1. 31 Oct, 2023 5 commits
    • Mikulas Patocka's avatar
      dm crypt: account large pages in cc->n_allocated_pages · 9793c269
      Mikulas Patocka authored
      The commit 5054e778 ("dm crypt: allocate compound pages if
      possible") changed dm-crypt to use compound pages to improve
      performance. Unfortunately, there was an oversight: the allocation of
      compound pages was not accounted at all. Normal pages are accounted in
      a percpu counter cc->n_allocated_pages and dm-crypt is limited to
      allocate at most 2% of memory. Because compound pages were not
      accounted at all, dm-crypt could allocate memory over the 2% limit.
      
      Fix this by adding the accounting of compound pages, so that memory
      consumption of dm-crypt is properly limited.
      Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Fixes: 5054e778 ("dm crypt: allocate compound pages if possible")
      Cc: stable@vger.kernel.org	# v6.5+
      Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      9793c269
    • Eric Biggers's avatar
      dm integrity: use crypto_shash_digest() in sb_mac() · 070bb43a
      Eric Biggers authored
      Simplify sb_mac() by using crypto_shash_digest() instead of an
      init+update+final sequence.  This should also improve performance.
      Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      070bb43a
    • Eric Biggers's avatar
      dm crypt: use crypto_shash_digest() in crypt_iv_tcw_whitening() · 6d0ee3b6
      Eric Biggers authored
      Simplify crypt_iv_tcw_whitening() by using crypto_shash_digest() instead
      of an init+update+final sequence.  This should also improve performance.
      Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      6d0ee3b6
    • Damien Le Moal's avatar
      dm error: Add support for zoned block devices · a9511043
      Damien Le Moal authored
      dm-error is used in several test cases in the xfstests test suite to
      check the handling of IO errors in file systems. However, with several
      file systems getting native support for zoned block devices (e.g.
      btrfs and f2fs), dm-error's lack of zoned block device support creates
      problems as the file system attempts executing zone commands (e.g. a
      zone append operation) against a dm-error non-zoned block device,
      which causes various issues in the block layer (e.g. WARN_ON
      triggers).
      
      This commit adds supports for zoned block devices to dm-error, allowing
      a DM device table containing an error target to be exposed as a zoned
      block device (if all targets have a compatible zoned model support and
      mapping). This is done as follows:
      1) Allow passing 2 arguments to an error target, similar to dm-linear:
         a backing device and a start sector. These arguments are optional and
         dm-error retains its characteristics if the arguments are not
         specified.
      2) Implement the iterate_devices method so that dm-core can normally
         check the zone support and restrictions (e.g. zone alignment of the
         targets). When the backing device arguments are not specified, the
         iterate_devices method never calls the fn() argument.
      When no backing device is specified, as before, we assume that the DM
      device is not zoned. When the backing device arguments are specified,
      the zoned model of the DM device will depend on the backing device
      type:
       - If the backing device is zoned and its model and mapping is
         compatible with other targets of the device, the resulting device
         will be zoned, with the dm-error mapped portion always returning
         errors (similar to the default non-zoned case).
       - If the backing device is not zoned, then the DM device will not be
         either.
      
      This zone support for dm-error requires the definition of a functional
      report_zones operation so that dm_revalidate_zones() can operate
      correctly and resources for emulating zone append operations
      initialized. This is necessary for cases where dm-error is used to
      partially map a device and have an overall correct handling of zone
      append. This means that dm-error does not fail report zones operations.
      
      Two changes that are not obvious are included to avoid issues:
      1) dm_table_supports_zoned_model() is changed to directly check if
         the backing device of a wildcard target (= dm-error target) is
         zoned. Otherwise, we wouldn't be able to catch the invalid setup of
         dm-error without a backing device (non zoned case) being combined
         with zoned targets.
      2) dm_table_supports_dax() is modified to return false if the wildcard
         target is found. Otherwise, when dm-error is set without a backing
         device, we end up with a NULL pointer dereference in
         set_dax_synchronous (dax_dev is NULL). This is consistent with the
         current behavior because dm_table_supports_dax() always returned
         false for targets that do not define the iterate_devices method.
      Signed-off-by: default avatarDamien Le Moal <dlemoal@kernel.org>
      Tested-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      a9511043
    • Christian Loehle's avatar
      dm delay: for short delays, use kthread instead of timers and wq · 70bbeb29
      Christian Loehle authored
      DM delay's current design of using timers and wq to realize the delays
      is insufficient for delays below ~50ms.
      
