The discard bio doesn't attach the original bio cgroup info. Normal bio
is cloned, so is fine.
Signed-off-by: NShaohua Li <shli@fb.com>

While pci_irq_get_affinity should never fail for SMP kernel that
implement the affinity mapping, it will always return NULL in the
UP case, so provide a fallback mapping of all queues to CPU 0 in
that case.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Reviewed-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

blk_mq_get_request() does not release the callers queue usage counter
when allocation fails. The caller still needs to account for its own
queue usage when it is unable to allocate a request.

Fixes: 1ad43c00 ("blk-mq: don't leak preempt counter/q_usage_counter when allocating rq failed")
Reported-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Tested-by: NMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The blk_mq_delay_kick_requeue_list() function is used by the device
mapper and only by the device mapper to rerun the queue and requeue
list after a delay. This function is called once per request that
gets requeued. Modify this function such that the queue is run once
per path change event instead of once per request that is requeued.

Fixes: commit 2849450a ("blk-mq: introduce blk_mq_delay_kick_requeue_list()")
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This gets us back to the behavior in 4.12 and earlier.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Fixes: 7c20f116 ("bio-integrity: stop abusing bi_end_io")
Signed-off-by: NJens Axboe <axboe@kernel.dk>

In dm-integrity target we register integrity profile that have
both generate_fn and verify_fn callbacks set to NULL.

This is used if dm-integrity is stacked under a dm-crypt device
for authenticated encryption (integrity payload contains authentication
tag and IV seed).

In this case the verification is done through own crypto API
processing inside dm-crypt; integrity profile is only holder
of these data. (And memory is owned by dm-crypt as well.)

After the commit (and previous changes)
  Commit 7c20f116
  Author: Christoph Hellwig <hch@lst.de>
  Date:   Mon Jul 3 16:58:43 2017 -0600

    bio-integrity: stop abusing bi_end_io

we get this crash:

: BUG: unable to handle kernel NULL pointer dereference at   (null)
: IP:   (null)
: *pde = 00000000
...
:
: Workqueue: kintegrityd bio_integrity_verify_fn
: task: f48ae180 task.stack: f4b5c000
: EIP:   (null)
: EFLAGS: 00210286 CPU: 0
: EAX: f4b5debc EBX: 00001000 ECX: 00000001 EDX: 00000000
: ESI: 00001000 EDI: ed25f000 EBP: f4b5dee8 ESP: f4b5dea4
:  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
: CR0: 80050033 CR2: 00000000 CR3: 32823000 CR4: 001406d0
: Call Trace:
:  ? bio_integrity_process+0xe3/0x1e0
:  bio_integrity_verify_fn+0xea/0x150
:  process_one_work+0x1c7/0x5c0
:  worker_thread+0x39/0x380
:  kthread+0xd6/0x110
:  ? process_one_work+0x5c0/0x5c0
:  ? kthread_worker_fn+0x100/0x100
:  ? kthread_worker_fn+0x100/0x100
:  ret_from_fork+0x19/0x24
: Code:  Bad EIP value.
: EIP:   (null) SS:ESP: 0068:f4b5dea4
: CR2: 0000000000000000

Patch just skip the whole verify workqueue if verify_fn is set to NULL.

Fixes: 7c20f116 ("bio-integrity: stop abusing bi_end_io")
Signed-off-by: NMilan Broz <gmazyland@gmail.com>
[hch: trivial whitespace fix]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

When blk_mq_get_request() failed, preempt counter isn't
released, and blk_mq_make_request() doesn't release the counter
too.

This patch fixes the issue, and makes sure that preempt counter
is only held if rq is allocated successfully. The same policy is
applied on .q_usage_counter too.
Signed-off-by: NMing Lei <minlei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Groups of BFQ queues are represented by generic entities in BFQ. When
a queue belonging to a parent entity is deactivated, the parent entity
may need to be deactivated too, in case the deactivated queue was the
only active queue for the parent entity. This deactivation may need to
be propagated upwards if the entity belongs, in its turn, to a further
higher-level entity, and so on. In particular, the upward propagation
of deactivation stops at the first parent entity that remains active
even if one of its child entities has been deactivated.

To decide whether the last non-deactivation condition holds for a
parent entity, BFQ checks whether the field next_in_service is still
not NULL for the parent entity, after the deactivation of one of its
child entity. If it is not NULL, then there are certainly other active
entities in the parent entity, and deactivations can stop.

