1. 14 Oct, 2016 10 commits
  2. 12 Oct, 2016 15 commits
    • Steve French's avatar
      SMB3: Add mount parameter to allow user to override max credits · 141891f4
      Steve French authored
      
      
      Add mount option "max_credits" to allow setting maximum SMB3
      credits to any value from 10 to 64000 (default is 32000).
      This can be useful to workaround servers with problems allocating
      credits, or to throttle the client to use smaller amount of
      simultaneous i/o or to workaround server performance issues.
      
      Also adds a cap, so that even if the server granted us more than
      65000 credits due to a server bug, we would not use that many.
      
      Signed-off-by: default avatarSteve French <steve.french@primarydata.com>
      141891f4
    • Steve French's avatar
      fs/cifs: reopen persistent handles on reconnect · 52ace1ef
      Steve French authored
      
      
      Continuous Availability features like persistent handles
      require that clients reconnect their open files, not
      just the sessions, soon after the network connection comes
      back up, otherwise the server will throw away the state
      (byte range locks, leases, deny modes) on those handles
      after a timeout.
      
      Add code to reconnect handles when use_persistent set
      (e.g. Continuous Availability shares) after tree reconnect.
      
      Signed-off-by: default avatarAurelien Aptel <aaptel@suse.com>
      Reviewed-by: default avatarGermano Percossi <germano.percossi@citrix.com>
      Signed-off-by: default avatarSteve French <smfrench@gmail.com>
      52ace1ef
    • Steve French's avatar
      Clarify locking of cifs file and tcon structures and make more granular · 3afca265
      Steve French authored
      
      
      Remove the global file_list_lock to simplify cifs/smb3 locking and
      have spinlocks that more closely match the information they are
      protecting.
      
      Add new tcon->open_file_lock and file->file_info_lock spinlocks.
      Locks continue to follow a heirachy,
      	cifs_socket --> cifs_ses --> cifs_tcon --> cifs_file
      where global tcp_ses_lock still protects socket and cifs_ses, while the
      the newer locks protect the lower level structure's information
      (tcon and cifs_file respectively).
      
      CC: Stable <stable@vger.kernel.org>
      Signed-off-by: default avatarSteve French <steve.french@primarydata.com>
      Signed-off-by: default avatarPavel Shilovsky <pshilov@microsoft.com>
      Reviewed-by: default avatarAurelien Aptel <aaptel@suse.com>
      Reviewed-by: default avatarGermano Percossi <germano.percossi@citrix.com>
      3afca265
    • Sachin Prabhu's avatar
      Fix regression which breaks DFS mounting · d171356f
      Sachin Prabhu authored
      Patch a6b5058f
      
       results in -EREMOTE returned by is_path_accessible() in
      cifs_mount() to be ignored which breaks DFS mounting.
      
      Signed-off-by: default avatarSachin Prabhu <sprabhu@redhat.com>
      Reviewed-by: default avatarAurelien Aptel <aaptel@suse.com>
      CC: Stable <stable@vger.kernel.org>
      Signed-off-by: default avatarSteve French <smfrench@gmail.com>
      d171356f
    • Aurelien Aptel's avatar
      fs/cifs: keep guid when assigning fid to fileinfo · 94f87371
      Aurelien Aptel authored
      
      
      When we open a durable handle we give a Globally Unique
      Identifier (GUID) to the server which we must keep for later reference
      e.g. when reopening persistent handles on reconnection.
      
      Without this the GUID generated for a new persistent handle was lost and
      16 zero bytes were used instead on re-opening.
      
      Signed-off-by: default avatarAurelien Aptel <aaptel@suse.com>
      CC: Stable <stable@vger.kernel.org>
      Signed-off-by: default avatarSteve French <smfrench@gmail.com>
      94f87371
    • Steve French's avatar
      SMB3: GUIDs should be constructed as random but valid uuids · fa70b87c
      Steve French authored
      
      
      GUIDs although random, and 16 bytes, need to be generated as
      proper uuids.
      