      This commit enhances the design to use a kthread to flush the expired
      delays, trading some CPU time (in some cases) for better delay
      accuracy and delays closer to what the user requested for smaller
      delays. The new design is chosen as long as all the delays are below
      50ms.
      
      Since bios can't be completed in interrupt context using a kthread
      is probably the most reasonable way to approach this.
      
      Testing with
      echo "0 2097152 zero" | dmsetup create dm-zeros
      for i in $(seq 0 20);
      do
        echo "0 2097152 delay /dev/mapper/dm-zeros 0 $i" | dmsetup create dm-delay-${i}ms;
      done
      
      Some performance numbers for comparison, on beaglebone black (single
      core) CONFIG_HZ_1000=y:
      
      fio --name=1msread --rw=randread --bs=4k --runtime=60 --time_based \
          --filename=/dev/mapper/dm-delay-1ms
      Theoretical maximum: 1000 IOPS
      Previous: 250 IOPS
      Kthread: 500 IOPS
      
      fio --name=10msread --rw=randread --bs=4k --runtime=60 --time_based \
          --filename=/dev/mapper/dm-delay-10ms
      Theoretical maximum: 100 IOPS
      Previous: 45 IOPS
      Kthread: 50 IOPS
      
      fio --name=1mswrite --rw=randwrite --direct=1 --bs=4k --runtime=60 \
          --time_based --filename=/dev/mapper/dm-delay-1ms
      Theoretical maximum: 1000 IOPS
      Previous: 498 IOPS
      Kthread: 1000 IOPS
      
      fio --name=10mswrite --rw=randwrite --direct=1 --bs=4k --runtime=60 \
          --time_based --filename=/dev/mapper/dm-delay-10ms
      Theoretical maximum: 100 IOPS
      Previous: 90 IOPS
      Kthread: 100 IOPS
      
      (This one is just to prove the new design isn't impacting throughput,
      not really about delays):
      fio --name=10mswriteasync --rw=randwrite --direct=1 --bs=4k \
          --runtime=60 --time_based --filename=/dev/mapper/dm-delay-10ms \
          --numjobs=32 --iodepth=64 --ioengine=libaio --group_reporting
      Previous: 13.3k IOPS
      Kthread: 13.3k IOPS
      Signed-off-by: default avatarChristian Loehle <christian.loehle@arm.com>
      [Harshit: kthread_create error handling fix in delay_ctr]
      Signed-off-by: default avatarHarshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      70bbeb29
  2. 27 Oct, 2023 3 commits
    • Mike Snitzer's avatar
      MAINTAINERS: add Mikulas Patocka as a DM maintainer · 8388cba9
      Mike Snitzer authored
      Mikulas is a long-time contributor to the DM subsystem and has
      effectively been a shadow DM maintainer.  It is time to formally
      name Mikulas as a DM maintainer.
      
      In practice this doesn't imply any process changes for DM maintenance
      (Mikulas can still just feed changes and contribute review like
      normal).
      
      This change does allow the possibility for Mikulas to take on more
      responsibility in actually sending DM changes upstream.
      Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      8388cba9
    • Mike Snitzer's avatar
      dm: respect REQ_NOWAIT flag in normal bios issued to DM · 6f25dd1c
      Mike Snitzer authored
      Update DM core's normal IO submission to allocate required memory
      using GFP_NOWAIT if REQ_NOWAIT is set.
      
      Tested with simple test provided in commit a9ce3853 ("dm: don't
      attempt to queue IO under RCU protection") that was enhanced to check
      error codes.  Also tested using fio's pvsync2 with nowait=1.
      
