1. 22 Apr, 2020 3 commits
  2. 20 Apr, 2020 14 commits
    • Christoph Hellwig's avatar
      block: fold bdev_unhash_inode into invalidate_partition · 9bc5c397
      Christoph Hellwig authored
      invalidate_partition and bdev_unhash_inode are always paired, and
      invalidate_partition already does an icache lookup for the block device
      inode.  Piggy back on that to remove the inode from the hash.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      9bc5c397
    • Christoph Hellwig's avatar
      block: mark invalidate_partition static · 02d33b67
      Christoph Hellwig authored
      invalidate_partition is only used in genhd.c, so mark it static.  Also
      drop the return value given that is is always ignored.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      02d33b67
    • Christoph Hellwig's avatar
      block: simplify block device syncing in bdev_del_partition · d5f3178e
      Christoph Hellwig authored
      We just checked a little above that the block device for the partition
      im busy.  That implies no file system is mounted, and thus the only
      thing in fsync_bdev that actually is used is sync_blockdev.  Just call
      sync_blockdev directly.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      d5f3178e
    • Christoph Hellwig's avatar
      block: don't call invalidate_partition from blk_drop_partitions · e669c1da
      Christoph Hellwig authored
      Given that the device must not be busy, most of the calls from
      invalidate_partition that are related to file system metadata are
      guranteed to not happen.  Just open code the calls to sync_blockdev
      and invalidate_bdev instead.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      e669c1da
    • Christoph Hellwig's avatar
      dasd: use blk_drop_partitions instead of badly reimplementing it · 21be6cdc
      Christoph Hellwig authored
      Use the blk_drop_partitions function instead of messing around with
      ioctls that get kernel pointers.  For this blk_drop_partitions needs
      to be exported, which it normally shouldn't - make an exception for
      s390 only.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      21be6cdc
    • Christoph Hellwig's avatar
      block: remove the disk argument from blk_drop_partitions · d46430bf
      Christoph Hellwig authored
      The gendisk can be trivially deducted from the block_device.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      d46430bf
    • Christoph Hellwig's avatar
      block: remove hd_struct_kill · 4377b48d
      Christoph Hellwig authored
      The function has a single caller, so just open code it.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      4377b48d
    • Christoph Hellwig's avatar
      block: cleanup hd_struct freeing · 8da2892e
      Christoph Hellwig authored
      Move hd_ref_init out of line as there it isn't anywhere near a fast path,
      and rename the rcu ref freeing callbacks to be more descriptive.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      8da2892e
    • Christoph Hellwig's avatar
      block: pass a hd_struct to delete_partition · cddae808
      Christoph Hellwig authored
      All callers have the hd_struct at hand, so pass it instead of performing
      another lookup.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      cddae808
    • Christoph Hellwig's avatar
      block: refactor blkpg_ioctl · fa9156ae
      Christoph Hellwig authored
      Split each sub-command out into a separate helper, and move those helpers
      to block/partitions/core.c instead of having a lot of partition
      manipulation logic open coded in block/ioctl.c.
      
      Signed-off-by: Christoph Hellwig <hch@lst.de
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      fa9156ae
    • Douglas Anderson's avatar
      Revert "scsi: core: run queue if SCSI device queue isn't ready and queue is idle" · b4fd63f4
      Douglas Anderson authored
      This reverts commit 7e70aa78.
      
      Now that we have the patches ("blk-mq: In blk_mq_dispatch_rq_list()
      "no budget" is a reason to kick") and ("blk-mq: Rerun dispatching in
      the case of budget contention") we should no longer need the fix in
      the SCSI code.  Revert it, resolving conflicts with other patches that
      have touched this code.
      
      With this revert (and the two new patches) I can run the script that
      was in commit 7e70aa78 ("scsi: core: run queue if SCSI device
      queue isn't ready and queue is idle") in a loop with no failure.  If I
      do this revert without the two new patches I can easily get a failure.
      Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
      Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
      Acked-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      b4fd63f4
    • Douglas Anderson's avatar
      blk-mq: Rerun dispatching in the case of budget contention · a0823421
      Douglas Anderson authored
      If ever a thread running blk-mq code tries to get budget and fails it
      immediately stops doing work and assumes that whenever budget is freed
      up that queues will be kicked and whatever work the thread was trying
      to do will be tried again.
      
