1. 20 Jun, 2018 1 commit
  2. 02 Nov, 2017 1 commit
    • Greg Kroah-Hartman's avatar
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman authored
      Many source files in the tree are missing licensing information, which
      makes it harder for compliance tools to determine the correct license.
      By default all files without license information are under the default
      license of the kernel, which is GPL version 2.
      Update the files which contain no license information with the 'GPL-2.0'
      SPDX license identifier.  The SPDX identifier is a legally binding
      shorthand, which can be used instead of the full boiler plate text.
      This patch is based on work done by Thomas Gleixner and Kate Stewart and
      Philippe Ombredanne.
      How this work was done:
      Patches were generated and checked against linux-4.14-rc6 for a subset of
      the use cases:
       - file had no licensing information it it.
       - file was a */uapi/* one with no licensing information in it,
       - file was a */uapi/* one with existing licensing information,
      Further patches will be generated in subsequent months to fix up cases
      where non-standard license headers were used, and references to license
      had to be inferred by heuristics based on keywords.
      The analysis to determine which SPDX License Identifier to be applied to
      a file was done in a spreadsheet of side by side results from of the
      output of two independent scanners (ScanCode & Windriver) producing SPDX
      tag:value files created by Philippe Ombredanne.  Philippe prepared the
      base worksheet, and did an initial spot review of a few 1000 files.
      The 4.13 kernel was the starting point of the analysis with 60,537 files
      assessed.  Kate Stewart did a file by file comparison of the scanner
      results in the spreadsheet to determine which SPDX license identifier(s)
      to be applied to the file. She confirmed any determination that was not
      immediately clear with lawyers working with the Linux Foundation.
      Criteria used to select files for SPDX license identifier tagging was:
       - Files considered eligible had to be source code files.
       - Make and config files were included as candidates if they contained >5
         lines of source
       - File already had some variant of a license header in it (even if <5
      All documentation files were explicitly excluded.
      The following heuristics were used to determine which SPDX license
      identifiers to apply.
       - when both scanners couldn't find any license traces, file was
         considered to have no license information in it, and the top level
         COPYING file license applied.
         For non */uapi/* files that summary was:
         SPDX license identifier                            # files
         GPL-2.0                                              11139
         and resulted in the first patch in this series.
         If that file was a */uapi/* path one, it was "GPL-2.0 WITH
         Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:
         SPDX license identifier                            # files
         GPL-2.0 WITH Linux-syscall-note                        930
         and resulted in the second patch in this series.
       - if a file had some form of licensing information in it, and was one
         of the */uapi/* ones, it was denoted with the Linux-syscall-note if
         any GPL family license was found in the file or had no licensing in
         it (per prior point).  Results summary:
         SPDX license identifier                            # files
         GPL-2.0 WITH Linux-syscall-note                       270
         GPL-2.0+ WITH Linux-syscall-note                      169
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
         LGPL-2.1+ WITH Linux-syscall-note                      15
         GPL-1.0+ WITH Linux-syscall-note                       14
         ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
         LGPL-2.0+ WITH Linux-syscall-note                       4
         LGPL-2.1 WITH Linux-syscall-note                        3
         ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
         ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1
         and that resulted in the third patch in this series.
       - when the two scanners agreed on the detected license(s), that became
         the concluded license(s).
       - when there was disagreement between the two scanners (one detected a
         license but the other didn't, or they both detected different
         licenses) a manual inspection of the file occurred.
       - In most cases a manual inspection of the information in the file
         resulted in a clear resolution of the license that should apply (and
         which scanner probably needed to revisit its heuristics).
       - When it was not immediately clear, the license identifier was
         confirmed with lawyers working with the Linux Foundation.
       - If there was any question as to the appropriate license identifier,
         the file was flagged for further research and to be revisited later
         in time.
      In total, over 70 hours of logged manual review was done on the
      spreadsheet to determine the SPDX license identifiers to apply to the
      source files by Kate, Philippe, Thomas and, in some cases, confirmation
      by lawyers working with the Linux Foundation.