Unfortunately, this check misses a corner case: if in_service_entity
is not NULL, then next_in_service may happen to be NULL, although the
parent entity is evidently active. This happens if: 1) the entity
pointed by in_service_entity is the only active entity in the parent
entity, and 2) according to the definition of next_in_service, the
in_service_entity cannot be considered as next_in_service. See the
comments on the definition of next_in_service for details on this
second point.

Hitting the above corner case causes crashes.

To address this issue, this commit:
1) Extends the above check on only next_in_service to controlling both
next_in_service and in_service_entity (if any of them is not NULL,
then no further deactivation is performed)
2) Improves the (important) comments on how next_in_service is defined
and updated; in particular it fixes a few rather obscure paragraphs
Reported-by: NEric Wheeler <bfq-sched@lists.ewheeler.net>
Reported-by: NRick Yiu <rick_yiu@htc.com>
Reported-by: NTom X Nguyen <tom81094@gmail.com>
Signed-off-by: NPaolo Valente <paolo.valente@linaro.org>
Tested-by: NEric Wheeler <bfq-sched@lists.ewheeler.net>
Tested-by: NRick Yiu <rick_yiu@htc.com>
Tested-by: NLaurentiu Nicola <lnicola@dend.ro>
Tested-by: NTom X Nguyen <tom81094@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

BFQ implements hierarchical scheduling by representing each group of
queues with a generic parent entity. For each parent entity, BFQ
maintains an in_service_entity pointer: if one of the child entities
happens to be in service, in_service_entity points to it.  The
resetting of these pointers happens only on queue expirations: when
the in-service queue is expired, i.e., stops to be the queue in
service, BFQ resets all in_service_entity pointers along the
parent-entity path from this queue to the root entity.

Functions handling the scheduling of entities assume, naturally, that
in-service entities are active, i.e., have pending I/O requests (or,
as a special case, even if they have no pending requests, they are
expected to receive a new request very soon, with the scheduler idling
the storage device while waiting for such an event). Unfortunately,
the above resetting scheme of the in_service_entity pointers may cause
this assumption to be violated.  For example, the in-service queue may
happen to remain without requests because of a request merge. In this
case the queue does become idle, and all related data structures are
updated accordingly. But in_service_entity still points to the queue
in the parent entity. This inconsistency may even propagate to
higher-level parent entities, if they happen to become idle as well,
as a consequence of the leaf queue becoming idle. For this queue and
parent entities, scheduling functions have an undefined behaviour,
and, as reported, may easily lead to kernel crashes or hangs.

This commit addresses this issue by simply resetting the
in_service_entity field also when it is detected to point to an entity
becoming idle (regardless of why the entity becomes idle).
Reported-by: NLaurentiu Nicola <lnicola@dend.ro>
Signed-off-by: NPaolo Valente <paolo.valente@linaro.org>
Tested-by: NLaurentiu Nicola <lnicola@dend.ro>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

We already do this for PCI mappings, and the higher level code now
expects that CPU on/offlining doesn't have an affect on the queue
mappings.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Tested-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The blk-mq code lacks support for looking at the rpm_status field, tracking
active requests and the RQF_PM flag.

Due to the default switch to blk-mq for scsi people start to run into
suspend / resume issue due to this fact, so make sure we disable the runtime
PM functionality until it is properly implemented.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

There are mq devices (eg., virtio-blk, nbd and loopback) which don't
invoke blk_mq_run_hw_queues() after the completion of a request.
If bfq is enabled on these devices and the slice_idle attribute or
strict_guarantees attribute is set as zero, it is possible that
after a request completion the remaining requests of busy bfq queue
will stalled in the bfq schedule until a new request arrives.

To fix the scheduler latency problem, we need to check whether or not
all issued requests have completed and dispatch more requests to driver
if there is no request in driver.

