subject:"\[PATCH v2 1\/5\] nbd\: fix might_sleep warning on socket shutdown."

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

2016-06-14 Thread Pranay Srivastava

Hi

On Tue, Jun 14, 2016 at 2:22 PM, Markus Pargmann  wrote:
> Hi,
>
> On Thursday 02 June 2016 13:24:57 Pranay Kr. Srivastava wrote:
>> spinlocked ranges should be small and not contain calls into huge
>> subfunctions. Fix my mistake and just get the pointer to the socket
>> instead of doing everything with spinlock held.
>>
>> Reported-by: Mikulas Patocka 
>> Signed-off-by: Markus Pargmann 
>>
>> Changelog:
>> Pranay Kr. Srivastava:
>>
>> 1) Use spin_lock instead of irq version for sock_shutdown.
>>
>> 2) Use system work queue to actually trigger the shutdown of
>>socket. This solves the issue when kernel_sendmsg is currently
>>blocked while a timeout occurs.
>>
>> Signed-off-by: Pranay Kr. Srivastava 
>
> This looks better. Some smaller things inline. Also this patch does not
> apply on my tree anymore. Can you please rebase it onto:
> 
> http://git.pengutronix.de/?p=mpa/linux-nbd.git;a=shortlog;h=refs/heads/master
>

Ok will do.

>> ---
>>  drivers/block/nbd.c | 65 
>> ++---
>>  1 file changed, 42 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
>> index 31e73a7..0339d40 100644
>> --- a/drivers/block/nbd.c
>> +++ b/drivers/block/nbd.c
>> @@ -39,6 +39,7 @@
>>  #include 
>>
>>  #include 
>> +#include 
>>
>>  struct nbd_device {
>>   u32 flags;
>> @@ -69,6 +70,10 @@ struct nbd_device {
>>  #if IS_ENABLED(CONFIG_DEBUG_FS)
>>   struct dentry *dbg_dir;
>>  #endif
>> + /*
>> +  *This is specifically for calling sock_shutdown, for now.
>> +  */
>> + struct work_struct ws_shutdown;
>>  };
>>
>>  #if IS_ENABLED(CONFIG_DEBUG_FS)
>> @@ -95,6 +100,11 @@ static int max_part;
>>   */
>>  static DEFINE_SPINLOCK(nbd_lock);
>>
>> +/*
>> + * Shutdown function for nbd_dev work struct.
>> + */
>> +static void nbd_ws_func_shutdown(struct work_struct *);
>> +
>>  static inline struct device *nbd_to_dev(struct nbd_device *nbd)
>>  {
>>   return disk_to_dev(nbd->disk);
>> @@ -172,39 +182,35 @@ static void nbd_end_request(struct nbd_device *nbd, 
>> struct request *req)
>>   */
>>  static void sock_shutdown(struct nbd_device *nbd)
>>  {
>> - spin_lock_irq(>sock_lock);
>> -
>> - if (!nbd->sock) {
>> - spin_unlock_irq(>sock_lock);
>> - return;
>> - }
>> + struct socket *sock;
>>
>> - dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
>> - kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
>> - sockfd_put(nbd->sock);
>> + spin_lock(>sock_lock);
>> + sock = nbd->sock;
>>   nbd->sock = NULL;
>> - spin_unlock_irq(>sock_lock);
>> + spin_unlock(>sock_lock);
>> +
>> + if (!sock)
>> + return;
>>
>>   del_timer(>timeout_timer);
>> + dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
>> + kernel_sock_shutdown(sock, SHUT_RDWR);
>> + sockfd_put(sock);
>>  }
>>
>>  static void nbd_xmit_timeout(unsigned long arg)
>>  {
>>   struct nbd_device *nbd = (struct nbd_device *)arg;
>> - unsigned long flags;
>>
>>   if (list_empty(>queue_head))
>>   return;
>> -
>> - spin_lock_irqsave(>sock_lock, flags);
>> -
>>   nbd->timedout = true;
>> -
>> - if (nbd->sock)
>> - kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
>> -
>> - spin_unlock_irqrestore(>sock_lock, flags);
>> -
>> + schedule_work(>ws_shutdown);
>> + /*
>> +  * Make sure sender thread sees nbd->timedout.
>> +  */
>> + smp_wmb();
>
> I am not sure that we need this memory barrier here. But as it is just
> the timeout path it probably won't hurt.
>
>> + wake_up(>waiting_wq);
>>   dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down 
>> connection\n");
>>  }
>>
>> @@ -592,7 +598,11 @@ static int nbd_thread_send(void *data)
>>   spin_unlock_irq(>queue_lock);
>>
>>   /* handle request */
>> - nbd_handle_req(nbd, req);
>> + if (nbd->timedout) {
>> + req->errors++;
>> + nbd_end_request(nbd, req);
>> + } else
>> + nbd_handle_req(nbd, req);
>>   }
>>
>>   nbd->task_send = NULL;
>> @@ -672,6 +682,7 @@ static void nbd_reset(struct nbd_device *nbd)
>>   set_capacity(nbd->disk, 0);
>>   nbd->flags = 0;
>>   nbd->xmit_timeout = 0;
>> + INIT_WORK(>ws_shutdown, nbd_ws_func_shutdown);
>>   queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
>>   del_timer_sync(>timeout_timer);
>>  }
>> @@ -804,15 +815,15 @@ static int __nbd_ioctl(struct block_device *bdev, 
>> struct nbd_device *nbd,
>>   nbd_dev_dbg_close(nbd);
>>   kthread_stop(thread);
>>
>> - mutex_lock(>tx_lock);
>> -
>>   sock_shutdown(nbd);
>> + mutex_lock(>tx_lock);
>>   nbd_clear_que(nbd);

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

2016-06-14 Thread Pranay Srivastava

Hi

On Tue, Jun 14, 2016 at 2:22 PM, Markus Pargmann  wrote:
> Hi,
>
> On Thursday 02 June 2016 13:24:57 Pranay Kr. Srivastava wrote:
>> spinlocked ranges should be small and not contain calls into huge
>> subfunctions. Fix my mistake and just get the pointer to the socket
>> instead of doing everything with spinlock held.
>>
>> Reported-by: Mikulas Patocka 
>> Signed-off-by: Markus Pargmann 
>>
>> Changelog:
>> Pranay Kr. Srivastava:
>>
>> 1) Use spin_lock instead of irq version for sock_shutdown.
>>
>> 2) Use system work queue to actually trigger the shutdown of
>>socket. This solves the issue when kernel_sendmsg is currently
>>blocked while a timeout occurs.
>>
>> Signed-off-by: Pranay Kr. Srivastava 
>
> This looks better. Some smaller things inline. Also this patch does not
> apply on my tree anymore. Can you please rebase it onto:
> 
> http://git.pengutronix.de/?p=mpa/linux-nbd.git;a=shortlog;h=refs/heads/master
>

Ok will do.