      One path where budget is freed and queues are kicked in the normal
      case can be seen in scsi_finish_command().  Specifically:
      - scsi_finish_command()
        - scsi_device_unbusy()
          - # Decrement "device_busy", AKA release budget
        - scsi_io_completion()
          - scsi_end_request()
            - blk_mq_run_hw_queues()
      
      The above is all well and good.  The problem comes up when a thread
      claims the budget but then releases it without actually dispatching
      any work.  Since we didn't schedule any work we'll never run the path
      of finishing work / kicking the queues.
      
      This isn't often actually a problem which is why this issue has
      existed for a while and nobody noticed.  Specifically we only get into
      this situation when we unexpectedly found that we weren't going to do
      any work.  Code that later receives new work kicks the queues.  All
      good, right?
      
      The problem shows up, however, if timing is just wrong and we hit a
      race.  To see this race let's think about the case where we only have
      a budget of 1 (only one thread can hold budget).  Now imagine that a
      thread got budget and then decided not to dispatch work.  It's about
      to call put_budget() but then the thread gets context switched out for
      a long, long time.  While in this state, any and all kicks of the
      queue (like the when we received new work) will be no-ops because
      nobody can get budget.  Finally the thread holding budget gets to run
      again and returns.  All the normal kicks will have been no-ops and we
      have an I/O stall.
      
      As you can see from the above, you need just the right timing to see
      the race.  To start with, the only case it happens if we thought we
      had work, actually managed to get the budget, but then actually didn't
      have work.  That's pretty rare to start with.  Even then, there's
      usually a very small amount of time between realizing that there's no
      work and putting the budget.  During this small amount of time new
      work has to come in and the queue kick has to make it all the way to
      trying to get the budget and fail.  It's pretty unlikely.
      
      One case where this could have failed is illustrated by an example of
      threads running blk_mq_do_dispatch_sched():
      
      * Threads A and B both run has_work() at the same time with the same
        "hctx".  Imagine has_work() is exact.  There's no lock, so it's OK
        if Thread A and B both get back true.
      * Thread B gets interrupted for a long time right after it decides
        that there is work.  Maybe its CPU gets an interrupt and the
        interrupt handler is slow.
      * Thread A runs, get budget, dispatches work.
      * Thread A's work finishes and budget is released.
      * Thread B finally runs again and gets budget.
      * Since Thread A already took care of the work and no new work has
        come in, Thread B will get NULL from dispatch_request().  I believe
        this is specifically why dispatch_request() is allowed to return
        NULL in the first place if has_work() must be exact.
      * Thread B will now be holding the budget and is about to call
        put_budget(), but hasn't called it yet.
      * Thread B gets interrupted for a long time (again).  Dang interrupts.
      * Now Thread C (maybe with a different "hctx" but the same queue)
        comes along and runs blk_mq_do_dispatch_sched().
      * Thread C won't do anything because it can't get budget.
      * Finally Thread B will run again and put the budget without kicking
        any queues.
      
      Even though the example above is with blk_mq_do_dispatch_sched() I
      believe the race is possible any time someone is holding budget but
      doesn't do work.
      
      Unfortunately, the unlikely has become more likely if you happen to be
      using the BFQ I/O scheduler.  BFQ, by design, sometimes returns "true"
      for has_work() but then NULL for dispatch_request() and stays in this
      state for a while (currently up to 9 ms).  Suddenly you only need one
      race to hit, not two races in a row.  With my current setup this is
      easy to reproduce in reboot tests and traces have actually shown that
      we hit a race similar to the one described above.
      
      Note that we only need to fix blk_mq_do_dispatch_sched() and
      blk_mq_do_dispatch_ctx() and not the other places that put budget.  In
      other cases we know that we have work to do on at least one "hctx" and
      code already exists to kick that "hctx"'s queue.  When that work
      finally finishes all the queues will be kicked using the normal flow.
      
