linux.git/drivers/md/bcache, branch v4.3-rc2

bcache: remove driver private bio splitting code

2015-08-13T18:31:40+00:00

The bcache driver has always accepted arbitrarily large bios and split
them internally.  Now that every driver must accept arbitrarily large
bios this code isn't nessecary anymore.

Cc: linux-bcache@vger.kernel.org
Signed-off-by: Kent Overstreet 
[dpark: add more description in commit message]
Signed-off-by: Dongsu Park 
Signed-off-by: Ming Lin 
Signed-off-by: Jens Axboe

block: add a bi_error field to struct bio

2015-07-29T14:55:15+00:00

Currently we have two different ways to signal an I/O error on a BIO:

 (1) by clearing the BIO_UPTODATE flag
 (2) by returning a Linux errno value to the bi_end_io callback

The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario.  Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.

So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Hannes Reinecke 
Reviewed-by: NeilBrown 
Signed-off-by: Jens Axboe

block: have drivers use blk_queue_max_discard_sectors()

2015-07-17T14:41:53+00:00

Some drivers use it now, others just set the limits field manually.
But in preparation for splitting this into a hard and soft limit,
ensure that they all call the proper function for setting the hw
limit for discards.

Reviewed-by: Jeff Moyer 
Signed-off-by: Jens Axboe

bcache: don't embed 'return' statements in closure macros

2015-07-11T15:57:32+00:00

This is horribly confusing, it breaks the flow of the code without
it being apparent in the caller.

Signed-off-by: Jens Axboe 
Acked-by: Christoph Hellwig

MAINTAINERS: BCACHE: Kent Overstreet has changed email address

2015-07-01T02:45:01+00:00

Kent's email address in MAINTAINERS seems to be invalid.
This was his last sign-off address, so use that if appropriate.

Fix the S: status entry while there.

Signed-off-by: Joe Perches 
Acked-by: Kent Overstreet 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bcache: use kvfree() in various places

2015-07-01T02:45:00+00:00

Use kvfree() instead of open-coding it.

Signed-off-by: Pekka Enberg 
Cc: Kent Overstreet 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

writeback: separate out include/linux/backing-dev-defs.h

2015-06-02T14:33:34+00:00

With the planned cgroup writeback support, backing-dev related
declarations will be more widely used across block and cgroup;
unfortunately, including backing-dev.h from include/linux/blkdev.h
makes cyclic include dependency quite likely.

This patch separates out backing-dev-defs.h which only has the
essential definitions and updates blkdev.h to include it.  c files
which need access to more backing-dev details now include
backing-dev.h directly.  This takes backing-dev.h off the common
include dependency chain making it a lot easier to use it across block
and cgroup.

v2: fs/fat build failure fixed.

Signed-off-by: Tejun Heo 
Reviewed-by: Jan Kara 
Cc: Jens Axboe 
Signed-off-by: Jens Axboe

block: remove management of bi_remaining when restoring original bi_end_io

2015-05-22T14:58:55+00:00

Commit c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for
non-chains") regressed all existing callers that followed this pattern:
 1) saving a bio's original bi_end_io
 2) wiring up an intermediate bi_end_io
 3) restoring the original bi_end_io from intermediate bi_end_io
 4) calling bio_endio() to execute the restored original bi_end_io

The regression was due to BIO_CHAIN only ever getting set if
bio_inc_remaining() is called.  For the above pattern it isn't set until
step 3 above (step 2 would've needed to establish BIO_CHAIN).  As such
the first bio_endio(), in step 2 above, never decremented __bi_remaining
before calling the intermediate bi_end_io -- leaving __bi_remaining with
the value 1 instead of 0.  When bio_inc_remaining() occurred during step
3 it brought it to a value of 2.  When the second bio_endio() was
called, in step 4 above, it should've called the original bi_end_io but
it didn't because there was an extra reference that wasn't dropped (due
to atomic operations being optimized away since BIO_CHAIN wasn't set
upfront).

Fix this issue by removing the __bi_remaining management complexity for
all callers that use the above pattern -- bio_chain() is the only
interface that _needs_ to be concerned with __bi_remaining.  For the
above pattern callers just expect the bi_end_io they set to get called!
Remove bio_endio_nodec() and also remove all bio_inc_remaining() calls
that aren't associated with the bio_chain() interface.

Also, the bio_inc_remaining() interface has been moved local to bio.c.

Fixes: c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for non-chains")
Reviewed-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Signed-off-by: Mike Snitzer 
Signed-off-by: Jens Axboe

bio: skip atomic inc/dec of ->bi_cnt for most use cases

2015-05-05T19:32:49+00:00

Struct bio has a reference count that controls when it can be freed.
Most uses cases is allocating the bio, which then returns with a
single reference to it, doing IO, and then dropping that single
reference. We can remove this atomic_dec_and_test() in the completion
path, if nobody else is holding a reference to the bio.

If someone does call bio_get() on the bio, then we flag the bio as
now having valid count and that we must properly honor the reference
count when it's being put.

Tested-by: Robert Elliott 
Signed-off-by: Jens Axboe

md/bcache: use generic io stats accounting functions to simplify io stat accounting

2014-11-24T15:05:12+00:00

Use generic io stats accounting help functions (generic_{start,end}_io_acct)
to simplify io stat accounting.

Signed-off-by: Gu Zheng 
Acked-by: Kent Overstreet 
Signed-off-by: Jens Axboe