>> ---
>>  drivers/block/nbd.c | 65 
>> ++---
>>  1 file changed, 42 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
>> index 31e73a7..0339d40 100644
>> --- a/drivers/block/nbd.c
>> +++ b/drivers/block/nbd.c
>> @@ -39,6 +39,7 @@
>>  #include 
>>
>>  #include 
>> +#include 
>>
>>  struct nbd_device {
>>   u32 flags;
>> @@ -69,6 +70,10 @@ struct nbd_device {
>>  #if IS_ENABLED(CONFIG_DEBUG_FS)
>>   struct dentry *dbg_dir;
>>  #endif
>> + /*
>> +  *This is specifically for calling sock_shutdown, for now.
>> +  */
>> + struct work_struct ws_shutdown;
>>  };
>>
>>  #if IS_ENABLED(CONFIG_DEBUG_FS)
>> @@ -95,6 +100,11 @@ static int max_part;
>>   */
>>  static DEFINE_SPINLOCK(nbd_lock);
>>
>> +/*
>> + * Shutdown function for nbd_dev work struct.
>> + */
>> +static void nbd_ws_func_shutdown(struct work_struct *);
>> +
>>  static inline struct device *nbd_to_dev(struct nbd_device *nbd)
>>  {
>>   return disk_to_dev(nbd->disk);
>> @@ -172,39 +182,35 @@ static void nbd_end_request(struct nbd_device *nbd, 
>> struct request *req)
>>   */
>>  static void sock_shutdown(struct nbd_device *nbd)
>>  {
>> - spin_lock_irq(>sock_lock);
>> -
>> - if (!nbd->sock) {
>> - spin_unlock_irq(>sock_lock);
>> - return;
>> - }
>> + struct socket *sock;
>>
>> - dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
>> - kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
>> - sockfd_put(nbd->sock);
>> + spin_lock(>sock_lock);
>> + sock = nbd->sock;
>>   nbd->sock = NULL;
>> - spin_unlock_irq(>sock_lock);
>> + spin_unlock(>sock_lock);
>> +
>> + if (!sock)
>> + return;
>>
>>   del_timer(>timeout_timer);
>> + dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
>> + kernel_sock_shutdown(sock, SHUT_RDWR);
>> + sockfd_put(sock);
>>  }
>>
>>  static void nbd_xmit_timeout(unsigned long arg)
>>  {
>>   struct nbd_device *nbd = (struct nbd_device *)arg;
>> - unsigned long flags;
>>
>>   if (list_empty(>queue_head))
>>   return;
>> -
>> - spin_lock_irqsave(>sock_lock, flags);
>> -
>>   nbd->timedout = true;
>> -
>> - if (nbd->sock)
>> - kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
>> -
>> - spin_unlock_irqrestore(>sock_lock, flags);
>> -
>> + schedule_work(>ws_shutdown);
>> + /*
>> +  * Make sure sender thread sees nbd->timedout.
>> +  */
>> + smp_wmb();
>
> I am not sure that we need this memory barrier here. But as it is just
> the timeout path it probably won't hurt.
>
>> + wake_up(>waiting_wq);
>>   dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down 
>> connection\n");
>>  }
>>
>> @@ -592,7 +598,11 @@ static int nbd_thread_send(void *data)
>>   spin_unlock_irq(>queue_lock);
>>
>>   /* handle request */
>> - nbd_handle_req(nbd, req);
>> + if (nbd->timedout) {
>> + req->errors++;
>> + nbd_end_request(nbd, req);
>> + } else
>> + nbd_handle_req(nbd, req);
>>   }
>>
>>   nbd->task_send = NULL;
>> @@ -672,6 +682,7 @@ static void nbd_reset(struct nbd_device *nbd)
>>   set_capacity(nbd->disk, 0);
>>   nbd->flags = 0;
>>   nbd->xmit_timeout = 0;
>> + INIT_WORK(>ws_shutdown, nbd_ws_func_shutdown);
>>   queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
>>   del_timer_sync(>timeout_timer);
>>  }
>> @@ -804,15 +815,15 @@ static int __nbd_ioctl(struct block_device *bdev, 
>> struct nbd_device *nbd,
>>   nbd_dev_dbg_close(nbd);
>>   kthread_stop(thread);
>>
>> - mutex_lock(>tx_lock);
>> -
>>   sock_shutdown(nbd);
>> + mutex_lock(>tx_lock);
>>   nbd_clear_que(nbd);
>>   kill_bdev(bdev);
>>   nbd_bdev_reset(bdev);
>>
>>   if

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

2016-06-14 Thread Markus Pargmann

Hi,

On Thursday 02 June 2016 13:24:57 Pranay Kr. Srivastava wrote:
> spinlocked ranges should be small and not contain calls into huge
> subfunctions. Fix my mistake and just get the pointer to the socket
> instead of doing everything with spinlock held.
> 
> Reported-by: Mikulas Patocka 
> Signed-off-by: Markus Pargmann 
> 
> Changelog:
> Pranay Kr. Srivastava:
> 
> 1) Use spin_lock instead of irq version for sock_shutdown.
> 
> 2) Use system work queue to actually trigger the shutdown of
>socket. This solves the issue when kernel_sendmsg is currently
>blocked while a timeout occurs.
> 
> Signed-off-by: Pranay Kr. Srivastava 