      But testing with induced GFP_NOWAIT allocation failures wasn't
      performed (yet).
      Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      6f25dd1c
    • Mike Snitzer's avatar
      dm: enhance alloc_multiple_bios() to be more versatile · 4a2fe296
      Mike Snitzer authored
      alloc_multiple_bios() has the useful ability to try allocating bios
      with GFP_NOWAIT but will fallback to using GFP_NOIO.  The callers
      service both empty flush bios and abnormal bios (e.g. discard).
      
      alloc_multiple_bios() enhancements offered in this commit:
      - don't require table_devices_lock if num_bios = 1
      - allow caller to pass GFP_NOWAIT to do usual GFP_NOWAIT with GFP_NOIO
        fallback
      - allow caller to pass GFP_NOIO to _only_ allocate using GFP_NOIO
      
      Flush bios with data may be issued to DM with REQ_NOWAIT, as such it
      makes sense to attempt servicing them with GFP_NOWAIT allocations.
      
      But abnormal IO should never be issued using REQ_NOWAIT (if that
      changes in the future that's fine, but no sense supporting it now).
      
      While at it, rename __send_changing_extent_only() to
      __send_abnormal_io().
      
      [Thanks to both Ming and Mikulas for help with translating known
      possible IO scenarios to requirements.]
      Suggested-by: default avatarMing Lei <ming.lei@redhat.com>
      Suggested-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      4a2fe296
  3. 23 Oct, 2023 5 commits
  4. 06 Oct, 2023 2 commits
  5. 20 Sep, 2023 1 commit
    • Fedor Pchelkin's avatar
      dm zoned: free dmz->ddev array in dmz_put_zoned_devices · 9850ccd5
      Fedor Pchelkin authored
      Commit 4dba1288 ("dm zoned: support arbitrary number of devices")
      made the pointers to additional zoned devices to be stored in a
      dynamically allocated dmz->ddev array. However, this array is not freed.
      
      Rename dmz_put_zoned_device to dmz_put_zoned_devices and fix it to
      free the dmz->ddev array when cleaning up zoned device information.
      Remove NULL assignment for all dmz->ddev elements and just free the
      dmz->ddev array instead.
      
      Found by Linux Verification Center (linuxtesting.org).
      
      Fixes: 4dba1288 ("dm zoned: support arbitrary number of devices")
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarFedor Pchelkin <pchelkin@ispras.ru>
      Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      9850ccd5
  6. 17 Sep, 2023 11 commits
  7. 16 Sep, 2023 12 commits
    • Linus Torvalds's avatar
      Merge tag 'kbuild-fixes-v6.6' of... · f0b0d403
      Linus Torvalds authored
      Merge tag 'kbuild-fixes-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
      
      Pull Kbuild fixes from Masahiro Yamada:
      
       - Fix kernel-devel RPM and linux-headers Deb package
      
       - Fix too long argument list error in 'make modules_install'
      
      * tag 'kbuild-fixes-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
        kbuild: avoid long argument lists in make modules_install
        kbuild: fix kernel-devel RPM package and linux-headers Deb package
      f0b0d403
    • Linus Torvalds's avatar
      vm: fix move_vma() memory accounting being off · 3cec5049
      Linus Torvalds authored
      Commit 408579cd ("mm: Update do_vmi_align_munmap() return
      semantics") seems to have updated one of the callers of do_vmi_munmap()
      incorrectly: it used to check for the error case (which didn't
      change: negative means error).
      
      That commit changed the check to the success case (which did change:
      before that commit, 0 was success, and 1 was "success and lock
      downgraded".  After the change, it's always 0 for success, and the lock
      will have been released if requested).
      
      This didn't change any actual VM behavior _except_ for memory accounting
      when 'VM_ACCOUNT' was set on the vma.  Which made the wrong return value
      test fairly subtle, since everything continues to work.
      
