bio.h: fix kernel-doc warnings

Fix all kernel-doc warnings in <linux/bio.h>:

include/linux/bio.h:136: warning: Function parameter or member 'nbytes' not described in 'bio_advance'
include/linux/bio.h:136: warning: Excess function parameter 'bytes' description in 'bio_advance'
include/linux/bio.h:391: warning: No description found for return value of 'bio_next_split'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Link: https://lore.kernel.org/r/20211222211532.24060-1-rdunlap@infradead.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: check minor range in device_add_disk()

ioctl(fd, LOOP_CTL_ADD, 1048576) causes

  sysfs: cannot create duplicate filename '/dev/block/7:0'

message because such request is treated as if ioctl(fd, LOOP_CTL_ADD, 0)
due to MINORMASK == 1048575. Verify that all minor numbers for that device
fit in the minor range.

Reported-by: wangyangbo <wangyangbo@uniontech.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/b1b19379-23ee-5379-0eb5-94bf5f79f1b4@i-love.sakura.ne.jp
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: use "unsigned long" for blk_validate_block_size().

Since lo_simple_ioctl(LOOP_SET_BLOCK_SIZE) and ioctl(NBD_SET_BLKSIZE) pass
user-controlled "unsigned long arg" to blk_validate_block_size(),
"unsigned long" should be used for validation.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/9ecbf057-4375-c2db-ab53-e4cc0dff953d@i-love.sakura.ne.jp
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: fix error unwinding in device_add_disk

One device_add is called disk->ev will be freed by disk_release, so we
should free it twice.  Fix this by allocating disk->ev after device_add
so that the extra local unwinding can be removed entirely.

Based on an earlier patch from Tetsuo Handa.

Reported-by: syzbot <syzbot+28a66a9fbc621c939000@syzkaller.appspotmail.com>
Tested-by: syzbot <syzbot+28a66a9fbc621c939000@syzkaller.appspotmail.com>
Fixes: 83cbce9574462c6b ("block: add error handling for device_add_disk / add_disk")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211221161851.788424-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: call blk_exit_queue() before freeing q->stats

blk_stat_disable_accounting() is added in commit 68497092bde9
("block: make queue stat accounting a reference"), and called in
kyber_exit_sched().

So we have to free q->stats after elevator is unloaded from
blk_exit_queue() in blk_release_queue(). Otherwise kernel panic
is caused.

Fixes: 68497092bde9 ("block: make queue stat accounting a reference")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211221040436.1333880-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: fix error in handling dead task for ioprio setting

Don't combine the task exiting and "already have io_context" case, we
need to just abort if the task is marked as dead. Return -ESRCH, which
is the documented value for ioprio_set() if the specified task could not
be found.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reported-by: syzbot+8836466a79f4175961b0@syzkaller.appspotmail.com
Fixes: 5fc11eebb4a9 ("block: open code create_task_io_context in set_task_ioprio")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: blk-mq: check quiesce state before queue_rqs

The low level drivers don't expect to see new requests after a
successful quiesce completes. Check the queue quiesce state within the
rcu protected area prior to calling the driver's queue_rqs().

Fixes: 3c67d44de787 ("block: add mq_ops->queue_rqs hook")
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20211220205919.180191-1-kbusch@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blktrace: switch trace spinlock to a raw spinlock

The running_trace_lock protects running_trace_list and is acquired
within the tracepoint which implies disabled preemption. The spinlock_t
typed lock can not be acquired with disabled preemption on PREEMPT_RT
because it becomes a sleeping lock.
The runtime of the tracepoint depends on the number of entries in
running_trace_list and has no limit. The blk-tracer is considered debug
code and higher latencies here are okay.