This looks better. Some smaller things inline. Also this patch does not
apply on my tree anymore. Can you please rebase it onto:

http://git.pengutronix.de/?p=mpa/linux-nbd.git;a=shortlog;h=refs/heads/master

> ---
>  drivers/block/nbd.c | 65 
> ++---
>  1 file changed, 42 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 31e73a7..0339d40 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -39,6 +39,7 @@
>  #include 
>  
>  #include 
> +#include 
>  
>  struct nbd_device {
>   u32 flags;
> @@ -69,6 +70,10 @@ struct nbd_device {
>  #if IS_ENABLED(CONFIG_DEBUG_FS)
>   struct dentry *dbg_dir;
>  #endif
> + /*
> +  *This is specifically for calling sock_shutdown, for now.
> +  */
> + struct work_struct ws_shutdown;
>  };
>  
>  #if IS_ENABLED(CONFIG_DEBUG_FS)
> @@ -95,6 +100,11 @@ static int max_part;
>   */
>  static DEFINE_SPINLOCK(nbd_lock);
>  
> +/*
> + * Shutdown function for nbd_dev work struct.
> + */
> +static void nbd_ws_func_shutdown(struct work_struct *);
> +
>  static inline struct device *nbd_to_dev(struct nbd_device *nbd)
>  {
>   return disk_to_dev(nbd->disk);
> @@ -172,39 +182,35 @@ static void nbd_end_request(struct nbd_device *nbd, 
> struct request *req)
>   */
>  static void sock_shutdown(struct nbd_device *nbd)
>  {
> - spin_lock_irq(>sock_lock);
> -
> - if (!nbd->sock) {
> - spin_unlock_irq(>sock_lock);
> - return;
> - }
> + struct socket *sock;
>  
> - dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
> - kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
> - sockfd_put(nbd->sock);
> + spin_lock(>sock_lock);
> + sock = nbd->sock;
>   nbd->sock = NULL;
> - spin_unlock_irq(>sock_lock);
> + spin_unlock(>sock_lock);
> +
> + if (!sock)
> + return;
>  
>   del_timer(>timeout_timer);
> + dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
> + kernel_sock_shutdown(sock, SHUT_RDWR);
> + sockfd_put(sock);
>  }
>  
>  static void nbd_xmit_timeout(unsigned long arg)
>  {
>   struct nbd_device *nbd = (struct nbd_device *)arg;
> - unsigned long flags;
>  
>   if (list_empty(>queue_head))
>   return;
> -
> - spin_lock_irqsave(>sock_lock, flags);
> -
>   nbd->timedout = true;
> -
> - if (nbd->sock)
> - kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
> -
> - spin_unlock_irqrestore(>sock_lock, flags);
> -
> + schedule_work(>ws_shutdown);
> + /*
> +  * Make sure sender thread sees nbd->timedout.
> +  */
> + smp_wmb();

I am not sure that we need this memory barrier here. But as it is just
the timeout path it probably won't hurt.

> + wake_up(>waiting_wq);
>   dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down 
> connection\n");
>  }
>  
> @@ -592,7 +598,11 @@ static int nbd_thread_send(void *data)
>   spin_unlock_irq(>queue_lock);
>  
>   /* handle request */
> - nbd_handle_req(nbd, req);
> + if (nbd->timedout) {
> + req->errors++;
> + nbd_end_request(nbd, req);
> + } else
> + nbd_handle_req(nbd, req);
>   }
>  
>   nbd->task_send = NULL;
> @@ -672,6 +682,7 @@ static void nbd_reset(struct nbd_device *nbd)
>   set_capacity(nbd->disk, 0);
>   nbd->flags = 0;
>   nbd->xmit_timeout = 0;
> + INIT_WORK(>ws_shutdown, nbd_ws_func_shutdown);
>   queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
>   del_timer_sync(>timeout_timer);
>  }
> @@ -804,15 +815,15 @@ static int __nbd_ioctl(struct block_device *bdev, 
> struct nbd_device *nbd,
>   nbd_dev_dbg_close(nbd);
>   kthread_stop(thread);
>  
> - mutex_lock(>tx_lock);
> -
>   sock_shutdown(nbd);
> + mutex_lock(>tx_lock);
>   nbd_clear_que(nbd);
>   kill_bdev(bdev);
>   nbd_bdev_reset(bdev);
>  
>   if (nbd->disconnect) /* user requested, ignore socket errors */
>   error = 0;
> +

Random newline here.

Best Regards,

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

2016-06-14 Thread Markus Pargmann

Hi,

On Thursday 02 June 2016 13:24:57 Pranay Kr. Srivastava wrote:
> spinlocked ranges should be small and not contain calls into huge
> subfunctions. Fix my mistake and just get the pointer to the socket
> instead of doing everything with spinlock held.
> 
> Reported-by: Mikulas Patocka 
> Signed-off-by: Markus Pargmann 
> 
> Changelog:
> Pranay Kr. Srivastava:
> 
> 1) Use spin_lock instead of irq version for sock_shutdown.
> 
> 2) Use system work queue to actually trigger the shutdown of
>socket. This solves the issue when kernel_sendmsg is currently
>blocked while a timeout occurs.
> 
> Signed-off-by: Pranay Kr. Srivastava 

This looks better. Some smaller things inline. Also this patch does not
apply on my tree anymore. Can you please rebase it onto:

http://git.pengutronix.de/?p=mpa/linux-nbd.git;a=shortlog;h=refs/heads/master

> ---
>  drivers/block/nbd.c | 65 
> ++---
>  1 file changed, 42 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 31e73a7..0339d40 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -39,6 +39,7 @@
>  #include 
>  
>  #include 
> +#include 
>  
>  struct nbd_device {
>   u32 flags;
> @@ -69,6 +70,10 @@ struct nbd_device {
>  #if IS_ENABLED(CONFIG_DEBUG_FS)
>   struct dentry *dbg_dir;
>  #endif
> + /*
> +  *This is specifically for calling sock_shutdown, for now.
> +  */
> + struct work_struct ws_shutdown;
>  };
>  
>  #if IS_ENABLED(CONFIG_DEBUG_FS)
> @@ -95,6 +100,11 @@ static int max_part;
>   */
>  static DEFINE_SPINLOCK(nbd_lock);
>  
> +/*
> + * Shutdown function for nbd_dev work struct.
> + */
> +static void nbd_ws_func_shutdown(struct work_struct *);
> +
>  static inline struct device *nbd_to_dev(struct nbd_device *nbd)
>  {
>   return disk_to_dev(nbd->disk);
> @@ -172,39 +182,35 @@ static void nbd_end_request(struct nbd_device *nbd, 
> struct request *req)
>   */
>  static void sock_shutdown(struct nbd_device *nbd)
>  {
> - spin_lock_irq(>sock_lock);
> -
> - if (!nbd->sock) {
> - spin_unlock_irq(>sock_lock);
> - return;
> - }
> + struct socket *sock;
>  
> - dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
> - kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
> - sockfd_put(nbd->sock);
> + spin_lock(>sock_lock);
> + sock = nbd->sock;
>   nbd->sock = NULL;
> - spin_unlock_irq(>sock_lock);
> + spin_unlock(>sock_lock);
> +
> + if (!sock)
> + return;
>  
>   del_timer(>timeout_timer);
> + dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
> + kernel_sock_shutdown(sock, SHUT_RDWR);
> + sockfd_put(sock);
>  }
>  
>  static void nbd_xmit_timeout(unsigned long arg)
>  {
>   struct nbd_device *nbd = (struct nbd_device *)arg;
> - unsigned long flags;
>  
>   if (list_empty(>queue_head))
>   return;
> -
> - spin_lock_irqsave(>sock_lock, flags);
> -
>   nbd->timedout = true;
> -
> - if (nbd->sock)
> - kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
> -
> - spin_unlock_irqrestore(>sock_lock, flags);
> -
> + schedule_work(>ws_shutdown);
> + /*
> +  * Make sure sender thread sees nbd->timedout.
> +  */
> + smp_wmb();

I am not sure that we need this memory barrier here. But as it is just
the timeout path it probably won't hurt.

