[PATCH 9/12] repost: cciss: add busy_configuring flag

[PATCH 9/12] repost: cciss: add busy_configuring flag

[Mike Miller (OS Dev)]

PATCH 9 of 12

This patch adds a check for busy_configuring to prevent starting a queue
on a drive that may be in the midst of updating, configuring, deleting, etc.

This had a test for if the queue was stopped or plugged but that seemed
to cause issues.
Please consider this for inclusion.

Thanks,
mikem

Signed-off-by: Mike Miller <mike.miller@hp.com>

--------------------------------------------------------------------------------

---

 drivers/block/cciss.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletion(-)

diff -puN drivers/block/cciss.c~cciss_busy_conf_for_lx2619-rc4 drivers/block/cciss.c
--- linux-2.6/drivers/block/cciss.c~cciss_busy_conf_for_lx2619-rc4	2006-11-06 13:27:53.000000000 -0600
+++ linux-2.6-root/drivers/block/cciss.c	2006-11-06 13:27:53.000000000 -0600
@@ -1190,8 +1190,11 @@ static void cciss_check_queues(ctlr_info
 		/* make sure the disk has been added and the drive is real
 		 * because this can be called from the middle of init_one.
 		 */
-		if (!(h->drv[curr_queue].queue) || !(h->drv[curr_queue].heads))
+		if (!(h->drv[curr_queue].queue) ||
+		    !(h->drv[curr_queue].heads) ||
+		    h->drv[curr_queue].busy_configuring)
 			continue;
+
 		blk_start_queue(h->gendisk[curr_queue]->queue);
 
 		/* check to see if we have maxed out the number of commands
_

Re: [PATCH 9/12] repost: cciss: add busy_configuring flag

[Jens Axboe]

On Mon, Nov 06 2006, Mike Miller (OS Dev) wrote:
> PATCH 9 of 12
> 
> This patch adds a check for busy_configuring to prevent starting a queue
> on a drive that may be in the midst of updating, configuring, deleting, etc.
> 
> This had a test for if the queue was stopped or plugged but that seemed
> to cause issues.
> Please consider this for inclusion.
> 
> Thanks,
> mikem
> 
> Signed-off-by: Mike Miller <mike.miller@hp.com>
> 
> --------------------------------------------------------------------------------
> 
> ---
> 
>  drivers/block/cciss.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff -puN drivers/block/cciss.c~cciss_busy_conf_for_lx2619-rc4 drivers/block/cciss.c
> --- linux-2.6/drivers/block/cciss.c~cciss_busy_conf_for_lx2619-rc4	2006-11-06 13:27:53.000000000 -0600
> +++ linux-2.6-root/drivers/block/cciss.c	2006-11-06 13:27:53.000000000 -0600
> @@ -1190,8 +1190,11 @@ static void cciss_check_queues(ctlr_info
>  		/* make sure the disk has been added and the drive is real
>  		 * because this can be called from the middle of init_one.
>  		 */
> -		if (!(h->drv[curr_queue].queue) || !(h->drv[curr_queue].heads))
> +		if (!(h->drv[curr_queue].queue) ||
> +		    !(h->drv[curr_queue].heads) ||
> +		    h->drv[curr_queue].busy_configuring)
>  			continue;
> +
>  		blk_start_queue(h->gendisk[curr_queue]->queue);

This is racy, because you don't start the queue when you unset
->busy_configuring later on. For this to be safe, you need to call
blk_start_queue() when you set ->busy_configuring to 0.

