Hi Mike,
I have another question about dm, though it's irrelevant to this original
mail.
Currently abnormal IO will call blk_queue_split() and normal IO will
be split considering @max_sectors/@chunk_sectos (in max_io_len()).
Question 1: Why bio should be split considering queue_limits in dm layer?
After all the underlying device will split themselves by queue_limits if
the dm layer doesn't split by queue_limits.
Then Question 2: Currently only @max_sectors is considered when splitting
normal IO in dm layer. Should we also consider
@max_segments/@max_segment_size
as blk_queue_split() does?
Thanks,
Jeffle
On 11/3/20 5:23 PM, Jeffle Xu wrote:
Hi Mike,
Why queue_work() is unnecessary here for bio with BLK_STS_DM_REQUEUE
returned?
Thanks
Jeffle Xu
---
drivers/md/dm.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index c18fc2548518..ae550daa99b5 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -908,9 +908,11 @@ static void dec_pending(struct dm_io *io, blk_status_t error)
* Target requested pushing back the I/O.
*/
spin_lock_irqsave(&md->deferred_lock, flags);
- if (__noflush_suspending(md))
+ if (__noflush_suspending(md)) {
/* NOTE early return due to BLK_STS_DM_REQUEUE below */
bio_list_add_head(&md->deferred, io->orig_bio);
+ queue_work(md->wq, &md->work);
+ }
else
/* noflush suspend was interrupted. */
io->status = BLK_STS_IOERR;
--
Thanks,
Jeffle
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