Make running_trace_lock a raw_spinlock_t.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20211220192827.38297-1-wander@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: only build the icq tracking code when needed

Only bfq needs to code to track icq, so make it conditional.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211209063131.18537-12-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: fold create_task_io_context into ioc_find_get_icq

Fold create_task_io_context into the only remaining caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211209063131.18537-11-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: open code create_task_io_context in set_task_ioprio

The flow in set_task_ioprio can be simplified by simply open coding
create_task_io_context, which removes a refcount roundtrip on the I/O
context.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211209063131.18537-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: fold get_task_io_context into set_task_ioprio

Fold get_task_io_context into its only caller, and simplify the code
as no reference to the I/O context is required to just set the ioprio
field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211209063131.18537-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: move set_task_ioprio to blk-ioc.c

Keep set_task_ioprio with the other low-level code that accesses the
io_context structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211209063131.18537-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: cleanup ioc_clear_queue

Fold __ioc_clear_queue into ioc_clear_queue and switch to always
use plain _irq locking instead of the more expensive _irqsave that
is not needed here.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211209063131.18537-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: refactor put_io_context

Move the code to delay freeing the icqs into a separate helper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211209063131.18537-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove the NULL ioc check in put_io_context

No caller passes in a NULL pointer, so remove the check.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211209063131.18537-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: refactor put_iocontext_active

Factor out a ioc_exit_icqs helper to tear down the icqs and the fold
the rest of put_iocontext_active into exit_io_context.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211209063131.18537-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: simplify struct io_context refcounting

Don't hold a reference to ->refcount for each active reference, but
just one for all active references.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211209063131.18537-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove the nr_task field from struct io_context

Nothing ever looks at ->nr_tasks, so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211209063131.18537-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: add support for mq_ops->queue_rqs()

This enables the block layer to send us a full plug list of requests
that need submitting. The block layer guarantees that they all belong
to the same queue, but we do have to check the hardware queue mapping
for each request.

If errors are encountered, leave them in the passed in list. Then the
block layer will handle them individually.

This is good for about a 4% improvement in peak performance, taking us
from 9.6M to 10M IOPS/core.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: separate command prep and issue

Add a nvme_prep_rq() helper to setup a command, and nvme_queue_rq() is
adapted to use this helper.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: split command copy into a helper

We'll need it for batched submit as well. Since we now have a copy
helper, get rid of the nvme_submit_cmd() wrapper.

Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: add mq_ops->queue_rqs hook

If we have a list of requests in our plug list, send it to the driver in
one go, if possible. The driver must set mq_ops->queue_rqs() to support
this, if not the usual one-by-one path is used.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: use singly linked list for bio cache

Pointless to maintain a head/tail for the list, as we never need to
access the tail. Entries are always LIFO for cache hotness reasons.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: add completion handler for fast path

The batched completions only deal with non-partial requests anyway,
and it doesn't deal with any requests that have errors. Add a completion
handler that assumes it's a full request and that it's all being ended
successfully.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: make queue stat accounting a reference

kyber turns on IO statistics when it is loaded on a queue, which means
that even if kyber is then later unloaded, we're still stuck with stats
enabled on the queue.

Change the account enabled from a bool to an int, and pair the enable call
with the equivalent disable call. This ensures that stats gets turned off
again appropriately.

Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bdev: Improve lookup_bdev documentation

Add a Context section and rewrite the rest to be clearer.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Link: https://lore.kernel.org/r/20211213171113.3097631-1-willy@infradead.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mtd_blkdevs: don't scan partitions for plain mtdblock

mtdblock / mtdblock_ro set part_bits to 0 and thus nevever scanned
partitions.  Restore that behavior by setting the GENHD_FL_NO_PART flag.

Fixes: 1ebe2e5f9d68e94c ("block: remove GENHD_FL_EXT_DEVT")
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20211206070409.2836165-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: Optimise blk_mq_queue_tag_busy_iter() for shared tags

Kashyap reports high CPU usage in blk_mq_queue_tag_busy_iter() and callees
using megaraid SAS RAID card since moving to shared tags [0].

Previously, when shared tags was shared sbitmap, this function was less
than optimum since we would iter through all tags for all hctx's,
yet only ever match upto tagset depth number of rqs.