> + wake_up(>waiting_wq);
>   dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down 
> connection\n");
>  }
>  
> @@ -592,7 +598,11 @@ static int nbd_thread_send(void *data)
>   spin_unlock_irq(>queue_lock);
>  
>   /* handle request */
> - nbd_handle_req(nbd, req);
> + if (nbd->timedout) {
> + req->errors++;
> + nbd_end_request(nbd, req);
> + } else
> + nbd_handle_req(nbd, req);
>   }
>  
>   nbd->task_send = NULL;
> @@ -672,6 +682,7 @@ static void nbd_reset(struct nbd_device *nbd)
>   set_capacity(nbd->disk, 0);
>   nbd->flags = 0;
>   nbd->xmit_timeout = 0;
> + INIT_WORK(>ws_shutdown, nbd_ws_func_shutdown);
>   queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
>   del_timer_sync(>timeout_timer);
>  }
> @@ -804,15 +815,15 @@ static int __nbd_ioctl(struct block_device *bdev, 
> struct nbd_device *nbd,
>   nbd_dev_dbg_close(nbd);
>   kthread_stop(thread);
>  
> - mutex_lock(>tx_lock);
> -
>   sock_shutdown(nbd);
> + mutex_lock(>tx_lock);
>   nbd_clear_que(nbd);
>   kill_bdev(bdev);
>   nbd_bdev_reset(bdev);
>  
>   if (nbd->disconnect) /* user requested, ignore socket errors */
>   error = 0;
> +

Random newline here.

Best Regards,

Markus

>   if (nbd->timedout)
>   error =

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

2016-06-13 Thread Pranay Srivastava

Hello,

On Thu, Jun 9, 2016 at 3:33 PM, Pranay Srivastava  wrote:
>
> Hello
>
>
> On Thu, Jun 2, 2016 at 3:54 PM, Pranay Kr. Srivastava  
> wrote:
> > spinlocked ranges should be small and not contain calls into huge
> > subfunctions. Fix my mistake and just get the pointer to the socket
> > instead of doing everything with spinlock held.
> >
> > Reported-by: Mikulas Patocka 
> > Signed-off-by: Markus Pargmann 
> >
> > Changelog:
> > Pranay Kr. Srivastava:
> >
> > 1) Use spin_lock instead of irq version for sock_shutdown.
> >
> > 2) Use system work queue to actually trigger the shutdown of
> >socket. This solves the issue when kernel_sendmsg is currently
> >blocked while a timeout occurs.
> >
> > Signed-off-by: Pranay Kr. Srivastava 
> > ---
> >  drivers/block/nbd.c | 65 
> > ++---
> >  1 file changed, 42 insertions(+), 23 deletions(-)
> >
> > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> > index 31e73a7..0339d40 100644
> > --- a/drivers/block/nbd.c
> > +++ b/drivers/block/nbd.c
> > @@ -39,6 +39,7 @@
> >  #include 
> >
> >  #include 
> > +#include 
> >
> >  struct nbd_device {
> > u32 flags;
> > @@ -69,6 +70,10 @@ struct nbd_device {
> >  #if IS_ENABLED(CONFIG_DEBUG_FS)
> > struct dentry *dbg_dir;
> >  #endif
> > +   /*
> > +*This is specifically for calling sock_shutdown, for now.
> > +*/
> > +   struct work_struct ws_shutdown;
> >  };
> >
> >  #if IS_ENABLED(CONFIG_DEBUG_FS)
> > @@ -95,6 +100,11 @@ static int max_part;
> >   */
> >  static DEFINE_SPINLOCK(nbd_lock);
> >
> > +/*
> > + * Shutdown function for nbd_dev work struct.
> > + */
> > +static void nbd_ws_func_shutdown(struct work_struct *);
> > +
> >  static inline struct device *nbd_to_dev(struct nbd_device *nbd)
> >  {
> > return disk_to_dev(nbd->disk);
> > @@ -172,39 +182,35 @@ static void nbd_end_request(struct nbd_device *nbd, 
> > struct request *req)
> >   */
> >  static void sock_shutdown(struct nbd_device *nbd)
> >  {
> > -   spin_lock_irq(>sock_lock);
> > -
> > -   if (!nbd->sock) {
> > -   spin_unlock_irq(>sock_lock);
> > -   return;
> > -   }
> > +   struct socket *sock;
> >
> > -   dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
> > -   kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
> > -   sockfd_put(nbd->sock);
> > +   spin_lock(>sock_lock);
> > +   sock = nbd->sock;
> > nbd->sock = NULL;
> > -   spin_unlock_irq(>sock_lock);
> > +   spin_unlock(>sock_lock);
> > +
> > +   if (!sock)
> > +   return;
> >
> > del_timer(>timeout_timer);
> > +   dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
> > +   kernel_sock_shutdown(sock, SHUT_RDWR);
> > +   sockfd_put(sock);
> >  }
> >
> >  static void nbd_xmit_timeout(unsigned long arg)
> >  {
> > struct nbd_device *nbd = (struct nbd_device *)arg;
> > -   unsigned long flags;
> >
> > if (list_empty(>queue_head))
> > return;
> > -
> > -   spin_lock_irqsave(>sock_lock, flags);
> > -
> > nbd->timedout = true;
> > -
> > -   if (nbd->sock)
> > -   kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
> > -
> > -   spin_unlock_irqrestore(>sock_lock, flags);
> > -
> > +   schedule_work(>ws_shutdown);
> > +   /*
> > +* Make sure sender thread sees nbd->timedout.
> > +*/
> > +   smp_wmb();
> > +   wake_up(>waiting_wq);
> > dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down 
> > connection\n");
> >  }
> >
> > @@ -592,7 +598,11 @@ static int nbd_thread_send(void *data)
> > spin_unlock_irq(>queue_lock);
> >
> > /* handle request */
> > -   nbd_handle_req(nbd, req);
> > +   if (nbd->timedout) {
> > +   req->errors++;
> > +   nbd_end_request(nbd, req);
> > +   } else
> > +   nbd_handle_req(nbd, req);
> > }
> >
> > nbd->task_send = NULL;
> > @@ -672,6 +682,7 @@ static void nbd_reset(struct nbd_device *nbd)
> > set_capacity(nbd->disk, 0);
> > nbd->flags = 0;
> > nbd->xmit_timeout = 0;
> > +   INIT_WORK(>ws_shutdown, nbd_ws_func_shutdown);
> > queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
> > del_timer_sync(>timeout_timer);
> >  }
> > @@ -804,15 +815,15 @@ static int __nbd_ioctl(struct block_device *bdev, 
> > struct nbd_device *nbd,
> > nbd_dev_dbg_close(nbd);
> > kthread_stop(thread);
> >
> > -   mutex_lock(>tx_lock);
> > -
> > sock_shutdown(nbd);
> > +   mutex_lock(>tx_lock);
> > nbd_clear_que(nbd);
> > kill_bdev(bdev);
> >

