No need to be so fancy.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Indirect calls are inefficient because of retpolines that are used for
spectre workaround. This patch replaces an indirect call with a condition
(that can be predicted by the branch predictor).
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

There's a single user of this function, dm, and dm just wants
to check if IO is inflight, not that it's just allocated.

This fixes a hang with srp/002 in blktests with dm, where it tries
to suspend but waits for inflight IO to finish first. As it checks
for just allocated requests, this fails.
Tested-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The md->wait waitqueue is used by both bio-based and request-based DM.
Commit dbd3bbd2 ("dm rq: leverage blk_mq_queue_busy() to check for
outstanding IO") lost sight of the requirement that
dm_wait_for_completion() must work with all types of DM devices.

Fix md_in_flight() to call the blk-mq or bio-based method accordingly.

Fixes: dbd3bbd2 ("dm rq: leverage blk_mq_queue_busy() to check for outstanding IO")
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

After switching to percpu inflight counters, the inflight check
is totally buggy. It's perfectly valid for some counters to be
non-zero while having a total inflight IO count of 0, that's how
these kinds of counters work (inc on one CPU, dec on another).
Fix the md_in_flight() check to sum all counters before returning
a false positive, potentially.

While at it, remove the inflight read for IO completion. We don't
need it, just wake anyone that's waiting for the IO count to drop
to zero. The caller needs to re-check that value anyway when woken,
which it does.

Fixes: 6f757231 ("dm: remove the pending IO accounting")
Acked-by: NMike Snitzer <snitzer@redhat.com>
Reported-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Remove the "pending" atomic counters, that duplicate block-core's
in_flight counters, and update md_in_flight() to look at percpu
in_flight counters.
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

generic_start_io_acct and generic_end_io_acct already update the variable
in_flight using atomic operations, so we don't have to overwrite them
again.
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The next patch changes the macro bio_set_dev() to associate a bio with a
blkg based on the device set. However, dm creates a static bio to be
used as the basis for cloning empty flush bios on creation. The
bio_set_dev() call in alloc_dev() will cause problems with the next
patch adding association to bio_set_dev() because the call is before the
bdev is associated with a gendisk (bd_disk is %NULL). To get around
this, set the device on the static bio every time and use that to clone
to the other bios.
Signed-off-by: NDennis Zhou <dennis@kernel.org>
Acked-by: NMike Snitzer <snitzer@redhat.com>
Cc: Alasdair Kergon <agk@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

With the legacy request path gone there is no real need to override the
queue_lock.
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Dispatching a report zones command through the request queue is a major
pain due to the command reply payload rewriting necessary. Given that
blkdev_report_zones() is executing everything synchronously, implement
report zones as a block device file operation instead, allowing major
simplification of the code in many places.

sd, null-blk, dm-linear and dm-flakey being the only block device
drivers supporting exposing zoned block devices, these drivers are
modified to provide the device side implementation of the
report_zones() block device file operation.

For device mappers, a new report_zones() target type operation is
defined so that the upper block layer calls blkdev_report_zones() can
be propagated down to the underlying devices of the dm targets.
Implementation for this new operation is added to the dm-linear and
dm-flakey targets.
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
[Damien]
* Changed method block_device argument to gendisk
* Various bug fixes and improvements
* Added support for null_blk, dm-linear and dm-flakey.
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

WARN_ON() already contains an unlikely(), so it's not necessary to
wrap it into another.
Signed-off-by: NIgor Stoppa <igor.stoppa@huawei.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Now that request-based DM is only using blk-mq, there is no need to
differentiate between legacy "rq" and new "mq".  We're back to a single
request-based DM -- and there was much rejoicing!
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

dm supports both, and since we're killing off the legacy path in
general, get rid of it in dm.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

If dm-linear or dm-flakey are layered on top of a partition of a zoned
block device, remapping of the start sector and write pointer position
of the zones reported by a report zones BIO must be modified to account
for the target table entry mapping (start offset within the device and
entry mapping with the dm device).  If the target's backing device is a
partition of a whole disk, the start sector on the physical device of
the partition must also be accounted for when modifying the zone
information.  However, dm_remap_zone_report() was not considering this
last case, resulting in incorrect zone information remapping with
targets using disk partitions.

