Read/write/flush are the most common operations, optimize switch in
is_abnormal_io() for those cases. Follows same pattern established in
block perf-wip commit ("block: optimise blk_may_split for normal rw")

Also, push is_abnormal_io() check and blk_queue_split() down from
dm_submit_bio() to dm_split_and_process_bio() and set new
'is_abnormal_io' flag in clone_info. Optimize __split_and_process_bio
and __process_abnormal_io by leveraging ci.is_abnormal_io flag.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Now that io splitting is recorded prior to, or during, ->map IO
accounting can happen immediately rather than defer until after
bio splitting in dm_split_and_process_bio().

Remove the DM_IO_START_ACCT flag and also remove dm_io's map_task
member because there is no longer any need to wait for splitting to
occur before accounting.

Also move dm_io struct's 'flags' member to consolidate struct holes.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Now that bio_split() isn't used by DM's bio splitting, it is a bit
overkill to link dm_io into an hlist given there is only single dm_io
in the list.

Convert to using a single list for holding all dm_io instances
associated with this bio.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Currently each dm_io's reference counter is grabbed before calling
__map_bio(), this way isn't efficient since we can move this grabbing
to initialization time inside alloc_io().

Meantime it becomes typical async io reference counter model: one is
for submission side, the other is for completion side, and the io won't
be completed until both sides are done.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

dm_zone_map_bio() is only called from __map_bio in which the io's
reference is grabbed already, and the reference won't be released
until the bio is submitted, so not necessary to do it dm_zone_map_bio
any more.
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

The current DM code (ab)uses late assignment of dm_io->orig_bio (after
__map_bio() returns and any bio splitting is complete) to indicate the
FS bio has been processed and can be accounted. This results in
awkward waiting until ->orig_bio is set in dm_submit_bio_remap().

Also the bio splitting was implemented using bio_split()+bio_chain()
-- a well-worn pattern but it requires bio cloning purely for the
benefit of more natural IO accounting.  The bio_split() result was
stored in ->orig_bio to represent the mapped part of the original FS
bio.

DM has switched to the bdev based IO accounting interface.  DM's IO
accounting can be implemented in terms of the original FS bio (now
stored early in ->orig_bio) via access to its sectors/bio_op. And
if/when splitting is needed, set a new DM_IO_WAS_SPLIT flag and use
new dm_io fields of .sector_offset & .sectors to allow IO accounting
for split bios _without_ needing to clone a new bio to store in
->orig_bio.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Co-developed-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

DM splits flush with data into empty flush followed by bio with data
payload, switch dm_io_acct() to use bdev_{start,end}_io_acct() to do
this accoiunting more naturally (rather than temporarily changing the
bio's bi_size).

This will allow DM to more easily account bios that are split (in
following commit).
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

All the other 4 parameters are retrieved from the 'dm_io' instance, so
it's not necessary to pass all four to dm_io_acct().
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

dm->orig_bio is always passed to __dm_start_io_acct and dm_end_io_acct,
so it isn't necessary to take one bio parameter for the two helpers.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Rename 'bi_size' to 'bio_sectors' given bi_size is being stored in
sectors.  Also, use bio_sectors() rather than open-coding it.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Remove needless factoring and remap bi_sector regardless of
bio_sectors() being non-zero.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Use jump_labels to further reduce cost of unlikely branches for zoned
block devices, dm-stats and swap_bios throttling.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

If a bio is marked REQ_NOWAIT optimize dm_submit_bio()'s dm_table RCU
usage to dm_{get,put}_live_table_fast.

DM core offers protection against blocking (via suspend) if REQ_NOWAIT.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Just saves some cacheline bouncing for members accessed during cloned
bio submission and completion.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Avoid redundant dereferences in both functions.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Pull common DM_IO_ACCOUNTED check out to beginning of dm_start_io_acct.
Also, use dm_tio_is_normal (and move it to dm-core.h).
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Use local variable instead of redudant access using ci.io
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Also eliminate need to use errno_to_blk_status().
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

A bioset's per-cpu alloc cache may have broader utility in the future
but for now constrain it to being tightly coupled to QUEUE_FLAG_POLL.

