Implement the ->free_disk method to free the virtio_blk structure only
once the last gendisk reference goes away instead of keeping a local
refcount.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/20220215094514.3828912-6-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Implement the ->free_disk method to free the msb_data structure only once
the last gendisk reference goes away instead of keeping a local
refcount.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220215094514.3828912-5-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Use set_disk_ro to propagate the read-only state to the block layer
instead of checking for it in ->open and leaking a reference in case
of a read-only device.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220215094514.3828912-4-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Implement the ->free_disk method to free the msb_data structure only once
the last gendisk reference goes away instead of keeping a local refcount.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220215094514.3828912-3-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Add a method to notify the driver that the gendisk is about to be freed.
This allows drivers to tie the lifetime of their private data to that of
the gendisk and thus deal with device removal races without expensive
synchronization and boilerplate code.

A new flag is added so that ->free_disk is only called after a successful
call to add_disk, which significantly simplifies the error handling path
during probing.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220215094514.3828912-2-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Revert commit 4f1e9630 ("blk-throtl: optimize IOPS throttle for large
IO scenarios") since we have another easier way to address this issue and
get better iops throttling result.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220216044514.2903784-9-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

We need to throttle split bio in case of IOPS limit even though the
split bio has been marked as BIO_THROTTLED since block layer
accounts split bio actually.

If only throughput throttle is setup, no need to throttle any more
if BIO_THROTTLED is set since we have accounted & considered the
whole bio bytes already.

Add one flag of THROTL_TG_HAS_IOPS_LIMIT for serving this purpose.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220216044514.2903784-8-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Commit 111be883 ("block-throttle: avoid double charge") marks bio as
BIO_THROTTLED unconditionally if __blk_throtl_bio() is called on this bio,
then this bio won't be called into __blk_throtl_bio() any more. This way
is to avoid double charge in case of bio splitting. It is reasonable for
read/write throughput limit, but not reasonable for IOPS limit because
block layer provides io accounting against split bio.

Chunguang Xu has already observed this issue and fixed it in commit
4f1e9630 ("blk-throtl: optimize IOPS throttle for large IO scenarios").
However, that patch only covers bio splitting in __blk_queue_split(), and
we have other kind of bio splitting, such as bio_split() &
submit_bio_noacct() and other ways.

This patch tries to fix the issue in one generic way by always charging
the bio for iops limit in blk_throtl_bio(). This way is reasonable:
re-submission & fast-cloned bio is charged if it is submitted to same
disk/queue, and BIO_THROTTLED will be cleared if bio->bi_bdev is changed.

This new approach can get much more smooth/stable iops limit compared with
commit 4f1e9630 ("blk-throtl: optimize IOPS throttle for large IO
scenarios") since that commit can't throttle current split bios actually.

Also this way won't cause new double bio iops charge in
blk_throtl_dispatch_work_fn() in which blk_throtl_bio() won't be called
any more.
Reported-by: Ning Li <lining2020x@163.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Chunguang Xu <brookxu@tencent.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220216044514.2903784-7-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Now submit_bio_checks() is only called by submit_bio_noacct(), so merge
it into submit_bio_noacct().
Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220216044514.2903784-6-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

The bio has been checked already before throttling, so no need to check
it again before dispatching it from throttle queue.

Add a helper of submit_bio_noacct_nocheck() for this purpose.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220216044514.2903784-5-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

submit_bio_checks() won't be called outside of block/blk-core.c any more
since commit 9d497e29 ("block: don't protect submit_bio_checks by
q_usage_counter"), so mark it as one local helper.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220216044514.2903784-4-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

blk_crypto_bio_prep() is called for both bio based and blk-mq drivers,
so move it out of blk-mq.c, then we can unify this kind of handling.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220216044514.2903784-3-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

It is more clean & readable to check bio when starting to submit it,
instead of just before calling ->submit_bio() or blk_mq_submit_bio().

Also it provides us chance to optimize bio submission without checking
bio.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220216044514.2903784-2-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Fold dm_dispatch_clone_request into it's only caller, and use a switch
statement to single dispatch for the handling of the different return
values from blk_insert_cloned_request.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220215100540.3892965-6-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Both ->start_time_ns and the RQF_IO_STAT are set when the request is
allocated using blk_mq_alloc_request by dm-mpath in blk_mq_rq_ctx_init.
The block layer also ensures ->start_time_ns is only set when actually
needed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220215100540.3892965-5-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

The request must be submitted to the queue it was allocated for, so
remove the extra request_queue argument.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220215100540.3892965-4-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Fold blk_cloned_rq_check_limits into its only caller.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220215100540.3892965-3-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

The code to stack blk-mq drivers is only used by dm-multipath, and
will preferably stay that way.  Make it optional and only selected
by device mapper, so that the buildbots more easily catch abuses
like the one that slipped in in the ufs driver in the last merged
window.  Another positive side effects is that kernel builds without
device mapper shrink a little bit as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220215100540.3892965-2-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Don't need to do blkg_iostat_set for top blkg iostat on each CPU,
so move it after percpu stat aggregation.

