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Filename Latest commit message Latest commit date
Can Guo 2e0034f5e2 BACKPORT: FROMGIT: scsi: ufs: Fix concurrency of error handler and other error recovery paths
Error recovery can be invoked from multiple code paths, including hibern8
enter/exit (from ufshcd_link_recovery), ufshcd_eh_host_reset_handler() and
eh_work scheduled from IRQ context. Ultimately, these paths are all trying
to invoke ufshcd_reset_and_restore() in either a synchronous or
asynchronous manner. This causes problems:

 - If link recovery happens during ungate work, ufshcd_hold() would be
   called recursively. Although commit 53c12d0ef6 ("scsi: ufs: fix error
   recovery after the hibern8 exit failure") fixed a deadlock due to
   recursive calls of ufshcd_hold() by adding a check of eh_in_progress
   into ufshcd_hold, this check allows eh_work to run in parallel while
   link recovery is running.

 - Similar concurrency can also happen when error recovery is invoked from
   ufshcd_eh_host_reset_handler and ufshcd_link_recovery.

 - Concurrency can even happen between eh_works. eh_work, currently queued
   on system_wq, is allowed to have multiple instances running in parallel,
   but we don't have proper protection for that.

If any of above concurrency scenarios happen, error recovery would fail and
lead ufs device and host into bad states. To fix the concurrency problem,
this change queues eh_work on a single threaded workqueue and removes link
recovery calls from the hibern8 enter/exit path. In addition, make use of
eh_work in eh_host_reset_handler instead of calling
ufshcd_reset_and_restore. This unifies the UFS error recovery mechanism.

According to the UFSHCI JEDEC spec, hibern8 enter/exit error occurs when
the link is broken. This essentially applies to any power mode change
operations (since they all use PACP_PWR cmds in UniPro layer). So, if a
power mode change operation (including AH8 enter/exit) fails, mark link
state as UIC_LINK_BROKEN_STATE and schedule the eh_work.  In this case,
error handler needs to do a full reset and restore to recover the link back
to active. Before the link state is recovered to active,
ufshcd_uic_pwr_ctrl simply returns -ENOLINK to avoid more errors.

Link: https://lore.kernel.org/r/1596975355-39813-6-git-send-email-cang@codeaurora.org
Reviewed-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Bug: 165343119
(cherry picked from commit 4db7a23605973ac4a2cb24e759bebaaa82054f21
https://git.kernel.org/pub/scm/linux/kernel/git/mkp/scsi.git 5.10/scsi-queue)
Change-Id: I9718d7752016682607fc6735402fad7c0059ed3a
[can: Resolved minor conflict in ufshcd.c]
Signed-off-by: Can Guo <cang@codeaurora.org>
2020-08-19 10:52:39 -07:00
android ANDROID: ABI: Update allowed list for QCOM 2020-08-18 13:59:56 -07:00
arch This is the 5.4.59 stable release 2020-08-19 08:40:57 +02:00
block This is the 5.4.59 stable release 2020-08-19 08:40:57 +02:00
certs
crypto This is the 5.4.53 stable release 2020-07-23 12:36:54 +02:00
Documentation This is the 5.4.59 stable release 2020-08-19 08:40:57 +02:00
drivers BACKPORT: FROMGIT: scsi: ufs: Fix concurrency of error handler and other error recovery paths 2020-08-19 10:52:39 -07:00
fs This is the 5.4.59 stable release 2020-08-19 08:40:57 +02:00
include ANDROID: vendor_hooks: Add vendor hook to the net 2020-08-19 14:29:16 +00:00
init ANDROID: GKI: Build CEC_{CORE,NOTIFIER,PIN} in 2020-08-18 00:56:35 +00:00
ipc Revert "ANDROID: vfs: Add permission2 for filesystems with per mount permissions" 2020-05-29 14:48:37 +02:00
kernel This is the 5.4.59 stable release 2020-08-19 08:40:57 +02:00
lib This is the 5.4.59 stable release 2020-08-19 08:40:57 +02:00
LICENSES
mm This is the 5.4.59 stable release 2020-08-19 08:40:57 +02:00
net ANDROID: vendor_hooks: Add vendor hook to the net 2020-08-19 14:29:16 +00:00
samples This is the 5.4.59 stable release 2020-08-19 08:40:57 +02:00
scripts ANDROID: kbuild: don't preprocess module-lto.lds 2020-08-19 09:15:50 -07:00
security This is the 5.4.59 stable release 2020-08-19 08:40:57 +02:00
sound Revert "ALSA: usb-audio: work around streaming quirk for MacroSilicon MS2109" 2020-08-19 11:03:25 +02:00
tools This is the 5.4.59 stable release 2020-08-19 08:40:57 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: arm64: Don't inherit exec permission across page-table levels 2020-08-05 09:59:51 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
build.config.aarch64 ANDROID: add compat cross compiler 2020-04-27 20:20:28 -07:00
build.config.allmodconfig ANDROID: GKI: Fix up "do not export symbol_get/put()" commit 2020-08-01 14:28:51 +02:00
build.config.allmodconfig.aarch64
build.config.allmodconfig.arm ANDROID: Add build.config files for ARM 32-bit 2020-03-15 22:51:11 +00:00
build.config.allmodconfig.x86_64
build.config.arm ANDROID: Add build.config files for ARM 32-bit 2020-03-15 22:51:11 +00:00
build.config.common ANDROID: update the kernel release format for GKI 2020-07-27 22:22:25 +00:00
build.config.db845c ANDROID: db845c: set BUILD_INITRAMFS=1 2020-08-18 16:40:40 +00:00
build.config.gki
build.config.gki-debug.aarch64 ANDROID: build: update ABI definitions 2020-07-28 17:39:34 +00:00
build.config.gki-debug.x86_64 ANDROID: build: update ABI definitions 2020-07-28 17:39:34 +00:00
build.config.gki.aarch64 ANDROID: GKI: add abi_gki_aarch64_oplus 2020-08-13 11:48:42 +02:00
build.config.gki.x86_64
build.config.gki_kasan ANDROID: Rename build.config.gki.arch_kasan 2020-05-05 20:50:24 +00:00
build.config.gki_kasan.aarch64 ANDROID: Drop ABI monitoring from KASAN build config 2020-05-06 16:43:25 +00:00
build.config.gki_kasan.x86_64 ANDROID: Rename build.config.gki.arch_kasan 2020-05-05 20:50:24 +00:00
build.config.hikey960 ANDROID: hikey960: Add external mali driver support to build.config.hikey960 2020-03-23 22:55:17 +00:00
build.config.x86_64
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile ANDROID: kbuild: don't preprocess module-lto.lds 2020-08-19 09:15:50 -07:00
README
README.md

