1. 30 May, 2018 1 commit
    • Maurizio Lombardi's avatar
      cdrom: do not call check_disk_change() inside cdrom_open() · e6e5de32
      Maurizio Lombardi authored
      [ Upstream commit 2bbea6e1 ]
      
      when mounting an ISO filesystem sometimes (very rarely)
      the system hangs because of a race condition between two tasks.
      
      PID: 6766   TASK: ffff88007b2a6dd0  CPU: 0   COMMAND: "mount"
       #0 [ffff880078447ae0] __schedule at ffffffff8168d605
       #1 [ffff880078447b48] schedule_preempt_disabled at ffffffff8168ed49
       #2 [ffff880078447b58] __mutex_lock_slowpath at ffffffff8168c995
       #3 [ffff880078447bb8] mutex_lock at ffffffff8168bdef
       #4 [ffff880078447bd0] sr_block_ioctl at ffffffffa00b6818 [sr_mod]
       #5 [ffff880078447c10] blkdev_ioctl at ffffffff812fea50
       #6 [ffff880078447c70] ioctl_by_bdev at ffffffff8123a8b3
       #7 [ffff880078447c90] isofs_fill_super at ffffffffa04fb1e1 [isofs]
       #8 [ffff880078447da8] mount_bdev at ffffffff81202570
       #9 [ffff880078447e18] isofs_mount at ffffffffa04f9828 [isofs]
      #10 [ffff880078447e28] mount_fs at ffffffff81202d09
      #11 [ffff880078447e70] vfs_kern_mount at ffffffff8121ea8f
      #12 [ffff880078447ea8] do_mount at ffffffff81220fee
      #13 [ffff880078447f28] sys_mount at ffffffff812218d6
      #14 [ffff880078447f80] system_call_fastpath at ffffffff81698c49
          RIP: 00007fd9ea914e9a  RSP: 00007ffd5d9bf648  RFLAGS: 00010246
          RAX: 00000000000000a5  RBX: ffffffff81698c49  RCX: 0000000000000010
          RDX: 00007fd9ec2bc210  RSI: 00007fd9ec2bc290  RDI: 00007fd9ec2bcf30
          RBP: 0000000000000000   R8: 0000000000000000   R9: 0000000000000010
          R10: 00000000c0ed0001  R11: 0000000000000206  R12: 00007fd9ec2bc040
          R13: 00007fd9eb6b2380  R14: 00007fd9ec2bc210  R15: 00007fd9ec2bcf30
          ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b
      
      This task was trying to mount the cdrom.  It allocated and configured a
      super_block struct and owned the write-lock for the super_block->s_umount
      rwsem. While exclusively owning the s_umount lock, it called
      sr_block_ioctl and waited to acquire the global sr_mutex lock.
      