      Signed-off-by: default avatarSteve French <steve.french@primarydata.com>
      Reviewed-by: default avatarAurelien Aptel <aaptel@suse.com>
      Reported-by: default avatarDavid Goebels <davidgoe@microsoft.com>
      CC: Stable <stable@vger.kernel.org>
      fa70b87c
    • Steve French's avatar
      Set previous session id correctly on SMB3 reconnect · c2afb814
      Steve French authored
      
      
      Signed-off-by: default avatarSteve French <steve.french@primarydata.com>
      CC: Stable <stable@vger.kernel.org>
      Reported-by: default avatarDavid Goebel <davidgoe@microsoft.com>
      c2afb814
    • Ross Lagerwall's avatar
      cifs: Limit the overall credit acquired · 7d414f39
      Ross Lagerwall authored
      
      
      The kernel client requests 2 credits for many operations even though
      they only use 1 credit (presumably to build up a buffer of credit).
      Some servers seem to give the client as much credit as is requested.  In
      this case, the amount of credit the client has continues increasing to
      the point where (server->credits * MAX_BUFFER_SIZE) overflows in
      smb2_wait_mtu_credits().
      
      Fix this by throttling the credit requests if an set limit is reached.
      For async requests where the credit charge may be > 1, request as much
      credit as what is charged.
      The limit is chosen somewhat arbitrarily. The Windows client
      defaults to 128 credits, the Windows server allows clients up to
      512 credits (or 8192 for Windows 2016), and the NetApp server
      (and at least one other) does not limit clients at all.
      Choose a high enough value such that the client shouldn't limit
      performance.
      
      This behavior was seen with a NetApp filer (NetApp Release 9.0RC2).
      
      Signed-off-by: default avatarRoss Lagerwall <ross.lagerwall@citrix.com>
      CC: Stable <stable@vger.kernel.org>
      Signed-off-by: default avatarSteve French <smfrench@gmail.com>
      7d414f39
    • Steve French's avatar
      Display number of credits available · 9742805d
      Steve French authored
      
      
      In debugging smb3, it is useful to display the number
      of credits available, so we can see when the server has not granted
      sufficient operations for the client to make progress, or alternatively
      the client has requested too many credits (as we saw in a recent bug)
      so we can compare with the number of credits the server thinks
      we have.
      
      Add a /proc/fs/cifs/DebugData line to display the client view
      on how many credits are available.
      
      Signed-off-by: default avatarSteve French <steve.french@primarydata.com>
      Reported-by: default avatarGermano Percossi <germano.percossi@citrix.com>
      CC: Stable <stable@vger.kernel.org>
      9742805d
    • Steve French's avatar
      Add way to query creation time of file via cifs xattr · 66098044
      Steve French authored
      
      
      Add parsing for new pseudo-xattr user.cifs.creationtime file
      attribute to allow backup and test applications to view
      birth time of file on cifs/smb3 mounts.
      
      Signed-off-by: default avatarSteve French <steve.french@primarydata.com>
      66098044
    • Steve French's avatar
      Add way to query file attributes via cifs xattr · a958fff2
      Steve French authored
      
      
      Add parsing for new pseudo-xattr user.cifs.dosattrib file attribute
      so tools can recognize what kind of file it is, and verify if common
      SMB3 attributes (system, hidden, archive, sparse, indexed etc.) are
      set.
      
      Signed-off-by: default avatarSteve French <steve.french@primarydata.com>
      Reviewed-by: default avatarPavel Shilovsky <pshilovsky@samba.org>
      a958fff2
    • Linus Torvalds's avatar
      Merge branch 'parisc-4.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux · 1573d2ca
      Linus Torvalds authored
      Pull parisc fixes from Helge Deller:
       "Some final updates and fixes for this merge window for the parisc
        architecture. Changes include:
      
         - Fix boot problems with new memblock allocator on rp3410 machine
      
         - Increase initial kernel mapping size for 32- and 64-bit kernels,
           this allows to boot bigger kernels which have many modules built-in
      
         - Fix kernel layout regarding __gp and move exception table into RO
           section
      
         - Show trap names in crashes, use extable.h header instead of
           module.h"
      