      Or rather - it continues to work but the "Committed memory" accounting
      goes all wonky (Committed_AS value in /proc/meminfo), and depending on
      settings that then causes problems much much later as the VM relies on
      bogus statistics for its heuristics.
      
      Revert that one line of the change back to the original logic.
      
      Fixes: 408579cd ("mm: Update do_vmi_align_munmap() return semantics")
      Reported-by: default avatarChristoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
      Reported-bisected-and-tested-by: default avatarMichael Labiuk <michael.labiuk@virtuozzo.com>
      Cc: Bagas Sanjaya <bagasdotme@gmail.com>
      Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
      Link: https://lore.kernel.org/all/1694366957@msgid.manchmal.in-ulm.de/Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3cec5049
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · ad8a69f3
      Linus Torvalds authored
      Pull SCSI fixes from James Bottomley:
       "16 small(ish) fixes all in drivers.
      
        The major fixes are in pm8001 (fixes MSI-X issue going back to its
        origin), the qla2xxx endianness fix, which fixes a bug on big endian
        and the lpfc ones which can cause an oops on module removal without
        them"
      
      * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
        scsi: lpfc: Prevent use-after-free during rmmod with mapped NVMe rports
        scsi: lpfc: Early return after marking final NLP_DROPPED flag in dev_loss_tmo
        scsi: lpfc: Fix the NULL vs IS_ERR() bug for debugfs_create_file()
        scsi: target: core: Fix target_cmd_counter leak
        scsi: pm8001: Setup IRQs on resume
        scsi: pm80xx: Avoid leaking tags when processing OPC_INB_SET_CONTROLLER_CONFIG command
        scsi: pm80xx: Use phy-specific SAS address when sending PHY_START command
        scsi: ufs: core: Poll HCS.UCRDY before issuing a UIC command
        scsi: ufs: core: Move __ufshcd_send_uic_cmd() outside host_lock
        scsi: qedf: Add synchronization between I/O completions and abort
        scsi: target: Replace strlcpy() with strscpy()
        scsi: qla2xxx: Fix NULL vs IS_ERR() bug for debugfs_create_dir()
        scsi: qla2xxx: Use raw_smp_processor_id() instead of smp_processor_id()
        scsi: qla2xxx: Correct endianness for rqstlen and rsplen
        scsi: ppa: Fix accidentally reversed conditions for 16-bit and 32-bit EPP
        scsi: megaraid_sas: Fix deadlock on firmware crashdump
      ad8a69f3
    • Linus Torvalds's avatar
      Merge tag 'ata-6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/libata · cc3e5afc
      Linus Torvalds authored
      Pull ata fixes from Damien Le Moal:
      
       - Fix link power management transitions to disallow unsupported states
         (Niklas)
      
       - A small string handling fix for the sata_mv driver (Christophe)
      
       - Clear port pending interrupts before reset, as per AHCI
         specifications (Szuying).
      
         Followup fixes for this one are to not clear ATA_PFLAG_EH_PENDING in
         ata_eh_reset() to allow EH to continue on with other actions recorded
         with error interrupts triggered before EH completes. And an
         additional fix to avoid thawing a port twice in EH (Niklas)
      
       - Small code style fixes in the pata_parport driver to silence the
         build bot as it keeps complaining about bad indentation (me)
      
       - A fix for the recent CDL code to avoid fetching sense data for
         successful commands when not necessary for correct operation (Niklas)
      
      * tag 'ata-6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/libata:
        ata: libata-core: fetch sense data for successful commands iff CDL enabled
        ata: libata-eh: do not thaw the port twice in ata_eh_reset()
        ata: libata-eh: do not clear ATA_PFLAG_EH_PENDING in ata_eh_reset()
        ata: pata_parport: Fix code style issues
        ata: libahci: clear pending interrupt status
        ata: sata_mv: Fix incorrect string length computation in mv_dump_mem()
        ata: libata: disallow dev-initiated LPM transitions to unsupported states
      cc3e5afc
    • Linus Torvalds's avatar
      Merge tag 'usb-6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb · cce67b6b
      Linus Torvalds authored
      Pull USB fix from Greg KH:
       "Here is a single USB fix for a much-reported regression for 6.6-rc1.
      