      PID: 6785   TASK: ffff880078720fb0  CPU: 0   COMMAND: "systemd-udevd"
       #0 [ffff880078417898] __schedule at ffffffff8168d605
       #1 [ffff880078417900] schedule at ffffffff8168dc59
       #2 [ffff880078417910] rwsem_down_read_failed at ffffffff8168f605
       #3 [ffff880078417980] call_rwsem_down_read_failed at ffffffff81328838
       #4 [ffff8800784179d0] down_read at ffffffff8168cde0
       #5 [ffff8800784179e8] get_super at ffffffff81201cc7
       #6 [ffff880078417a10] __invalidate_device at ffffffff8123a8de
       #7 [ffff880078417a40] flush_disk at ffffffff8123a94b
       #8 [ffff880078417a88] check_disk_change at ffffffff8123ab50
       #9 [ffff880078417ab0] cdrom_open at ffffffffa00a29e1 [cdrom]
      #10 [ffff880078417b68] sr_block_open at ffffffffa00b6f9b [sr_mod]
      #11 [ffff880078417b98] __blkdev_get at ffffffff8123ba86
      #12 [ffff880078417bf0] blkdev_get at ffffffff8123bd65
      #13 [ffff880078417c78] blkdev_open at ffffffff8123bf9b
      #14 [ffff880078417c90] do_dentry_open at ffffffff811fc7f7
      #15 [ffff880078417cd8] vfs_open at ffffffff811fc9cf
      #16 [ffff880078417d00] do_last at ffffffff8120d53d
      #17 [ffff880078417db0] path_openat at ffffffff8120e6b2
      #18 [ffff880078417e48] do_filp_open at ffffffff8121082b
      #19 [ffff880078417f18] do_sys_open at ffffffff811fdd33
      #20 [ffff880078417f70] sys_open at ffffffff811fde4e
      #21 [ffff880078417f80] system_call_fastpath at ffffffff81698c49
          RIP: 00007f29438b0c20  RSP: 00007ffc76624b78  RFLAGS: 00010246
          RAX: 0000000000000002  RBX: ffffffff81698c49  RCX: 0000000000000000
          RDX: 00007f2944a5fa70  RSI: 00000000000a0800  RDI: 00007f2944a5fa70
          RBP: 00007f2944a5f540   R8: 0000000000000000   R9: 0000000000000020
          R10: 00007f2943614c40  R11: 0000000000000246  R12: ffffffff811fde4e
          R13: ffff880078417f78  R14: 000000000000000c  R15: 00007f2944a4b010
          ORIG_RAX: 0000000000000002  CS: 0033  SS: 002b
      
      This task tried to open the cdrom device, the sr_block_open function
      acquired the global sr_mutex lock. The call to check_disk_change()
      then saw an event flag indicating a possible media change and tried
      to flush any cached data for the device.
      As part of the flush, it tried to acquire the super_block->s_umount
      lock associated with the cdrom device.
      This was the same super_block as created and locked by the previous task.
      
      The first task acquires the s_umount lock and then the sr_mutex_lock;
      the second task acquires the sr_mutex_lock and then the s_umount lock.
      
      This patch fixes the issue by moving check_disk_change() out of
      cdrom_open() and let the caller take care of it.
      Signed-off-by: default avatarMaurizio Lombardi <mlombard@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      Signed-off-by: default avatarSasha Levin <alexander.levin@microsoft.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      e6e5de32
  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
         lines).
      
      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>
      b2441318
  3. 27 Jun, 2017 1 commit
  4. 09 Jun, 2017 1 commit
    • Christoph Hellwig's avatar
      block: introduce new block status code type · 2a842aca
      Christoph Hellwig authored
      Currently we use nornal Linux errno values in the block layer, and while
      we accept any error a few have overloaded magic meanings.  This patch
      instead introduces a new  blk_status_t value that holds block layer specific
      status codes and explicitly explains their meaning.  Helpers to convert from
      and to the previous special meanings are provided for now, but I suspect
      we want to get rid of them in the long run - those drivers that have a
      errno input (e.g. networking) usually get errnos that don't know about
      the special block layer overloads, and similarly returning them to userspace
      will usually return somethings that strictly speaking isn't correct
      for file system operations, but that's left as an exercise for later.
      
      For now the set of errors is a very limited set that closely corresponds
      to the previous overloaded errno values, but there is some low hanging
      fruite to improve it.
      
      blk_status_t (ab)uses the sparse __bitwise annotations to allow for sparse
      typechecking, so that we can easily catch places passing the wrong values.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      2a842aca
  5. 20 Apr, 2017 1 commit
  6. 28 Mar, 2017 3 commits
  7. 10 Mar, 2017 1 commit
  8. 14 Feb, 2017 1 commit
  9. 31 Jan, 2017 2 commits
  10. 24 Dec, 2016 1 commit
  11. 15 Mar, 2016 1 commit
    • Arnd Bergmann's avatar
      paride: make 'verbose' parameter an 'int' again · dec63a4d
      Arnd Bergmann authored
      gcc-6.0 found an ancient bug in the paride driver, which had a
      "module_param(verbose, bool, 0);" since before 2.6.12, but actually uses
      it to accept '0', '1' or '2' as arguments:
      
        drivers/block/paride/pd.c: In function 'pd_init_dev_parms':
        drivers/block/paride/pd.c:298:29: warning: comparison of constant '1' with boolean expression is always false [-Wbool-compare]
         #define DBMSG(msg) ((verbose>1)?(msg):NULL)
      
      In 2012, Rusty did a cleanup patch that also changed the type of the
      variable to 'bool', which introduced what is now a gcc warning.
      