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

2016-06-13 Thread Pranay Srivastava

Hello,

On Thu, Jun 9, 2016 at 3:33 PM, Pranay Srivastava  wrote:
>
> Hello
>
>
> On Thu, Jun 2, 2016 at 3:54 PM, Pranay Kr. Srivastava  
> wrote:
> > spinlocked ranges should be small and not contain calls into huge
> > subfunctions. Fix my mistake and just get the pointer to the socket
> > instead of doing everything with spinlock held.
> >
> > Reported-by: Mikulas Patocka 
> > Signed-off-by: Markus Pargmann 
> >
> > Changelog:
> > Pranay Kr. Srivastava:
> >
> > 1) Use spin_lock instead of irq version for sock_shutdown.
> >
> > 2) Use system work queue to actually trigger the shutdown of
> >socket. This solves the issue when kernel_sendmsg is currently
> >blocked while a timeout occurs.
> >
> > Signed-off-by: Pranay Kr. Srivastava 
> > ---
> >  drivers/block/nbd.c | 65 
> > ++---
> >  1 file changed, 42 insertions(+), 23 deletions(-)
> >
> > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> > index 31e73a7..0339d40 100644
> > --- a/drivers/block/nbd.c
> > +++ b/drivers/block/nbd.c
> > @@ -39,6 +39,7 @@
> >  #include 
> >
> >  #include 
> > +#include 
> >
> >  struct nbd_device {
> > u32 flags;
> > @@ -69,6 +70,10 @@ struct nbd_device {
> >  #if IS_ENABLED(CONFIG_DEBUG_FS)
> > struct dentry *dbg_dir;
> >  #endif
> > +   /*
> > +*This is specifically for calling sock_shutdown, for now.
> > +*/
> > +   struct work_struct ws_shutdown;
> >  };
> >
> >  #if IS_ENABLED(CONFIG_DEBUG_FS)
> > @@ -95,6 +100,11 @@ static int max_part;
> >   */
> >  static DEFINE_SPINLOCK(nbd_lock);
> >
> > +/*
> > + * Shutdown function for nbd_dev work struct.
> > + */
> > +static void nbd_ws_func_shutdown(struct work_struct *);
> > +
> >  static inline struct device *nbd_to_dev(struct nbd_device *nbd)
> >  {
> > return disk_to_dev(nbd->disk);
> > @@ -172,39 +182,35 @@ static void nbd_end_request(struct nbd_device *nbd, 
> > struct request *req)
> >   */
> >  static void sock_shutdown(struct nbd_device *nbd)
> >  {
> > -   spin_lock_irq(>sock_lock);
> > -
> > -   if (!nbd->sock) {
> > -   spin_unlock_irq(>sock_lock);
> > -   return;
> > -   }
> > +   struct socket *sock;
> >
> > -   dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
> > -   kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
> > -   sockfd_put(nbd->sock);
> > +   spin_lock(>sock_lock);
> > +   sock = nbd->sock;
> > nbd->sock = NULL;
> > -   spin_unlock_irq(>sock_lock);
> > +   spin_unlock(>sock_lock);
> > +
> > +   if (!sock)
> > +   return;
> >
> > del_timer(>timeout_timer);
> > +   dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
> > +   kernel_sock_shutdown(sock, SHUT_RDWR);
> > +   sockfd_put(sock);
> >  }
> >
> >  static void nbd_xmit_timeout(unsigned long arg)
> >  {
> > struct nbd_device *nbd = (struct nbd_device *)arg;
> > -   unsigned long flags;
> >
> > if (list_empty(>queue_head))
> > return;
> > -
> > -   spin_lock_irqsave(>sock_lock, flags);
> > -
> > nbd->timedout = true;
> > -
> > -   if (nbd->sock)
> > -   kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
> > -
> > -   spin_unlock_irqrestore(>sock_lock, flags);
> > -
> > +   schedule_work(>ws_shutdown);
> > +   /*
> > +* Make sure sender thread sees nbd->timedout.
> > +*/
> > +   smp_wmb();
> > +   wake_up(>waiting_wq);
> > dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down 
> > connection\n");
> >  }
> >
> > @@ -592,7 +598,11 @@ static int nbd_thread_send(void *data)
> > spin_unlock_irq(>queue_lock);
> >
> > /* handle request */
> > -   nbd_handle_req(nbd, req);
> > +   if (nbd->timedout) {
> > +   req->errors++;
> > +   nbd_end_request(nbd, req);
> > +   } else
> > +   nbd_handle_req(nbd, req);
> > }
> >
> > nbd->task_send = NULL;
> > @@ -672,6 +682,7 @@ static void nbd_reset(struct nbd_device *nbd)
> > set_capacity(nbd->disk, 0);
> > nbd->flags = 0;
> > nbd->xmit_timeout = 0;
> > +   INIT_WORK(>ws_shutdown, nbd_ws_func_shutdown);
> > queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
> > del_timer_sync(>timeout_timer);
> >  }
> > @@ -804,15 +815,15 @@ static int __nbd_ioctl(struct block_device *bdev, 
> > struct nbd_device *nbd,
> > nbd_dev_dbg_close(nbd);
> > kthread_stop(thread);
> >
> > -   mutex_lock(>tx_lock);
> > -
> > sock_shutdown(nbd);
> > +   mutex_lock(>tx_lock);
> > nbd_clear_que(nbd);
> > kill_bdev(bdev);
> > nbd_bdev_reset(bdev);
> >
> > if (nbd->disconnect) /* user requested, ignore socket 
> > errors */
> >

