbd->waiting_queue)) {
@@ -567,7 +582,13 @@ static int nbd_thread_send(void *data)
                nbd_handle_req(nbd, req);
        }
 
+       spin_lock_irqsave(&nbd->tasks_lock, flags);
        nbd->task_send = NULL;
+       spin_unlock_irqrestore(&nbd->tasks_lock, flags);
+
+       /* Clear maybe pending signals */
+       if (signal_pending(current))
+               kernel_dequeue_signal(NULL);
 
        return 0;
 }
@@ -1047,6 +1068,7 @@ static int __init nbd_init(void)
                nbd_dev[i].magic = NBD_MAGIC;
                INIT_LIST_HEAD(&nbd_dev[i].waiting_queue);
                spin_lock_init(&nbd_dev[i].queue_lock);
+               spin_lock_init(&nbd_dev[i].tasks_lock);
                INIT_LIST_HEAD(&nbd_dev[i].queue_head);
                mutex_init(&nbd_dev[i].tx_lock);
                init_timer(&nbd_dev[i].timeout_timer);