The problem can be reproduced by running the following script
on a virtio-blk device with nr_hw_queues as 1:

#!/bin/sh

dev=vdb
# mount point for dev
mp=/tmp/mnt
cd $mp

job=strict.job
cat <<EOF > $job
[global]
direct=1
bs=4k
size=256M
rw=write
ioengine=libaio
iodepth=128
runtime=5
time_based

[1]
filename=1.data

[2]
new_group
filename=2.data
EOF

echo bfq > /sys/block/$dev/queue/scheduler
echo 1 > /sys/block/$dev/queue/iosched/strict_guarantees
fio $job
Signed-off-by: NHou Tao <houtao1@huawei.com>
Reviewed-by: NPaolo Valente <paolo.valente@linaro.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The start time of eligible entity should be less than or equal to
the current virtual time, and the entity in idle tree has a finish
time being greater than the current virtual time.
Signed-off-by: NHou Tao <houtao1@huawei.com>
Reviewed-by: NPaolo Valente <paolo.valente@linaro.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

bio_free isn't a good place to free cgroup info. There are a
lot of cases bio is allocated in special way (for example, in stack) and
never gets called by bio_put hence bio_free, we are leaking memory. This
patch moves the free to bio endio, which should be called anyway. The
bio_uninit call in bio_free is kept, in case the bio never gets called
bio endio.

This assumes ->bi_end_io() doesn't access cgroup info, which seems true
in my audit.

This along with Christoph's integrity patch should fix the memory leak
issue.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NShaohua Li <shli@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The BIO issuing loop in __blkdev_issue_zeroout() is allocating BIOs
with a maximum number of bvec (pages) equal to

min(nr_sects, (sector_t)BIO_MAX_PAGES)

This works since the requested number of bvecs will always be limited
to the absolute maximum number supported (BIO_MAX_PAGES), but this is
ineficient as too many bvec entries may be requested due to the
different units being used in the min() operation (number of sectors vs
number of pages).
To fix this, introduce the helper __blkdev_sectors_to_bio_pages() to
correctly calculate the number of bvecs for zeroout BIOs as the issuing
loop progresses. The calculation is done using consistent units and
makes sure that the number of pages return is at least 1 (for cases
where the number of sectors is less that the number of sectors in
a page).

Also remove a trailing space after the bit shift in the internal loop
min() call.
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

block/bio-integrity.c:318:10-11: WARNING: return of 0/1 in function 'bio_integrity_prep' with return type bool

 Return statements in functions returning bool should use
 true/false instead of 1/0.
Generated by: scripts/coccinelle/misc/boolreturn.cocci

Fixes: e23947bd ("bio-integrity: fold bio_integrity_enabled to bio_integrity_prep")
CC: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

And instead call directly into the integrity code from bio_end_io.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Currently ->verify_fn not woks at all because at the moment it is called
bio->bi_iter.bi_size == 0, so we do not iterate integrity bvecs at all.

In order to perform verification we need to know original data vector,
with new bvec rewind API this is trivial.

testcase: https://github.com/dmonakhov/xfstests/commit/3c6509eaa83b9c17cd0bc95d73fcdd76e1c54a85Reviewed-by: NHannes Reinecke <hare@suse.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
[hch: adopted for new status values]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Currently all integrity prep hooks are open-coded, and if prepare fails
we ignore it's code and fail bio with EIO. Let's return real error to
upper layer, so later caller may react accordingly.

In fact no one want to use bio_integrity_prep() w/o bio_integrity_enabled,
so it is reasonable to fold it in to one function.
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
[hch: merged with the latest block tree,
	return bool from bio_integrity_prep]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

bio_integrity_trim inherent it's interface from bio_trim and accept
offset and size, but this API is error prone because data offset
must always be insync with bio's data offset. That is why we have
integrity update hook in bio_advance()

So only meaningful values are: offset == 0, sectors == bio_sectors(bio)
Let's just remove them completely.
Reviewed-by: NHannes Reinecke <hare@suse.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

SCSI drivers do care about bip_seed so we must update it accordingly.
Reviewed-by: NHannes Reinecke <hare@suse.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

When mq-deadline is taken, IOPS of sequential read and
seqential write is observed more than 20% drop on sata(scsi-mq)
devices, compared with using 'none' scheduler.

The reason is that the default nr_requests for scheduler is
too big for small queuedepth devices, and latency is increased
much.