Fix this by calculating the target backing device start sector using
the position of the completed report zones BIO and the unchanged
position and size of the original report zone BIO. With this value
calculated, the start sector and write pointer position of the target
zones can be correctly remapped.

Fixes: 10999307 ("dm: introduce dm_remap_zone_report()")
Cc: stable@vger.kernel.org
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Add and use a new op_stat_group() function for indexing partition stat
fields rather than indexing them by rq_data_dir() or bio_data_dir().
This function works similarly to op_is_sync() in that it takes the
request::cmd_flags or bio::bi_opf flags and determines which stats
should et updated.

In addition, the second parameter to generic_start_io_acct() and
generic_end_io_acct() is now a REQ_OP rather than simply a read or
write bit and it uses op_stat_group() on the parameter to determine
the stat group.

Note that the partition in_flight counts are not part of the per-cpu
statistics and as such are not indexed via this function.  It's now
indexed by op_is_write().

tj: Refreshed on top of v4.17.  Updated to pass around REQ_OP.
Signed-off-by: NMichael Callahan <michaelcallahan@fb.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joshua Morris <josh.h.morris@us.ibm.com>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Matias Bjorling <mb@lightnvm.io>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Alasdair Kergon <agk@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Currently device_supports_dax() just checks to see if the QUEUE_FLAG_DAX
flag is set on the device's request queue to decide whether or not the
device supports filesystem DAX.  Really we should be using
bdev_dax_supported() like filesystems do at mount time.  This performs
other tests like checking to make sure the dax_direct_access() path works.

We also explicitly clear QUEUE_FLAG_DAX on the DM device's request queue if
any of the underlying devices do not support DAX.  This makes the handling
of QUEUE_FLAG_DAX consistent with the setting/clearing of most other flags
in dm_table_set_restrictions().

Now that bdev_dax_supported() explicitly checks for QUEUE_FLAG_DAX, this
will ensure that filesystems built upon DM devices will only be able to
mount with DAX if all underlying devices also support DAX.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Fixes: commit 545ed20e ("dm: add infrastructure for DAX support")
Cc: stable@vger.kernel.org
Acked-by: NDan Williams <dan.j.williams@intel.com>
Reviewed-by: NToshi Kani <toshi.kani@hpe.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Use of bio_clone_bioset() is inefficient if there is no need to clone
the original bio's bio_vec array.  Best to use the bio_clone_fast()
variant.  Also, just using bio_advance() is only part of what is needed
to properly setup the clone -- it doesn't account for the various
bio_integrity() related work that also needs to be performed (see
bio_split).

Address both of these issues by switching from bio_clone_bioset() to
bio_split().

Fixes: 18a25da8 ("dm: ensure bio submission follows a depth-first tree walk")
Cc: stable@vger.kernel.org # 4.15+, requires removal of '&' before md->queue->bio_split
Reported-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

We can't just copy and clear a bio_set, use the bio helper to
setup a new bio_set with the settings from another one.

Fixes: 6f1c819c ("dm: convert to bioset_init()/mempool_init()")
Reported-by: NVenkat R.B <vrbagal1@linux.vnet.ibm.com>
Tested-by: NVenkat R.B <vrbagal1@linux.vnet.ibm.com>
Tested-by: NLi Wang <liwang@redhat.com>
Reviewed-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Convert dm to embedded bio sets.
Acked-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NKent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Convert the core block functionality to embedded bio sets.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Similar to the ->copy_from_iter() operation, a platform may want to
deploy an architecture or device specific routine for handling reads
from a dax_device like /dev/pmemX. On x86 this routine will point to a
machine check safe version of copy_to_iter(). For now, add the plumbing
to device-mapper and the dax core.

Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Eliminate these sparse warnings:
drivers/md/dm.c:1062:9: warning: context imbalance in 'dm_dax_direct_access' - unexpected unlock
drivers/md/dm.c:1086:9: warning: context imbalance in 'dm_dax_copy_from_iter' - unexpected unlock
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Use the fmode_t that is passed to dm_blk_ioctl() rather than
inconsistently (varies across targets) drop it on the floor by
overriding it with the fmode_t stored in 'struct dm_dev'.

All the persistent reservation functions weren't using the fmode_t they
got back from .prepare_ioctl so remove them.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Commit 519049af ("dm: use blkdev_get rather than bdgrab when issuing
pass-through ioctl") inadvertantly introduced a regression relative to
users of device cgroups that issue ioctls (e.g. libvirt).  Using
blkdev_get() in DM's passthrough ioctl support implicitly introduced a
cgroup permissions check that would fail unless care were taken to add
all devices in the IO stack to the device cgroup.  E.g. rather than just
adding the top-level DM multipath device to the cgroup all the
underlying devices would need to be allowed.

Fix this, to no longer require allowing all underlying devices, by
simply holding the live DM table (which includes the table's original
blkdev_get() reference on the blockdevice that the ioctl will be issued
to) for the duration of the ioctl.

Also, bump the DM ioctl version so a user can know that their device
cgroup allow workaround is no longer needed.
Reported-by: NMichal Privoznik <mprivozn@redhat.com>
Suggested-by: NMikulas Patocka <mpatocka@redhat.com>
Fixes: 519049af ("dm: use blkdev_get rather than bdgrab when issuing pass-through ioctl")
Cc: stable@vger.kernel.org # 4.16
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Set QUEUE_FLAG_SECERASE in DM device's queue_flags if a DM table's
data devices support secure erase.

Also, add support for secure erase to both the linear and striped
targets.
Signed-off-by: NDenis Semakin <d.semakin@omprussia.ru>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Otherwise, these abnormal IOs would be sent to the DM target
regardless of whether the target advertised support for them.

Factor out __process_abnormal_io() from __split_and_process_non_flush()
so that discards, write same, etc may be conditionally processed.

Fixes: 978e51ba ("dm: optimize bio-based NVMe IO submission")
Cc: stable@vger.kernel.org # 4.16
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Change device-mapper's DAX dependency to require the presence of at
least one DAX_DRIVER. This allows device-mapper to be built without
bringing the DAX core along which is especially wasteful when there are
no DAX drivers, like BLK_DEV_PMEM, configured.

Cc: Alasdair Kergon <agk@redhat.com>
Reported-by: NBart Van Assche <Bart.VanAssche@wdc.com>
Reported-by: Nkbuild test robot <lkp@intel.com>
Reported-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

dm_get_bdev_for_ioctl()'s return of 0 or 1 must be the result from
prepare_ioctl (1 means the ioctl was issued to a partition, 0 means it
wasn't).  Unfortunately commit 519049af ("dm: use blkdev_get rather
than bdgrab when issuing pass-through ioctl") reused the variable 'r'
to store the return from blkdev_get() that follows prepare_ioctl()
-- whereby dropping prepare_ioctl()'s result on the floor.

This can lead to an ioctl or persistent reservation being issued to a
partition going unnoticed, which implies the extra permission check for
CAP_SYS_RAWIO is skipped.

Fix this by using a different variable to store blkdev_get()'s return.

Fixes: 519049af ("dm: use blkdev_get rather than bdgrab when issuing pass-through ioctl")
Reported-by: NAlasdair G Kergon <agk@redhat.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Otherwise an underlying device's teardown (e.g. SCSI) may race with the
DM ioctl or persistent reservation and result in dereferencing driver
memory that gets freed when the underlying device's final blkdev_put()
occurs.

bdgrab() only increases the refcount for the block_device's inode to
ensure the block_device struct itself will not be freed, but does not
guarantee the block_device will remain associated with the gendisk or
its storage.

