Patch 12 of 12
This patch replaces complete_buffers with end_that_request_first to fix
programs like iostat. This has been broken for the last few kernel releases.
Please consider this for inclusion.
Thanks,
mikem
Signed-off-by: Mike Miller <[email protected]>
---
---
drivers/block/cciss.c | 20 ++++----------------
1 files changed, 4 insertions(+), 16 deletions(-)
diff -puN drivers/block/cciss.c~cciss_update_diskstats_fix drivers/block/cciss.c
--- linux-2.6/drivers/block/cciss.c~cciss_update_diskstats_fix 2006-11-06 13:28:53.000000000 -0600
+++ linux-2.6-root/drivers/block/cciss.c 2006-11-06 13:28:53.000000000 -0600
@@ -1156,18 +1156,6 @@ static int cciss_ioctl(struct inode *ino
}
}
-static inline void complete_buffers(struct bio *bio, int status)
-{
- while (bio) {
- struct bio *xbh = bio->bi_next;
- int nr_sectors = bio_sectors(bio);
-
- bio->bi_next = NULL;
- bio_endio(bio, nr_sectors << 9, status ? 0 : -EIO);
- bio = xbh;
- }
-}
-
static void cciss_check_queues(ctlr_info_t *h)
{
int start_queue = h->next_to_run;
@@ -1236,15 +1224,15 @@ static void cciss_softirq_done(struct re
pci_unmap_page(h->pdev, temp64.val, cmd->SG[i].Len, ddir);
}
- complete_buffers(rq->bio, rq->errors);
-
#ifdef CCISS_DEBUG
printk("Done with %p\n", rq);
#endif /* CCISS_DEBUG */
- add_disk_randomness(rq->rq_disk);
spin_lock_irqsave(&h->lock, flags);
- end_that_request_last(rq, rq->errors);
+ if (!end_that_request_first(rq, rq->errors, rq->nr_sectors)) {
+ add_disk_randomness(rq->rq_disk);
+ end_that_request_last(rq, rq->errors);
+ }
cmd_free(h, cmd, 1);
cciss_check_queues(h);
spin_unlock_irqrestore(&h->lock, flags);
_
On Mon, Nov 06 2006, Mike Miller (OS Dev) wrote:
> Patch 12 of 12
>
> This patch replaces complete_buffers with end_that_request_first to fix
> programs like iostat. This has been broken for the last few kernel releases.
> Please consider this for inclusion.
>
> Thanks,
> mikem
>
> Signed-off-by: Mike Miller <[email protected]>
>
>
> ---
>
>
> ---
>
> drivers/block/cciss.c | 20 ++++----------------
> 1 files changed, 4 insertions(+), 16 deletions(-)
>
> diff -puN drivers/block/cciss.c~cciss_update_diskstats_fix drivers/block/cciss.c
> --- linux-2.6/drivers/block/cciss.c~cciss_update_diskstats_fix 2006-11-06 13:28:53.000000000 -0600
> +++ linux-2.6-root/drivers/block/cciss.c 2006-11-06 13:28:53.000000000 -0600
> @@ -1156,18 +1156,6 @@ static int cciss_ioctl(struct inode *ino
> }
> }
>
> -static inline void complete_buffers(struct bio *bio, int status)
> -{
> - while (bio) {
> - struct bio *xbh = bio->bi_next;
> - int nr_sectors = bio_sectors(bio);
> -
> - bio->bi_next = NULL;
> - bio_endio(bio, nr_sectors << 9, status ? 0 : -EIO);
> - bio = xbh;
> - }
> -}
> -
> static void cciss_check_queues(ctlr_info_t *h)
> {
> int start_queue = h->next_to_run;
> @@ -1236,15 +1224,15 @@ static void cciss_softirq_done(struct re
> pci_unmap_page(h->pdev, temp64.val, cmd->SG[i].Len, ddir);
> }
>
> - complete_buffers(rq->bio, rq->errors);
> -
> #ifdef CCISS_DEBUG
> printk("Done with %p\n", rq);
> #endif /* CCISS_DEBUG */
>
> - add_disk_randomness(rq->rq_disk);
> spin_lock_irqsave(&h->lock, flags);
> - end_that_request_last(rq, rq->errors);
> + if (!end_that_request_first(rq, rq->errors, rq->nr_sectors)) {
> + add_disk_randomness(rq->rq_disk);
> + end_that_request_last(rq, rq->errors);
> + }
> cmd_free(h, cmd, 1);
> cciss_check_queues(h);
> spin_unlock_irqrestore(&h->lock, flags);
Ah, so there's where that went. Your code isn't clear, though -
end_that_request_first() _must_ return 0, so the above looks confusing.
