Fix might sleep warning.
Subsystems (2)
PATCH 1/1 Fix might sleep warning.
When an nbd request times out then the nbd_xmit_timeout tries to close the socket by taking a spin_lock over the socket. This however generates a warning on kernel_sock_shutdown. This patch fixes this issue.
Pranay Kr. Srivastava (1):
fix might_sleep warning on socket shutdown
drivers/block/nbd.c | 85 +++++++++++++++++++++++++++++++---------------------- 1 file changed, 50 insertions(+), 35 deletions(-)
Signature · 1 line
2.6.2
PATCH 1/1 fix might_sleep warning on socket shutdown
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.
3. Move sock_shutdown outside the tx_lock in NBD_DO_IT.
--- drivers/block/nbd.c | 85 +++++++++++++++++++++++++++++++---------------------- 1 file changed, 50 insertions(+), 35 deletions(-)
drivers/block/nbd.c +50 -35
@@ -3,7 +3,7 @@* * Note that you can not swap over this thing, yet. Seems to work but * deadlocks sometimes - you can not swap over TCP in general. -* +* * Copyright 1997-2000, 2008 Pavel Machek <[email protected]> * Parts copyright 2001 Steven Whitehouse <[email protected]> *
@@ -35,14 +35,14 @@#include <linux/types.h> #include <linux/debugfs.h> -#include <asm/uaccess.h> +#include <linux/uaccess.h> #include <asm/types.h> #include <linux/nbd.h> struct nbd_device {u32 flags; -struct socket * sock;/* If == NULL, device is not ready, yet */ +struct socket *sock;/* If == NULL, device is not ready, yet */ int magic;spinlock_t queue_lock;
@@ -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" ); }
@@ -266,6 +257,7 @@ static inline int sock_send_bvec(struct nbd_device *nbd, struct bio_vec *bvec, {int result;void *kaddr =kmap (bvec->bv_page); + result =sock_xmit (nbd,1 , kaddr + bvec->bv_offset, bvec->bv_len, flags);kunmap (bvec->bv_page);
@@ -278,6 +270,7 @@ static int nbd_send_req(struct nbd_device *nbd, struct request *req)int result, flags;struct nbd_request request;unsigned long size =blk_rq_bytes (req); +u32 type;if (req->cmd_type ==REQ_TYPE_DRV_PRIV )
@@ -363,6 +356,7 @@ static inline int sock_recv_bvec(struct nbd_device *nbd, struct bio_vec *bvec) {int result;void *kaddr =kmap (bvec->bv_page); + result =sock_xmit (nbd,0 , kaddr + bvec->bv_offset, bvec->bv_len,MSG_WAITALL );kunmap (bvec->bv_page);
@@ -579,7 +573,27 @@ 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 +606,11 @@ 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 ;
@@ -601,8 +619,8 @@ static int nbd_thread_send(void *data) }/* -* We always wait for result of write, for now. It would be nice to make it optional -* in future +* We always wait for result of write, for now. +* It would be nice to make it optional in future * if ((rq_data_dir(req) == WRITE) && (nbd->flags & NBD_WRITE_NOCHK)) * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); } */
@@ -611,7 +629,7 @@ static void nbd_request_handler(struct request_queue *q) __releases(q->queue_lock) __acquires(q->queue_lock) {struct request *req; - +while ((req =blk_fetch_request (q)) !=NULL ) {struct nbd_device *nbd;
@@ -647,7 +665,7 @@ 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 +675,7 @@ 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 +684,7 @@ 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 );
@@ -729,7 +747,7 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,nbd_send_req (nbd, &sreq);return 0 ; } - +case NBD_CLEAR_SOCK :sock_shutdown (nbd);nbd_clear_que (nbd);
@@ -803,17 +821,15 @@ 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);
@@ -856,8 +872,7 @@ static int nbd_ioctl(struct block_device *bdev, fmode_t mode,return error; } -static const struct block_device_operations nbd_fops = -{ +static const struct block_device_operations nbd_fops = { .owner =THIS_MODULE , .ioctl = nbd_ioctl, .compat_ioctl = nbd_ioctl,
@@ -1075,7 +1090,7 @@ 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);
Signature · 1 line
2.6.2