-- 
Jens Axboe

Re: [PATCH 9/12] repost: cciss: add busy_configuring flag

[Mike Miller (OS Dev)]

On Mon, Nov 06, 2006 at 09:32:00PM +0100, Jens Axboe wrote:
> On Mon, Nov 06 2006, Mike Miller (OS Dev) wrote:
> > PATCH 9 of 12
> > 
> > This patch adds a check for busy_configuring to prevent starting a queue
> > on a drive that may be in the midst of updating, configuring, deleting, etc.
> > 
> > This had a test for if the queue was stopped or plugged but that seemed
> > to cause issues.
> > Please consider this for inclusion.
> > 
> > Thanks,
> > mikem
> > 
> > Signed-off-by: Mike Miller <mike.miller@hp.com>
> > 
> > --------------------------------------------------------------------------------
> > 
> > ---
> > 
> >  drivers/block/cciss.c |    5 ++++-
> >  1 files changed, 4 insertions(+), 1 deletion(-)
> > 
> > diff -puN drivers/block/cciss.c~cciss_busy_conf_for_lx2619-rc4 drivers/block/cciss.c
> > --- linux-2.6/drivers/block/cciss.c~cciss_busy_conf_for_lx2619-rc4	2006-11-06 13:27:53.000000000 -0600
> > +++ linux-2.6-root/drivers/block/cciss.c	2006-11-06 13:27:53.000000000 -0600
> > @@ -1190,8 +1190,11 @@ static void cciss_check_queues(ctlr_info
> >  		/* make sure the disk has been added and the drive is real
> >  		 * because this can be called from the middle of init_one.
> >  		 */
> > -		if (!(h->drv[curr_queue].queue) || !(h->drv[curr_queue].heads))
> > +		if (!(h->drv[curr_queue].queue) ||
> > +		    !(h->drv[curr_queue].heads) ||
> > +		    h->drv[curr_queue].busy_configuring)
> >  			continue;
> > +
> >  		blk_start_queue(h->gendisk[curr_queue]->queue);
> 
> This is racy, because you don't start the queue when you unset
> ->busy_configuring later on. For this to be safe, you need to call
> blk_start_queue() when you set ->busy_configuring to 0.

Jens, please see Chase's reply to your concerns:
> busy_configuring - I do not think this is racy.  This
> flag is used only when we are removing/deleting a disk.  In
> this case the queue is cleaned up and the disk is deleted.
> If we are doing that then there is no queue to start later.
> The check of this flag in the interrupt handler is to prevent
> us from trying to start a queue that is in the middle of
> being deleted.  This flag could be called busy_deleting.
>

Thanks,
mikem, Chase

Re: [PATCH 9/12] repost: cciss: add busy_configuring flag

[Jens Axboe]

On Tue, Dec 12 2006, Mike Miller (OS Dev) wrote:
> On Mon, Nov 06, 2006 at 09:32:00PM +0100, Jens Axboe wrote:
> > On Mon, Nov 06 2006, Mike Miller (OS Dev) wrote:
> > > PATCH 9 of 12
> > > 
> > > This patch adds a check for busy_configuring to prevent starting a queue
> > > on a drive that may be in the midst of updating, configuring, deleting, etc.
> > > 
> > > This had a test for if the queue was stopped or plugged but that seemed
> > > to cause issues.
> > > Please consider this for inclusion.
> > > 
> > > Thanks,
> > > mikem
> > > 
> > > Signed-off-by: Mike Miller <mike.miller@hp.com>
> > > 
> > > --------------------------------------------------------------------------------
> > > 
> > > ---
> > > 
> > >  drivers/block/cciss.c |    5 ++++-
> > >  1 files changed, 4 insertions(+), 1 deletion(-)
> > > 
> > > diff -puN drivers/block/cciss.c~cciss_busy_conf_for_lx2619-rc4 drivers/block/cciss.c
> > > --- linux-2.6/drivers/block/cciss.c~cciss_busy_conf_for_lx2619-rc4	2006-11-06 13:27:53.000000000 -0600
> > > +++ linux-2.6-root/drivers/block/cciss.c	2006-11-06 13:27:53.000000000 -0600
> > > @@ -1190,8 +1190,11 @@ static void cciss_check_queues(ctlr_info
> > >  		/* make sure the disk has been added and the drive is real
> > >  		 * because this can be called from the middle of init_one.
> > >  		 */
> > > -		if (!(h->drv[curr_queue].queue) || !(h->drv[curr_queue].heads))
> > > +		if (!(h->drv[curr_queue].queue) ||
> > > +		    !(h->drv[curr_queue].heads) ||
> > > +		    h->drv[curr_queue].busy_configuring)
> > >  			continue;
> > > +
> > >  		blk_start_queue(h->gendisk[curr_queue]->queue);
> > 
> > This is racy, because you don't start the queue when you unset
> > ->busy_configuring later on. For this to be safe, you need to call
> > blk_start_queue() when you set ->busy_configuring to 0.
> 
> Jens, please see Chase's reply to your concerns:
> > busy_configuring - I do not think this is racy.  This
> > flag is used only when we are removing/deleting a disk.  In
> > this case the queue is cleaned up and the disk is deleted.
> > If we are doing that then there is no queue to start later.
> > The check of this flag in the interrupt handler is to prevent
> > us from trying to start a queue that is in the middle of
> > being deleted.  This flag could be called busy_deleting.