      One last note is that (at least in the SCSI case) budget is shared by
      all "hctx"s that have the same queue.  Thus we need to make sure to
      kick the whole queue, not just re-run dispatching on a single "hctx".
      Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
      Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      a0823421
    • Douglas Anderson's avatar
      blk-mq: Add blk_mq_delay_run_hw_queues() API call · b9151e7b
      Douglas Anderson authored
      We have:
      * blk_mq_run_hw_queue()
      * blk_mq_delay_run_hw_queue()
      * blk_mq_run_hw_queues()
      
      ...but not blk_mq_delay_run_hw_queues(), presumably because nobody
      needed it before now.  Since we need it for a later patch in this
      series, add it.
      Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
      Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      b9151e7b
    • Douglas Anderson's avatar
      blk-mq: In blk_mq_dispatch_rq_list() "no budget" is a reason to kick · ab3cee37
      Douglas Anderson authored
      In blk_mq_dispatch_rq_list(), if blk_mq_sched_needs_restart() returns
      true and the driver returns BLK_STS_RESOURCE then we'll kick the
      queue.  However, there's another case where we might need to kick it.
      If we were unable to get budget we can be in much the same state as
      when the driver returns BLK_STS_RESOURCE, so we should treat it the
      same.
      
      It should be noted that even if we add a whole bunch of extra kicking
      to the queue in other patches this patch is still important.
      Specifically any kicking that happened before we re-spliced leftover
      requests into 'hctx->dispatch' wouldn't have found any work, so we
      really need to make sure we kick ourselves after we've done the
      splicing.
      Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
      Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      ab3cee37
  3. 19 Apr, 2020 12 commits
    • Linus Torvalds's avatar
      Linux 5.7-rc2 · ae83d0b4
      Linus Torvalds authored
      ae83d0b4
    • Brian Geffon's avatar
      mm: Fix MREMAP_DONTUNMAP accounting on VMA merge · dadbd85f
      Brian Geffon authored
      When remapping a mapping where a portion of a VMA is remapped
      into another portion of the VMA it can cause the VMA to become
      split. During the copy_vma operation the VMA can actually
      be remerged if it's an anonymous VMA whose pages have not yet
      been faulted. This isn't normally a problem because at the end
      of the remap the original portion is unmapped causing it to
      become split again.
      
      However, MREMAP_DONTUNMAP leaves that original portion in place which
      means that the VMA which was split and then remerged is not actually
      split at the end of the mremap. This patch fixes a bug where
      we don't detect that the VMAs got remerged and we end up
      putting back VM_ACCOUNT on the next mapping which is completely
      unreleated. When that next mapping is unmapped it results in
      incorrectly unaccounting for the memory which was never accounted,
      and eventually we will underflow on the memory comittment.
      
      There is also another issue which is similar, we're currently
      accouting for the number of pages in the new_vma but that's wrong.
      We need to account for the length of the remap operation as that's
      all that is being added. If there was a mapping already at that
      location its comittment would have been adjusted as part of
      the munmap at the start of the mremap.
      
      A really simple repro can be seen in:
      https://gist.github.com/bgaff/e101ce99da7d9a8c60acc641d07f312c
      
      Fixes: e346b381 ("mm/mremap: add MREMAP_DONTUNMAP to mremap()")
      Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
      Signed-off-by: default avatarBrian Geffon <bgeffon@google.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      dadbd85f
    • Linus Torvalds's avatar
      Merge tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux · 86cc3398
      Linus Torvalds authored
      Pull clk fixes from Stephen Boyd:
       "Two build fixes for a couple clk drivers and a fix for the Unisoc
        serial clk where we want to keep it on for earlycon"
      
      * tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
        clk: sprd: don't gate uart console clock
        clk: mmp2: fix link error without mmp2
        clk: asm9260: fix __clk_hw_register_fixed_rate_with_accuracy typo
      86cc3398
    • Linus Torvalds's avatar
      Merge tag 'x86-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 0fe5f9ca
      Linus Torvalds authored
      Pull x86 and objtool fixes from Thomas Gleixner:
       "A set of fixes for x86 and objtool:
      
        objtool:
      
         - Ignore the double UD2 which is emitted in BUG() when
           CONFIG_UBSAN_TRAP is enabled.
      