It would look cleaner and more informative like:
if (end_that_request_first(rq, rq->errors, rq->nr_sectors))
BUG();
add_disk_randomness(rq->rq_disk);
end_that_request_last(rq, rq->errors);
...
and so on. Additionally you don't need the lock for
end_that_request_first(), so it's a lot more optimal to rearrange it
again.
add_disk_randomness(rq->rq_disk);
if (end_that_request_first(rq, rq->errors, rq->nr_sectors))
BUG();
spin_lock_irqsave(&h->lock, flags);
end_that_request_last(rq, rq->errors);
cmd_free(h, cmd, 1);
...
Not only cleaner to read since it's obvious what will happen, also moves
the heavy path (end_that_request_first()) outside of the controller
lock.
--
Jens Axboe
On Mon, Nov 06 2006, Jens Axboe wrote:
> On Mon, Nov 06 2006, Mike Miller (OS Dev) wrote:
> > Patch 12 of 12
> >
> > This patch replaces complete_buffers with end_that_request_first to fix
> > programs like iostat. This has been broken for the last few kernel releases.
> > Please consider this for inclusion.
> >
> > Thanks,
> > mikem
> >
> > Signed-off-by: Mike Miller <[email protected]>
> >
> >
> > ---
> >
> >
> > ---
> >
> > drivers/block/cciss.c | 20 ++++----------------
> > 1 files changed, 4 insertions(+), 16 deletions(-)
> >
> > diff -puN drivers/block/cciss.c~cciss_update_diskstats_fix drivers/block/cciss.c
> > --- linux-2.6/drivers/block/cciss.c~cciss_update_diskstats_fix 2006-11-06 13:28:53.000000000 -0600
> > +++ linux-2.6-root/drivers/block/cciss.c 2006-11-06 13:28:53.000000000 -0600
> > @@ -1156,18 +1156,6 @@ static int cciss_ioctl(struct inode *ino
> > }
> > }
> >
> > -static inline void complete_buffers(struct bio *bio, int status)
> > -{
> > - while (bio) {
> > - struct bio *xbh = bio->bi_next;
> > - int nr_sectors = bio_sectors(bio);
> > -
> > - bio->bi_next = NULL;
> > - bio_endio(bio, nr_sectors << 9, status ? 0 : -EIO);
> > - bio = xbh;
> > - }
> > -}
> > -
> > static void cciss_check_queues(ctlr_info_t *h)
> > {
> > int start_queue = h->next_to_run;
> > @@ -1236,15 +1224,15 @@ static void cciss_softirq_done(struct re
> > pci_unmap_page(h->pdev, temp64.val, cmd->SG[i].Len, ddir);
> > }
> >
> > - complete_buffers(rq->bio, rq->errors);
> > -
> > #ifdef CCISS_DEBUG
> > printk("Done with %p\n", rq);
> > #endif /* CCISS_DEBUG */
> >
> > - add_disk_randomness(rq->rq_disk);
> > spin_lock_irqsave(&h->lock, flags);
> > - end_that_request_last(rq, rq->errors);
> > + if (!end_that_request_first(rq, rq->errors, rq->nr_sectors)) {
> > + add_disk_randomness(rq->rq_disk);
> > + end_that_request_last(rq, rq->errors);
> > + }
> > cmd_free(h, cmd, 1);
> > cciss_check_queues(h);
> > spin_unlock_irqrestore(&h->lock, flags);
>
> Ah, so there's where that went. Your code isn't clear, though -
> end_that_request_first() _must_ return 0, so the above looks confusing.
> It would look cleaner and more informative like:
>
> if (end_that_request_first(rq, rq->errors, rq->nr_sectors))
> BUG();
>
> add_disk_randomness(rq->rq_disk);
> end_that_request_last(rq, rq->errors);
> ...
>
> and so on. Additionally you don't need the lock for
> end_that_request_first(), so it's a lot more optimal to rearrange it
> again.
>
> add_disk_randomness(rq->rq_disk);
> if (end_that_request_first(rq, rq->errors, rq->nr_sectors))
> BUG();
>
> spin_lock_irqsave(&h->lock, flags);
> end_that_request_last(rq, rq->errors);
> cmd_free(h, cmd, 1);
> ...