Ok, no worries then if it's simply a going away flag. I wonder if it's
needed at all, but it certainly doesn't hurt.

-- 
Jens Axboe

Re: [PATCH 9/12] repost: cciss: add busy_configuring flag

[dann frazier]

On Wed, Dec 13, 2006 at 01:52:36PM +0100, Jens Axboe wrote:
> On Tue, Dec 12 2006, Mike Miller (OS Dev) wrote:
> > On Mon, Nov 06, 2006 at 09:32:00PM +0100, Jens Axboe wrote:
> > > On Mon, Nov 06 2006, Mike Miller (OS Dev) wrote:
> > > > PATCH 9 of 12
> > > > 
> > > > This patch adds a check for busy_configuring to prevent starting a queue
> > > > on a drive that may be in the midst of updating, configuring, deleting, etc.
> > > > 
> > > > This had a test for if the queue was stopped or plugged but that seemed
> > > > to cause issues.
> > > > Please consider this for inclusion.
> > > > 
> > > > Thanks,
> > > > mikem
> > > > 
> > > > Signed-off-by: Mike Miller <mike.miller@hp.com>
> > > > 
> > > > --------------------------------------------------------------------------------
> > > > 
> > > > ---
> > > > 
> > > >  drivers/block/cciss.c |    5 ++++-
> > > >  1 files changed, 4 insertions(+), 1 deletion(-)
> > > > 
> > > > diff -puN drivers/block/cciss.c~cciss_busy_conf_for_lx2619-rc4 drivers/block/cciss.c
> > > > --- linux-2.6/drivers/block/cciss.c~cciss_busy_conf_for_lx2619-rc4	2006-11-06 13:27:53.000000000 -0600
> > > > +++ linux-2.6-root/drivers/block/cciss.c	2006-11-06 13:27:53.000000000 -0600
> > > > @@ -1190,8 +1190,11 @@ static void cciss_check_queues(ctlr_info
> > > >  		/* make sure the disk has been added and the drive is real
> > > >  		 * because this can be called from the middle of init_one.
> > > >  		 */
> > > > -		if (!(h->drv[curr_queue].queue) || !(h->drv[curr_queue].heads))
> > > > +		if (!(h->drv[curr_queue].queue) ||
> > > > +		    !(h->drv[curr_queue].heads) ||
> > > > +		    h->drv[curr_queue].busy_configuring)
> > > >  			continue;
> > > > +
> > > >  		blk_start_queue(h->gendisk[curr_queue]->queue);
> > > 
> > > This is racy, because you don't start the queue when you unset
> > > ->busy_configuring later on. For this to be safe, you need to call
> > > blk_start_queue() when you set ->busy_configuring to 0.
> > 
> > Jens, please see Chase's reply to your concerns:
> > > busy_configuring - I do not think this is racy.  This
> > > flag is used only when we are removing/deleting a disk.  In
> > > this case the queue is cleaned up and the disk is deleted.
> > > If we are doing that then there is no queue to start later.
> > > The check of this flag in the interrupt handler is to prevent
> > > us from trying to start a queue that is in the middle of
> > > being deleted.  This flag could be called busy_deleting.
> 
> Ok, no worries then if it's simply a going away flag. I wonder if it's
> needed at all, but it certainly doesn't hurt.

hey Jens,
  Just a poke since I haven't seen this change go into your block
tree. Is it still in-plan?