Since the change to shared tags, things are even less efficient if we have
parallel callers of blk_mq_queue_tag_busy_iter(). This is because in
bt_iter() -> blk_mq_find_and_get_req() there would be more contention on
accessing each request ref and tags->lock since they are now shared among
all HW queues.

Optimise by having separate calls to bt_for_each() for when we're using
shared tags. In this case no longer pass a hctx, as it is no longer
relevant, and teach bt_iter() about this.

Ming suggested something along the lines of this change, apart from a
different implementation.

[0] https://lore.kernel.org/linux-block/e4e92abbe9d52bcba6b8cc6c91c442cc@mail.gmail.com/

Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reported-and-tested-by: Kashyap Desai <kashyap.desai@broadcom.com>
Fixes: e155b0c238b2 ("blk-mq: Use shared tags for shared sbitmap support")
Link: https://lore.kernel.org/r/1638794990-137490-4-git-send-email-john.garry@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: Delete busy_iter_fn

Typedefs busy_iter_fn and busy_tag_iter_fn are now identical, so delete
busy_iter_fn to reduce duplication.

It would be nicer to delete busy_tag_iter_fn, as the name busy_iter_fn is
less specific.

However busy_tag_iter_fn is used in many different parts of the tree,
unlike busy_iter_fn which is just use in block/, so just take the
straightforward path now, so that we could rename later treewide.

Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Tested-by: Kashyap Desai <kashyap.desai@broadcom.com>
Link: https://lore.kernel.org/r/1638794990-137490-3-git-send-email-john.garry@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: Drop busy_iter_fn blk_mq_hw_ctx argument

The only user of blk_mq_hw_ctx blk_mq_hw_ctx argument is
blk_mq_rq_inflight().

Function blk_mq_rq_inflight() uses the hctx to find the associated request
queue to match against the request. However this same check is already
done in caller bt_iter(), so drop this check.

With that change there are no more users of busy_iter_fn blk_mq_hw_ctx
argument, so drop the argument.

Reviewed-by Hannes Reinecke <hare@suse.de>

Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Kashyap Desai <kashyap.desai@broadcom.com>
Link: https://lore.kernel.org/r/1638794990-137490-2-git-send-email-john.garry@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: don't use plug->mq_list->q directly in blk_mq_run_dispatch_ops()

blk_mq_run_dispatch_ops() is defined as one macro, and plug->mq_list
will be changed when running 'dispatch_ops', so add one local variable
for holding request queue.

Reported-and-tested-by: Yi Zhang <yi.zhang@redhat.com>
Fixes: 4cafe86c9267 ("blk-mq: run dispatch lock once in case of issuing from list")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: don't run might_sleep() if the operation needn't blocking

The operation protected via blk_mq_run_dispatch_ops() in blk_mq_run_hw_queue
won't sleep, so don't run might_sleep() for it.

Reported-and-tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: run dispatch lock once in case of issuing from list

It isn't necessary to call blk_mq_run_dispatch_ops() once for issuing
single request directly, and enough to do it one time when issuing from
whole list.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211203131534.3668411-5-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: pass request queue to blk_mq_run_dispatch_ops

We have switched to allocate srcu into request queue, so it is fine
to pass request queue to blk_mq_run_dispatch_ops().

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211203131534.3668411-4-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: move srcu from blk_mq_hw_ctx to request_queue

In case of BLK_MQ_F_BLOCKING, per-hctx srcu is used to protect dispatch
critical area. However, this srcu instance stays at the end of hctx, and
it often takes standalone cacheline, often cold.

Inside srcu_read_lock() and srcu_read_unlock(), WRITE is always done on
the indirect percpu variable which is allocated from heap instead of
being embedded, srcu->srcu_idx is read only in srcu_read_lock(). It
doesn't matter if srcu structure stays in hctx or request queue.