      * 'parisc-4.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
        parisc: Show trap name in kernel crash
        parisc: Zero-initialize newly alloced memblock
        parisc: Move exception table into read-only section
        parisc: Fix kernel memory layout regarding position of __gp
        parisc: Increase initial kernel mapping size
        parisc: Migrate exception table users off module.h and onto extable.h
      1573d2ca
    • Linus Torvalds's avatar
      Merge branch 'work.uaccess2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · 4cdf8dbe
      Linus Torvalds authored
      Pull uaccess.h prepwork from Al Viro:
       "Preparations to tree-wide switch to use of linux/uaccess.h (which,
        obviously, will allow to start unifying stuff for real). The last step
        there, ie
      
          PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
          sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
                  `git grep -l "$PATT"|grep -v ^include/linux/uaccess.h`
      
        is not taken here - I would prefer to do it once just before or just
        after -rc1.  However, everything should be ready for it"
      
      * 'work.uaccess2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
        remove a stray reference to asm/uaccess.h in docs
        sparc64: separate extable_64.h, switch elf_64.h to it
        score: separate extable.h, switch module.h to it
        mips: separate extable.h, switch module.h to it
        x86: separate extable.h, switch sections.h to it
        remove stray include of asm/uaccess.h from cacheflush.h
        mn10300: remove a bogus processor.h->uaccess.h include
        xtensa: split uaccess.h into C and asm sides
        bonding: quit messing with IOCTL
        kill __kernel_ds_p off
        mn10300: finish verify_area() off
        frv: move HAVE_ARCH_UNMAPPED_AREA to pgtable.h
        exceptions: detritus removal
      4cdf8dbe
    • Linus Torvalds's avatar
      Merge tag 'drm-for-v4.9' of git://people.freedesktop.org/~airlied/linux · 6b25e21f
      Linus Torvalds authored
      Pull drm updates from Dave Airlie:
       "Core:
         - Fence destaging work
         - DRIVER_LEGACY to split off legacy drm drivers
         - drm_mm refactoring
         - Splitting drm_crtc.c into chunks and documenting better
         - Display info fixes
         - rbtree support for prime buffer lookup
         - Simple VGA DAC driver
      
        Panel:
         - Add Nexus 7 panel
         - More simple panels
      
        i915:
         - Refactoring GEM naming
         - Refactored vma/active tracking
         - Lockless request lookups
         - Better stolen memory support
         - FBC fixes
         - SKL watermark fixes
         - VGPU improvements
         - dma-buf fencing support
         - Better DP dongle support
      
        amdgpu:
         - Powerplay for Iceland asics
         - Improved GPU reset support
         - UVD/VEC powergating support for CZ/ST
         - Preinitialised VRAM buffer support
         - Virtual display support
         - Initial SI support
         - GTT rework
         - PCI shutdown callback support
         - HPD IRQ storm fixes
      
        amdkfd:
         - bugfixes
      
        tilcdc:
         - Atomic modesetting support
      
        mediatek:
         - AAL + GAMMA engine support
         - Hook up gamma LUT
         - Temporal dithering support
      
        imx:
         - Pixel clock from devicetree
         - drm bridge support for LVDS bridges
         - active plane reconfiguration
         - VDIC deinterlacer support
         - Frame synchronisation unit support
         - Color space conversion support
      
        analogix:
         - PSR support
         - Better panel on/off support
      
        rockchip:
         - rk3399 vop/crtc support
         - PSR support
      
        vc4:
         - Interlaced vblank timing
         - 3D rendering CPU overhead reduction
         - HDMI output fixes
      
        tda998x:
         - HDMI audio ASoC support
      
        sunxi:
         - Allwinner A33 support
         - better TCON support
      
        msm:
         - DT binding cleanups
         - Explicit fence-fd support
      
        sti:
         - remove sti415/416 support
      
        etnaviv:
         - MMUv2 refactoring
         - GC3000 support
      
        exynos:
         - Refactoring HDMI DCC/PHY
         - G2D pm regression fix
         - Page fault issues with wait for vblank
      
        There is no nouveau work in this tree, as Ben didn't get a pull
        request in, and he was fighting moving to atomic and adding mst
        support, so maybe best it waits for a cycle"
      
