linux-stable.git/include/linux/blk_types.h, branch v4.18.2 Linux kernel stable tree block: don't use blocking queue entered for recursive bio submits 2018-06-03T02:35:00+00:00 Jens Axboe axboe@kernel.dk 2018-06-02T20:04:07+00:00 cd4a4ae4683dc2e09380118e205e057896dcda2b If we end up splitting a bio and the queue goes away between the initial submission and the later split submission, then we can block forever in blk_queue_enter() waiting for the reference to drop to zero. This will never happen, since we already hold a reference. Mark a split bio as already having entered the queue, so we can just use the live non-blocking queue enter variant. Thanks to Tetsuo Handa for the analysis. Reported-by: syzbot+c4f9cebf9d651f6e54de@syzkaller.appspotmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> 
If we end up splitting a bio and the queue goes away between
the initial submission and the later split submission, then we
can block forever in blk_queue_enter() waiting for the reference
to drop to zero. This will never happen, since we already hold
a reference.

Mark a split bio as already having entered the queue, so we can
just use the live non-blocking queue enter variant.

Thanks to Tetsuo Handa for the analysis.

Reported-by: syzbot+c4f9cebf9d651f6e54de@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block: get rid of struct blk_issue_stat 2018-05-09T14:33:05+00:00 Omar Sandoval osandov@fb.com 2018-05-09T09:08:50+00:00 544ccc8dc904db55d4576c27a1eb66a888ffacea struct blk_issue_stat squashes three things into one u64: - The time the driver started working on a request - The original size of the request (for the io.low controller) - Flags for writeback throttling It turns out that on x86_64, we have a 4 byte hole in struct request which we can fill with the non-timestamp fields from blk_issue_stat, simplifying things quite a bit. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
struct blk_issue_stat squashes three things into one u64:

- The time the driver started working on a request
- The original size of the request (for the io.low controller)
- Flags for writeback throttling

It turns out that on x86_64, we have a 4 byte hole in struct request
which we can fill with the non-timestamp fields from blk_issue_stat,
simplifying things quite a bit.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block: replace bio->bi_issue_stat with bio-specific type 2018-05-09T14:33:03+00:00 Omar Sandoval osandov@fb.com 2018-05-09T09:08:49+00:00 5238dcf4136fd7287be8e7d38752645bfa5782ec struct blk_issue_stat is going away, and bio->bi_issue_stat doesn't even use the blk-stats interface, so we can provide a separate implementation specific for bios. The helpers work the same way as the blk-stats helpers. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
struct blk_issue_stat is going away, and bio->bi_issue_stat doesn't even
use the blk-stats interface, so we can provide a separate implementation
specific for bios. The helpers work the same way as the blk-stats
helpers.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block: use 32-bit blk_status_t on Alpha 2018-03-22T01:23:33+00:00 Mikulas Patocka mpatocka@redhat.com 2018-03-21T16:42:25+00:00 6e2fb22103b99c26ae30a46512abe75526d8e4c9 Early alpha processors cannot write a single byte or word; they read 8 bytes, modify the value in registers and write back 8 bytes. The type blk_status_t is defined as one byte, it is often written asynchronously by I/O completion routines, this asynchronous modification can corrupt content of nearby bytes if these nearby bytes can be written simultaneously by another CPU. - one example of such corruption is the structure dm_io where "blk_status_t status" is written by an asynchronous completion routine and "atomic_t io_count" is modified synchronously - another example is the structure dm_buffer where "unsigned hold_count" is modified synchronously from process context and "blk_status_t write_error" is modified asynchronously from bio completion routine This patch fixes the bug by changing the type blk_status_t to 32 bits if we are on Alpha and if we are compiling for a processor that doesn't have the byte-word-extension. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org # 4.13+ Signed-off-by: Jens Axboe <axboe@kernel.dk> 
Early alpha processors cannot write a single byte or word; they read 8
bytes, modify the value in registers and write back 8 bytes.

The type blk_status_t is defined as one byte, it is often written
asynchronously by I/O completion routines, this asynchronous modification
can corrupt content of nearby bytes if these nearby bytes can be written
simultaneously by another CPU.