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

2016-06-09 Thread Pranay Srivastava

Hello


On Thu, Jun 2, 2016 at 3:54 PM, Pranay Kr. Srivastava  wrote:
> spinlocked ranges should be small and not contain calls into huge
> subfunctions. Fix my mistake and just get the pointer to the socket
> instead of doing everything with spinlock held.
>
> Reported-by: Mikulas Patocka 
> Signed-off-by: Markus Pargmann 
>
> Changelog:
> Pranay Kr. Srivastava:
>
> 1) Use spin_lock instead of irq version for sock_shutdown.
>
> 2) Use system work queue to actually trigger the shutdown of
>socket. This solves the issue when kernel_sendmsg is currently
>blocked while a timeout occurs.
>
> Signed-off-by: Pranay Kr. Srivastava 
> ---
>  drivers/block/nbd.c | 65 
> ++---
>  1 file changed, 42 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 31e73a7..0339d40 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -39,6 +39,7 @@
>  #include 
>
>  #include 
> +#include 
>
>  struct nbd_device {
> u32 flags;
> @@ -69,6 +70,10 @@ struct nbd_device {
>  #if IS_ENABLED(CONFIG_DEBUG_FS)
> struct dentry *dbg_dir;
>  #endif
> +   /*
> +*This is specifically for calling sock_shutdown, for now.
> +*/
> +   struct work_struct ws_shutdown;
>  };
>
>  #if IS_ENABLED(CONFIG_DEBUG_FS)
> @@ -95,6 +100,11 @@ static int max_part;
>   */
>  static DEFINE_SPINLOCK(nbd_lock);
>
> +/*
> + * Shutdown function for nbd_dev work struct.
> + */
> +static void nbd_ws_func_shutdown(struct work_struct *);
> +
>  static inline struct device *nbd_to_dev(struct nbd_device *nbd)
>  {
> return disk_to_dev(nbd->disk);
> @@ -172,39 +182,35 @@ static void nbd_end_request(struct nbd_device *nbd, 
> struct request *req)
>   */
>  static void sock_shutdown(struct nbd_device *nbd)
>  {
> -   spin_lock_irq(>sock_lock);
> -
> -   if (!nbd->sock) {
> -   spin_unlock_irq(>sock_lock);
> -   return;
> -   }
> +   struct socket *sock;
>
> -   dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
> -   kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
> -   sockfd_put(nbd->sock);
> +   spin_lock(>sock_lock);
> +   sock = nbd->sock;
> nbd->sock = NULL;
> -   spin_unlock_irq(>sock_lock);
> +   spin_unlock(>sock_lock);
> +
> +   if (!sock)
> +   return;
>
> del_timer(>timeout_timer);
> +   dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
> +   kernel_sock_shutdown(sock, SHUT_RDWR);
> +   sockfd_put(sock);
>  }
>
>  static void nbd_xmit_timeout(unsigned long arg)
>  {
> struct nbd_device *nbd = (struct nbd_device *)arg;
> -   unsigned long flags;
>
> if (list_empty(>queue_head))
> return;
> -
> -   spin_lock_irqsave(>sock_lock, flags);
> -
> nbd->timedout = true;
> -
> -   if (nbd->sock)
> -   kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
> -
> -   spin_unlock_irqrestore(>sock_lock, flags);
> -
> +   schedule_work(>ws_shutdown);
> +   /*
> +* Make sure sender thread sees nbd->timedout.
> +*/
> +   smp_wmb();
> +   wake_up(>waiting_wq);
> dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down 
> connection\n");
>  }
>
> @@ -592,7 +598,11 @@ static int nbd_thread_send(void *data)
> spin_unlock_irq(>queue_lock);
>
> /* handle request */
> -   nbd_handle_req(nbd, req);
> +   if (nbd->timedout) {
> +   req->errors++;
> +   nbd_end_request(nbd, req);
> +   } else
> +   nbd_handle_req(nbd, req);
> }
>
> nbd->task_send = NULL;
> @@ -672,6 +682,7 @@ static void nbd_reset(struct nbd_device *nbd)
> set_capacity(nbd->disk, 0);
> nbd->flags = 0;
> nbd->xmit_timeout = 0;
> +   INIT_WORK(>ws_shutdown, nbd_ws_func_shutdown);
> queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
> del_timer_sync(>timeout_timer);
>  }
> @@ -804,15 +815,15 @@ static int __nbd_ioctl(struct block_device *bdev, 
> struct nbd_device *nbd,
> nbd_dev_dbg_close(nbd);
> kthread_stop(thread);
>
> -   mutex_lock(>tx_lock);
> -
> sock_shutdown(nbd);
> +   mutex_lock(>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)
> error = -ETIMEDOUT;
>
> @@ -863,6 +874,14 @@ static const struct block_device_operations nbd_fops =
> .compat_ioctl = nbd_ioctl,
>  };
>
> +static void