      * tag 'drm-for-v4.9' of git://people.freedesktop.org/~airlied/linux: (1412 commits)
        drm/crtc: constify drm_crtc_index parameter
        drm/i915: Fix conflict resolution from backmerge of v4.8-rc8 to drm-next
        drm/i915/guc: Unwind GuC workqueue reservation if request construction fails
        drm/i915: Reset the breadcrumbs IRQ more carefully
        drm/i915: Force relocations via cpu if we run out of idle aperture
        drm/i915: Distinguish last emitted request from last submitted request
        drm/i915: Allow DP to work w/o EDID
        drm/i915: Move long hpd handling into the hotplug work
        drm/i915/execlists: Reinitialise context image after GPU hang
        drm/i915: Use correct index for backtracking HUNG semaphores
        drm/i915: Unalias obj->phys_handle and obj->userptr
        drm/i915: Just clear the mmiodebug before a register access
        drm/i915/gen9: only add the planes actually affected by ddb changes
        drm/i915: Allow PCH DPLL sharing regardless of DPLL_SDVO_HIGH_SPEED
        drm/i915/bxt: Fix HDMI DPLL configuration
        drm/i915/gen9: fix the watermark res_blocks value
        drm/i915/gen9: fix plane_blocks_per_line on watermarks calculations
        drm/i915/gen9: minimum scanlines for Y tile is not always 4
        drm/i915/gen9: fix the WaWmMemoryReadLatency implementation
        drm/i915/kbl: KBL also needs to run the SAGV code
        ...
      6b25e21f
    • Linus Torvalds's avatar
      Merge branch 'akpm' (patches from Andrew) · a379f71a
      Linus Torvalds authored
      Merge more updates from Andrew Morton:
      
       - a few block updates that fell in my lap
      
       - lib/ updates
      
       - checkpatch
      
       - autofs
      
       - ipc
      
       - a ton of misc other things
      
      * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (100 commits)
        mm: split gfp_mask and mapping flags into separate fields
        fs: use mapping_set_error instead of opencoded set_bit
        treewide: remove redundant #include <linux/kconfig.h>
        hung_task: allow hung_task_panic when hung_task_warnings is 0
        kthread: add kerneldoc for kthread_create()
        kthread: better support freezable kthread workers
        kthread: allow to modify delayed kthread work
        kthread: allow to cancel kthread work
        kthread: initial support for delayed kthread work
        kthread: detect when a kthread work is used by more workers
        kthread: add kthread_destroy_worker()
        kthread: add kthread_create_worker*()
        kthread: allow to call __kthread_create_on_node() with va_list args
        kthread/smpboot: do not park in kthread_create_on_cpu()
        kthread: kthread worker API cleanup
        kthread: rename probe_kthread_data() to kthread_probe_data()
        scripts/tags.sh: enable code completion in VIM
        mm: kmemleak: avoid using __va() on addresses that don't have a lowmem mapping
        kdump, vmcoreinfo: report memory sections virtual addresses
        ipc/sem.c: add cond_resched in exit_sme
        ...
      a379f71a
  3. 11 Oct, 2016 15 commits
    • Michal Hocko's avatar
      mm: split gfp_mask and mapping flags into separate fields · 9c5d760b
      Michal Hocko authored
      mapping->flags currently encodes two different things into a single flag.
      It contains sticky gfp_mask for page cache allocations and AS_ codes used
      to report errors/enospace and other states which are mapping specific.
      Condensing the two semantically unrelated things saves few bytes but it
      also complicates other things.  For one thing the gfp flags space is
      reduced and in fact we are already running out of available bits.  It can
      be assumed that more gfp flags will be necessary later on.
      
      To not introduce the address_space grow (at least on x86_64) we can stick
      it right after private_lock because we have a hole there.
      
      struct address_space {
              struct inode *             host;                 /*     0     8 */
              struct radix_tree_root     page_tree;            /*     8    16 */
              spinlock_t                 tree_lock;            /*    24     4 */
              atomic_t                   i_mmap_writable;      /*    28     4 */
              struct rb_root             i_mmap;               /*    32     8 */
              struct rw_semaphore        i_mmap_rwsem;         /*    40    40 */
              /* --- cacheline 1 boundary (64 bytes) was 16 bytes ago --- */
              long unsigned int          nrpages;              /*    80     8 */
              long unsigned int          nrexceptional;        /*    88     8 */
              long unsigned int          writeback_index;      /*    96     8 */
              const struct address_space_operations  * a_ops;  /*   104     8 */
              long unsigned int          flags;                /*   112     8 */
              spinlock_t                 private_lock;         /*   120     4 */
      
