Commit Graph

933130 Commits

Author SHA1 Message Date
Jens Axboe b53ac8b891 dm: remove unused variable
Since merging the commit identified in Fixes below, we trigger this
compile time warning:

drivers/md/dm.c: In function ‘__map_bio’:
drivers/md/dm.c:1296:24: warning: unused variable ‘md’ [-Wunused-variable]
 1296 |  struct mapped_device *md = io->md;
       |                        ^~

Remove the 'md' variable.

Fixes: 5a6c35f9af ("block: remove direct_make_request")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 15:45:19 -06:00
John Garry 6bf0eb5504 sbitmap: Consider cleared bits in sbitmap_bitmap_show()
sbitmap works by maintaining separate bitmaps of set and cleared bits.
The set bits are cleared in a batch, to save the burden of continuously
locking the "word" map to unset.

sbitmap_bitmap_show() only shows the set bits (in "word"), which is not
too much use, so mask out the cleared bits.

Fixes: ea86ea2cdc ("sbitmap: ammortize cost of clearing bits")
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 10:53:00 -06:00
Christoph Hellwig 1008fe6dc3 block: remove the all_bdevs list
Instead just iterate over the inodes for the block device superblock.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 08:08:25 -06:00
Christoph Hellwig 47b5e00322 block: remove the unused bd_private field from struct block_device
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 08:08:23 -06:00
Christoph Hellwig e556f6ba10 block: remove the bd_queue field from struct block_device
Just use bd_disk->queue instead.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 08:08:20 -06:00
Christoph Hellwig 6b7b181b67 block: remove the bd_block_size field from struct block_device
We can trivially calculate the block size from the inodes i_blkbits
variable.  Use that instead of keeping two redundant copies of the
information in slightly different formats.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 08:08:17 -06:00
Christoph Hellwig 5ff9f19231 block: simplify set_init_blocksize
The loop to increase the initial block size doesn't really make any
sense, as the AND operation won't match for powers of two if it didn't
for the initial block size.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 08:08:17 -06:00
Christoph Hellwig 9011495c94 dcssblk: don't set bd_block_size in ->open
bd_block_size contains a value that matches the logic block size when
opening, so the statement is redundant.  Even if it wasn't the dumb
assignment would cause a a mismatch with bd_inode->i_blkbits.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 08:08:15 -06:00
Christoph Hellwig fe4ec12e18 floppy: use block_size
Use the block_size helper instead of open coding it.  Also remove the
check for a 0 block size, as that can't happen.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 08:08:08 -06:00
Hongnan Li 6e2fa4dd68 blk-iolatency: only call ktime_get() if needed
ktime_to_ns(ktime_get()), which is expensive, does not need to be called
if blk_iolatency_enabled() return false in blkcg_iolatency_done_bio().
Postponing ktime_to_ns(ktime_get()) execution reduces the CPU usage when
blk_iolatency is disabled.