      This changes the type back to 'int' and adapts the module_param() line
      instead, so it should work as documented in case anyone ever cares about
      running the ancient driver with debugging.
      
      Fixes: 90ab5ee9 ("module_param: make bool parameters really bool (drivers & misc)")
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Rusty Russell <rusty@rustcorp.com.au>
      Cc: Tim Waugh <tim@cyberelk.net>
      Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
      Cc: Jens Axboe <axboe@fb.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      dec63a4d
  12. 07 Nov, 2015 1 commit
  13. 31 May, 2015 1 commit
  14. 05 May, 2015 1 commit
  15. 15 Apr, 2015 1 commit
  16. 28 Aug, 2014 1 commit
    • Joe Lawrence's avatar
      block,scsi: fixup blk_get_request dead queue scenarios · a492f075
      Joe Lawrence authored
      The blk_get_request function may fail in low-memory conditions or during
      device removal (even if __GFP_WAIT is set). To distinguish between these
      errors, modify the blk_get_request call stack to return the appropriate
      ERR_PTR. Verify that all callers check the return status and consider
      IS_ERR instead of a simple NULL pointer check.
      
      For consistency, make a similar change to the blk_mq_alloc_request leg
      of blk_get_request.  It may fail if the queue is dead, or the caller was
      unwilling to wait.
      Signed-off-by: default avatarJoe Lawrence <joe.lawrence@stratus.com>
      Acked-by: Jiri Kosina <jkosina@suse.cz> [for pktdvd]
      Acked-by: Boaz Harrosh <bharrosh@panasas.com> [for osd]
      Reviewed-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      a492f075
  17. 26 Aug, 2014 2 commits
  18. 15 Apr, 2014 1 commit
    • Jens Axboe's avatar
      block: remove struct request buffer member · b4f42e28
      Jens Axboe authored
      This was used in the olden days, back when onions were proper
      yellow. Basically it mapped to the current buffer to be
      transferred. With highmem being added more than a decade ago,
      most drivers map pages out of a bio, and rq->buffer isn't
      pointing at anything valid.
      
      Convert old style drivers to just use bio_data().
      
      For the discard payload use case, just reference the page
      in the bio.
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      b4f42e28
  19. 22 Jan, 2014 1 commit
  20. 07 May, 2013 1 commit
  21. 21 Jan, 2013 1 commit
  22. 12 Jan, 2012 2 commits
  23. 16 Nov, 2011 1 commit
  24. 01 Jun, 2011 1 commit
    • Linus Torvalds's avatar
      block: fix mismerge of the DISK_EVENT_MEDIA_CHANGE removal · 0f48f260
      Linus Torvalds authored
      Jens' back-merge commit 698567f3 ("Merge commit 'v2.6.39' into
      for-2.6.40/core") was incorrectly done, and re-introduced the
      DISK_EVENT_MEDIA_CHANGE lines that had been removed earlier in commits
      
       - 9fd097b1 ("block: unexport DISK_EVENT_MEDIA_CHANGE for
         legacy/fringe drivers")
      
       - 7eec77a1 ("ide: unexport DISK_EVENT_MEDIA_CHANGE for ide-gd
         and ide-cd")
      
      because of conflicts with the "g->flags" updates near-by by commit
      d4dc210f ("block: don't block events on excl write for non-optical
      devices")
      
      As a result, we re-introduced the hanging behavior due to infinite disk
      media change reports.
      