      Kate also obtained a third independent scan of the 4.13 code base from
      FOSSology, and compared selected files where the other two scanners
      disagreed against that SPDX file, to see if there was new insights.  The
      Windriver scanner is based on an older version of FOSSology in part, so
      they are related.
      Thomas did random spot checks in about 500 files from the spreadsheets
      for the uapi headers and agreed with SPDX license identifier in the
      files he inspected. For the non-uapi files Thomas did random spot checks
      in about 15000 files.
      In initial set of patches against 4.14-rc6, 3 files were found to have
      copy/paste license identifier errors, and have been fixed to reflect the
      correct identifier.
      Additionally Philippe spent 10 hours this week doing a detailed manual
      inspection and review of the 12,461 patched files from the initial patch
      version early this week with:
       - a full scancode scan run, collecting the matched texts, detected
         license ids and scores
       - reviewing anything where there was a license detected (about 500+
         files) to ensure that the applied SPDX license was correct
       - reviewing anything where there was no detection but the patch license
         was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
         SPDX license was correct
      This produced a worksheet with 20 files needing minor correction.  This
      worksheet was then exported into 3 different .csv files for the
      different types of files to be modified.
      These .csv files were then reviewed by Greg.  Thomas wrote a script to
      parse the csv files and add the proper SPDX tag to the file, in the
      format that the file expected.  This script was further refined by Greg
      based on the output to detect more types of files automatically and to
      distinguish between header and source .c files (which need different
      comment types.)  Finally Greg ran the script using the .csv files to
      generate the patches.
      Reviewed-by: default avatarKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: default avatarPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
  3. 11 Sep, 2017 1 commit
    • Jens Axboe's avatar
      block: directly insert blk-mq request from blk_insert_cloned_request() · 157f377b
      Jens Axboe authored
      A NULL pointer crash was reported for the case of having the BFQ IO
      scheduler attached to the underlying blk-mq paths of a DM multipath
      device.  The crash occured in blk_mq_sched_insert_request()'s call to
      Paolo Valente correctly summarized why the crash occured with:
      "the call chain (dm_mq_queue_rq -> map_request -> setup_clone ->
      blk_rq_prep_clone) creates a cloned request without invoking
      e->type->ops.mq.prepare_request for the target elevator e.  The cloned
      request is therefore not initialized for the scheduler, but it is
      however inserted into the scheduler by blk_mq_sched_insert_request."
      All said, a request-based DM multipath device's IO scheduler should be
      the only one used -- when the original requests are issued to the
      underlying paths as cloned requests they are inserted directly in the
      underlying dispatch queue(s) rather than through an additional elevator.
      But commit bd166ef1 ("blk-mq-sched: add framework for MQ capable IO
      schedulers") switched blk_insert_cloned_request() from using
      blk_mq_insert_request() to blk_mq_sched_insert_request().  Which
      incorrectly added elevator machinery into a call chain that isn't
      supposed to have any.
      To fix this introduce a blk-mq private blk_mq_request_bypass_insert()
      that blk_insert_cloned_request() calls to insert the request without
      involving any elevator that may be attached to the cloned request's
      Fixes: bd166ef1 ("blk-mq-sched: add framework for MQ capable IO schedulers")
      Cc: stable@vger.kernel.org
      Reported-by: default avatarBart Van Assche <Bart.VanAssche@wdc.com>
      Tested-by: default avatarMike Snitzer <snitzer@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
  4. 09 Aug, 2017 1 commit
  5. 28 Jun, 2017 1 commit
  6. 18 Jun, 2017 3 commits
  7. 04 May, 2017 1 commit
  8. 26 Apr, 2017 3 commits
  9. 14 Apr, 2017 1 commit
  10. 07 Apr, 2017 1 commit
    • Omar Sandoval's avatar
      blk-mq: use the right hctx when getting a driver tag fails · 81380ca1
      Omar Sandoval authored
      While dispatching requests, if we fail to get a driver tag, we mark the
      hardware queue as waiting for a tag and put the requests on a
      hctx->dispatch list to be run later when a driver tag is freed. However,
      blk_mq_dispatch_rq_list() may dispatch requests from multiple hardware
      queues if using a single-queue scheduler with a multiqueue device. If
      blk_mq_get_driver_tag() fails, it doesn't update the hardware queue we
      are processing. This means we end up using the hardware queue of the
      previous request, which may or may not be the same as that of the
      current request. If it isn't, the wrong hardware queue will end up
      waiting for a tag, and the requests will be on the wrong dispatch list,
      leading to a hang.