              /* XXX 4 bytes hole, try to pack */
      
              /* --- cacheline 2 boundary (128 bytes) --- */
              struct list_head           private_list;         /*   128    16 */
              void *                     private_data;         /*   144     8 */
      
              /* size: 152, cachelines: 3, members: 14 */
              /* sum members: 148, holes: 1, sum holes: 4 */
              /* last cacheline: 24 bytes */
      };
      
      Link: http://lkml.kernel.org/r/20160912114852.GI14524@dhcp22.suse.cz
      
      
      Signed-off-by: default avatarMichal Hocko <mhocko@suse.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9c5d760b
    • Michal Hocko's avatar
      fs: use mapping_set_error instead of opencoded set_bit · 5114a97a
      Michal Hocko authored
      The mapping_set_error() helper sets the correct AS_ flag for the mapping
      so there is no reason to open code it.  Use the helper directly.
      
      [akpm@linux-foundation.org: be honest about conversion from -ENXIO to -EIO]
      Link: http://lkml.kernel.org/r/20160912111608.2588-2-mhocko@kernel.org
      
      
      Signed-off-by: default avatarMichal Hocko <mhocko@suse.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5114a97a
    • Masahiro Yamada's avatar
      treewide: remove redundant #include <linux/kconfig.h> · 97139d4a
      Masahiro Yamada authored
      Kernel source files need not include <linux/kconfig.h> explicitly
      because the top Makefile forces to include it with:
      
        -include $(srctree)/include/linux/kconfig.h
      
      This commit removes explicit includes except the following:
      
        * arch/s390/include/asm/facilities_src.h
        * tools/testing/radix-tree/linux/kernel.h
      
      These two are used for host programs.
      
      Link: http://lkml.kernel.org/r/1473656164-11929-1-git-send-email-yamada.masahiro@socionext.com
      
      
      Signed-off-by: Masahiro Yamada's avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      97139d4a
    • John Siddle's avatar
      hung_task: allow hung_task_panic when hung_task_warnings is 0 · 48a6d64e
      John Siddle authored
      Previously hung_task_panic would not be respected if enabled after
      hung_task_warnings had already been decremented to 0.
      
      Permit the kernel to panic if hung_task_panic is enabled after
      hung_task_warnings has already been decremented to 0 and another task
      hangs for hung_task_timeout_secs seconds.
      
      Check if hung_task_panic is enabled so we don't return prematurely, and
      check if hung_task_warnings is non-zero so we don't print the warning
      unnecessarily.
      
      [akpm@linux-foundation.org: fix off-by-one]
      Link: http://lkml.kernel.org/r/1473450214-4049-1-git-send-email-jsiddle@redhat.com
      
      
      Signed-off-by: default avatarJohn Siddle <jsiddle@redhat.com>
      Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      48a6d64e
    • Jonathan Corbet's avatar
      kthread: add kerneldoc for kthread_create() · e154ccc8
      Jonathan Corbet authored
      This macro is referenced in other kerneldoc comments, but lacks one of its
      own; fix that.
      
      Link: http://lkml.kernel.org/r/20160826072313.726a3485@lwn.net
      
      
      Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
      Reported-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e154ccc8
    • Petr Mladek's avatar
      kthread: better support freezable kthread workers · dbf52682
      Petr Mladek authored
      This patch allows to make kthread worker freezable via a new @flags
      parameter. It will allow to avoid an init work in some kthreads.
      
      It currently does not affect the function of kthread_worker_fn()
      but it might help to do some optimization or fixes eventually.
      
      I currently do not know about any other use for the @flags
      parameter but I believe that we will want more flags
      in the future.
      
      Finally, I hope that it will not cause confusion with @flags member
      in struct kthread. Well, I guess that we will want to rework the
      basic kthreads implementation once all kthreads are converted into
      kthread workers or workqueues. It is possible that we will merge
      the two structures.
      
      Link: http://lkml.kernel.org/r/1470754545-17632-12-git-send-email-pmladek@suse.com
      
      
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
      Cc: Josh Triplett <josh@joshtriplett.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Jiri Kosina <jkosina@suse.cz>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      dbf52682
    • Petr Mladek's avatar
      kthread: allow to modify delayed kthread work · 9a6b06c8
      Petr Mladek authored
      There are situations when we need to modify the delay of a delayed kthread
      work. For example, when the work depends on an event and the initial delay
      means a timeout. Then we want to queue the work immediately when the event
      happens.
      