>
> Not only cleaner to read since it's obvious what will happen, also moves
> the heavy path (end_that_request_first()) outside of the controller
> lock.
IOW, simple one-liner fix:
diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 6ffe2b2..f9f128a 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -1299,6 +1299,7 @@ static void cciss_softirq_done(struct re
}
complete_buffers(rq->bio, rq->errors);
+ disk_stat_add(rq->rq_disk, sectors[rq_data_dir(rq)], rq->nr_sectors);
#ifdef CCISS_DEBUG
printk("Done with %p\n", rq);
--
Jens Axboe
On Mon, Nov 06, 2006 at 09:45:51PM +0100, Jens Axboe wrote:
> On Mon, Nov 06 2006, Mike Miller (OS Dev) wrote:
> > Patch 12 of 12
> >
> > This patch replaces complete_buffers with end_that_request_first to fix
> > programs like iostat. This has been broken for the last few kernel releases.
> > Please consider this for inclusion.
> >
> > Thanks,
> > mikem
> >
> > Signed-off-by: Mike Miller <[email protected]>
> >
> >
> > ---
> >
> >
> > ---
> >
> > drivers/block/cciss.c | 20 ++++----------------
> > 1 files changed, 4 insertions(+), 16 deletions(-)
> >
> > diff -puN drivers/block/cciss.c~cciss_update_diskstats_fix drivers/block/cciss.c
> > --- linux-2.6/drivers/block/cciss.c~cciss_update_diskstats_fix 2006-11-06 13:28:53.000000000 -0600
> > +++ linux-2.6-root/drivers/block/cciss.c 2006-11-06 13:28:53.000000000 -0600
> > @@ -1156,18 +1156,6 @@ static int cciss_ioctl(struct inode *ino
> > }
> > }
> >
> > -static inline void complete_buffers(struct bio *bio, int status)
> > -{
> > - while (bio) {
> > - struct bio *xbh = bio->bi_next;
> > - int nr_sectors = bio_sectors(bio);
> > -
> > - bio->bi_next = NULL;
> > - bio_endio(bio, nr_sectors << 9, status ? 0 : -EIO);
> > - bio = xbh;
> > - }
> > -}
> > -
> > static void cciss_check_queues(ctlr_info_t *h)
> > {
> > int start_queue = h->next_to_run;
> > @@ -1236,15 +1224,15 @@ static void cciss_softirq_done(struct re
> > pci_unmap_page(h->pdev, temp64.val, cmd->SG[i].Len, ddir);
> > }
> >
> > - complete_buffers(rq->bio, rq->errors);
> > -
> > #ifdef CCISS_DEBUG
> > printk("Done with %p\n", rq);
> > #endif /* CCISS_DEBUG */
> >
> > - add_disk_randomness(rq->rq_disk);
> > spin_lock_irqsave(&h->lock, flags);
> > - end_that_request_last(rq, rq->errors);
> > + if (!end_that_request_first(rq, rq->errors, rq->nr_sectors)) {
> > + add_disk_randomness(rq->rq_disk);
> > + end_that_request_last(rq, rq->errors);
> > + }
> > cmd_free(h, cmd, 1);
> > cciss_check_queues(h);
> > spin_unlock_irqrestore(&h->lock, flags);
>
> Ah, so there's where that went. Your code isn't clear, though -
> end_that_request_first() _must_ return 0, so the above looks confusing.
> It would look cleaner and more informative like:
>
> if (end_that_request_first(rq, rq->errors, rq->nr_sectors))
> BUG();
>
> add_disk_randomness(rq->rq_disk);
> end_that_request_last(rq, rq->errors);
> ...
>
> and so on. Additionally you don't need the lock for
> end_that_request_first(), so it's a lot more optimal to rearrange it
> again.
>
> add_disk_randomness(rq->rq_disk);
> if (end_that_request_first(rq, rq->errors, rq->nr_sectors))
> BUG();
>
> spin_lock_irqsave(&h->lock, flags);
> end_that_request_last(rq, rq->errors);
> cmd_free(h, cmd, 1);
> ...
>
> Not only cleaner to read since it's obvious what will happen, also moves
> the heavy path (end_that_request_first()) outside of the controller
> lock.
>
> --
> Jens Axboe
>
Thanks Jens. I'm fighting several fires right now so the cleanup will
be done in a day or 2.
mikem