- one example of such corruption is the structure dm_io where
  "blk_status_t status" is written by an asynchronous completion routine
  and "atomic_t io_count" is modified synchronously
- another example is the structure dm_buffer where "unsigned hold_count"
  is modified synchronously from process context and "blk_status_t
  write_error" is modified asynchronously from bio completion routine

This patch fixes the bug by changing the type blk_status_t to 32 bits if
we are on Alpha and if we are compiling for a processor that doesn't have
the byte-word-extension.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org	# 4.13+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk-mq: introduce BLK_STS_DEV_RESOURCE 2018-01-31T03:18:28+00:00 Ming Lei ming.lei@redhat.com 2018-01-31T03:04:57+00:00 86ff7c2a80cd357f6156a53b354f6a0b357dc0c9 This status is returned from driver to block layer if device related resource is unavailable, but driver can guarantee that IO dispatch will be triggered in future when the resource is available. Convert some drivers to return BLK_STS_DEV_RESOURCE. Also, if driver returns BLK_STS_RESOURCE and SCHED_RESTART is set, rerun queue after a delay (BLK_MQ_DELAY_QUEUE) to avoid IO stalls. BLK_MQ_DELAY_QUEUE is 3 ms because both scsi-mq and nvmefc are using that magic value. If a driver can make sure there is in-flight IO, it is safe to return BLK_STS_DEV_RESOURCE because: 1) If all in-flight IOs complete before examining SCHED_RESTART in blk_mq_dispatch_rq_list(), SCHED_RESTART must be cleared, so queue is run immediately in this case by blk_mq_dispatch_rq_list(); 2) if there is any in-flight IO after/when examining SCHED_RESTART in blk_mq_dispatch_rq_list(): - if SCHED_RESTART isn't set, queue is run immediately as handled in 1) - otherwise, this request will be dispatched after any in-flight IO is completed via blk_mq_sched_restart() 3) if SCHED_RESTART is set concurently in context because of BLK_STS_RESOURCE, blk_mq_delay_run_hw_queue() will cover the above two cases and make sure IO hang can be avoided. One invariant is that queue will be rerun if SCHED_RESTART is set. Suggested-by: Jens Axboe <axboe@kernel.dk> Tested-by: Laurence Oberman <loberman@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
This status is returned from driver to block layer if device related
resource is unavailable, but driver can guarantee that IO dispatch
will be triggered in future when the resource is available.

Convert some drivers to return BLK_STS_DEV_RESOURCE.  Also, if driver
returns BLK_STS_RESOURCE and SCHED_RESTART is set, rerun queue after
a delay (BLK_MQ_DELAY_QUEUE) to avoid IO stalls.  BLK_MQ_DELAY_QUEUE is
3 ms because both scsi-mq and nvmefc are using that magic value.

If a driver can make sure there is in-flight IO, it is safe to return
BLK_STS_DEV_RESOURCE because:

1) If all in-flight IOs complete before examining SCHED_RESTART in
blk_mq_dispatch_rq_list(), SCHED_RESTART must be cleared, so queue
is run immediately in this case by blk_mq_dispatch_rq_list();

2) if there is any in-flight IO after/when examining SCHED_RESTART
in blk_mq_dispatch_rq_list():
- if SCHED_RESTART isn't set, queue is run immediately as handled in 1)
- otherwise, this request will be dispatched after any in-flight IO is
  completed via blk_mq_sched_restart()

3) if SCHED_RESTART is set concurently in context because of
BLK_STS_RESOURCE, blk_mq_delay_run_hw_queue() will cover the above two
cases and make sure IO hang can be avoided.

One invariant is that queue will be rerun if SCHED_RESTART is set.