      This patch implements kthread_mod_delayed_work() as inspired workqueues.
      It cancels the timer, removes the work from any worker list and queues it
      again with the given timeout.
      
      A very special case is when the work is being canceled at the same time.
      It might happen because of the regular kthread_cancel_delayed_work_sync()
      or by another kthread_mod_delayed_work(). In this case, we do nothing and
      let the other operation win. This should not normally happen as the caller
      is supposed to synchronize these operations a reasonable way.
      
      Link: http://lkml.kernel.org/r/1470754545-17632-11-git-send-email-pmladek@suse.com
      
      
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
      Cc: Josh Triplett <josh@joshtriplett.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Jiri Kosina <jkosina@suse.cz>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9a6b06c8
    • Petr Mladek's avatar
      kthread: allow to cancel kthread work · 37be45d4
      Petr Mladek authored
      We are going to use kthread workers more widely and sometimes we will need
      to make sure that the work is neither pending nor running.
      
      This patch implements cancel_*_sync() operations as inspired by
      workqueues.  Well, we are synchronized against the other operations via
      the worker lock, we use del_timer_sync() and a counter to count parallel
      cancel operations.  Therefore the implementation might be easier.
      
      First, we check if a worker is assigned.  If not, the work has newer been
      queued after it was initialized.
      
      Second, we take the worker lock.  It must be the right one.  The work must
      not be assigned to another worker unless it is initialized in between.
      
      Third, we try to cancel the timer when it exists.  The timer is deleted
      synchronously to make sure that the timer call back is not running.  We
      need to temporary release the worker->lock to avoid a possible deadlock
      with the callback.  In the meantime, we set work->canceling counter to
      avoid any queuing.
      
      Fourth, we try to remove the work from a worker list. It might be
      the list of either normal or delayed works.
      
      Fifth, if the work is running, we call kthread_flush_work().  It might
      take an arbitrary time.  We need to release the worker-lock again.  In the
      meantime, we again block any queuing by the canceling counter.
      
      As already mentioned, the check for a pending kthread work is done under a
      lock.  In compare with workqueues, we do not need to fight for a single
      PENDING bit to block other operations.  Therefore we do not suffer from
      the thundering storm problem and all parallel canceling jobs might use
      kthread_flush_work().  Any queuing is blocked until the counter gets zero.
      
      Link: http://lkml.kernel.org/r/1470754545-17632-10-git-send-email-pmladek@suse.com
      
      
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
      Cc: Josh Triplett <josh@joshtriplett.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Jiri Kosina <jkosina@suse.cz>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      37be45d4
    • Petr Mladek's avatar
      kthread: initial support for delayed kthread work · 22597dc3
      Petr Mladek authored
      We are going to use kthread_worker more widely and delayed works
      will be pretty useful.
      
      The implementation is inspired by workqueues.  It uses a timer to queue
      the work after the requested delay.  If the delay is zero, the work is
      queued immediately.
      
      In compare with workqueues, each work is associated with a single worker
      (kthread).  Therefore the implementation could be much easier.  In
      particular, we use the worker->lock to synchronize all the operations with
      the work.  We do not need any atomic operation with a flags variable.
      
      In fact, we do not need any state variable at all.  Instead, we add a list
      of delayed works into the worker.  Then the pending work is listed either
      in the list of queued or delayed works.  And the existing check of pending
      works is the same even for the delayed ones.
      
      A work must not be assigned to another worker unless reinitialized.
      Therefore the timer handler might expect that dwork->work->worker is valid
      and it could simply take the lock.  We just add some sanity checks to help
      with debugging a potential misuse.
      
      Link: http://lkml.kernel.org/r/1470754545-17632-9-git-send-email-pmladek@suse.com
      
      
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
      Cc: Josh Triplett <josh@joshtriplett.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Jiri Kosina <jkosina@suse.cz>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      22597dc3
    • Petr Mladek's avatar
      kthread: detect when a kthread work is used by more workers · 8197b3d4
      Petr Mladek authored
      Nothing currently prevents a work from queuing for a kthread worker when
      it is already running on another one.  This means that the work might run
      in parallel on more than one worker.  Also some operations are not
      reliable, e.g.  flush.
      