      The fix is twofold:
      1. Make sure we save which hardware queue we were trying to get a
         request for in blk_mq_get_driver_tag() regardless of whether it
         succeeds or not.
      2. Make blk_mq_dispatch_rq_list() take a request_queue instead of a
         blk_mq_hw_queue to make it clear that it must handle multiple
         hardware queues, since I've already messed this up on a couple of
      This didn't appear in testing with nvme and mq-deadline because nvme has
      more driver tags than the default number of scheduler tags. However,
      with the blk_mq_update_nr_hw_queues() fix, it showed up with nbd.
      Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
  11. 21 Mar, 2017 1 commit
    • Omar Sandoval's avatar
      blk-stat: convert to callback-based statistics reporting · 34dbad5d
      Omar Sandoval authored
      Currently, statistics are gathered in ~0.13s windows, and users grab the
      statistics whenever they need them. This is not ideal for both in-tree
      1. Writeback throttling wants its own dynamically sized window of
         statistics. Since the blk-stats statistics are reset after every
         window and the wbt windows don't line up with the blk-stats windows,
         wbt doesn't see every I/O.
      2. Polling currently grabs the statistics on every I/O. Again, depending
         on how the window lines up, we may miss some I/Os. It's also
         unnecessary overhead to get the statistics on every I/O; the hybrid
         polling heuristic would be just as happy with the statistics from the
         previous full window.
      This reworks the blk-stats infrastructure to be callback-based: users
      register a callback that they want called at a given time with all of
      the statistics from the window during which the callback was active.
      Users can dynamically bucketize the statistics. wbt and polling both
      currently use read vs. write, but polling can be extended to further
      subdivide based on request size.
      The callbacks are kept on an RCU list, and each callback has percpu
      stats buffers. There will only be a few users, so the overhead on the
      I/O completion side is low. The stats flushing is also simplified
      considerably: since the timer function is responsible for clearing the
      statistics, we don't have to worry about stale statistics.
      wbt is a trivial conversion. After the conversion, the windowing problem
      mentioned above is fixed.
      For polling, we register an extra callback that caches the previous
      window's statistics in the struct request_queue for the hybrid polling
      heuristic to use.
      Since we no longer have a single stats buffer for the request queue,
      this also removes the sysfs and debugfs stats entries. To replace those,
      we add a debugfs entry for the poll statistics.
      Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
  12. 08 Mar, 2017 2 commits
    • Ming Lei's avatar
      blk-mq: make lifetime consitent between q/ctx and its kobject · 7ea5fe31
      Ming Lei authored
      Currently from kobject view, both q->mq_kobj and ctx->kobj can
      be released during one cycle of blk_mq_register_dev() and
      blk_mq_unregister_dev(). Actually, sw queue's lifetime is
      same with its request queue's, which is covered by request_queue->kobj.
      So we don't need to call kobject_put() for the two kinds of
      kobject in __blk_mq_unregister_dev(), instead we do that
      in release handler of request queue.
      Signed-off-by: default avatarMing Lei <tom.leiming@gmail.com>
      Tested-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
    • Ming Lei's avatar
      blk-mq: initialize mq kobjects in blk_mq_init_allocated_queue() · 737f98cf
      Ming Lei authored
      Both q->mq_kobj and sw queues' kobjects should have been initialized
      once, instead of doing that each add_disk context.
      Also this patch removes clearing of ctx in blk_mq_init_cpu_queues()
      because percpu allocator fills zero to allocated variable.