         - Support clang non-section symbols in objtool ORC dump
      
         - Fix switch table detection in .text.unlikely
      
         - Make the BP scratch register warning more robust.
      
        x86:
      
         - Increase microcode maximum patch size for AMD to cope with new CPUs
           which have a larger patch size.
      
         - Fix a crash in the resource control filesystem when the removal of
           the default resource group is attempted.
      
         - Preserve Code and Data Prioritization enabled state accross CPU
           hotplug.
      
         - Update split lock cpu matching to use the new X86_MATCH macros.
      
         - Change the split lock enumeration as Intel finaly decided that the
           IA32_CORE_CAPABILITIES bits are not architectural contrary to what
           the SDM claims. !@#%$^!
      
         - Add Tremont CPU models to the split lock detection cpu match.
      
         - Add a missing static attribute to make sparse happy"
      
      * tag 'x86-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        x86/split_lock: Add Tremont family CPU models
        x86/split_lock: Bits in IA32_CORE_CAPABILITIES are not architectural
        x86/resctrl: Preserve CDP enable over CPU hotplug
        x86/resctrl: Fix invalid attempt at removing the default resource group
        x86/split_lock: Update to use X86_MATCH_INTEL_FAM6_MODEL()
        x86/umip: Make umip_insns static
        x86/microcode/AMD: Increase microcode PATCH_MAX_SIZE
        objtool: Make BP scratch register warning more robust
        objtool: Fix switch table detection in .text.unlikely
        objtool: Support Clang non-section symbols in ORC generation
        objtool: Support Clang non-section symbols in ORC dump
        objtool: Fix CONFIG_UBSAN_TRAP unreachable warnings
      0fe5f9ca
    • Linus Torvalds's avatar
      Merge tag 'timers-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 3e0dea57
      Linus Torvalds authored
      Pull time namespace fix from Thomas Gleixner:
       "An update for the proc interface of time namespaces: Use symbolic
        names instead of clockid numbers. The usability nuisance of numbers
        was noticed by Michael when polishing the man page"
      
      * tag 'timers-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        proc, time/namespace: Show clock symbolic names in /proc/pid/timens_offsets
      3e0dea57
    • Linus Torvalds's avatar
      Merge tag 'perf-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · b7374586
      Linus Torvalds authored
      Pull perf tooling fixes and updates from Thomas Gleixner:
      
       - Fix the header line of perf stat output for '--metric-only --per-socket'
      
       - Fix the python build with clang
      
       - The usual tools UAPI header synchronization
      
      * tag 'perf-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        tools headers: Synchronize linux/bits.h with the kernel sources
        tools headers: Adopt verbatim copy of compiletime_assert() from kernel sources
        tools headers: Update x86's syscall_64.tbl with the kernel sources
        tools headers UAPI: Sync drm/i915_drm.h with the kernel sources
        tools headers UAPI: Update tools's copy of drm.h headers
        tools headers kvm: Sync linux/kvm.h with the kernel sources
        tools headers UAPI: Sync linux/fscrypt.h with the kernel sources
        tools include UAPI: Sync linux/vhost.h with the kernel sources
        tools arch x86: Sync asm/cpufeatures.h with the kernel sources
        tools headers UAPI: Sync linux/mman.h with the kernel
        tools headers UAPI: Sync sched.h with the kernel
        tools headers: Update linux/vdso.h and grab a copy of vdso/const.h
        perf stat: Fix no metric header if --per-socket and --metric-only set
        perf python: Check if clang supports -fno-semantic-interposition
        tools arch x86: Sync the msr-index.h copy with the kernel sources
      b7374586
    • Linus Torvalds's avatar
      Merge tag 'irq-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 80ade29e
      Linus Torvalds authored
      Pull irq fixes from Thomas Gleixner:
       "A set of fixes/updates for the interrupt subsystem:
      
         - Remove setup_irq() and remove_irq(). All users have been converted
           so remove them before new users surface.
      