        It resolves a crash in the typec debugfs code for many systems. It's
        been in linux-next with no reported issues, and many people have
        reported it resolving their problem with 6.6-rc1"
      
      * tag 'usb-6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
        usb: typec: ucsi: Fix NULL pointer dereference
      cce67b6b
    • Linus Torvalds's avatar
      Merge tag 'driver-core-6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core · 205d0494
      Linus Torvalds authored
      Pull driver core fixes from Greg KH:
       "Here is a single driver core fix for a much-reported-by-sysbot issue
        that showed up in 6.6-rc1. It's been submitted by many people, all in
        the same way, so it obviously fixes things for them all.
      
        Also in here is a single documentation update adding riscv to the
        embargoed hardware document in case there are any future issues with
        that processor family.
      
        Both of these have been in linux-next with no reported problems"
      
      * tag 'driver-core-6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
        Documentation: embargoed-hardware-issues.rst: Add myself for RISC-V
        driver core: return an error when dev_set_name() hasn't happened
      205d0494
    • Linus Torvalds's avatar
      Merge tag 'char-misc-6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc · fd455e77
      Linus Torvalds authored
      Pull char/misc fix from Greg KH:
       "Here is a single patch for 6.6-rc2 that reverts a 6.5 change for the
        comedi subsystem that has ended up being incorrect and caused drivers
        that were working for people to be unable to be able to be selected to
        build at all.
      
        To fix this, the Kconfig change needs to be reverted and a future set
        of fixes for the ioport dependancies will show up in 6.7-rc1 (there's
        no rush for them.)
      
        This has been in linux-next with no reported issues"
      
      * tag 'char-misc-6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
        Revert "comedi: add HAS_IOPORT dependencies"
      fd455e77
    • Linus Torvalds's avatar
      Merge tag 'i2c-for-6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux · c37f8efc
      Linus Torvalds authored
      Pull i2c fixes from Wolfram Sang:
       "The main thing is the removal of 'probe_new' because all i2c client
        drivers are converted now. Thanks Uwe, this marks the end of a long
        conversion process.
      
        Other than that, we have a few Kconfig updates and driver bugfixes"
      
      * tag 'i2c-for-6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
        i2c: cadence: Fix the kernel-doc warnings
        i2c: aspeed: Reset the i2c controller when timeout occurs
        i2c: I2C_MLXCPLD on ARM64 should depend on ACPI
        i2c: Make I2C_ATR invisible
        i2c: Drop legacy callback .probe_new()
        w1: ds2482: Switch back to use struct i2c_driver's .probe()
      c37f8efc
    • Niklas Cassel's avatar
      ata: libata-core: fetch sense data for successful commands iff CDL enabled · 5e35a9ac
      Niklas Cassel authored
      Currently, we fetch sense data for a _successful_ command if either:
      1) Command was NCQ and ATA_DFLAG_CDL_ENABLED flag set (flag
         ATA_DFLAG_CDL_ENABLED will only be set if the Successful NCQ command
         sense data supported bit is set); or
      2) Command was non-NCQ and regular sense data reporting is enabled.
      
      This means that case 2) will trigger for a non-NCQ command which has
      ATA_SENSE bit set, regardless if CDL is enabled or not.
      
      This decision was by design. If the device reports that it has sense data
      available, it makes sense to fetch that sense data, since the sk/asc/ascq
      could be important information regardless if CDL is enabled or not.
      
      However, the fetching of sense data for a successful command is done via
      ATA EH. Considering how intricate the ATA EH is, we really do not want to
      invoke ATA EH unless absolutely needed.
      
      Before commit 18bd7718 ("scsi: ata: libata: Handle completion of CDL
      commands using policy 0xD") we never fetched sense data for successful
      commands.
      