      Tssk, tssk, people! Don't do back-merges at all, and *definitely* don't
      do them to hide merge conflicts from me - especially as I'm likely
      better at merging them than you are, since I do so many merges.
      Reported-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Cc: Jens Axboe <jaxboe@fusionio.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0f48f260
  25. 21 Apr, 2011 2 commits
    • Tejun Heo's avatar
      block: unexport DISK_EVENT_MEDIA_CHANGE for legacy/fringe drivers · 9fd097b1
      Tejun Heo authored
      In-kernel disk event polling doesn't matter for legacy/fringe drivers
      and may lead to infinite event loop if ->check_events() implementation
      generates events on level condition instead of edge.
      
      Now that block layer supports suppressing exporting unlisted events,
      simply leaving disk->events cleared allows these drivers to keep the
      internal revalidation behavior intact while avoiding weird
      interactions with userland event handler.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Kay Sievers <kay.sievers@vrfy.org>
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      9fd097b1
    • Tejun Heo's avatar
      block: don't block events on excl write for non-optical devices · d4dc210f
      Tejun Heo authored
      Disk event code automatically blocks events on excl write.  This is
      primarily to avoid issuing polling commands while burning is in
      progress.  This behavior doesn't fit other types of devices with
      removeable media where polling commands don't have adverse side
      effects and door locking usually doesn't exist.
      
      This patch introduces new genhd flag which controls the auto-blocking
      behavior and uses it to enable auto-blocking only on optical devices.
      
      Note for stable: 2.6.38 and later only
      
      Cc: stable@kernel.org
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Reported-by: default avatarKay Sievers <kay.sievers@vrfy.org>
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      d4dc210f
  26. 09 Mar, 2011 1 commit
    • Tejun Heo's avatar
      paride: Convert to bdops->check_events() · b1b56b93
      Tejun Heo authored
      Convert paride drivers from ->media_changed() to ->check_events().
      
      pcd and pd buffer and clear events after reporting; however, pf
      unconditionally reports MEDIA_CHANGE and will generate spurious events
      when polled.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Kay Sievers <kay.sievers@vrfy.org>
      Cc: Tim Waugh <tim@cyberelk.net>
      b1b56b93
  27. 15 Oct, 2010 1 commit
    • Arnd Bergmann's avatar
      llseek: automatically add .llseek fop · 6038f373
      Arnd Bergmann authored
      All file_operations should get a .llseek operation so we can make
      nonseekable_open the default for future file operations without a
      .llseek pointer.
      
      The three cases that we can automatically detect are no_llseek, seq_lseek
      and default_llseek. For cases where we can we can automatically prove that
      the file offset is always ignored, we use noop_llseek, which maintains
      the current behavior of not returning an error from a seek.
      
      New drivers should normally not use noop_llseek but instead use no_llseek
      and call nonseekable_open at open time.  Existing drivers can be converted
      to do the same when the maintainer knows for certain that no user code
      relies on calling seek on the device file.
      
      The generated code is often incorrectly indented and right now contains
      comments that clarify for each added line why a specific variant was
      chosen. In the version that gets submitted upstream, the comments will
      be gone and I will manually fix the indentation, because there does not
      seem to be a way to do that using coccinelle.
      
      Some amount of new code is currently sitting in linux-next that should get
      the same modifications, which I will do at the end of the merge window.
      
      Many thanks to Julia Lawall for helping me learn to write a semantic
      patch that does all this.
      
      ===== begin semantic patch =====
      // This adds an llseek= method to all file operations,
      // as a preparation for making no_llseek the default.
      //
      // The rules are
      // - use no_llseek explicitly if we do nonseekable_open
      // - use seq_lseek for sequential files
      // - use default_llseek if we know we access f_pos
      // - use noop_llseek if we know we don't access f_pos,
      //   but we still want to allow users to call lseek
      //
      @ open1 exists @
      identifier nested_open;
      @@
      nested_open(...)
      {
      <+...
      nonseekable_open(...)
      ...+>
      }
      