      This patch fixes one issue[1] reported from Omar.
      [1] kernel wearning when doing unbind/bind on one scsi-mq device
      [   19.347924] kobject (ffff8800791ea0b8): tried to init an initialized object, something is seriously wrong.
      [   19.349781] CPU: 1 PID: 84 Comm: kworker/u8:1 Not tainted 4.10.0-rc7-00210-g53f39eeaa263 #34
      [   19.350686] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.1-20161122_114906-anatol 04/01/2014
      [   19.350920] Workqueue: events_unbound async_run_entry_fn
      [   19.350920] Call Trace:
      [   19.350920]  dump_stack+0x63/0x83
      [   19.350920]  kobject_init+0x77/0x90
      [   19.350920]  blk_mq_register_dev+0x40/0x130
      [   19.350920]  blk_register_queue+0xb6/0x190
      [   19.350920]  device_add_disk+0x1ec/0x4b0
      [   19.350920]  sd_probe_async+0x10d/0x1c0 [sd_mod]
      [   19.350920]  async_run_entry_fn+0x48/0x150
      [   19.350920]  process_one_work+0x1d0/0x480
      [   19.350920]  worker_thread+0x48/0x4e0
      [   19.350920]  kthread+0x101/0x140
      [   19.350920]  ? process_one_work+0x480/0x480
      [   19.350920]  ? kthread_create_on_node+0x60/0x60
      [   19.350920]  ret_from_fork+0x2c/0x40
      Cc: Omar Sandoval <osandov@osandov.com>
      Signed-off-by: default avatarMing Lei <tom.leiming@gmail.com>
      Tested-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
  13. 02 Mar, 2017 1 commit
  14. 02 Feb, 2017 1 commit
  15. 27 Jan, 2017 4 commits
  16. 17 Jan, 2017 4 commits
  17. 09 Dec, 2016 1 commit
  18. 10 Nov, 2016 1 commit
    • Jens Axboe's avatar
      block: add scalable completion tracking of requests · cf43e6be
      Jens Axboe authored
      For legacy block, we simply track them in the request queue. For
      blk-mq, we track them on a per-sw queue basis, which we can then
      sum up through the hardware queues and finally to a per device
      The stats are tracked in, roughly, 0.1s interval windows.
      Add sysfs files to display the stats.
      The feature is off by default, to avoid any extra overhead. In-kernel
      users of it can turn it on by setting QUEUE_FLAG_STATS in the queue
      flags. We currently don't turn it on if someone just reads any of
      the stats files, that is something we could add as well.
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
  19. 08 Nov, 2016 1 commit
  20. 02 Nov, 2016 1 commit
  21. 22 Sep, 2016 1 commit
  22. 17 Sep, 2016 2 commits
  23. 15 Sep, 2016 2 commits
  24. 09 Feb, 2016 1 commit
    • Keith Busch's avatar
      blk-mq: dynamic h/w context count · 868f2f0b
      Keith Busch authored
      The hardware's provided queue count may change at runtime with resource
      provisioning. This patch allows a block driver to alter the number of
      h/w queues available when its resource count changes.
      The main part is a new blk-mq API to request a new number of h/w queues
      for a given live tag set. The new API freezes all queues using that set,
      then adjusts the allocated count prior to remapping these to CPUs.
      The bulk of the rest just shifts where h/w contexts and all their
      artifacts are allocated and freed.
      The number of max h/w contexts is capped to the number of possible cpus
      since there is no use for more than that. As such, all pre-allocated
      memory for pointers need to account for the max possible rather than
      the initial number of queues.
      A side effect of this is that the blk-mq will proceed successfully as
      long as it can allocate at least one h/w context. Previously it would
      fail request queue initialization if less than the requested number
      was allocated.
      Signed-off-by: default avatarKeith Busch <keith.busch@intel.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Tested-by: default avatarJon Derrick <jonathan.derrick@intel.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
  25. 01 Dec, 2015 1 commit
  26. 11 Nov, 2015 1 commit
  27. 09 Oct, 2015 1 commit