So switch to per-request-queue srcu for protecting dispatch, and this
way simplifies quiesce a lot, not mention quiesce is always done on the
request queue wide.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211203131534.3668411-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: remove hctx_lock and hctx_unlock

Remove hctx_lock and hctx_unlock, and add one helper of
blk_mq_run_dispatch_ops() to run code block defined in dispatch_ops
with rcu/srcu read held.

Compared with hctx_lock()/hctx_unlock():

1) remove 2 branch to 1, so we just need to check
(hctx->flags & BLK_MQ_F_BLOCKING) once when running one dispatch_ops

2) srcu_idx needn't to be touched in case of non-blocking

3) might_sleep_if() can be moved to the blocking branch

Also put the added blk_mq_run_dispatch_ops() in private header, so that
the following patch can use it out of blk-mq.c.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211203131534.3668411-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: switch to atomic_t for request references

refcount_t is not as expensive as it used to be, but it's still more
expensive than the io_uring method of using atomic_t and just checking
for potential over/underflow.

This borrows that same implementation, which in turn is based on the
mm implementation from Linus.

Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: move direct_IO into our own read_iter handler

Don't call into generic_file_read_iter() if we know it's O_DIRECT, just
set it up ourselves and call our own handler. This avoids an indirect call
for O_DIRECT.

Fall back to filemap_read() if we fail.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

mm: move filemap_range_needs_writeback() into header

No functional changes in this patch, just in preparation for efficiently
calling this light function from the block O_DIRECT handling.

Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: fix double bio queue when merging in cached request path

When we attempt to merge off the cached request path, we return NULL
if successful. This makes the caller believe that it's should allocate
a new request, and hence we end up with the bio both merged and associated
with a new request. This, predictably, leads to all sorts of crashes.

Pass in a pointer to the bio pointer, and clear it for the merge case.
Then the caller knows that the bio is already queued, and no new requests
need to get allocated.

Fixes: 5b13bc8a3fd5 ("blk-mq: cleanup request allocation")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: get rid of useless goto and label in blk_mq_get_new_requests()

Expected case is returning a request, just check for success and return
the request rather than having an error label.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: check q->poll_stat in queue_poll_stat_show

Without checking q->poll_stat in queue_poll_stat_show(), kernel panic
may be caused if q->poll_stat isn't allocated.

Fixes: 48b5c1fbcd8c ("block: only allocate poll_stats if there's a user of them")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211202090716.3292244-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: Fix fsync always failed if once failed

We do test with inject error fault base on v4.19, after test some time we found
sync /dev/sda always failed.
[root@localhost] sync /dev/sda
sync: error syncing '/dev/sda': Input/output error

scsi log as follows:
[19069.812296] sd 0:0:0:0: [sda] tag#64 Send: scmd 0x00000000d03a0b6b
[19069.812302] sd 0:0:0:0: [sda] tag#64 CDB: Synchronize Cache(10) 35 00 00 00 00 00 00 00 00 00
[19069.812533] sd 0:0:0:0: [sda] tag#64 Done: SUCCESS Result: hostbyte=DID_OK driverbyte=DRIVER_OK
[19069.812536] sd 0:0:0:0: [sda] tag#64 CDB: Synchronize Cache(10) 35 00 00 00 00 00 00 00 00 00
[19069.812539] sd 0:0:0:0: [sda] tag#64 scsi host busy 1 failed 0
[19069.812542] sd 0:0:0:0: Notifying upper driver of completion (result 0)
[19069.812546] sd 0:0:0:0: [sda] tag#64 sd_done: completed 0 of 0 bytes
[19069.812549] sd 0:0:0:0: [sda] tag#64 0 sectors total, 0 bytes done.
[19069.812564] print_req_error: I/O error, dev sda, sector 0

ftrace log as follows:
 rep-306069 [007] .... 19654.923315: block_bio_queue: 8,0 FWS 0 + 0 [rep]
 rep-306069 [007] .... 19654.923333: block_getrq: 8,0 FWS 0 + 0 [rep]
 kworker/7:1H-250   [007] .... 19654.923352: block_rq_issue: 8,0 FF 0 () 0 + 0 [kworker/7:1H]
 <idle>-0     [007] ..s. 19654.923562: block_rq_complete: 8,0 FF () 18446744073709551615 + 0 [0]
 <idle>-0     [007] d.s. 19654.923576: block_rq_complete: 8,0 WS () 0 + 0 [-5]

