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Date: Tue, 3 May 2016 19:38:26 +0300
From: "Pranay Kr. Srivastava" <pranjas@...il.com>
To: mpa@...gutronix.de, nbd-general@...ts.sourceforge.net,
linux-kernel@...r.kernel.org, gregkh@...uxfoundation.org
Cc: "Pranay Kr. Srivastava" <pranjas@...il.com>
Subject: [PATCH v2 1/2] nbd: Fix might_sleep warning on xmit timeout
This patch fixes the warning generated when a timeout occurs
on the request and socket is closed from a non-sleep context
by
1. Moving the socket closing on a timeout to nbd_thread_send
2. Make sock lock to be a mutex instead of a spin lock, since
nbd_xmit_timeout doesn't need to hold it anymore.
Signed-off-by: Pranay Kr. Srivastava <pranjas@...il.com>
---
drivers/block/nbd.c | 65 ++++++++++++++++++++++++++++++++---------------------
1 file changed, 39 insertions(+), 26 deletions(-)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 31e73a7..c79bcd7 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -57,12 +57,12 @@ struct nbd_device {
int blksize;
loff_t bytesize;
int xmit_timeout;
- bool timedout;
+ atomic_t timedout;
bool disconnect; /* a disconnect has been requested by user */
struct timer_list timeout_timer;
/* protects initialization and shutdown of the socket */
- spinlock_t sock_lock;
+ struct mutex sock_lock;
struct task_struct *task_recv;
struct task_struct *task_send;
@@ -172,10 +172,9 @@ static void nbd_end_request(struct nbd_device *nbd, struct request *req)
*/
static void sock_shutdown(struct nbd_device *nbd)
{
- spin_lock_irq(&nbd->sock_lock);
-
+ mutex_lock(&nbd->sock_lock);
if (!nbd->sock) {
- spin_unlock_irq(&nbd->sock_lock);
+ mutex_unlock(&nbd->sock_lock);
return;
}
@@ -183,27 +182,19 @@ static void sock_shutdown(struct nbd_device *nbd)
kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
sockfd_put(nbd->sock);
nbd->sock = NULL;
- spin_unlock_irq(&nbd->sock_lock);
-
+ mutex_unlock(&nbd->sock_lock);
del_timer(&nbd->timeout_timer);
}
static void nbd_xmit_timeout(unsigned long arg)
{
struct nbd_device *nbd = (struct nbd_device *)arg;
- unsigned long flags;
if (list_empty(&nbd->queue_head))
return;
- spin_lock_irqsave(&nbd->sock_lock, flags);
-
- nbd->timedout = true;
-
- if (nbd->sock)
- kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
-
- spin_unlock_irqrestore(&nbd->sock_lock, flags);
+ atomic_inc(&nbd->timedout);
+ wake_up(&nbd->waiting_wq);
dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down connection\n");
}
@@ -579,7 +570,27 @@ static int nbd_thread_send(void *data)
/* wait for something to do */
wait_event_interruptible(nbd->waiting_wq,
kthread_should_stop() ||
- !list_empty(&nbd->waiting_queue));
+ !list_empty(&nbd->waiting_queue) ||
+ atomic_read(&nbd->timedout));
+
+ if (atomic_read(&nbd->timedout)) {
+ mutex_lock(&nbd->sock_lock);
+ if (nbd->sock) {
+ struct request sreq;
+
+ blk_rq_init(NULL, &sreq);
+ sreq.cmd_type = REQ_TYPE_DRV_PRIV;
+ mutex_lock(&nbd->tx_lock);
+ nbd->disconnect = true;
+ nbd_send_req(nbd, &sreq);
+ mutex_unlock(&nbd->tx_lock);
+ dev_err(disk_to_dev(nbd->disk),
+ "Device Timeout occured.Shutting down"
+ " socket.");
+ }
+ mutex_unlock(&nbd->sock_lock);
+ sock_shutdown(nbd);
+ }
/* extract request */
if (list_empty(&nbd->waiting_queue))
@@ -592,7 +603,11 @@ static int nbd_thread_send(void *data)
spin_unlock_irq(&nbd->queue_lock);
/* handle request */
- nbd_handle_req(nbd, req);
+ if (atomic_read(&nbd->timedout)) {
+ req->errors++;
+ nbd_end_request(nbd, req);
+ } else
+ nbd_handle_req(nbd, req);
}
nbd->task_send = NULL;
@@ -647,7 +662,7 @@ static int nbd_set_socket(struct nbd_device *nbd, struct socket *sock)
{
int ret = 0;
- spin_lock_irq(&nbd->sock_lock);
+ mutex_lock(&nbd->sock_lock);
if (nbd->sock) {
ret = -EBUSY;
@@ -657,7 +672,7 @@ static int nbd_set_socket(struct nbd_device *nbd, struct socket *sock)
nbd->sock = sock;
out:
- spin_unlock_irq(&nbd->sock_lock);
+ mutex_unlock(&nbd->sock_lock);
return ret;
}
@@ -666,7 +681,7 @@ out:
static void nbd_reset(struct nbd_device *nbd)
{
nbd->disconnect = false;
- nbd->timedout = false;
+ atomic_set(&nbd->timedout, 0);
nbd->blksize = 1024;
nbd->bytesize = 0;
set_capacity(nbd->disk, 0);
@@ -803,17 +818,15 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
error = nbd_thread_recv(nbd, bdev);
nbd_dev_dbg_close(nbd);
kthread_stop(thread);
-
- mutex_lock(&nbd->tx_lock);
-
sock_shutdown(nbd);
+ mutex_lock(&nbd->tx_lock);
nbd_clear_que(nbd);
kill_bdev(bdev);
nbd_bdev_reset(bdev);
if (nbd->disconnect) /* user requested, ignore socket errors */
error = 0;
- if (nbd->timedout)
+ if (atomic_read(&nbd->timedout))
error = -ETIMEDOUT;
nbd_reset(nbd);
@@ -1075,7 +1088,7 @@ 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].sock_lock);
+ mutex_init(&nbd_dev[i].sock_lock);
INIT_LIST_HEAD(&nbd_dev[i].queue_head);
mutex_init(&nbd_dev[i].tx_lock);
init_timer(&nbd_dev[i].timeout_timer);
--
2.6.2
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