      In order to not invoke the ATA EH unless absolutely necessary, even if the
      device claims support for sense data reporting, only fetch sense data for
      successful (NCQ and non-NCQ commands) commands that are using CDL.
      
      [Damien] Modified the check to test the qc flag ATA_QCFLAG_HAS_CDL
      instead of the device support for CDL, which is implied for commands
      using CDL.
      
      Fixes: 3ac873c7 ("ata: libata-core: fix when to fetch sense data for successful commands")
      Signed-off-by: default avatarNiklas Cassel <niklas.cassel@wdc.com>
      Signed-off-by: default avatarDamien Le Moal <dlemoal@kernel.org>
      5e35a9ac
    • Niklas Cassel's avatar
      ata: libata-eh: do not thaw the port twice in ata_eh_reset() · 7a3bc2b3
      Niklas Cassel authored
      commit 1e641060 ("libata: clear eh_info on reset completion") added
      a workaround that broke the retry mechanism in ATA EH.
      
      Tejun himself suggested to remove this workaround when it was identified
      to cause additional problems:
      https://lore.kernel.org/linux-ide/20110426135027.GI878@htj.dyndns.org/
      
      He even said:
      "Hmm... it seems I wasn't thinking straight when I added that work around."
      https://lore.kernel.org/linux-ide/20110426155229.GM878@htj.dyndns.org/
      
      While removing the workaround solved the issue, however, the workaround was
      kept to avoid "spurious hotplug events during reset", and instead another
      workaround was added on top of the existing workaround in commit
      8c56cacc ("libata: fix unexpectedly frozen port after ata_eh_reset()").
      
      Because these IRQs happened when the port was frozen, we know that they
      were actually a side effect of PxIS and IS.IPS(x) not being cleared before
      the COMRESET. This is now done in commit 94152042eaa9 ("ata: libahci: clear
      pending interrupt status"), so these workarounds can now be removed.
      
      Since commit 1e641060 ("libata: clear eh_info on reset completion") has
      now been reverted, the ATA EH retry mechanism is functional again, so there
      is once again no need to thaw the port more than once in ata_eh_reset().
      
      This reverts "the workaround on top of the workaround" introduced in commit
      8c56cacc ("libata: fix unexpectedly frozen port after ata_eh_reset()").
      Signed-off-by: default avatarNiklas Cassel <niklas.cassel@wdc.com>
      Signed-off-by: default avatarDamien Le Moal <dlemoal@kernel.org>
      7a3bc2b3
    • Niklas Cassel's avatar
      ata: libata-eh: do not clear ATA_PFLAG_EH_PENDING in ata_eh_reset() · 80cc944e
      Niklas Cassel authored
      ata_scsi_port_error_handler() starts off by clearing ATA_PFLAG_EH_PENDING,
      before calling ap->ops->error_handler() (without holding the ap->lock).
      
      If an error IRQ is received while ap->ops->error_handler() is running,
      the irq handler will set ATA_PFLAG_EH_PENDING.
      
      Once ap->ops->error_handler() returns, ata_scsi_port_error_handler()
      checks if ATA_PFLAG_EH_PENDING is set, and if it is, another iteration
      of ATA EH is performed.
      
      The problem is that ATA_PFLAG_EH_PENDING is not only cleared by
      ata_scsi_port_error_handler(), it is also cleared by ata_eh_reset().
      
      ata_eh_reset() is called by ap->ops->error_handler(). This additional
      clearing done by ata_eh_reset() breaks the whole retry logic in
      ata_scsi_port_error_handler(). Thus, if an error IRQ is received while
      ap->ops->error_handler() is running, the port will currently remain
      frozen and will never get re-enabled.
      
      The additional clearing in ata_eh_reset() was introduced in commit
      1e641060 ("libata: clear eh_info on reset completion").
      