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

2016-06-09 Thread Pranay Srivastava

Hello


On Thu, Jun 2, 2016 at 3:54 PM, Pranay Kr. Srivastava  wrote:
> spinlocked ranges should be small and not contain calls into huge
> subfunctions. Fix my mistake and just get the pointer to the socket
> instead of doing everything with spinlock held.
>
> Reported-by: Mikulas Patocka 
> Signed-off-by: Markus Pargmann 
>
> Changelog:
> Pranay Kr. Srivastava:
>
> 1) Use spin_lock instead of irq version for sock_shutdown.
>
> 2) Use system work queue to actually trigger the shutdown of
>socket. This solves the issue when kernel_sendmsg is currently
>blocked while a timeout occurs.
>
> Signed-off-by: Pranay Kr. Srivastava 
> ---
>  drivers/block/nbd.c | 65 
> ++---
>  1 file changed, 42 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 31e73a7..0339d40 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -39,6 +39,7 @@
>  #include 
>
>  #include 
> +#include 
>
>  struct nbd_device {
> u32 flags;
> @@ -69,6 +70,10 @@ struct nbd_device {
>  #if IS_ENABLED(CONFIG_DEBUG_FS)
> struct dentry *dbg_dir;
>  #endif
> +   /*
> +*This is specifically for calling sock_shutdown, for now.
> +*/
> +   struct work_struct ws_shutdown;
>  };
>
>  #if IS_ENABLED(CONFIG_DEBUG_FS)
> @@ -95,6 +100,11 @@ static int max_part;
>   */
>  static DEFINE_SPINLOCK(nbd_lock);
>
> +/*
> + * Shutdown function for nbd_dev work struct.
> + */
> +static void nbd_ws_func_shutdown(struct work_struct *);
> +
>  static inline struct device *nbd_to_dev(struct nbd_device *nbd)
>  {
> return disk_to_dev(nbd->disk);
> @@ -172,39 +182,35 @@ static void nbd_end_request(struct nbd_device *nbd, 
> struct request *req)
>   */
>  static void sock_shutdown(struct nbd_device *nbd)
>  {
> -   spin_lock_irq(>sock_lock);
> -
> -   if (!nbd->sock) {
> -   spin_unlock_irq(>sock_lock);
> -   return;
> -   }
> +   struct socket *sock;
>
> -   dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
> -   kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
> -   sockfd_put(nbd->sock);
> +   spin_lock(>sock_lock);
> +   sock = nbd->sock;
> nbd->sock = NULL;
> -   spin_unlock_irq(>sock_lock);
> +   spin_unlock(>sock_lock);
> +
> +   if (!sock)
> +   return;
>
> del_timer(>timeout_timer);
> +   dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
> +   kernel_sock_shutdown(sock, SHUT_RDWR);
> +   sockfd_put(sock);
>  }
>
>  static void nbd_xmit_timeout(unsigned long arg)
>  {
> struct nbd_device *nbd = (struct nbd_device *)arg;
> -   unsigned long flags;
>
> if (list_empty(>queue_head))
> return;
> -
> -   spin_lock_irqsave(>sock_lock, flags);
> -
> nbd->timedout = true;
> -
> -   if (nbd->sock)
> -   kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
> -
> -   spin_unlock_irqrestore(>sock_lock, flags);
> -
> +   schedule_work(>ws_shutdown);
> +   /*
> +* Make sure sender thread sees nbd->timedout.
> +*/
> +   smp_wmb();
> +   wake_up(>waiting_wq);
> dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down 
> connection\n");
>  }
>
> @@ -592,7 +598,11 @@ static int nbd_thread_send(void *data)
> spin_unlock_irq(>queue_lock);
>
> /* handle request */
> -   nbd_handle_req(nbd, req);
> +   if (nbd->timedout) {
> +   req->errors++;
> +   nbd_end_request(nbd, req);
> +   } else
> +   nbd_handle_req(nbd, req);
> }
>
> nbd->task_send = NULL;
> @@ -672,6 +682,7 @@ static void nbd_reset(struct nbd_device *nbd)
> set_capacity(nbd->disk, 0);
> nbd->flags = 0;
> nbd->xmit_timeout = 0;
> +   INIT_WORK(>ws_shutdown, nbd_ws_func_shutdown);
> queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
> del_timer_sync(>timeout_timer);
>  }
> @@ -804,15 +815,15 @@ static int __nbd_ioctl(struct block_device *bdev, 
> struct nbd_device *nbd,
> nbd_dev_dbg_close(nbd);
> kthread_stop(thread);
>
> -   mutex_lock(>tx_lock);
> -
> sock_shutdown(nbd);
> +   mutex_lock(>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)
> error = -ETIMEDOUT;
>
> @@ -863,6 +874,14 @@ static const struct block_device_operations nbd_fops =
> .compat_ioctl = nbd_ioctl,
>  };
>
> +static void nbd_ws_func_shutdown(struct work_struct *ws_nbd)
> +{
> +   struct nbd_device *nbd_dev = container_of(ws_nbd,

[PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

2016-06-02 Thread Pranay Kr. Srivastava

spinlocked ranges should be small and not contain calls into huge
subfunctions. Fix my mistake and just get the pointer to the socket
instead of doing everything with spinlock held.

Reported-by: Mikulas Patocka 
Signed-off-by: Markus Pargmann 

Changelog:
Pranay Kr. Srivastava:

1) Use spin_lock instead of irq version for sock_shutdown.

2) Use system work queue to actually trigger the shutdown of
   socket. This solves the issue when kernel_sendmsg is currently
   blocked while a timeout occurs.

Signed-off-by: Pranay Kr. Srivastava 
---
 drivers/block/nbd.c | 65 ++---
 1 file changed, 42 insertions(+), 23 deletions(-)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 31e73a7..0339d40 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -39,6 +39,7 @@
 #include 
 
 #include 
+#include 
 
 struct nbd_device {
u32 flags;
@@ -69,6 +70,10 @@ struct nbd_device {
 #if IS_ENABLED(CONFIG_DEBUG_FS)
struct dentry *dbg_dir;
 #endif
+   /*
+*This is specifically for calling sock_shutdown, for now.
+*/
+   struct work_struct ws_shutdown;
 };
 
 #if IS_ENABLED(CONFIG_DEBUG_FS)
@@ -95,6 +100,11 @@ static int max_part;
  */
 static DEFINE_SPINLOCK(nbd_lock);
 
+/*
+ * Shutdown function for nbd_dev work struct.
+ */
+static void nbd_ws_func_shutdown(struct work_struct *);
+
 static inline struct device *nbd_to_dev(struct nbd_device *nbd)
 {
return disk_to_dev(nbd->disk);
@@ -172,39 +182,35 @@ static void nbd_end_request(struct nbd_device *nbd, 
struct request *req)
  */
 static void sock_shutdown(struct nbd_device *nbd)
 {
-   spin_lock_irq(>sock_lock);
-
-   if (!nbd->sock) {
-   spin_unlock_irq(>sock_lock);
-   return;
-   }
+   struct socket *sock;
 
-   dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
-   kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
-   sockfd_put(nbd->sock);
+   spin_lock(>sock_lock);
+   sock = nbd->sock;
nbd->sock = NULL;
-   spin_unlock_irq(>sock_lock);
+   spin_unlock(>sock_lock);
+
+   if (!sock)
+   return;
 
del_timer(>timeout_timer);
+   dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
+   kernel_sock_shutdown(sock, SHUT_RDWR);
+   sockfd_put(sock);
 }
 
 static void nbd_xmit_timeout(unsigned long arg)
 {
struct nbd_device *nbd = (struct nbd_device *)arg;
-   unsigned long flags;
 
if (list_empty(>queue_head))
return;
-
-   spin_lock_irqsave(>sock_lock, flags);
-
nbd->timedout = true;
-
-   if (nbd->sock)
-   kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
-
-   spin_unlock_irqrestore(>sock_lock, flags);
-
+   schedule_work(>ws_shutdown);
+   /*
+* Make sure sender thread sees nbd->timedout.
+*/
+   smp_wmb();
+   wake_up(>waiting_wq);
dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down 
connection\n");
 }
 