Suggested-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Merge branch 'for-4.16/block' of git://git.kernel.dk/linux-block 2018-01-29T19:51:49+00:00 Linus Torvalds torvalds@linux-foundation.org 2018-01-29T19:51:49+00:00 0a4b6e2f80aad46fb55a5cf7b1664c0aef030ee0 Pull block updates from Jens Axboe: "This is the main pull request for block IO related changes for the 4.16 kernel. Nothing major in this pull request, but a good amount of improvements and fixes all over the map. This contains: - BFQ improvements, fixes, and cleanups from Angelo, Chiara, and Paolo. - Support for SMR zones for deadline and mq-deadline from Damien and Christoph. - Set of fixes for bcache by way of Michael Lyle, including fixes from himself, Kent, Rui, Tang, and Coly. - Series from Matias for lightnvm with fixes from Hans Holmberg, Javier, and Matias. Mostly centered around pblk, and the removing rrpc 1.2 in preparation for supporting 2.0. - A couple of NVMe pull requests from Christoph. Nothing major in here, just fixes and cleanups, and support for command tracing from Johannes. - Support for blk-throttle for tracking reads and writes separately. From Joseph Qi. A few cleanups/fixes also for blk-throttle from Weiping. - Series from Mike Snitzer that enables dm to register its queue more logically, something that's alwways been problematic on dm since it's a stacked device. - Series from Ming cleaning up some of the bio accessor use, in preparation for supporting multipage bvecs. - Various fixes from Ming closing up holes around queue mapping and quiescing. - BSD partition fix from Richard Narron, fixing a problem where we can't mount newer (10/11) FreeBSD partitions. - Series from Tejun reworking blk-mq timeout handling. The previous scheme relied on atomic bits, but it had races where we would think a request had timed out if it to reused at the wrong time. - null_blk now supports faking timeouts, to enable us to better exercise and test that functionality separately. From me. - Kill the separate atomic poll bit in the request struct. After this, we don't use the atomic bits on blk-mq anymore at all. From me. - sgl_alloc/free helpers from Bart. - Heavily contended tag case scalability improvement from me. - Various little fixes and cleanups from Arnd, Bart, Corentin, Douglas, Eryu, Goldwyn, and myself" * 'for-4.16/block' of git://git.kernel.dk/linux-block: (186 commits) block: remove smart1,2.h nvme: add tracepoint for nvme_complete_rq nvme: add tracepoint for nvme_setup_cmd nvme-pci: introduce RECONNECTING state to mark initializing procedure nvme-rdma: remove redundant boolean for inline_data nvme: don't free uuid pointer before printing it nvme-pci: Suspend queues after deleting them bsg: use pr_debug instead of hand crafted macros blk-mq-debugfs: don't allow write on attributes with seq_operations set nvme-pci: Fix queue double allocations block: Set BIO_TRACE_COMPLETION on new bio during split blk-throttle: use queue_is_rq_based block: Remove kblockd_schedule_delayed_work{,_on}() blk-mq: Avoid that blk_mq_delay_run_hw_queue() introduces unintended delays blk-mq: Rename blk_mq_request_direct_issue() into blk_mq_request_issue_directly() lib/scatterlist: Fix chaining support in sgl_alloc_order() blk-throttle: track read and write request individually block: add bdev_read_only() checks to common helpers block: fail op_is_write() requests to read-only partitions blk-throttle: export io_serviced_recursive, io_service_bytes_recursive ... 
Pull block updates from Jens Axboe:
 "This is the main pull request for block IO related changes for the
  4.16 kernel. Nothing major in this pull request, but a good amount of
  improvements and fixes all over the map. This contains:

   - BFQ improvements, fixes, and cleanups from Angelo, Chiara, and
     Paolo.

   - Support for SMR zones for deadline and mq-deadline from Damien and
     Christoph.

   - Set of fixes for bcache by way of Michael Lyle, including fixes
     from himself, Kent, Rui, Tang, and Coly.

   - Series from Matias for lightnvm with fixes from Hans Holmberg,
     Javier, and Matias. Mostly centered around pblk, and the removing
     rrpc 1.2 in preparation for supporting 2.0.

   - A couple of NVMe pull requests from Christoph. Nothing major in
     here, just fixes and cleanups, and support for command tracing from
     Johannes.

   - Support for blk-throttle for tracking reads and writes separately.
     From Joseph Qi. A few cleanups/fixes also for blk-throttle from
     Weiping.

   - Series from Mike Snitzer that enables dm to register its queue more
     logically, something that's alwways been problematic on dm since
     it's a stacked device.