Since the principle of taking 256 requests for mq scheduler
is based on 128 queue depth, this patch changes into
double size of min(hw queue_depth, 128).
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

On each deactivation or re-scheduling (after being served) of a
bfq_queue, BFQ invokes the function __bfq_entity_update_weight_prio(),
to perform pending updates of ioprio, weight and ioprio class for the
bfq_queue. BFQ also invokes this function on I/O-request dispatches,
to raise or lower weights more quickly when needed, thereby improving
latency. However, the entity representing the bfq_queue may be on the
active (sub)tree of a service tree when this happens, and, although
with a very low probability, the bfq_queue may happen to also have a
pending change of its ioprio class. If both conditions hold when
__bfq_entity_update_weight_prio() is invoked, then the entity moves to
a sort of hybrid state: the new service tree for the entity, as
returned by bfq_entity_service_tree(), differs from service tree on
which the entity still is. The functions that handle activations and
deactivations of entities do not cope with such a hybrid state (and
would need to become more complex to cope).

This commit addresses this issue by just making
__bfq_entity_update_weight_prio() not perform also a possible pending
change of ioprio class, when invoked on an I/O-request dispatch for a
bfq_queue. Such a change is thus postponed to when
__bfq_entity_update_weight_prio() is invoked on deactivation or
re-scheduling of the bfq_queue.
Reported-by: NMarco Piazza <mpiazza@gmail.com>
Reported-by: NLaurentiu Nicola <lnicola@dend.ro>
Signed-off-by: NPaolo Valente <paolo.valente@linaro.org>
Tested-by: NMarco Piazza <mpiazza@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

all other drivers recognizing those ioctls are very much *not*
biarch.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This patch performs sequential mapping between CPUs and queues.
In case the system has more CPUs than HWQs then there are still
CPUs to map to HWQs. In hyperthreaded system, map the unmapped CPUs
and their siblings to the same HWQ.
This actually fixes a bug that found unmapped HWQs in a system with
2 sockets, 18 cores per socket, 2 threads per core (total 72 CPUs)
running NVMEoF (opens upto maximum of 64 HWQs).

Performance results running fio (72 jobs, 128 iodepth)
using null_blk (w/w.o patch):

bs      IOPS(read submit_queues=72)   IOPS(write submit_queues=72)   IOPS(read submit_queues=24)  IOPS(write submit_queues=24)
-----  ----------------------------  ------------------------------ ---------------------------- -----------------------------
512    4890.4K/4723.5K                 4524.7K/4324.2K                   4280.2K/4264.3K               3902.4K/3909.5K
1k     4910.1K/4715.2K                 4535.8K/4309.6K                   4296.7K/4269.1K               3906.8K/3914.9K
2k     4906.3K/4739.7K                 4526.7K/4330.6K                   4301.1K/4262.4K               3890.8K/3900.1K
4k     4918.6K/4730.7K                 4556.1K/4343.6K                   4297.6K/4264.5K               3886.9K/3893.9K
8k     4906.4K/4748.9K                 4550.9K/4346.7K                   4283.2K/4268.8K               3863.4K/3858.2K
16k    4903.8K/4782.6K                 4501.5K/4233.9K                   4292.3K/4282.3K               3773.1K/3773.5K
32k    4885.8K/4782.4K                 4365.9K/4184.2K                   4307.5K/4289.4K               3780.3K/3687.3K
64k    4822.5K/4762.7K                 2752.8K/2675.1K                   4308.8K/4312.3K               2651.5K/2655.7K
128k   2388.5K/2313.8K                 1391.9K/1375.7K                   2142.8K/2152.2K               1395.5K/1374.2K
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Wen reports significant memory leaks with DIF and O_DIRECT:

"With nvme devive + T10 enabled, On a system it has 256GB and started
logging /proc/meminfo & /proc/slabinfo for every minute and in an hour
it increased by 15968128 kB or ~15+GB.. Approximately 256 MB / minute
leaking.

/proc/meminfo | grep SUnreclaim...

SUnreclaim:      6752128 kB
SUnreclaim:      6874880 kB
SUnreclaim:      7238080 kB
....
SUnreclaim:     22307264 kB
SUnreclaim:     22485888 kB
SUnreclaim:     22720256 kB

When testcases with T10 enabled call into __blkdev_direct_IO_simple,
code doesn't free memory allocated by bio_integrity_alloc. The patch
fixes the issue. HTX has been run with +60 hours without failure."

Since __blkdev_direct_IO_simple() allocates the bio on the stack, it
doesn't go through the regular bio free. This means that any ancillary
data allocated with the bio through the stack is not freed. Hence, we
can leak the integrity data associated with the bio, if the device is
using DIF/DIX.