@@ -592,7 +598,11 @@ static int nbd_thread_send(void *data)
spin_unlock_irq(>queue_lock);
 
/* handle request */
-   nbd_handle_req(nbd, req);
+   if (nbd->timedout) {
+   req->errors++;
+   nbd_end_request(nbd, req);
+   } else
+   nbd_handle_req(nbd, req);
}
 
nbd->task_send = NULL;
@@ -672,6 +682,7 @@ static void nbd_reset(struct nbd_device *nbd)
set_capacity(nbd->disk, 0);
nbd->flags = 0;
nbd->xmit_timeout = 0;
+   INIT_WORK(>ws_shutdown, nbd_ws_func_shutdown);
queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
del_timer_sync(>timeout_timer);
 }
@@ -804,15 +815,15 @@ static int __nbd_ioctl(struct block_device *bdev, struct 
nbd_device *nbd,
nbd_dev_dbg_close(nbd);
kthread_stop(thread);
 
-   mutex_lock(>tx_lock);
-
sock_shutdown(nbd);
+   mutex_lock(>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)
error = -ETIMEDOUT;
 
@@ -863,6 +874,14 @@ static const struct block_device_operations nbd_fops =
.compat_ioctl = nbd_ioctl,
 };
 
+static void nbd_ws_func_shutdown(struct work_struct *ws_nbd)
+{
+   struct nbd_device *nbd_dev = container_of(ws_nbd, struct nbd_device,
+   ws_shutdown);
+
+   sock_shutdown(nbd_dev);
+}
+
 #if IS_ENABLED(CONFIG_DEBUG_FS)
 
 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
-- 
2.6.2

[PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

2016-06-02 Thread Pranay Kr. Srivastava

spinlocked ranges should be small and not contain calls into huge
subfunctions. Fix my mistake and just get the pointer to the socket
instead of doing everything with spinlock held.

Reported-by: Mikulas Patocka 
Signed-off-by: Markus Pargmann 

Changelog:
Pranay Kr. Srivastava:

1) Use spin_lock instead of irq version for sock_shutdown.

2) Use system work queue to actually trigger the shutdown of
   socket. This solves the issue when kernel_sendmsg is currently
   blocked while a timeout occurs.

Signed-off-by: Pranay Kr. Srivastava 
---
 drivers/block/nbd.c | 65 ++---
 1 file changed, 42 insertions(+), 23 deletions(-)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 31e73a7..0339d40 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -39,6 +39,7 @@
 #include 
 
 #include 
+#include 
 
 struct nbd_device {
u32 flags;
@@ -69,6 +70,10 @@ struct nbd_device {
 #if IS_ENABLED(CONFIG_DEBUG_FS)
struct dentry *dbg_dir;
 #endif
+   /*
+*This is specifically for calling sock_shutdown, for now.
+*/
+   struct work_struct ws_shutdown;
 };
 
 #if IS_ENABLED(CONFIG_DEBUG_FS)
@@ -95,6 +100,11 @@ static int max_part;
  */
 static DEFINE_SPINLOCK(nbd_lock);
 
+/*
+ * Shutdown function for nbd_dev work struct.
+ */
+static void nbd_ws_func_shutdown(struct work_struct *);
+
 static inline struct device *nbd_to_dev(struct nbd_device *nbd)
 {
return disk_to_dev(nbd->disk);
@@ -172,39 +182,35 @@ static void nbd_end_request(struct nbd_device *nbd, 
struct request *req)
  */
 static void sock_shutdown(struct nbd_device *nbd)
 {
-   spin_lock_irq(>sock_lock);
-
-   if (!nbd->sock) {
-   spin_unlock_irq(>sock_lock);
-   return;
-   }
+   struct socket *sock;
 
-   dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
-   kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
-   sockfd_put(nbd->sock);
+   spin_lock(>sock_lock);
+   sock = nbd->sock;
nbd->sock = NULL;
-   spin_unlock_irq(>sock_lock);
+   spin_unlock(>sock_lock);
+
+   if (!sock)
+   return;
 
del_timer(>timeout_timer);
+   dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
+   kernel_sock_shutdown(sock, SHUT_RDWR);
+   sockfd_put(sock);
 }
 
 static void nbd_xmit_timeout(unsigned long arg)
 {
struct nbd_device *nbd = (struct nbd_device *)arg;
-   unsigned long flags;
 
if (list_empty(>queue_head))
return;
-
-   spin_lock_irqsave(>sock_lock, flags);
-
nbd->timedout = true;
-
-   if (nbd->sock)
-   kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
-
-   spin_unlock_irqrestore(>sock_lock, flags);
-
+   schedule_work(>ws_shutdown);
+   /*
+* Make sure sender thread sees nbd->timedout.
+*/
+   smp_wmb();
+   wake_up(>waiting_wq);
dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down 
connection\n");
 }
 
@@ -592,7 +598,11 @@ static int nbd_thread_send(void *data)
spin_unlock_irq(>queue_lock);
 
/* handle request */
-   nbd_handle_req(nbd, req);
+   if (nbd->timedout) {
+   req->errors++;
+   nbd_end_request(nbd, req);
+   } else
+   nbd_handle_req(nbd, req);
}
 
nbd->task_send = NULL;
@@ -672,6 +682,7 @@ static void nbd_reset(struct nbd_device *nbd)
set_capacity(nbd->disk, 0);
nbd->flags = 0;
nbd->xmit_timeout = 0;
+   INIT_WORK(>ws_shutdown, nbd_ws_func_shutdown);
queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
del_timer_sync(>timeout_timer);
 }
@@ -804,15 +815,15 @@ static int __nbd_ioctl(struct block_device *bdev, struct 
nbd_device *nbd,
nbd_dev_dbg_close(nbd);
kthread_stop(thread);
 
-   mutex_lock(>tx_lock);
-
sock_shutdown(nbd);
+   mutex_lock(>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)
error = -ETIMEDOUT;
 
@@ -863,6 +874,14 @@ static const struct block_device_operations nbd_fops =
.compat_ioctl = nbd_ioctl,
 };
 
+static void nbd_ws_func_shutdown(struct work_struct *ws_nbd)
+{
+   struct nbd_device *nbd_dev = container_of(ws_nbd, struct nbd_device,
+   ws_shutdown);
+
+   sock_shutdown(nbd_dev);
+}
+
 #if IS_ENABLED(CONFIG_DEBUG_FS)
 
 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
-- 
2.6.2

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

Re: [PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

[PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

[PATCH v2 1/5] nbd: fix might_sleep warning on socket shutdown.

10 matches

Site Navigation

Mail list logo

Footer information