      This problem will be even more visible after we add kthread_cancel_work()
      function.  It will only have "work" as the parameter and will use
      worker->lock to synchronize with others.
      
      Well, normally this is not a problem because the API users are sane.
      But bugs might happen and users also might be crazy.
      
      This patch adds a warning when we try to insert the work for another
      worker.  It does not fully prevent the misuse because it would make the
      code much more complicated without a big benefit.
      
      It adds the same warning also into kthread_flush_work() instead of the
      repeated attempts to get the right lock.
      
      A side effect is that one needs to explicitly reinitialize the work if it
      must be queued into another worker.  This is needed, for example, when the
      worker is stopped and started again.  It is a bit inconvenient.  But it
      looks like a good compromise between the stability and complexity.
      
      I have double checked all existing users of the kthread worker API and
      they all seems to initialize the work after the worker gets started.
      
      Just for completeness, the patch adds a check that the work is not already
      in a queue.
      
      The patch also puts all the checks into a separate function.  It will be
      reused when implementing delayed works.
      
      Link: http://lkml.kernel.org/r/1470754545-17632-8-git-send-email-pmladek@suse.com
      
      
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
      Cc: Josh Triplett <josh@joshtriplett.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Jiri Kosina <jkosina@suse.cz>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8197b3d4
    • Petr Mladek's avatar
      kthread: add kthread_destroy_worker() · 35033fe9
      Petr Mladek authored
      The current kthread worker users call flush() and stop() explicitly.
      This function does the same plus it frees the kthread_worker struct
      in one call.
      
      It is supposed to be used together with kthread_create_worker*() that
      allocates struct kthread_worker.
      
      Link: http://lkml.kernel.org/r/1470754545-17632-7-git-send-email-pmladek@suse.com
      
      
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
      Cc: Josh Triplett <josh@joshtriplett.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Jiri Kosina <jkosina@suse.cz>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      35033fe9
    • Petr Mladek's avatar
      kthread: add kthread_create_worker*() · fbae2d44
      Petr Mladek authored
      Kthread workers are currently created using the classic kthread API,
      namely kthread_run().  kthread_worker_fn() is passed as the @threadfn
      parameter.
      
      This patch defines kthread_create_worker() and
      kthread_create_worker_on_cpu() functions that hide implementation details.
      
      They enforce using kthread_worker_fn() for the main thread.  But I doubt
      that there are any plans to create any alternative.  In fact, I think that
      we do not want any alternative main thread because it would be hard to
      support consistency with the rest of the kthread worker API.
      
      The naming and function of kthread_create_worker() is inspired by the
      workqueues API like the rest of the kthread worker API.
      
      The kthread_create_worker_on_cpu() variant is motivated by the original
      kthread_create_on_cpu().  Note that we need to bind per-CPU kthread
      workers already when they are created.  It makes the life easier.
      kthread_bind() could not be used later for an already running worker.
      
      This patch does _not_ convert existing kthread workers.  The kthread
      worker API need more improvements first, e.g.  a function to destroy the
      worker.
      
      IMPORTANT:
      
      kthread_create_worker_on_cpu() allows to use any format of the worker
      name, in compare with kthread_create_on_cpu().  The good thing is that it
      is more generic.  The bad thing is that most users will need to pass the
      cpu number in two parameters, e.g.  kthread_create_worker_on_cpu(cpu,
      "helper/%d", cpu).
      
      To be honest, the main motivation was to avoid the need for an empty
      va_list.  The only legal way was to create a helper function that would be
      called with an empty list.  Other attempts caused compilation warnings or
      even errors on different architectures.
      
      There were also other alternatives, for example, using #define or
      splitting __kthread_create_worker().  The used solution looked like the
      least ugly.
      
      Link: http://lkml.kernel.org/r/1470754545-17632-6-git-send-email-pmladek@suse.com
      
      
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
      Cc: Josh Triplett <josh@joshtriplett.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Jiri Kosina <jkosina@suse.cz>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      fbae2d44
    • Petr Mladek's avatar
      kthread: allow to call __kthread_create_on_node() with va_list args · 255451e4
      Petr Mladek authored
      kthread_create_on_node() implements a bunch of logic to create the
      kthread.  It is already called by kthread_create_on_cpu().
      