         - A set of bugfixes for various interrupt chip drivers
      
         - Add a few missing static attributes to address sparse warnings"
      
      * tag 'irq-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        irqchip/irq-bcm7038-l1: Make bcm7038_l1_of_init() static
        irqchip/irq-mvebu-icu: Make legacy_bindings static
        irqchip/meson-gpio: Fix HARDIRQ-safe -> HARDIRQ-unsafe lock order
        irqchip/sifive-plic: Fix maximum priority threshold value
        irqchip/ti-sci-inta: Fix processing of masked irqs
        irqchip/mbigen: Free msi_desc on device teardown
        irqchip/gic-v4.1: Update effective affinity of virtual SGIs
        irqchip/gic-v4.1: Add support for VPENDBASER's Dirty+Valid signaling
        genirq: Remove setup_irq() and remove_irq()
      80ade29e
    • Linus Torvalds's avatar
      Merge tag 'sched-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 08dd3872
      Linus Torvalds authored
      Pull scheduler fixes from Thomas Gleixner:
       "Two fixes for the scheduler:
      
         - Work around an uninitialized variable warning where GCC can't
           figure it out.
      
         - Allow 'isolcpus=' to skip unknown subparameters so that older
           kernels work with the commandline of a newer kernel. Improve the
           error output while at it"
      
      * tag 'sched-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        sched/vtime: Work around an unitialized variable warning
        sched/isolation: Allow "isolcpus=" to skip unknown sub-parameters
      08dd3872
    • Linus Torvalds's avatar
      Merge tag 'core-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 5e7de581
      Linus Torvalds authored
      Pull RCU fix from Thomas Gleixner:
       "A single bugfix for RCU to prevent taking a lock in NMI context"
      
      * tag 'core-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        rcu: Don't acquire lock in NMI handler in rcu_nmi_enter_common()
      5e7de581
    • Linus Torvalds's avatar
      Merge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 · 439f1da9
      Linus Torvalds authored
      Pull ext4 fixes from Ted Ts'o:
       "Miscellaneous bug fixes and cleanups for ext4, including a fix for
        generic/388 in data=journal mode, removing some BUG_ON's, and cleaning
        up some compiler warnings"
      
      * tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
        ext4: convert BUG_ON's to WARN_ON's in mballoc.c
        ext4: increase wait time needed before reuse of deleted inode numbers
        ext4: remove set but not used variable 'es' in ext4_jbd2.c
        ext4: remove set but not used variable 'es'
        ext4: do not zeroout extents beyond i_disksize
        ext4: fix return-value types in several function comments
        ext4: use non-movable memory for superblock readahead
        ext4: use matching invalidatepage in ext4_writepage
      439f1da9
    • Linus Torvalds's avatar
      Merge tag '5.7-rc-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6 · aee0314b
      Linus Torvalds authored
      Pull cifs fixes from Steve French:
       "Three small smb3 fixes: two debug related (helping network tracing for
        SMB2 mounts, and the other removing an unintended debug line on
        signing failures), and one fixing a performance problem with 64K
        pages"
      
      * tag '5.7-rc-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
        smb3: remove overly noisy debug line in signing errors
        cifs: improve read performance for page size 64KB & cache=strict & vers=2.1+
        cifs: dump the session id and keys also for SMB2 sessions
      aee0314b
    • Linus Torvalds's avatar
      Merge tag 'flexible-array-member-5.7-rc2' of... · 13402837
      Linus Torvalds authored
      Merge tag 'flexible-array-member-5.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux
      
      Pull flexible-array member conversion from Gustavo Silva:
       "The current codebase makes use of the zero-length array language
        extension to the C90 standard, but the preferred mechanism to declare
        variable-length types such as these ones is a flexible array
        member[1][2], introduced in C99:
      
          struct foo {
              int stuff;
              struct boo array[];
          };
      
        By making use of the mechanism above, we will get a compiler warning
        in case the flexible array does not occur last in the structure, which
        will help us prevent some kind of undefined behavior bugs from being
        inadvertently introduced[3] to the codebase from now on.
      
        Also, notice that, dynamic memory allocations won't be affected by
        this change:
      
         "Flexible array members have incomplete type, and so the sizeof
          operator may not be applied. As a quirk of the original
          implementation of zero-length arrays, sizeof evaluates to zero."[1]
      
        sizeof(flexible-array-member) triggers a warning because flexible
        array members have incomplete type[1]. There are some instances of
        code in which the sizeof operator is being incorrectly/erroneously
        applied to zero-length arrays and the result is zero. Such instances
        may be hiding some bugs. So, this work (flexible-array member
        convertions) will also help to get completely rid of those sorts of
        issues.
      