Also change dm_io_complete() to use bio_clear_polled() so that it
properly clears all associated bio state on requeue.

This commit improves DM's hipri bio polling (REQ_POLLED) perf by
7 - 20% depending on the system.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Print the start sector and length separately instead of the combined
value to help with debugging.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Link: https://lore.kernel.org/r/20220504143355.568660-1-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Device mapper wants to allocate a bio before knowing the device it
gets send to, so add explicit support for that.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20220504142950.567582-3-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

blkcg_bio_issue_init is called in submit_bio.  There is no need to have
extra calls that just get overriden in __bio_clone and the two places
that copy and pasted from it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20220504142950.567582-2-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

kthread_blkcg is only used by the built-in blk-cgroup code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-16-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Use blkcg_css instead of opencoding it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-15-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Use blkcg_css instead of open coding it, and switch to a slightly
more natural for loop.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-14-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

blkcg_css is only used in blk-cgroup.c, so move it there.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-13-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Remove all the includes that aren't actually needed from
<linux/blk-cgroup.h> and push them to the actual source files where
needed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-12-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

No need to make BLK_CGROUP stubs conditional on CONFIG_BLOCK as they
can't be used without that.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-11-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

All callers of bio_blkcg actually want the CSS, so replace it with an
interface that does return the CSS.  This now allows to move
struct blkcg_gq to block/blk-cgroup.h instead of exposing it in a
public header.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-10-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Pass the cgroup_subsys_state instead of a the blkg so that blktrace
doesn't need to poke into blk-cgroup internals, and give the name a
blk prefix as the current name is way too generic for a public
interface.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-9-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

There is no real need to expose the blkcg structure to the whole kernel.
Move it to the private header an expose a helper to let the writeback
code access the cgwb_list member.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-8-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Move these two functions out of line as there is no good reason
to inline them.  Also switch to passing a cgroup_subsys_state
instead of doing the conversion in the caller to prepare for making
the blkcg structure private to blk-cgroup.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-7-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

There is no urgent need to inline this function, so move it out of line.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-6-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

No need to have these helpers inline.  Also remove the stubs and just use
an IS_ENABLED for the get side (the set side already is only built
conditionlly).
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-5-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

No need for this wrapper.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-4-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

nvme-fc appid support needs CONFIG_BLK_CGROUP_FC_APPID to work, so disable
the whole code if the option is not set.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-3-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Remove the unused and deprecated __bio_blkcg helper.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-2-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

So far bio is marked as REQ_POLLED if RWF_HIPRI/IOCB_HIPRI is passed
from userspace sync io interface, then block layer tries to poll until
the bio is completed. But the current implementation calls
blk_io_schedule() if bio_poll() returns 0, and this way causes io hang or
timeout easily.

But looks no one reports this kind of issue, which should have been
triggered in normal io poll sanity test or blktests block/007 as
observed by Changhui, that means it is very likely that no one uses it
or no one cares it.

Also after io_uring is invented, io poll for sync dio becomes legacy
interface.

So ignore RWF_HIPRI hint for sync dio.

CC: linux-mm@kvack.org
Cc: linux-xfs@vger.kernel.org
Reported-by: Changhui Zhong <czhong@redhat.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Changhui Zhong <czhong@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220420143110.2679002-1-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Get rid of the following redundant assignments:
- to a variable r_cols from function ldm_parse_cmp3
- to variables r_id1 and r_id2 from functions ldm_parse_dgr3 and ldm_parse_dgr4
- to a variable r_index from function ldm_parse_prt3
that end up in values not being read until the end of function.

Reported by clang-tidy [deadcode.DeadStores]
Signed-off-by: Michal Orzel <michalorzel.eng@gmail.com>
Link: https://lore.kernel.org/r/20220423113811.13335-5-michalorzel.eng@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>