Cc: stable@vger.kernel.org # 4.8+
Reported-by: NDavid Jeffery <djeffery@redhat.com>
Suggested-by: NDavid Jeffery <djeffery@redhat.com>
Reviewed-by: NBen Marzinski <bmarzins@redhat.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

This patch does not change any functionality.
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

dec_pending() is given an error status (possibly 0) to be recorded
against a bio.  It can be called several times on the one 'struct
dm_io', and it is careful to only assign a non-zero error to
io->status.  However when it then assigned io->status to bio->bi_status,
it is not careful and could overwrite a genuine error status with 0.

This can happen when chained bios are in use.  If a bio is chained
beneath the bio that this dm_io is handling, the child bio might
complete and set bio->bi_status before the dm_io completes.

This has been possible since chained bios were introduced in 3.14, and
has become a lot easier to trigger with commit 18a25da8 ("dm: ensure
bio submission follows a depth-first tree walk") as that commit caused
dm to start using chained bios itself.

A particular failure mode is that if a bio spans an 'error' target and a
working target, the 'error' fragment will complete instantly and set the
->bi_status, and the other fragment will normally complete a little
later, and will clear ->bi_status.

The fix is simply to only assign io_error to bio->bi_status when
io_error is not zero.
Reported-and-tested-by: NMilan Broz <gmazyland@gmail.com>
Cc: stable@vger.kernel.org (v3.14+)
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Also, add dm_sysfs_init() error handling to dm_create().
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Signed-off-by: NMike Snitzer <snitzer@redhat.com>

DM is no longer prone to having its request_queue be improperly
initialized.

Summary of changes:

- defer DM's blk_register_queue() from add_disk()-time until
  dm_setup_md_queue() by using add_disk_no_queue_reg() in alloc_dev().

- dm_setup_md_queue() is updated to fully initialize DM's request_queue
  (_after_ all table loads have occurred and the request_queue's type,
  features and limits are known).

A very welcome side-effect of these changes is DM no longer needs to:
1) backfill the "mq" sysfs entry (because historically DM didn't
initialize the request_queue to use blk-mq until _after_
blk_register_queue() was called via add_disk()).
2) call elv_register_queue() to get .request_fn request-based DM
device's "iosched" exposed in syfs.

In addition, blk-mq debugfs support is now made available because
request-based DM's blk-mq request_queue is now properly initialized
before dm_setup_md_queue() calls blk_register_queue().

These changes also stave off the need to introduce new DM-specific
workarounds in block core, e.g. this proposal:
https://patchwork.kernel.org/patch/10067961/

In the end DM devices should be less unicorn in nature (relative to
initialization and availability of block core infrastructure provided by
the request_queue).
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Tested-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

For BIO based DM, some targets aren't ready for dealing with bigger
incoming bio than 1Mbyte, such as crypt target.

Cc: Mike Snitzer <snitzer@redhat.com>
Cc:dm-devel@redhat.com
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Upper level bio-based drivers that stack immediately ontop of NVMe can
leverage direct_make_request().  In addition DM's NVMe bio-based
will initially only ever have one NVMe device that it submits IO to at a
time.  There is no splitting needed.  Enhance DM core so that
DM_TYPE_NVME_BIO_BASED's IO submission takes advantage of both of these
characteristics.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

If dm_table_determine_type() establishes DM_TYPE_NVME_BIO_BASED then
all devices in the DM table do not support partial completions.  Also,
the table has a single immutable target that doesn't require DM core to
split bios.

This will enable adding NVMe optimizations to bio-based DM.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

No apparent need to generic_start_io_acct() until before the IO is ready
for submission.  start_io_acct() is the proper place to do this
accounting -- it is also where DM accounts for pending IO and, if
enabled, starts dm-stats accounting.

Replace start_io_acct()'s part_round_stats() with generic_start_io_acct().
This eliminates needing to take part_stat_lock() multiple times when
starting an IO on bio-based devices.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

'struct dm_io' already has the same pointer.  So update all accesses
from ci->md to ci->io->md.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Signed-off-by: NMike Snitzer <snitzer@redhat.com>