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Sort the documentation for the files alphabetically by file path so that
there is a logical order and it's clear where to add new files.
With two small exceptions, this patch doesn't change the documentation
itself and just reorders it:
- In /sys/block/<disk>/<part>/stat, I replaced <part> with <partition>
to be consistent with the other files.
- The description for /sys/block/<disk>/<part>/stat referred to another
file "above", which I reworded.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20211209003833.6396-3-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The block layer sysfs ABI is widely used by userspace software and is
considered stable.
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20211209003833.6396-2-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit cc9c884dd7 ("block: call submit_bio_checks under q_usage_counter")
uses q_usage_counter to protect submit_bio_checks for avoiding IO after
disk is deleted by del_gendisk().
Turns out the protection isn't necessary, because once
blk_mq_freeze_queue_wait() in del_gendisk() returns:
1) all in-flight IO has been done
2) all new IO will be failed in __bio_queue_enter() because
q_usage_counter is dead, and GD_DEAD is set
3) both disk and request queue instance are safe since caller of
submit_bio() guarantees that the disk can't be closed.
Once submit_bio_checks() needn't the protection of q_usage_counter, we can
move submit_bio_checks before calling blk_mq_submit_bio() and
->submit_bio(). With this change, we needn't to throttle queue with
holding one allocated request, then precise driver tag or request won't be
wasted in throttling. Meantime we can unify the bio check for both bio
based and request based driver.
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220104134223.590803-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move the 'inline' keyword to the front of 'void'.
Remove a warning found by clang(make W=1 LLVM=1)
./include/linux/blk-mq.h:259:1: warning: ‘inline’ is not at beginning of
declaration
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220107005228.103927-1-yang.lee@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If command prep fails, current handling will orphan subsequent requests
in the list. Consider a simple example:
rqlist = [ 1 -> 2 ]
When prep for request '1' fails, it will be appended to the
'requeue_list', leaving request '2' disconnected from the original
rqlist and no longer tracked. Meanwhile, rqlist is still pointing to the
failed request '1' and will attempt to submit the unprepped command.
Fix this by updating the rqlist accordingly using the request list
helper functions.
Fixes: d62cbcf62f ("nvme: add support for mq_ops->queue_rqs()")
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220105170518.3181469-5-kbusch@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When iterating a list, a particular request may need to be moved for
special handling. Provide a helper function to achieve that so drivers
don't need to reimplement rqlist manipulation.
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220105170518.3181469-4-kbusch@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
While iterating a list, a particular request may need to be removed for
special handling. Provide an iterator that can safely handle that.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20220105170518.3181469-3-kbusch@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move the request list macros to the header file that defines that struct
they operate on.
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220105170518.3181469-2-kbusch@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit 5fc11eebb4 ("block: open code create_task_io_context in
set_task_ioprio") introduces a needless assignment
'ioc = task->io_context', as the local variable ioc is not further
used before returning.
Even after the further fix, commit a957b61254 ("block: fix error in
handling dead task for ioprio setting"), the assignment still remains
needless.
Drop this needless assignment in set_task_ioprio().
This code smell was identified with 'make clang-analyzer'.
Fixes: 5fc11eebb4 ("block: open code create_task_io_context in set_task_ioprio")
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211223125300.20691-1-lukas.bulwahn@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
While harmless, the blank line is certainly not intended to be part of
the rq_list_for_each() macro. Remove it.
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20211222215239.1768164-1-kbusch@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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>
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>
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>
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: 83cbce9574 ("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>
blk_stat_disable_accounting() is added in commit 68497092bd
("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: 68497092bd ("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>
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: 5fc11eebb4 ("block: open code create_task_io_context in set_task_ioprio")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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: 3c67d44de7 ("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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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: e155b0c238 ("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>
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>
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_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: 4cafe86c92 ("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>
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>
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>
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>
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>
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>
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>
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>
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>