      Looking at the original error report:
      https://marc.info/?l=linux-ide&m=124765325828495&w=2
      
      We can see the following happening:
      [    1.074659] ata3: XXX port freeze
      [    1.074700] ata3: XXX hardresetting link, stopping engine
      [    1.074746] ata3: XXX flipping SControl
      
      [    1.411471] ata3: XXX irq_stat=400040 CONN|PHY
      [    1.411475] ata3: XXX port freeze
      
      [    1.420049] ata3: XXX starting engine
      [    1.420096] ata3: XXX rc=0, class=1
      [    1.420142] ata3: XXX clearing IRQs for thawing
      [    1.420188] ata3: XXX port thawed
      [    1.420234] ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
      
      We are not supposed to be able to receive an error IRQ while the port is
      frozen (PxIE is set to 0, i.e. all IRQs for the port are disabled).
      
      AHCI 1.3.1 section 10.7.1.1 First Tier (IS Register) states:
      "Each bit location can be thought of as reporting a '1' if the virtual
      "interrupt line" for that port is indicating it wishes to generate an
      interrupt. That is, if a port has one or more interrupt status bit set,
      and the enables for those status bits are set, then this bit shall be set."
      
      Additionally, AHCI state P:ComInit clearly shows that the state machine
      will only jump to P:ComInitSetIS (which sets IS.IPS(x) to '1'), if PxIE.PCE
      is set to '1'. In our case, PxIE is set to 0, so IS.IPS(x) won't get set.
      
      So IS.IPS(x) only gets set if PxIS and PxIE is set.
      
      AHCI 1.3.1 section 10.7.1.1 First Tier (IS Register) also states:
      "The bits in this register are read/write clear. It is set by the level of
      the virtual interrupt line being a set, and cleared by a write of '1' from
      the software."
      
      So if IS.IPS(x) is set, you need to explicitly clear it by writing a 1 to
      IS.IPS(x) for that port.
      
      Since PxIE is cleared, the only way to get an interrupt while the port is
      frozen, is if IS.IPS(x) is set, and the only way IS.IPS(x) can be set when
      the port is frozen, is if it was set before the port was frozen.
      
      However, since commit 737dd811 ("ata: libahci: clear pending interrupt
      status"), we clear both PxIS and IS.IPS(x) after freezing the port, but
      before the COMRESET, so the problem that commit 1e641060 ("libata:
      clear eh_info on reset completion") fixed can no longer happen.
      
      Thus, revert commit 1e641060 ("libata: clear eh_info on reset
      completion"), so that the retry logic in ata_scsi_port_error_handler()
      works once again. (The retry logic is still needed, since we can still
      get an error IRQ _after_ the port has been thawed, but before
      ata_scsi_port_error_handler() takes the ap->lock in order to check
      if ATA_PFLAG_EH_PENDING is set.)
      Signed-off-by: default avatarNiklas Cassel <niklas.cassel@wdc.com>
      Signed-off-by: default avatarDamien Le Moal <dlemoal@kernel.org>
      80cc944e
    • Linus Torvalds's avatar
      Merge tag 'linux-kselftest-fixes-6.6-rc2' of... · 57d88e8a
      Linus Torvalds authored
      Merge tag 'linux-kselftest-fixes-6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
      
      Pull more kselftest fixes from Shuah Khan
       "Fixes to user_events test and ftrace test.
      
        The user_events test was enabled by default in Linux 6.6-rc1. The
        following fixes are for bugs found since then:
      
         - add checks for dependencies and skip the test if they aren't met.
      
           The user_events test requires root access, and tracefs and
           user_events enabled. It leaves tracefs mounted and a fix is in
           progress for that missing piece.
      
         - create user_events test-specific Kconfig fragments
      
        ftrace test fixes:
      
         - unmount tracefs for recovering environment. Fix identified during
           the above mentioned user_events dependencies fix.
      
         - adds softlink to latest log directory improving usage"
      
      * tag 'linux-kselftest-fixes-6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
        selftests: tracing: Fix to unmount tracefs for recovering environment
        selftests: user_events: create test-specific Kconfig fragments
        ftrace/selftests: Add softlink to latest log directory
        selftests/user_events: Fix failures when user_events is not installed
      57d88e8a
  8. 15 Sep, 2023 1 commit