Signed-off-by: Hongnan Li <hongnan.li@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 08:02:38 -06:00
Christoph Hellwig 5a6c35f9af block: remove direct_make_request
Now that submit_bio_noacct has a decent blk-mq fast path there is no
more need for this bypass.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:24 -06:00
Christoph Hellwig ff93ea0ce7 block: shortcut __submit_bio_noacct for blk-mq drivers
For blk-mq drivers bios can only be inserted for the same queue.  So
bypass the complicated sorting logic in __submit_bio_noacct with
a blk-mq simpler submission helper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:24 -06:00
Christoph Hellwig 566acf2daa block: refator submit_bio_noacct
Split out a __submit_bio_noacct helper for the actual de-recursion
algorithm, and simplify the loop by using a continue when we can't
enter the queue for a bio.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:24 -06:00
Christoph Hellwig ed00aabd5e block: rename generic_make_request to submit_bio_noacct
generic_make_request has always been very confusingly misnamed, so rename
it to submit_bio_noacct to make it clear that it is submit_bio minus
accounting and a few checks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:24 -06:00
Christoph Hellwig c62b37d96b block: move ->make_request_fn to struct block_device_operations
The make_request_fn is a little weird in that it sits directly in
struct request_queue instead of an operation vector.  Replace it with
a block_device_operations method called submit_bio (which describes much
better what it does).  Also remove the request_queue argument to it, as
the queue can be derived pretty trivially from the bio.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:24 -06:00
Christoph Hellwig e439ab710f block: remove the nr_sectors variable in generic_make_request_checks
The variable is only used once, so just open code the bio_sector()
there.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:24 -06:00
Christoph Hellwig 833f84e2b9 block: remove the NULL queue check in generic_make_request_checks
All registers disks must have a valid queue pointer, so don't bother to
log a warning for that case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:24 -06:00
Christoph Hellwig c817867460 block: tidy up a warning in bio_check_ro
The "generic_make_request: " prefix has no value, and will soon become
stale.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:23 -06:00
Christoph Hellwig f695ca3886 block: remove the request_queue argument from blk_queue_split
The queue can be trivially derived from the bio, so pass one less
argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:23 -06:00
Christoph Hellwig ed9b3196d2 fs: remove a weird comment in submit_bh_wbc
All bios can get remapped if submitted to partitions.  No need to
comment on that.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:23 -06:00
Christoph Hellwig c4a59c4e5d dm: stop using ->queuedata
Instead of setting up the queuedata as well just use one private data
field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:23 -06:00
Christoph Hellwig 987a0ef88b bcache: stop setting ->queuedata
Nothing in bcache actually uses the ->queuedata field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:23 -06:00
Christoph Hellwig 39ad70b568 zram: stop using ->queuedata
Instead of setting up the queuedata as well just use one private data
field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:23 -06:00
Christoph Hellwig 6c2eddd63b umem: stop using ->queuedata
Instead of setting up the queuedata as well just use one private data
field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:23 -06:00
Christoph Hellwig a2f143fc21 rsxx: stop using ->queuedata
Instead of setting up the queuedata as well just use one private data
field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:23 -06:00
Christoph Hellwig 53042f3cc4 ps3vram: stop using ->queuedata
Instead of setting up the queuedata as well just use one private data
field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:23 -06:00
Christoph Hellwig 6bbae86056 null_blk: stop using ->queuedata for bio mode
Instead of setting up the queuedata as well just use one private data
field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:23 -06:00
Christoph Hellwig 84bc83c3ba drbd: stop using ->queuedata
Instead of setting up the queuedata as well just use one private data
field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:23 -06:00
Christoph Hellwig 82bb454d07 simdisk: stop using ->queuedata
Instead of setting up the queuedata as well just use one private data
field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:23 -06:00
Christoph Hellwig 6d41bb4d46 nfblock: stop using ->queuedata
Instead of setting up the queuedata as well just use one private data
field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:23 -06:00
Hou Tao b5fc1e8bed blk-mq: remove pointless call of list_entry_rq() in hctx_show_busy_rq()
Just use rq directly, the usage of list_entry_rq() doesn't make any
sense.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:25:36 -06:00
Colin Ian King 0b8cc25d94 blk-cgroup: clean up indentation
There is a statement that is indented one level too deeply, fix it
by removing a tab.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-30 13:00:04 -06:00
Ming Lei 37f4a24c24 blk-mq: centralise related handling into blk_mq_get_driver_tag
Move .nr_active update and request assignment into blk_mq_get_driver_tag(),
all are good to do during getting driver tag.

Meantime blk-flush related code is simplified and flush request needn't
to update the request table manually any more.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-30 12:57:59 -06:00
Ming Lei 723bf178f1 blk-mq: move blk_mq_put_driver_tag() into blk-mq.c
It is used by blk-mq.c only, so move it to the source file.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-30 12:57:59 -06:00
Ming Lei 570e9b73b0 blk-mq: move blk_mq_get_driver_tag into blk-mq.c
blk_mq_get_driver_tag() is only used by blk-mq.c and is supposed to
stay in blk-mq.c, so move it and preparing for cleanup code of
get/put driver tag.

Meantime hctx_may_queue() is moved to header file and it is fine
since it is defined as inline always.

No functional change.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-30 12:57:59 -06:00
Ming Lei 6e6fcbc27e blk-mq: support batching dispatch in case of io
More and more drivers want to get batching requests queued from
block layer, such as mmc, and tcp based storage drivers. Also
current in-tree users have virtio-scsi, virtio-blk and nvme.

For none, we already support batching dispatch.

But for io scheduler, every time we just take one request from scheduler
and pass the single request to blk_mq_dispatch_rq_list(). This way makes
batching dispatch not possible when io scheduler is applied. One reason
is that we don't want to hurt sequential IO performance, becasue IO
merge chance is reduced if more requests are dequeued from scheduler
queue.

Try to support batching dispatch for io scheduler by starting with the
following simple approach:

1) still make sure we can get budget before dequeueing request

2) use hctx->dispatch_busy to evaluate if queue is busy, if it is busy
we fackback to non-batching dispatch, otherwise dequeue as many as
possible requests from scheduler, and pass them to blk_mq_dispatch_rq_list().

Wrt. 2), we use similar policy for none, and turns out that SCSI SSD
performance got improved much.

In future, maybe we can develop more intelligent algorithem for batching
dispatch.

Baolin has tested this patch and found that MMC performance is improved[3].

[1] https://lore.kernel.org/linux-block/20200512075501.GF1531898@T590/#r
[2] https://lore.kernel.org/linux-block/fe6bd8b9-6ed9-b225-f80c-314746133722@grimberg.me/
[3] https://lore.kernel.org/linux-block/CADBw62o9eTQDJ9RvNgEqSpXmg6Xcq=2TxH0Hfxhp29uF2W=TXA@mail.gmail.com/

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Baolin Wang <baolin.wang7@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-30 07:51:48 -06:00
Ming Lei 1fd40b5ea7 blk-mq: pass obtained budget count to blk_mq_dispatch_rq_list
Pass obtained budget count to blk_mq_dispatch_rq_list(), and prepare
for supporting fully batching submission.