      @ open exists@
      identifier open_f;
      identifier i, f;
      identifier open1.nested_open;
      @@
      int open_f(struct inode *i, struct file *f)
      {
      <+...
      (
      nonseekable_open(...)
      |
      nested_open(...)
      )
      ...+>
      }
      
      @ read disable optional_qualifier exists @
      identifier read_f;
      identifier f, p, s, off;
      type ssize_t, size_t, loff_t;
      expression E;
      identifier func;
      @@
      ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
      {
      <+...
      (
         *off = E
      |
         *off += E
      |
         func(..., off, ...)
      |
         E = *off
      )
      ...+>
      }
      
      @ read_no_fpos disable optional_qualifier exists @
      identifier read_f;
      identifier f, p, s, off;
      type ssize_t, size_t, loff_t;
      @@
      ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
      {
      ... when != off
      }
      
      @ write @
      identifier write_f;
      identifier f, p, s, off;
      type ssize_t, size_t, loff_t;
      expression E;
      identifier func;
      @@
      ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
      {
      <+...
      (
        *off = E
      |
        *off += E
      |
        func(..., off, ...)
      |
        E = *off
      )
      ...+>
      }
      
      @ write_no_fpos @
      identifier write_f;
      identifier f, p, s, off;
      type ssize_t, size_t, loff_t;
      @@
      ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
      {
      ... when != off
      }
      
      @ fops0 @
      identifier fops;
      @@
      struct file_operations fops = {
       ...
      };
      
      @ has_llseek depends on fops0 @
      identifier fops0.fops;
      identifier llseek_f;
      @@
      struct file_operations fops = {
      ...
       .llseek = llseek_f,
      ...
      };
      
      @ has_read depends on fops0 @
      identifier fops0.fops;
      identifier read_f;
      @@
      struct file_operations fops = {
      ...
       .read = read_f,
      ...
      };
      
      @ has_write depends on fops0 @
      identifier fops0.fops;
      identifier write_f;
      @@
      struct file_operations fops = {
      ...
       .write = write_f,
      ...
      };
      
      @ has_open depends on fops0 @
      identifier fops0.fops;
      identifier open_f;
      @@
      struct file_operations fops = {
      ...
       .open = open_f,
      ...
      };
      
      // use no_llseek if we call nonseekable_open
      ////////////////////////////////////////////
      @ nonseekable1 depends on !has_llseek && has_open @
      identifier fops0.fops;
      identifier nso ~= "nonseekable_open";
      @@
      struct file_operations fops = {
      ...  .open = nso, ...
      +.llseek = no_llseek, /* nonseekable */
      };
      
      @ nonseekable2 depends on !has_llseek @
      identifier fops0.fops;
      identifier open.open_f;
      @@
      struct file_operations fops = {
      ...  .open = open_f, ...
      +.llseek = no_llseek, /* open uses nonseekable */
      };
      
      // use seq_lseek for sequential files
      /////////////////////////////////////
      @ seq depends on !has_llseek @
      identifier fops0.fops;
      identifier sr ~= "seq_read";
      @@
      struct file_operations fops = {
      ...  .read = sr, ...
      +.llseek = seq_lseek, /* we have seq_read */
      };
      
      // use default_llseek if there is a readdir
      ///////////////////////////////////////////
      @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
      identifier fops0.fops;
      identifier readdir_e;
      @@
      // any other fop is used that changes pos
      struct file_operations fops = {
      ... .readdir = readdir_e, ...
      +.llseek = default_llseek, /* readdir is present */
      };
      
      // use default_llseek if at least one of read/write touches f_pos
      /////////////////////////////////////////////////////////////////
      @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
      identifier fops0.fops;
      identifier read.read_f;
      @@
      // read fops use offset
      struct file_operations fops = {
      ... .read = read_f, ...
      +.llseek = default_llseek, /* read accesses f_pos */
      };
      
      @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
      identifier fops0.fops;
      identifier write.write_f;
      @@
      // write fops use offset
      struct file_operations fops = {
      ... .write = write_f, ...
      +	.llseek = default_llseek, /* write accesses f_pos */
      };
      