        Notice that all of these patches have been baking in linux-next for
        quite a while now and, 238 more of these patches have already been
        merged into 5.7-rc1.
      
        There are a couple hundred more of these issues waiting to be
        addressed in the whole codebase"
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      
      * tag 'flexible-array-member-5.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux: (28 commits)
        xattr.h: Replace zero-length array with flexible-array member
        uapi: linux: fiemap.h: Replace zero-length array with flexible-array member
        uapi: linux: dlm_device.h: Replace zero-length array with flexible-array member
        tpm_eventlog.h: Replace zero-length array with flexible-array member
        ti_wilink_st.h: Replace zero-length array with flexible-array member
        swap.h: Replace zero-length array with flexible-array member
        skbuff.h: Replace zero-length array with flexible-array member
        sched: topology.h: Replace zero-length array with flexible-array member
        rslib.h: Replace zero-length array with flexible-array member
        rio.h: Replace zero-length array with flexible-array member
        posix_acl.h: Replace zero-length array with flexible-array member
        platform_data: wilco-ec.h: Replace zero-length array with flexible-array member
        memcontrol.h: Replace zero-length array with flexible-array member
        list_lru.h: Replace zero-length array with flexible-array member
        lib: cpu_rmap: Replace zero-length array with flexible-array member
        irq.h: Replace zero-length array with flexible-array member
        ihex.h: Replace zero-length array with flexible-array member
        igmp.h: Replace zero-length array with flexible-array member
        genalloc.h: Replace zero-length array with flexible-array member
        ethtool.h: Replace zero-length array with flexible-array member
        ...
      13402837
  4. 18 Apr, 2020 11 commits
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · 50cc09c1
      Linus Torvalds authored
      Pull SCSI fixes from James Bottomley:
       "Seven fixes: three in target, one on a sg error leg, two in qla2xxx
        fixing warnings introduced in the last merge window and updating
        MAINTAINERS and one in hisi_sas fixing a problem introduced by libata"
      
      * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
        scsi: sg: add sg_remove_request in sg_common_write
        scsi: target: tcmu: reset_ring should reset TCMU_DEV_BIT_BROKEN
        scsi: target: fix PR IN / READ FULL STATUS for FC
        scsi: target: Write NULL to *port_nexus_ptr if no ISID
        scsi: MAINTAINERS: Update qla2xxx FC-SCSI driver maintainer
        scsi: qla2xxx: Fix regression warnings
        scsi: hisi_sas: Fix build error without SATA_HOST
      50cc09c1
    • Gustavo A. R. Silva's avatar
      xattr.h: Replace zero-length array with flexible-array member · 43951585
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      43951585
    • Gustavo A. R. Silva's avatar
      uapi: linux: fiemap.h: Replace zero-length array with flexible-array member · 6e88abb8
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      6e88abb8
    • Gustavo A. R. Silva's avatar
      uapi: linux: dlm_device.h: Replace zero-length array with flexible-array member · d6cdad87
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      d6cdad87
    • Gustavo A. R. Silva's avatar
      tpm_eventlog.h: Replace zero-length array with flexible-array member · 06ccf63d
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      06ccf63d
    • Gustavo A. R. Silva's avatar
      ti_wilink_st.h: Replace zero-length array with flexible-array member · 4ea19ecf
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      4ea19ecf
    • Gustavo A. R. Silva's avatar
      swap.h: Replace zero-length array with flexible-array member · 16c3380f
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      16c3380f
    • Gustavo A. R. Silva's avatar
      skbuff.h: Replace zero-length array with flexible-array member · 5c91aa1d
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      5c91aa1d
    • Gustavo A. R. Silva's avatar
      sched: topology.h: Replace zero-length array with flexible-array member · fe946db6
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      fe946db6
    • Gustavo A. R. Silva's avatar
      rslib.h: Replace zero-length array with flexible-array member · 9dd8bb5f
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      9dd8bb5f
    • Gustavo A. R. Silva's avatar
      rio.h: Replace zero-length array with flexible-array member · a1c4b924
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      a1c4b924