-- 
dann frazier

Re: [PATCH 9/12] repost: cciss: add busy_configuring flag

[Jens Axboe]

On Fri, Jan 19 2007, dann frazier wrote:
> On Wed, Dec 13, 2006 at 01:52:36PM +0100, Jens Axboe wrote:
> > On Tue, Dec 12 2006, Mike Miller (OS Dev) wrote:
> > > On Mon, Nov 06, 2006 at 09:32:00PM +0100, Jens Axboe wrote:
> > > > On Mon, Nov 06 2006, Mike Miller (OS Dev) wrote:
> > > > > PATCH 9 of 12
> > > > > 
> > > > > This patch adds a check for busy_configuring to prevent starting a queue
> > > > > on a drive that may be in the midst of updating, configuring, deleting, etc.
> > > > > 
> > > > > This had a test for if the queue was stopped or plugged but that seemed
> > > > > to cause issues.
> > > > > Please consider this for inclusion.
> > > > > 
> > > > > Thanks,
> > > > > mikem
> > > > > 
> > > > > Signed-off-by: Mike Miller <mike.miller@hp.com>
> > > > > 
> > > > > --------------------------------------------------------------------------------
> > > > > 
> > > > > ---
> > > > > 
> > > > >  drivers/block/cciss.c |    5 ++++-
> > > > >  1 files changed, 4 insertions(+), 1 deletion(-)
> > > > > 
> > > > > diff -puN drivers/block/cciss.c~cciss_busy_conf_for_lx2619-rc4 drivers/block/cciss.c
> > > > > --- linux-2.6/drivers/block/cciss.c~cciss_busy_conf_for_lx2619-rc4	2006-11-06 13:27:53.000000000 -0600
> > > > > +++ linux-2.6-root/drivers/block/cciss.c	2006-11-06 13:27:53.000000000 -0600
> > > > > @@ -1190,8 +1190,11 @@ static void cciss_check_queues(ctlr_info
> > > > >  		/* make sure the disk has been added and the drive is real
> > > > >  		 * because this can be called from the middle of init_one.
> > > > >  		 */
> > > > > -		if (!(h->drv[curr_queue].queue) || !(h->drv[curr_queue].heads))
> > > > > +		if (!(h->drv[curr_queue].queue) ||
> > > > > +		    !(h->drv[curr_queue].heads) ||
> > > > > +		    h->drv[curr_queue].busy_configuring)
> > > > >  			continue;
> > > > > +
> > > > >  		blk_start_queue(h->gendisk[curr_queue]->queue);
> > > > 
> > > > This is racy, because you don't start the queue when you unset
> > > > ->busy_configuring later on. For this to be safe, you need to call
> > > > blk_start_queue() when you set ->busy_configuring to 0.
> > > 
> > > Jens, please see Chase's reply to your concerns:
> > > > busy_configuring - I do not think this is racy.  This
> > > > flag is used only when we are removing/deleting a disk.  In
> > > > this case the queue is cleaned up and the disk is deleted.
> > > > If we are doing that then there is no queue to start later.
> > > > The check of this flag in the interrupt handler is to prevent
> > > > us from trying to start a queue that is in the middle of
> > > > being deleted.  This flag could be called busy_deleting.
> > 
> > Ok, no worries then if it's simply a going away flag. I wonder if it's
> > needed at all, but it certainly doesn't hurt.
> 
> hey Jens,
>   Just a poke since I haven't seen this change go into your block
> tree. Is it still in-plan?

I had it stashed for a 2.6.21 merge, it'll go in by then.

-- 
Jens Axboe