      // Use noop_llseek if neither read nor write accesses f_pos
      ///////////////////////////////////////////////////////////
      
      @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
      identifier fops0.fops;
      identifier read_no_fpos.read_f;
      identifier write_no_fpos.write_f;
      @@
      // write fops use offset
      struct file_operations fops = {
      ...
       .write = write_f,
       .read = read_f,
      ...
      +.llseek = noop_llseek, /* read and write both use no f_pos */
      };
      
      @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
      identifier fops0.fops;
      identifier write_no_fpos.write_f;
      @@
      struct file_operations fops = {
      ... .write = write_f, ...
      +.llseek = noop_llseek, /* write uses no f_pos */
      };
      
      @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
      identifier fops0.fops;
      identifier read_no_fpos.read_f;
      @@
      struct file_operations fops = {
      ... .read = read_f, ...
      +.llseek = noop_llseek, /* read uses no f_pos */
      };
      
      @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
      identifier fops0.fops;
      @@
      struct file_operations fops = {
      ...
      +.llseek = noop_llseek, /* no read or write fn */
      };
      ===== End semantic patch =====
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Cc: Julia Lawall <julia@diku.dk>
      Cc: Christoph Hellwig <hch@infradead.org>
      6038f373
  28. 05 Oct, 2010 2 commits
    • Arnd Bergmann's avatar
      block: autoconvert trivial BKL users to private mutex · 2a48fc0a
      Arnd Bergmann authored
      The block device drivers have all gained new lock_kernel
      calls from a recent pushdown, and some of the drivers
      were already using the BKL before.
      
      This turns the BKL into a set of per-driver mutexes.
      Still need to check whether this is safe to do.
      
      file=$1
      name=$2
      if grep -q lock_kernel ${file} ; then
          if grep -q 'include.*linux.mutex.h' ${file} ; then
                  sed -i '/include.*<linux\/smp_lock.h>/d' ${file}
          else
                  sed -i 's/include.*<linux\/smp_lock.h>.*$/include <linux\/mutex.h>/g' ${file}
          fi
          sed -i ${file} \
              -e "/^#include.*linux.mutex.h/,$ {
                      1,/^\(static\|int\|long\)/ {
                           /^\(static\|int\|long\)/istatic DEFINE_MUTEX(${name}_mutex);
      
      } }"  \
          -e "s/\(un\)*lock_kernel\>[ ]*()/mutex_\1lock(\&${name}_mutex)/g" \
          -e '/[      ]*cycle_kernel_lock();/d'
      else
          sed -i -e '/include.*\<smp_lock.h\>/d' ${file}  \
                      -e '/cycle_kernel_lock()/d'
      fi
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      2a48fc0a
    • Arnd Bergmann's avatar
      drivers: autoconvert trivial BKL users to private mutex · 613655fa
      Arnd Bergmann authored
      All these files use the big kernel lock in a trivial
      way to serialize their private file operations,
      typically resulting from an earlier semi-automatic
      pushdown from VFS.
      
      None of these drivers appears to want to lock against
      other code, and they all use the BKL as the top-level
      lock in their file operations, meaning that there
      is no lock-order inversion problem.
      
      Consequently, we can remove the BKL completely,
      replacing it with a per-file mutex in every case.
      Using a scripted approach means we can avoid
      typos.
      
      These drivers do not seem to be under active
      maintainance from my brief investigation. Apologies
      to those maintainers that I have missed.
      
      file=$1
      name=$2
      if grep -q lock_kernel ${file} ; then
          if grep -q 'include.*linux.mutex.h' ${file} ; then
                  sed -i '/include.*<linux\/smp_lock.h>/d' ${file}
          else
                  sed -i 's/include.*<linux\/smp_lock.h>.*$/include <linux\/mutex.h>/g' ${file}
          fi
          sed -i ${file} \
              -e "/^#include.*linux.mutex.h/,$ {
                      1,/^\(static\|int\|long\)/ {
                           /^\(static\|int\|long\)/istatic DEFINE_MUTEX(${name}_mutex);
      