   - Series from Ming cleaning up some of the bio accessor use, in
     preparation for supporting multipage bvecs.

   - Various fixes from Ming closing up holes around queue mapping and
     quiescing.

   - BSD partition fix from Richard Narron, fixing a problem where we
     can't mount newer (10/11) FreeBSD partitions.

   - Series from Tejun reworking blk-mq timeout handling. The previous
     scheme relied on atomic bits, but it had races where we would think
     a request had timed out if it to reused at the wrong time.

   - null_blk now supports faking timeouts, to enable us to better
     exercise and test that functionality separately. From me.

   - Kill the separate atomic poll bit in the request struct. After
     this, we don't use the atomic bits on blk-mq anymore at all. From
     me.

   - sgl_alloc/free helpers from Bart.

   - Heavily contended tag case scalability improvement from me.

   - Various little fixes and cleanups from Arnd, Bart, Corentin,
     Douglas, Eryu, Goldwyn, and myself"

* 'for-4.16/block' of git://git.kernel.dk/linux-block: (186 commits)
  block: remove smart1,2.h
  nvme: add tracepoint for nvme_complete_rq
  nvme: add tracepoint for nvme_setup_cmd
  nvme-pci: introduce RECONNECTING state to mark initializing procedure
  nvme-rdma: remove redundant boolean for inline_data
  nvme: don't free uuid pointer before printing it
  nvme-pci: Suspend queues after deleting them
  bsg: use pr_debug instead of hand crafted macros
  blk-mq-debugfs: don't allow write on attributes with seq_operations set
  nvme-pci: Fix queue double allocations
  block: Set BIO_TRACE_COMPLETION on new bio during split
  blk-throttle: use queue_is_rq_based
  block: Remove kblockd_schedule_delayed_work{,_on}()
  blk-mq: Avoid that blk_mq_delay_run_hw_queue() introduces unintended delays
  blk-mq: Rename blk_mq_request_direct_issue() into blk_mq_request_issue_directly()
  lib/scatterlist: Fix chaining support in sgl_alloc_order()
  blk-throttle: track read and write request individually
  block: add bdev_read_only() checks to common helpers
  block: fail op_is_write() requests to read-only partitions
  blk-throttle: export io_serviced_recursive, io_service_bytes_recursive
  ...
block: Provide blk_status_t decoding for path errors 2018-01-10T17:52:16+00:00 Keith Busch keith.busch@intel.com 2018-01-09T19:04:16+00:00 9111e5686c8cf3905191d4feb819acd874437500 This patch provides a common decoder for block status path related errors that may be retried so various entities wishing to consult this do not have to duplicate this decision. Acked-by: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
This patch provides a common decoder for block status path related errors
that may be retried so various entities wishing to consult this do not
have to duplicate this decision.

Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block-throttle: avoid double charge 2017-12-20T18:10:17+00:00 Shaohua Li shli@fb.com 2017-12-20T18:10:17+00:00 111be883981748acc9a56e855c8336404a8e787c If a bio is throttled and split after throttling, the bio could be resubmited and enters the throttling again. This will cause part of the bio to be charged multiple times. If the cgroup has an IO limit, the double charge will significantly harm the performance. The bio split becomes quite common after arbitrary bio size change. To fix this, we always set the BIO_THROTTLED flag if a bio is throttled. If the bio is cloned/split, we copy the flag to new bio too to avoid a double charge. However, cloned bio could be directed to a new disk, keeping the flag be a problem. The observation is we always set new disk for the bio in this case, so we can clear the flag in bio_set_dev(). This issue exists for a long time, arbitrary bio size change just makes it worse, so this should go into stable at least since v4.2. V1-> V2: Not add extra field in bio based on discussion with Tejun Cc: Vivek Goyal <vgoyal@redhat.com> Cc: stable@vger.kernel.org Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
If a bio is throttled and split after throttling, the bio could be
resubmited and enters the throttling again. This will cause part of the
bio to be charged multiple times. If the cgroup has an IO limit, the
double charge will significantly harm the performance. The bio split
becomes quite common after arbitrary bio size change.