As 8d6996630c03 introduce 'fq->rq_status', this data only update when 'flush_rq'
reference count isn't zero. If flush request once failed and record error code
in 'fq->rq_status'. If there is no chance to update 'fq->rq_status',then do fsync
will always failed.
To address this issue reset 'fq->rq_status' after return error code to upper layer.

Fixes: 8d6996630c03("block: fix null pointer dereference in blk_mq_rq_timed_out()")
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211129012659.1553733-1-yebin10@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

scsi: remove the gendisk argument to scsi_ioctl

Now that blk_execute_rq does not take a gendisk argument there is no need
to pass it through the scsi_ioctl callchain either.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211126121802.2090656-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove the gendisk argument to blk_execute_rq

Remove the gendisk aregument to blk_execute_rq and blk_execute_rq_nowait
given that it is unused now.  Also convert the boolean at_head parameter
to actually use the bool type while touching the prototype.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211126121802.2090656-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove the ->rq_disk field in struct request

Just use the disk attached to the request_queue instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211126121802.2090656-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: don't check ->rq_disk in merges

There is a 1:1 relationship between request_queues and gendisks now, so
no need for these extra checks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211126121802.2090656-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mtd_blkdevs: remove the sector out of range check in do_blktrans_request

The block layer already performs this check, no need to duplicate it in
the driver.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211126121802.2090656-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: Remove redundant initialization of variable ret

The variable ret is being initialized with a value that is never
read, it is being updated later on. The assignment is redundant and
can be removed.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20211126230652.1175636-1-colin.i.king@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: simplify ioc_lookup_icq

Remove the ioc argument as it always points to current->io_context.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-15-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: simplify ioc_create_icq

Remove the ioc and gfp_mask argument, which are hard coded by the caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: return the io_context from create_task_io_context

Grab a reference to the newly allocated or existing io_context in
create_task_io_context and return it.  This simplifies the callers and
removes the need for double lookups.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-13-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: use alloc_io_context in __copy_io

In __copy_io we know that the newly allocate task_struct does not have
an I/O context yet and is not exiting.  So just allocate the I/O context
struct and install it directly.  There is no need to lock the task
either as it is just being created.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-12-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: factor out a alloc_io_context helper

Factor out a helper that just allocate an I/O context.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-11-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove get_io_context_active

Fold it into it's only caller, and remove a lof of the debug checks
that are not needed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: move the remaining elv.icq handling to the I/O scheduler

After the prepare side has been moved to the only I/O scheduler that
cares, do the same for the cleanup and the NULL initialization.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: move blk_mq_sched_assign_ioc to blk-ioc.c

Move blk_mq_sched_assign_ioc so that many interfaces from the file can
be marked static.  Rename the function to ioc_find_get_icq as well and
return the icq to simplify the interface.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: mark put_io_context_active static

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Revert "block: Provide blk_mq_sched_get_icq()"

This reverts commit 4896c4e64ba5d5d5acdbcf68c5910dd4f6d8fa62.

The helper is not needed any more.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bfq: use bfq_bic_lookup in bfq_limit_depth

No need to create a new I/O context if there is none present yet in
->limit_depth.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bfq: simplify bfq_bic_lookup

Remove the unused bfqd argument, and hardcode ioc to current->io_context.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fork: move copy_io to block/blk-ioc.c

Move the copying of the I/O context to the block layer as that is where
we can use the proper low-level interfaces.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

RDMA/qib: rename copy_io to qib_copy_io

Add the proper module prefix to avoid conflicts with a function
in the scheduler.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: use bio->bi_opf after bio is checked

bio->bi_opf isn't finalized before checking the bio, so use it after
submit_bio_checks() returns.