How do I submit patches to Android Common Kernels

  1. BEST: Make all of your changes to upstream Linux. If appropriate, backport to the stable releases. These patches will be merged automatically in the corresponding common kernels. If the patch is already in upstream Linux, post a backport of the patch that conforms to the patch requirements below.

  2. LESS GOOD: Develop your patches out-of-tree (from an upstream Linux point-of-view). Unless these are fixing an Android-specific bug, these are very unlikely to be accepted unless they have been coordinated with kernel-team@android.com. If you want to proceed, post a patch that conforms to the patch requirements below.

Common Kernel patch requirements

  • All patches must conform to the Linux kernel coding standards and pass script/checkpatch.pl
  • Patches shall not break gki_defconfig or allmodconfig builds for arm, arm64, x86, x86_64 architectures (see https://source.android.com/setup/build/building-kernels)
  • If the patch is not merged from an upstream branch, the subject must be tagged with the type of patch: UPSTREAM:, BACKPORT:, FROMGIT:, FROMLIST:, or ANDROID:.
  • All patches must have a Change-Id: tag (see https://gerrit-review.googlesource.com/Documentation/user-changeid.html)
  • If an Android bug has been assigned, there must be a Bug: tag.
  • All patches must have a Signed-off-by: tag by the author and the submitter

Additional requirements are listed below based on patch type

Requirements for backports from mainline Linux: UPSTREAM:, BACKPORT:

  • If the patch is a cherry-pick from Linux mainline with no changes at all
    • tag the patch subject with UPSTREAM:.
    • add upstream commit information with a (cherry-picked from ...) line
    • Example:
      • if the upstream commit message is
        important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>
    - then Joe Smith would upload the patch for the common kernel as
        UPSTREAM: important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>

        Bug: 135791357
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        (cherry-picked from c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
        Signed-off-by: Joe Smith <joe.smith@foo.org>
  • If the patch requires any changes from the upstream version, tag the patch with BACKPORT: instead of UPSTREAM:.
    • use the same tags as UPSTREAM:
    • add comments about the changes under the (cherry-picked from ...) line
    • Example:
        BACKPORT: important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>

        Bug: 135791357
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        (cherry-picked from c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
        [ Resolved minor conflict in drivers/foo/bar.c ]
        Signed-off-by: Joe Smith <joe.smith@foo.org>

Requirements for other backports: FROMGIT:, FROMLIST:,

  • If the patch has been merged into an upstream maintainer tree, but has not yet been merged into Linux mainline
    • tag the patch subject with FROMGIT:
    • add info on where the patch came from as (cherry picked from commit <sha1> <repo> <branch>). This must be a stable maintainer branch (not rebased, so don't use linux-next for example).
    • if changes were required, use BACKPORT: FROMGIT:
    • Example:
      • if the commit message in the maintainer tree is
        important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>
    - then Joe Smith would upload the patch for the common kernel as
        FROMGIT: important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>

        Bug: 135791357
        (cherry picked from commit 878a2fd9de10b03d11d2f622250285c7e63deace
         https://git.kernel.org/pub/scm/linux/kernel/git/foo/bar.git test-branch)
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        Signed-off-by: Joe Smith <joe.smith@foo.org>
  • If the patch has been submitted to LKML, but not accepted into any maintainer tree
    • tag the patch subject with FROMLIST:
    • add a Link: tag with a link to the submittal on lore.kernel.org
    • if changes were required, use BACKPORT: FROMLIST:
    • Example:
        FROMLIST: important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>

        Bug: 135791357
        Link: https://lore.kernel.org/lkml/20190619171517.GA17557@someone.com/
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        Signed-off-by: Joe Smith <joe.smith@foo.org>

Requirements for Android-specific patches: ANDROID:

  • If the patch is fixing a bug to Android-specific code
    • tag the patch subject with ANDROID:
    • add a Fixes: tag that cites the patch with the bug
    • Example:
        ANDROID: fix android-specific bug in foobar.c

        This is the detailed description of the important fix

        Fixes: 1234abcd2468 ("foobar: add cool feature")
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        Signed-off-by: Joe Smith <joe.smith@foo.org>
  • If the patch is a new feature
    • tag the patch subject with ANDROID:
    • add a Bug: tag with the Android bug (required for android-specific features)