To fix this, we always set the BIO_THROTTLED flag if a bio is throttled.
If the bio is cloned/split, we copy the flag to new bio too to avoid a
double charge. However, cloned bio could be directed to a new disk,
keeping the flag be a problem. The observation is we always set new disk
for the bio in this case, so we can clear the flag in bio_set_dev().

This issue exists for a long time, arbitrary bio size change just makes
it worse, so this should go into stable at least since v4.2.

V1-> V2: Not add extra field in bio based on discussion with Tejun

Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: stable@vger.kernel.org
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Merge branch 'for-4.15/block' of git://git.kernel.dk/linux-block 2017-11-14T23:32:19+00:00 Linus Torvalds torvalds@linux-foundation.org 2017-11-14T23:32:19+00:00 e2c5923c349c1738fe8fda980874d93f6fb2e5b6 Pull core block layer updates from Jens Axboe: "This is the main pull request for block storage for 4.15-rc1. Nothing out of the ordinary in here, and no API changes or anything like that. Just various new features for drivers, core changes, etc. In particular, this pull request contains: - A patch series from Bart, closing the whole on blk/scsi-mq queue quescing. - A series from Christoph, building towards hidden gendisks (for multipath) and ability to move bio chains around. - NVMe - Support for native multipath for NVMe (Christoph). - Userspace notifications for AENs (Keith). - Command side-effects support (Keith). - SGL support (Chaitanya Kulkarni) - FC fixes and improvements (James Smart) - Lots of fixes and tweaks (Various) - bcache - New maintainer (Michael Lyle) - Writeback control improvements (Michael) - Various fixes (Coly, Elena, Eric, Liang, et al) - lightnvm updates, mostly centered around the pblk interface (Javier, Hans, and Rakesh). - Removal of unused bio/bvec kmap atomic interfaces (me, Christoph) - Writeback series that fix the much discussed hundreds of millions of sync-all units. This goes all the way, as discussed previously (me). - Fix for missing wakeup on writeback timer adjustments (Yafang Shao). - Fix laptop mode on blk-mq (me). - {mq,name} tupple lookup for IO schedulers, allowing us to have alias names. This means you can use 'deadline' on both !mq and on mq (where it's called mq-deadline). (me). - blktrace race fix, oopsing on sg load (me). - blk-mq optimizations (me). - Obscure waitqueue race fix for kyber (Omar). - NBD fixes (Josef). - Disable writeback throttling by default on bfq, like we do on cfq (Luca Miccio). - Series from Ming that enable us to treat flush requests on blk-mq like any other request. This is a really nice cleanup. - Series from Ming that improves merging on blk-mq with schedulers, getting us closer to flipping the switch on scsi-mq again. - BFQ updates (Paolo). - blk-mq atomic flags memory ordering fixes (Peter Z). - Loop cgroup support (Shaohua). - Lots of minor fixes from lots of different folks, both for core and driver code" * 'for-4.15/block' of git://git.kernel.dk/linux-block: (294 commits) nvme: fix visibility of "uuid" ns attribute blk-mq: fixup some comment typos and lengths ide: ide-atapi: fix compile error with defining macro DEBUG blk-mq: improve tag waiting setup for non-shared tags brd: remove unused brd_mutex blk-mq: only run the hardware queue if IO is pending block: avoid null pointer dereference on null disk fs: guard_bio_eod() needs to consider partitions xtensa/simdisk: fix compile error nvme: expose subsys attribute to sysfs nvme: create 'slaves' and 'holders' entries for hidden controllers block: create 'slaves' and 'holders' entries for hidden gendisks nvme: also expose the namespace identification sysfs files for mpath nodes nvme: implement multipath access to nvme subsystems nvme: track shared namespaces nvme: introduce a nvme_ns_ids structure nvme: track subsystems block, nvme: Introduce blk_mq_req_flags_t block, scsi: Make SCSI quiesce and resume work reliably block: Add the QUEUE_FLAG_PREEMPT_ONLY request queue flag ... 
Pull core block layer updates from Jens Axboe:
 "This is the main pull request for block storage for 4.15-rc1.

  Nothing out of the ordinary in here, and no API changes or anything
  like that. Just various new features for drivers, core changes, etc.
  In particular, this pull request contains:

   - A patch series from Bart, closing the whole on blk/scsi-mq queue
     quescing.