      We are going to extend the kthread worker API and will need to call
      kthread_create_on_node() with va_list args there.
      
      This patch does only a refactoring and does not modify the existing
      behavior.
      
      Link: http://lkml.kernel.org/r/1470754545-17632-5-git-send-email-pmladek@suse.com
      
      
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
      Cc: Josh Triplett <josh@joshtriplett.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Jiri Kosina <jkosina@suse.cz>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      255451e4
    • Petr Mladek's avatar
      kthread/smpboot: do not park in kthread_create_on_cpu() · a65d4096
      Petr Mladek authored
      kthread_create_on_cpu() was added by the commit 2a1d4460
      ("kthread: Implement park/unpark facility").  It is currently used only
      when enabling new CPU.  For this purpose, the newly created kthread has to
      be parked.
      
      The CPU binding is a bit tricky.  The kthread is parked when the CPU has
      not been allowed yet.  And the CPU is bound when the kthread is unparked.
      
      The function would be useful for more per-CPU kthreads, e.g.
      bnx2fc_thread, fcoethread.  For this purpose, the newly created kthread
      should stay in the uninterruptible state.
      
      This patch moves the parking into smpboot.  It binds the thread already
      when created.  Then the function might be used universally.  Also the
      behavior is consistent with kthread_create() and kthread_create_on_node().
      
      Link: http://lkml.kernel.org/r/1470754545-17632-4-git-send-email-pmladek@suse.com
      
      
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
      Cc: Josh Triplett <josh@joshtriplett.org>
      Cc: Jiri Kosina <jkosina@suse.cz>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a65d4096
    • Petr Mladek's avatar
      kthread: kthread worker API cleanup · 3989144f
      Petr Mladek authored
      A good practice is to prefix the names of functions by the name
      of the subsystem.
      
      The kthread worker API is a mix of classic kthreads and workqueues.  Each
      worker has a dedicated kthread.  It runs a generic function that process
      queued works.  It is implemented as part of the kthread subsystem.
      
      This patch renames the existing kthread worker API to use
      the corresponding name from the workqueues API prefixed by
      kthread_:
      
      __init_kthread_worker()		-> __kthread_init_worker()
      init_kthread_worker()		-> kthread_init_worker()
      init_kthread_work()		-> kthread_init_work()
      insert_kthread_work()		-> kthread_insert_work()
      queue_kthread_work()		-> kthread_queue_work()
      flush_kthread_work()		-> kthread_flush_work()
      flush_kthread_worker()		-> kthread_flush_worker()
      
      Note that the names of DEFINE_KTHREAD_WORK*() macros stay
      as they are. It is common that the "DEFINE_" prefix has
      precedence over the subsystem names.
      
      Note that INIT() macros and init() functions use different
      naming scheme. There is no good solution. There are several
      reasons for this solution:
      
        + "init" in the function names stands for the verb "initialize"
          aka "initialize worker". While "INIT" in the macro names
          stands for the noun "INITIALIZER" aka "worker initializer".
      
        + INIT() macros are used only in DEFINE() macros
      
        + init() functions are used close to the other kthread()
          functions. It looks much better if all the functions
          use the same scheme.
      
        + There will be also kthread_destroy_worker() that will
          be used close to kthread_cancel_work(). It is related
          to the init() function. Again it looks better if all
          functions use the same naming scheme.
      
        + there are several precedents for such init() function
          names, e.g. amd_iommu_init_device(), free_area_init_node(),
          jump_label_init_type(),  regmap_init_mmio_clk(),
      
        + It is not an argument but it was inconsistent even before.
      
      [arnd@arndb.de: fix linux-next merge conflict]
       Link: http://lkml.kernel.org/r/20160908135724.1311726-1-arnd@arndb.de
      Link: http://lkml.kernel.org/r/1470754545-17632-3-git-send-email-pmladek@suse.com
      
      
      Suggested-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
      Cc: Josh Triplett <josh@joshtriplett.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Jiri Kosina <jkosina@suse.cz>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3989144f