nbd: Fix timeout detection

[firefly-linux-kernel-4.4.55.git] / drivers / block / nbd.c

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index f169faf9838a74f83136379f0528fe3ae30976aa..f3536e68e63fd9afa2e272d406eeac9b6dab9a94 100644 (file)
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -59,6 +59,10 @@ struct nbd_device {
        pid_t pid; /* pid of nbd-client, if attached */
        int xmit_timeout;
        int disconnect; /* a disconnect has been requested by user */
+
+       struct timer_list timeout_timer;
+       struct task_struct *task_recv;
+       struct task_struct *task_send;
 };
 
 #define NBD_MAGIC 0x68797548
@@ -121,6 +125,7 @@ static void sock_shutdown(struct nbd_device *nbd, int lock)
                dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
                kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
                nbd->sock = NULL;
+               del_timer_sync(&nbd->timeout_timer);
        }
        if (lock)
                mutex_unlock(&nbd->tx_lock);
@@ -128,11 +133,23 @@ static void sock_shutdown(struct nbd_device *nbd, int lock)
 
 static void nbd_xmit_timeout(unsigned long arg)
 {
-       struct task_struct *task = (struct task_struct *)arg;
+       struct nbd_device *nbd = (struct nbd_device *)arg;
+       struct task_struct *task;
+
+       if (list_empty(&nbd->queue_head))
+               return;
+
+       nbd->disconnect = 1;
+
+       task = READ_ONCE(nbd->task_recv);
+       if (task)
+               force_sig(SIGKILL, task);
 
-       printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n",
-               task->comm, task->pid);
-       force_sig(SIGKILL, task);
+       task = READ_ONCE(nbd->task_send);
+       if (task)
+               force_sig(SIGKILL, nbd->task_send);
+
+       dev_err(nbd_to_dev(nbd), "Connection timed out, killed receiver and sender, shutting down connection\n");
 }
 
 /*
@@ -171,33 +188,12 @@ static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size,
                msg.msg_controllen = 0;
                msg.msg_flags = msg_flags | MSG_NOSIGNAL;
 
-               if (send) {
-                       struct timer_list ti;
-
-                       if (nbd->xmit_timeout) {
-                               init_timer(&ti);
-                               ti.function = nbd_xmit_timeout;
-                               ti.data = (unsigned long)current;
-                               ti.expires = jiffies + nbd->xmit_timeout;
-                               add_timer(&ti);
-                       }
+               if (send)
                        result = kernel_sendmsg(sock, &msg, &iov, 1, size);
-                       if (nbd->xmit_timeout)
-                               del_timer_sync(&ti);
-               } else
+               else
                        result = kernel_recvmsg(sock, &msg, &iov, 1, size,
                                                msg.msg_flags);
 
-               if (signal_pending(current)) {
-                       siginfo_t info;
-                       printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n",
-                               task_pid_nr(current), current->comm,
-                               dequeue_signal_lock(current, &current->blocked, &info));
-                       result = -EINTR;
-                       sock_shutdown(nbd, !send);
-                       break;
-               }
-
                if (result <= 0) {
                        if (result == 0)
                                result = -EPIPE; /* short read */
@@ -210,6 +206,9 @@ static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size,
        sigprocmask(SIG_SETMASK, &oldset, NULL);
        tsk_restore_flags(current, pflags, PF_MEMALLOC);
 
+       if (!send && nbd->xmit_timeout)
+               mod_timer(&nbd->timeout_timer, jiffies + nbd->xmit_timeout);
+
        return result;
 }
 
@@ -415,12 +414,26 @@ static int nbd_do_it(struct nbd_device *nbd)
                return ret;
        }
 
+       nbd->task_recv = current;
+
        while ((req = nbd_read_stat(nbd)) != NULL)
                nbd_end_request(nbd, req);
 
+       nbd->task_recv = NULL;
+
+       if (signal_pending(current)) {
+               siginfo_t info;
+
+               ret = dequeue_signal_lock(current, &current->blocked, &info);
+               dev_warn(nbd_to_dev(nbd), "pid %d, %s, got signal %d\n",
+                        task_pid_nr(current), current->comm, ret);
+               sock_shutdown(nbd, 1);
+               ret = -ETIMEDOUT;
+       }
+
        device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
        nbd->pid = 0;
-       return 0;
+       return ret;
 }
 
 static void nbd_clear_que(struct nbd_device *nbd)
@@ -482,6 +495,9 @@ static void nbd_handle_req(struct nbd_device *nbd, struct request *req)
 
        nbd->active_req = req;
 
+       if (nbd->xmit_timeout && list_empty_careful(&nbd->queue_head))
+               mod_timer(&nbd->timeout_timer, jiffies + nbd->xmit_timeout);
+
        if (nbd_send_req(nbd, req) != 0) {
                dev_err(disk_to_dev(nbd->disk), "Request send failed\n");
                req->errors++;
@@ -508,6 +524,8 @@ static int nbd_thread(void *data)
        struct nbd_device *nbd = data;
        struct request *req;
 
+       nbd->task_send = current;
+
        set_user_nice(current, MIN_NICE);
        while (!kthread_should_stop() || !list_empty(&nbd->waiting_queue)) {
                /* wait for something to do */
@@ -515,6 +533,18 @@ static int nbd_thread(void *data)
                                         kthread_should_stop() ||
                                         !list_empty(&nbd->waiting_queue));
 
+               if (signal_pending(current)) {
+                       siginfo_t info;
+                       int ret;
+
+                       ret = dequeue_signal_lock(current, &current->blocked,
+                                                 &info);
+                       dev_warn(nbd_to_dev(nbd), "pid %d, %s, got signal %d\n",
+                                task_pid_nr(current), current->comm, ret);
+                       sock_shutdown(nbd, 1);
+                       break;
+               }
+
                /* extract request */
                if (list_empty(&nbd->waiting_queue))
                        continue;
@@ -528,6 +558,9 @@ static int nbd_thread(void *data)
                /* handle request */
                nbd_handle_req(nbd, req);
        }
+
+       nbd->task_send = NULL;
+
        return 0;
 }
 
@@ -648,6 +681,12 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
 
        case NBD_SET_TIMEOUT:
                nbd->xmit_timeout = arg * HZ;
+               if (arg)
+                       mod_timer(&nbd->timeout_timer,
+                                 jiffies + nbd->xmit_timeout);
+               else
+                       del_timer_sync(&nbd->timeout_timer);
+
                return 0;
 
        case NBD_SET_FLAGS:
@@ -842,6 +881,9 @@ static int __init nbd_init(void)
                spin_lock_init(&nbd_dev[i].queue_lock);
                INIT_LIST_HEAD(&nbd_dev[i].queue_head);
                mutex_init(&nbd_dev[i].tx_lock);
+               init_timer(&nbd_dev[i].timeout_timer);
+               nbd_dev[i].timeout_timer.function = nbd_xmit_timeout;
+               nbd_dev[i].timeout_timer.data = (unsigned long)&nbd_dev[i];
                init_waitqueue_head(&nbd_dev[i].active_wq);
                init_waitqueue_head(&nbd_dev[i].waiting_wq);
                nbd_dev[i].blksize = 1024;