Fixes: 5b13bc8a3fd5 ("blk-mq: cleanup request allocation")
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bfq: Do not let waker requests skip proper accounting

Commit 7cc4ffc55564 ("block, bfq: put reqs of waker and woken in
dispatch list") added a condition to bfq_insert_request() which added
waker's requests directly to dispatch list. The rationale was that
completing waker's IO is needed to get more IO for the current queue.
Although this rationale is valid, there is a hole in it. The waker does
not necessarily serve the IO only for the current queue and maybe it's
current IO is not needed for current queue to make progress. Furthermore
injecting IO like this completely bypasses any service accounting within
bfq and thus we do not properly track how much service is waker's queue
getting or that the waker is actually doing any IO. Depending on the
conditions this can result in the waker getting too much or too few
service.

Consider for example the following job file:

[global]
directory=/mnt/repro/
rw=write
size=8g
time_based
runtime=30
ramp_time=10
blocksize=1m
direct=0
ioengine=sync

[slowwriter]
numjobs=1
prioclass=2
prio=7
fsync=200

[fastwriter]
numjobs=1
prioclass=2
prio=0
fsync=200

Despite processes have very different IO priorities, they get the same
about of service. The reason is that bfq identifies these processes as
having waker-wakee relationship and once that happens, IO from
fastwriter gets injected during slowwriter's time slice. As a result bfq
is not aware that fastwriter has any IO to do and constantly schedules
only slowwriter's queue. Thus fastwriter is forced to compete with
slowwriter's IO all the time instead of getting its share of time based
on IO priority.

Drop the special injection condition from bfq_insert_request(). As a
result, requests will be tracked and queued in a normal way and on next
dispatch bfq_select_queue() can decide whether the waker's inserted
requests should be injected during the current queue's timeslice or not.

Fixes: 7cc4ffc55564 ("block, bfq: put reqs of waker and woken in dispatch list")
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211125133645.27483-8-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bfq: Log waker detections

Waker - wakee relationships are important in deciding whether one queue
can preempt the other one. Print information about detected waker-wakee
relationships so that scheduling decisions can be better understood from
block traces.

Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211125133645.27483-7-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bfq: Provide helper to generate bfqq name

Instead of having helper formating bfqq pid, provide a helper to
generate full bfqq name as used in the traces. It saves some code
duplication and will save more in the coming tracepoints.

Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211125133645.27483-6-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bfq: Limit waker detection in time

Currently, when process A starts issuing requests shortly after process
B has completed some IO three times in a row, we decide that B is a
"waker" of A meaning that completing IO of B is needed for A to make
progress and generally stop separating A's and B's IO much. This logic
is useful to avoid unnecessary idling and thus throughput loss for cases
where workload needs to switch e.g. between the process and the
journaling thread doing IO. However the detection heuristic tends to
frequently give false positives when A and B are fighting IO bandwidth
and other processes aren't doing much IO as we are basically deemed to
eventually accumulate three occurences of a situation where one process
starts issuing requests after the other has completed some IO. To reduce
these false positives, cancel the waker detection also if we didn't
accumulate three detected wakeups within given timeout. The rationale is
that if wakeups are really rare, the pointless idling doesn't hurt
throughput that much anyway.