Fixes: ef45fe47 ("blk-cgroup: show global disk stats in root cgroup io.stat")
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220213085902.88884-1-zhouchengming@bytedance.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Based on the comment present in the bdev_get_queue()
bdev->bd_queue can never be NULL. Remove the NULL check for the local
variable q that is set from bdev_get_queue() for discard, write_same,
and write_zeroes.
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220215115247.11717-2-kch@nvidia.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

This document is completely out of date and extremely misleading. In
general the existing kerneldoc comment serve as a much better
documentation of the still existing functionality, while the history
blurbs are pretty much irrelevant today.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220215081047.3693582-1-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Since commit 7eaceacc ("block: remove per-queue plugging"), kernel
has removed blk_run_address_space(), blk_unplug() and sync_buffer(),
and moved to on-stack plugging. The document has been obsolete for
years.
Given that there is no obvious counterparts in the new mechinism to
replace old APIs, this patch drops the content directly.
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Link: https://lore.kernel.org/r/20220207074931.20067-1-song.bao.hua@hisilicon.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Partition include/linux/blk-cgroup.h into two parts: one is public part,
the other is block layer private part.

Suggested by Christoph Hellwig.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220211101149.2368042-4-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

q->blkg_list is only used by blkcg code, so move it into
blkcg_init_queue.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220211101149.2368042-3-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

No one uses THROTL_IOPS_MAX any more, so remove it.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220211101149.2368042-2-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Currently, rasdaemon uses the existing tracepoint block_rq_complete
and filters out non-error cases in order to capture block disk errors.

But there are a few problems with this approach:

1. Even kernel trace filter could do the filtering work, there is
   still some overhead after we enable this tracepoint.

2. The filter is merely based on errno, which does not align with kernel
   logic to check the errors for print_req_error().

3. block_rq_complete only provides dev major and minor to identify
   the block device, it is not convenient to use in user-space.

So introduce a new tracepoint block_rq_error just for the error case.
With this patch, rasdaemon could switch to block_rq_error.

Since the new tracepoint has the similar implementation with
block_rq_complete, so move the existing code from TRACE_EVENT
block_rq_complete() into new event class block_rq_completion(). Then add
event for block_rq_complete and block_rq_err respectively from the newly
created event class per the suggestion from Chaitanya Kulkarni.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220210225222.260069-1-shy828301@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Since __sbitmap_queue_get_shallow() was introduced in commit c05e6673
("sbitmap: add sbitmap_get_shallow() operation"), it has not been used.

Delete __sbitmap_queue_get_shallow() and rename public
__sbitmap_queue_get_shallow() -> sbitmap_queue_get_shallow() as it is odd
to have public __foo but no foo at all.
Signed-off-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/1644322024-105340-1-git-send-email-john.garry@huawei.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Only the last sbitmap_word can have different depth, and all the others
must have same depth of 1U << sb->shift, so not necessary to store it in
sbitmap_word, and it can be retrieved easily and efficiently by adding
one internal helper of __map_depth(sb, index).

Remove 'depth' field from sbitmap_word, then the annotation of
____cacheline_aligned_in_smp for 'word' isn't needed any more.

Not see performance effect when running high parallel IOPS test on
null_blk.

This way saves us one cacheline(usually 64 words) per each sbitmap_word.

Cc: Martin Wilck <martin.wilck@suse.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin Wilck <mwilck@suse.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/20220110072945.347535-1-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Pass a block_device to bio_clone_fast and __bio_clone_fast and give
the functions more suitable names.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-14-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

All callers of __bio_clone_fast initialize the bio first.  Move that
initialization into __bio_clone_fast instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-13-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Replace open coded bio_clone_fast implementations with the actual helper.
Note that the bio allocated as part of the dm_io structure in alloc_io
will only actually be used later in alloc_tio, making this earlier
cloning of the information safe.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-12-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

__bio_clone_fast should also clone integrity and crypto data, as a clone
without those is incomplete.  Right now the only caller that can actually
support crypto and integrity data (dm) does it manually for the one
callchain that supports these, but we better do it properly in the core.

Note that all callers except for the above mentioned one also don't need
to handle failure at all, given that the integrity and crypto clones are
based on mempool allocations that won't fail for sleeping allocations.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-11-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Fold __remap_to_origin_clear_discard into the two callers to prepare
for bio cloning refactoring.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-10-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Most targets just need a single flush bio.  Open code that case in
__send_duplicate_bios without the need to add the bio to a list.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-9-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Return the clone bio embedded into the tio as that is what the callers
actually want.  Similar for the free side.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-8-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

This simplifies the callers a bit.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-7-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Move the call to __bio_clone_fast and the assignment of ->len_ptr from
the callers into alloc_tio to prepare for changes to the bio clone API.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-6-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Fold __send_duplicate_bios into its only caller to prepare for
refactoring.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-5-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Fold clone_bio into its only caller to prepare for refactoring.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-4-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Add a helper to stop open coding the container_of operations to get
from the clone bio to the tio structure.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-3-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>