Fix this by providing a bio_uninit() and export it, so that we can use
it to free this data. Note that this is a minimal fix for this issue.
Any current user of bio's that are allocated outside of
bio_alloc_bioset() suffers from this issue, most notably some drivers.
We will fix those in a more comprehensive patch for 4.13. This also
means that the commit marked as being fixed by this isn't the real
culprit, it's just the most obvious one out there.

Fixes: 542ff7bf ("block: new direct I/O implementation")
Reported-by: NWen Xiong <wenxiong@linux.vnet.ibm.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Currently we only create hctx for online CPUs, which can lead to a lot
of churn due to frequent soft offline / online operations.  Instead
allocate one for each present CPU to avoid this and dramatically simplify
the code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Cc: Keith Busch <keith.busch@intel.com>
Cc: linux-block@vger.kernel.org
Cc: linux-nvme@lists.infradead.org
Link: http://lkml.kernel.org/r/20170626102058.10200-3-hch@lst.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

This way we get a nice distribution independent of the current cpu
online / offline state.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Cc: Keith Busch <keith.busch@intel.com>
Cc: linux-block@vger.kernel.org
Cc: linux-nvme@lists.infradead.org
Link: http://lkml.kernel.org/r/20170626102058.10200-2-hch@lst.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

This commit fixes a bug triggered by a non-trivial sequence of
events. These events are briefly described in the next two
paragraphs. The impatiens, or those who are familiar with queue
merging and splitting, can jump directly to the last paragraph.

On each I/O-request arrival for a shared bfq_queue, i.e., for a
bfq_queue that is the result of the merge of two or more bfq_queues,
BFQ checks whether the shared bfq_queue has become seeky (i.e., if too
many random I/O requests have arrived for the bfq_queue; if the device
is non rotational, then random requests must be also small for the
bfq_queue to be tagged as seeky). If the shared bfq_queue is actually
detected as seeky, then a split occurs: the bfq I/O context of the
process that has issued the request is redirected from the shared
bfq_queue to a new non-shared bfq_queue. As a degenerate case, if the
shared bfq_queue actually happens to be shared only by one process
(because of previous splits), then no new bfq_queue is created: the
state of the shared bfq_queue is just changed from shared to non
shared.

Regardless of whether a brand new non-shared bfq_queue is created, or
the pre-existing shared bfq_queue is just turned into a non-shared
bfq_queue, several parameters of the non-shared bfq_queue are set
(restored) to the original values they had when the bfq_queue
associated with the bfq I/O context of the process (that has just
issued an I/O request) was merged with the shared bfq_queue. One of
these parameters is the weight-raising state.

If, on the split of a shared bfq_queue,
1) a pre-existing shared bfq_queue is turned into a non-shared
bfq_queue;
2) the previously shared bfq_queue happens to be busy;
3) the weight-raising state of the previously shared bfq_queue happens
to change;
the number of weight-raised busy queues changes. The field
wr_busy_queues must then be updated accordingly, but such an update
was missing. This commit adds the missing update.
Reported-by: NLuca Miccio <lucmiccio@gmail.com>
Signed-off-by: NPaolo Valente <paolo.valente@linaro.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Instead move it to the callers.  Those that either don't use bio_data() or
page_address() or are specific to architectures that do not support highmem
are skipped.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

And just move it into scsi_transport_sas which needs it due to low-level
drivers directly derferencing bio_data, and into blk_init_queue_node,
which will need a further push into the callers.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

For historical reasons we default to bouncing highmem pages for all block
queues.  But the blk-mq drivers are easy to audit to ensure that we don't
need this - scsi and mtip32xx set explicit limits and everyone else doesn't
have any particular ones.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

We only call blk_queue_bounce for request-based drivers, so stop messing
with it for make_request based drivers.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Only used inside the bounce code, and opencoding it makes it more obvious
what is going on.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This makes moves the knowledge about bouncing out of the callers into the
block core (just like we do for the normal I/O path), and allows to unexport
blk_queue_bounce.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Useful to verify that things are working the way they should.
Reading the file will return number of kb written with each
write hint. Writing the file will reset the statistics. No care
is taken to ensure that we don't race on updates.

Drivers will write to q->write_hints[] if they handle a given
write hint.
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>