This significantly reduces false waker detection for workload like:

[global]
directory=/mnt/repro/
rw=write
size=8g
time_based
runtime=30
ramp_time=10
blocksize=1m
direct=0
ioengine=sync

[slowwriter]
numjobs=1
fsync=200

[fastwriter]
numjobs=1
fsync=200

Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211125133645.27483-5-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bfq: Limit number of requests consumed by each cgroup

When cgroup IO scheduling is used with BFQ it does not really provide
service differentiation if the cgroup drives a big IO depth. That for
example happens with writeback which asynchronously submits lots of IO
but it can happen with AIO as well. The problem is that if we have two
cgroups that submit IO with different weights, the cgroup with higher
weight properly gets more IO time and is able to dispatch more IO.
However this causes lower weight cgroup to accumulate more requests
inside BFQ and eventually lower weight cgroup consumes most of IO
scheduler tags. At that point higher weight cgroup stops getting better
service as it is mostly blocked waiting for a scheduler tag while its
queues inside BFQ are empty and thus lower weight cgroup gets served.

Check how many requests submitting cgroup has allocated in
bfq_limit_depth() and if it consumes more requests than what would
correspond to its weight limit available depth to 1 so that the cgroup
cannot consume many more requests. With this limitation the higher
weight cgroup gets proper service even with writeback.

Reviewed-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211125133645.27483-4-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bfq: Store full bitmap depth in bfq_data

Store bitmap depth shift inside bfq_data so that we can use it in
bfq_limit_depth() for proportioning when limiting number of available
request tags for a cgroup.

Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211125133645.27483-3-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bfq: Track number of allocated requests in bfq_entity

When we want to limit number of requests used by each bfqq and also
cgroup, we need to track also number of requests used by each cgroup.
So track number of allocated requests for each bfq_entity.

Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211125133645.27483-2-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: Provide blk_mq_sched_get_icq()

Currently we lookup ICQ only after the request is allocated. However BFQ
will want to decide how many scheduler tags it allows a given bfq queue
(effectively a process) to consume based on cgroup weight. So provide a
function blk_mq_sched_get_icq() so that BFQ can lookup ICQ earlier.

Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211125133645.27483-1-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mmc: core: Use blk_mq_complete_request_direct().

The completion callback for the sdhci-pci device is invoked from a
kworker.
I couldn't identify in which context is mmc_blk_mq_req_done() invoke but
the remaining caller are from invoked from preemptible context. Here it
would make sense to complete the request directly instead scheduling
ksoftirqd for its completion.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20211025070658.1565848-3-bigeasy@linutronix.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: Add blk_mq_complete_request_direct()

Add blk_mq_complete_request_direct() which completes the block request
directly instead deferring it to softirq for single queue devices.

This is useful for devices which complete the requests in preemptible
context and raising softirq from means scheduling ksoftirqd.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211025070658.1565848-2-bigeasy@linutronix.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-crypto: remove blk_crypto_unregister()

This function is trivial and is only used in one place.  Having this
function is misleading because it implies that blk_crypto_register()
needs to be paired with blk_crypto_unregister(), which is not the case.
Just set disk->queue->crypto_profile to NULL directly.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211124013733.347612-1-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: cleanup request allocation

Refactor the request alloction so that blk_mq_get_cached_request tries
to find a cached request first, and the entirely separate and now
self contained blk_mq_get_new_requests allocates one or more requests
if that is not possible.

There is a small change in behavior as submit_bio_checks is called
twice now if a cached request is present but can't be used, but that
is a small price to pay for unwinding this code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211124062856.1444266-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: don't include <linux/part_stat.h> in blk.h

Not needed, shift it into the source files that need it instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123185312.1432157-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: don't include <linux/idr.h> in blk.h

Not needed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123185312.1432157-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: don't include <linux/blk-mq.h> in blk.h

Not needed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123185312.1432157-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: don't include blk-mq.h in blk.h

No needed, shift a blk-stat.h include into the source file that needs it
instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123185312.1432157-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: don't include blk-mq-sched.h in blk.h

No needed, shift it into the source files that need it instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123185312.1432157-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove the e argument to elevator_exit

All callers pass q->elevator.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123185312.1432157-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove elevator_exit

Open code elevator_exit in it's only caller, and rename __elevator_exit to
elevator_exit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123185312.1432157-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: move blk_get_flush_queue to blk-flush.c

blk_get_flush_queue is only used in blk-flush.c, so move it there.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123185312.1432157-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk_mq: remove repeated includes

Remove a repeated "#include<linux/sched/sysctl.h>".