   - A series from Christoph, building towards hidden gendisks (for
     multipath) and ability to move bio chains around.

   - NVMe
        - Support for native multipath for NVMe (Christoph).
        - Userspace notifications for AENs (Keith).
        - Command side-effects support (Keith).
        - SGL support (Chaitanya Kulkarni)
        - FC fixes and improvements (James Smart)
        - Lots of fixes and tweaks (Various)

   - bcache
        - New maintainer (Michael Lyle)
        - Writeback control improvements (Michael)
        - Various fixes (Coly, Elena, Eric, Liang, et al)

   - lightnvm updates, mostly centered around the pblk interface
     (Javier, Hans, and Rakesh).

   - Removal of unused bio/bvec kmap atomic interfaces (me, Christoph)

   - Writeback series that fix the much discussed hundreds of millions
     of sync-all units. This goes all the way, as discussed previously
     (me).

   - Fix for missing wakeup on writeback timer adjustments (Yafang
     Shao).

   - Fix laptop mode on blk-mq (me).

   - {mq,name} tupple lookup for IO schedulers, allowing us to have
     alias names. This means you can use 'deadline' on both !mq and on
     mq (where it's called mq-deadline). (me).

   - blktrace race fix, oopsing on sg load (me).

   - blk-mq optimizations (me).

   - Obscure waitqueue race fix for kyber (Omar).

   - NBD fixes (Josef).

   - Disable writeback throttling by default on bfq, like we do on cfq
     (Luca Miccio).

   - Series from Ming that enable us to treat flush requests on blk-mq
     like any other request. This is a really nice cleanup.

   - Series from Ming that improves merging on blk-mq with schedulers,
     getting us closer to flipping the switch on scsi-mq again.

   - BFQ updates (Paolo).

   - blk-mq atomic flags memory ordering fixes (Peter Z).

   - Loop cgroup support (Shaohua).

   - Lots of minor fixes from lots of different folks, both for core and
     driver code"

* 'for-4.15/block' of git://git.kernel.dk/linux-block: (294 commits)
  nvme: fix visibility of "uuid" ns attribute
  blk-mq: fixup some comment typos and lengths
  ide: ide-atapi: fix compile error with defining macro DEBUG
  blk-mq: improve tag waiting setup for non-shared tags
  brd: remove unused brd_mutex
  blk-mq: only run the hardware queue if IO is pending
  block: avoid null pointer dereference on null disk
  fs: guard_bio_eod() needs to consider partitions
  xtensa/simdisk: fix compile error
  nvme: expose subsys attribute to sysfs
  nvme: create 'slaves' and 'holders' entries for hidden controllers
  block: create 'slaves' and 'holders' entries for hidden gendisks
  nvme: also expose the namespace identification sysfs files for mpath nodes
  nvme: implement multipath access to nvme subsystems
  nvme: track shared namespaces
  nvme: introduce a nvme_ns_ids structure
  nvme: track subsystems
  block, nvme: Introduce blk_mq_req_flags_t
  block, scsi: Make SCSI quiesce and resume work reliably
  block: Add the QUEUE_FLAG_PREEMPT_ONLY request queue flag
  ...
block, nvme: Introduce blk_mq_req_flags_t 2017-11-11T02:53:25+00:00 Bart Van Assche bart.vanassche@wdc.com 2017-11-09T18:49:59+00:00 9a95e4ef709533efac4aafcb8bddf73f96db50ed Several block layer and NVMe core functions accept a combination of BLK_MQ_REQ_* flags through the 'flags' argument but there is no verification at compile time whether the right type of block layer flags is passed. Make it possible for sparse to verify this. This patch does not change any functionality. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Cc: linux-nvme@lists.infradead.org Cc: Christoph Hellwig <hch@lst.de> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
Several block layer and NVMe core functions accept a combination
of BLK_MQ_REQ_* flags through the 'flags' argument but there is
no verification at compile time whether the right type of block
layer flags is passed. Make it possible for sparse to verify this.
This patch does not change any functionality.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Cc: linux-nvme@lists.infradead.org
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>