      } }"  \
          -e "s/\(un\)*lock_kernel\>[ ]*()/mutex_\1lock(\&${name}_mutex)/g" \
          -e '/[      ]*cycle_kernel_lock();/d'
      else
          sed -i -e '/include.*\<smp_lock.h\>/d' ${file}  \
                      -e '/cycle_kernel_lock()/d'
      fi
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      613655fa
  29. 07 Aug, 2010 3 commits
  30. 30 Mar, 2010 1 commit
    • Tejun Heo's avatar
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
      Tejun Heo authored
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
      
      percpu.h is included by sched.h and module.h and thus ends up being
      included when building most .c files.  percpu.h includes slab.h which
      in turn includes gfp.h making everything defined by the two files
      universally available and complicating inclusion dependencies.
      
      percpu.h -> slab.h dependency is about to be removed.  Prepare for
      this change by updating users of gfp and slab facilities include those
      headers directly instead of assuming availability.  As this conversion
      needs to touch large number of source files, the following script is
      used as the basis of conversion.
      
        http://userweb.kernel.org/~tj/misc/slabh-sweep.py
      
      The script does the followings.
      
      * Scan files for gfp and slab usages and update includes such that
        only the necessary includes are there.  ie. if only gfp is used,
        gfp.h, if slab is used, slab.h.
      
      * When the script inserts a new include, it looks at the include
        blocks and try to put the new include such that its order conforms
        to its surrounding.  It's put in the include block which contains
        core kernel includes, in the same order that the rest are ordered -
        alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
        doesn't seem to be any matching order.
      
      * If the script can't find a place to put a new include (mostly
        because the file doesn't have fitting include block), it prints out
        an error message indicating which .h file needs to be added to the
        file.
      
      The conversion was done in the following steps.
      
      1. The initial automatic conversion of all .c files updated slightly
         over 4000 files, deleting around 700 includes and adding ~480 gfp.h
         and ~3000 slab.h inclusions.  The script emitted errors for ~400
         files.
      
      2. Each error was manually checked.  Some didn't need the inclusion,
         some needed manual addition while adding it to implementation .h or
         embedding .c file was more appropriate for others.  This step added
         inclusions to around 150 files.
      
      3. The script was run again and the output was compared to the edits
         from #2 to make sure no file was left behind.
      
      4. Several build tests were done and a couple of problems were fixed.
         e.g. lib/decompress_*.c used malloc/free() wrappers around slab
         APIs requiring slab.h to be added manually.
      
      5. The script was run on all .h files but without automatically
         editing them as sprinkling gfp.h and slab.h inclusions around .h
         files could easily lead to inclusion dependency hell.  Most gfp.h
         inclusion directives were ignored as stuff from gfp.h was usually
         wildly available and often used in preprocessor macros.  Each
         slab.h inclusion directive was examined and added manually as
         necessary.
      
      6. percpu.h was updated not to include slab.h.
      
      7. Build test were done on the following configurations and failures
         were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
         distributed build env didn't work with gcov compiles) and a few
         more options had to be turned off depending on archs to make things
         build (like ipr on powerpc/64 which failed due to missing writeq).
      
         * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
         * powerpc and powerpc64 SMP allmodconfig
         * sparc and sparc64 SMP allmodconfig
         * ia64 SMP allmodconfig
         * s390 SMP allmodconfig
         * alpha SMP allmodconfig
         * um on x86_64 SMP allmodconfig
      
      8. percpu.h modifications were reverted so that it could be applied as
         a separate patch and serve as bisection point.
      
      Given the fact that I had only a couple of failures from tests on step
      6, I'm fairly confident about the coverage of this conversion patch.
      If there is a breakage, it's likely to be something in one of the arch
      headers which should be easily discoverable easily on most builds of
      the specific arch.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Guess-its-ok-by: default avatarChristoph Lameter <cl@linux-foundation.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      5a0e3ad6
  31. 12 Mar, 2010 1 commit