Signed-off-by: Guo Zhengkui <guozhengkui@vivo.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20211123063340.25882-1-guozhengkui@vivo.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: move io_context creation into where it's needed

The only user of the io_context for IO is BFQ, yet we put the checking
and logic of it into the normal IO path.

Put the creation into blk_mq_sched_assign_ioc(), and have BFQ use that
helper.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: only allocate poll_stats if there's a user of them

This is essentially never used, yet it's about 1/3rd of the total
queue size. Allocate it when needed, and don't embed it in the queue.

Kill the queue flag for this while at it, since we can just check the
assigned pointer now.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-ioprio: don't set bio priority if not needed

We don't need to write to the bio if:

1) No ioprio value has ever been assigned to the blkcg
2) We wouldn't anyway, depending on bio and blkcg IO priority

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: move more plug handling from blk_mq_submit_bio into blk_add_rq_to_plug

Keep all the functionality for adding a request to a plug in a single place.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123160443.1315598-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: simplify the plug handling in blk_mq_submit_bio

blk_mq_submit_bio has two different plug cases, one that uses full
plugging and a limited plugging one.

The limited plugging case is only used for a corner case that does
not matter in real life:

 - no ->commit_rqs (so not NVMe)
 - no shared tags (so not SCSI)
 - not rotational (so no old disk or floppy driver)
 - must have multiple queues (so no eMMC)

Remove the limited merging case and all the related junk to simplify
blk_mq_submit_bio and the functions called from it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123160443.1315598-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

sr: set GENHD_FL_REMOVABLE earlier

Set up GENHD_FL_REMOVABLE together with the rest of the gendisk fields.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211122130625.1136848-15-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: cleanup the GENHD_FL_* definitions

Switch to an enum and tidy up the documentation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211122130625.1136848-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: don't set GENHD_FL_NO_PART for hidden gendisks

Hidden gendisks can't be opened using blkdev_get_*, so we can't really
reach any of the partition scanning paths or partitioning ioctls except
for the initial partition scan from add_disk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211122130625.1136848-13-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove GENHD_FL_EXT_DEVT

All modern drivers can support extra partitions using the extended
dev_t.  In fact except for the ioctl method drivers never even see
partitions in normal operation.

So remove the GENHD_FL_EXT_DEVT and allow extra partitions for all
block devices that do support partitions, and require those that
do not support partitions to explicit disallow them using
GENHD_FL_NO_PART.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211122130625.1136848-12-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove GENHD_FL_SUPPRESS_PARTITION_INFO

This flag is not set directly anywhere and only inherited from
GENHD_FL_HIDDEN.  Just check for GENHD_FL_HIDDEN instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211122130625.1136848-11-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mmc: don't set GENHD_FL_SUPPRESS_PARTITION_INFO

This manually reverts 07b652cdbec3 ("mmc: card: Don't show eMMC RPMB and
BOOT areas in /proc/partitions").  Based on the commit description that
change was purely cosmetic.  mmc is the last driver that sets this
flag and thus prevents it from being removed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20211122130625.1136848-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

null_blk: don't suppress partitioning information

This manually reverts commit 27290b469051 ("null_blk: suppress invalid
partition info").  The message in that commit log can't appearch as
the flag is never checked during probing, and there is no good reason
to treat null_blk special in /proc/partitions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211122130625.1136848-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove the GENHD_FL_HIDDEN check in blkdev_get_no_open

Hidden gendisks never hash the block device inode, so this can't happen.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211122130625.1136848-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: rename GENHD_FL_NO_PART_SCAN to GENHD_FL_NO_PART

The GENHD_FL_NO_PART_SCAN controls more than just partitions canning,
so rename it to GENHD_FL_NO_PART.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20211122130625.1136848-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>