With the obtained budget count, it is easier to put extra budgets
in case of .queue_rq failure.

Meantime remove the old 'got_budget' parameter.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Baolin Wang <baolin.wang7@gmail.com>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-30 07:51:48 -06:00
Ming Lei bbdb3c5d94 blk-mq: remove dead check from blk_mq_dispatch_rq_list
When BLK_STS_RESOURCE or BLK_STS_DEV_RESOURCE is returned from
.queue_rq, the 'list' variable always holds this rq which isn't
queued to LLD successfully.

So blk_mq_dispatch_rq_list() always returns false from the branch
of '!list_empty(list)'.

No functional change.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Baolin Wang <baolin.wang7@gmail.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-30 07:51:48 -06:00
Ming Lei 7538352453 blk-mq: move getting driver tag and budget into one helper
Move code for getting driver tag and budget into one helper, so
blk_mq_dispatch_rq_list gets a bit simplified, and easier to read.

Meantime move updating of 'no_tag' and 'no_budget_available' into
the branch for handling partial dispatch because that is exactly
consumer of the two local variables.

Also rename the parameter of 'got_budget' as 'ask_budget'.

No functional change.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Baolin Wang <baolin.wang7@gmail.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-30 07:51:48 -06:00
Ming Lei 445874e89f blk-mq: pass hctx to blk_mq_dispatch_rq_list
All requests in the 'list' of blk_mq_dispatch_rq_list belong to same
hctx, so it is better to pass hctx instead of request queue, because
blk-mq's dispatch target is hctx instead of request queue.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Baolin Wang <baolin.wang7@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-30 07:51:48 -06:00
Ming Lei 65c7636943 blk-mq: pass request queue into get/put budget callback
blk-mq budget is abstract from scsi's device queue depth, and it is
always per-request-queue instead of hctx.

It can be quite absurd to get a budget from one hctx, then dequeue a
request from scheduler queue, and this request may not belong to this
hctx, at least for bfq and deadline.

So fix the mess and always pass request queue to get/put budget
callback.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Baolin Wang <baolin.wang7@gmail.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-30 07:51:48 -06:00
Christoph Hellwig 42fdc5e49c blk-mq: remove the BLK_MQ_REQ_INTERNAL flag
Just check for a non-NULL elevator directly to make the code more clear.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-29 09:56:18 -06:00
Ming Lei 36a3df5a45 blk-mq: put driver tag when this request is completed
It is natural to release driver tag when this request is completed by
LLD or device since its purpose is for LLD use.

One big benefit is that the released tag can be re-used quicker since
bio_endio() may take too long.

Meantime we don't need to release driver tag for flush request.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-29 09:56:10 -06:00
Christoph Hellwig a2e83ef9c3 blk-cgroup: remove a dead check in blk_throtl_bio
bios must have a valid block group by the time they are submitted.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-29 09:09:08 -06:00
Christoph Hellwig db18a53e5b blk-cgroup: remove blkcg_bio_issue_check
blkcg_bio_issue_check is a giant inline function that does three entirely
different things.  Factor out the blk-cgroup related bio initalization
into a new helper, and the open code the sequence in the only caller,
relying on the fact that all the actual functionality is stubbed out for
non-cgroup builds.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-29 09:09:08 -06:00
Christoph Hellwig 93b8063804 blk-cgroup: move rcu locking from blkcg_bio_issue_check to blk_throtl_bio
The only thing in blkcg_bio_issue_check that needs to be under
rcu_read_lock is blk_throtl_bio, so move the locking there.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-29 09:09:08 -06:00
Christoph Hellwig 7582f30cc9 cgroup: unexport cgroup_rstat_updated
cgroup_rstat_updated is only used by core block code, no need to
export it.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-29 09:09:08 -06:00
Christoph Hellwig 81630e27ff blk-cgroup: remove the !bio->bi_blkg check in blkcg_bio_issue_check
This is purely a sanity check for grave programming errors.  Remove it
to simplify further work in this area.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-29 09:09:08 -06:00
Christoph Hellwig 13c7863d48 block: move the initial blkg lookup into blkg_tryget_closest
By moving the initial blkg lookup into blkg_tryget_closest we get
a nicely self contained routines that does all the RCU locking.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-29 09:09:08 -06:00
Christoph Hellwig a5b97526bf block: bypass blkg_tryget_closest for the root_blkg
The root_blkg is only torn down at the very end of removing a queue.
So in the I/O submission path is always has a life reference and we
can just grab another one using blkg_get instead of doing a tryget
and parent walk that won't lead anywhere.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-29 09:09:08 -06:00