Eric Lee / smarc-fsl-linux-kernel

17 Nov, 2015

1 commit

03 Jul, 2013

1 commit

  • d50235b7b   elevator: Fix a race in elevator switching ... Browse Code »

    There's a race between elevator switching and normal io operation.
    Because the allocation of struct elevator_queue and struct elevator_data
    don't in a atomic operation.So there are have chance to use NULL
    ->elevator_data.
    For example:
    Thread A: Thread B
    blk_queu_bio elevator_switch
    spin_lock_irq(q->queue_block) elevator_alloc
    elv_merge elevator_init_fn

    Because call elevator_alloc, it can't hold queue_lock and the
    ->elevator_data is NULL.So at the same time, threadA call elv_merge and
    nedd some info of elevator_data.So the crash happened.

    Move the elevator_alloc into func elevator_init_fn, it make the
    operations in a atomic operation.

    Using the follow method can easy reproduce this bug
    1:dd if=/dev/sdb of=/dev/null
    2:while true;do echo noop > scheduler;echo deadline > scheduler;done

    The test method also use this method.

    Signed-off-by: Jianpeng Ma
    Signed-off-by: Jens Axboe

    Jianpeng Ma
     

07 Mar, 2012

1 commit

  • b2fab5acd   elevator: make elevator_init_fn() return 0/-errno ... Browse Code »

    elevator_ops->elevator_init_fn() has a weird return value. It returns
    a void * which the caller should assign to q->elevator->elevator_data
    and %NULL return denotes init failure.

    Update such that it returns integer 0/-errno and sets elevator_data
    directly as necessary.

    This makes the interface more conventional and eases further cleanup.

    Signed-off-by: Tejun Heo
    Cc: Vivek Goyal
    Signed-off-by: Jens Axboe

    Tejun Heo
     

14 Dec, 2011

1 commit

  • 3d3c2379f   block, cfq: move icq cache management to block core ... Browse Code »

    Let elevators set ->icq_size and ->icq_align in elevator_type and
    elv_register() and elv_unregister() respectively create and destroy
    kmem_cache for icq.

    * elv_register() now can return failure. All callers updated.

    * icq caches are automatically named "ELVNAME_io_cq".

    * cfq_slab_setup/kill() are collapsed into cfq_init/exit().

    * While at it, minor indentation change for iosched_cfq.elevator_name
    for consistency.

    This will help moving icq management to block core. This doesn't
    introduce any functional change.

    Signed-off-by: Tejun Heo
    Signed-off-by: Jens Axboe

    Tejun Heo
     

10 Mar, 2011

1 commit

  • 7eaceacca   block: remove per-queue plugging ... Browse Code »
    86

    Code has been converted over to the new explicit on-stack plugging,
    and delay users have been converted to use the new API for that.
    So lets kill off the old plugging along with aops->sync_page().

    Signed-off-by: Jens Axboe

    Jens Axboe
     

30 Mar, 2010

1 commit

  • 5a0e3ad6a   include cleanup: Update gfp.h and slab.h includes to prepare for breaking implic… ... Browse Code »

    …it slab.h inclusion from percpu.h

    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files. percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.

    percpu.h -> slab.h dependency is about to be removed. Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability. As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.

    http://userweb.kernel.org/~tj/misc/slabh-sweep.py

    The script does the followings.

    * Scan files for gfp and slab usages and update includes such that
    only the necessary includes are there. ie. if only gfp is used,
    gfp.h, if slab is used, slab.h.

    * When the script inserts a new include, it looks at the include
    blocks and try to put the new include such that its order conforms
    to its surrounding. It's put in the include block which contains
    core kernel includes, in the same order that the rest are ordered -
    alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
    doesn't seem to be any matching order.

    * If the script can't find a place to put a new include (mostly
    because the file doesn't have fitting include block), it prints out
    an error message indicating which .h file needs to be added to the
    file.

    The conversion was done in the following steps.

    1. The initial automatic conversion of all .c files updated slightly
    over 4000 files, deleting around 700 includes and adding ~480 gfp.h
    and ~3000 slab.h inclusions. The script emitted errors for ~400
    files.

    2. Each error was manually checked. Some didn't need the inclusion,
    some needed manual addition while adding it to implementation .h or
    embedding .c file was more appropriate for others. This step added
    inclusions to around 150 files.

    3. The script was run again and the output was compared to the edits
    from #2 to make sure no file was left behind.

    4. Several build tests were done and a couple of problems were fixed.
    e.g. lib/decompress_*.c used malloc/free() wrappers around slab
    APIs requiring slab.h to be added manually.

    5. The script was run on all .h files but without automatically
    editing them as sprinkling gfp.h and slab.h inclusions around .h
    files could easily lead to inclusion dependency hell. Most gfp.h
    inclusion directives were ignored as stuff from gfp.h was usually
    wildly available and often used in preprocessor macros. Each
    slab.h inclusion directive was examined and added manually as
    necessary.

    6. percpu.h was updated not to include slab.h.

    7. Build test were done on the following configurations and failures
    were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
    distributed build env didn't work with gcov compiles) and a few
    more options had to be turned off depending on archs to make things
    build (like ipr on powerpc/64 which failed due to missing writeq).

    * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
    * powerpc and powerpc64 SMP allmodconfig
    * sparc and sparc64 SMP allmodconfig
    * ia64 SMP allmodconfig
    * s390 SMP allmodconfig
    * alpha SMP allmodconfig
    * um on x86_64 SMP allmodconfig

    8. percpu.h modifications were reverted so that it could be applied as
    a separate patch and serve as bisection point.

    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

    Tejun Heo
     

29 Dec, 2008

1 commit

18 Dec, 2007

1 commit

24 Jul, 2007

1 commit

  • 165125e1e   [BLOCK] Get rid of request_queue_t typedef ... Browse Code »

    Some of the code has been gradually transitioned to using the proper
    struct request_queue, but there's lots left. So do a full sweet of
    the kernel and get rid of this typedef and replace its uses with
    the proper type.

    Signed-off-by: Jens Axboe

    Jens Axboe
     

01 Dec, 2006

1 commit

01 Oct, 2006

1 commit

09 Jun, 2006

1 commit

  • bc1c11697   [PATCH] elevator switching race ... Browse Code »

    There's a race between shutting down one io scheduler and firing up the
    next, in which a new io could enter and cause the io scheduler to be
    invoked with bad or NULL data.

    To fix this, we need to maintain the queue lock for a bit longer.
    Unfortunately we cannot do that, since the elevator init requires to be
    run without the lock held. This isn't easily fixable, without also
    changing the mempool API. So split the initialization into two parts,
    and alloc-init operation and an attach operation. Then we can
    preallocate the io scheduler and related structures, and run the attach
    inside the lock after we detach the old one.

    This patch has survived 30 minutes of 1 second io scheduler switching
    with a very busy io load.

    Signed-off-by: Jens Axboe
    Signed-off-by: Linus Torvalds

    Jens Axboe
     

12 Nov, 2005

1 commit

  • 5a7c47eef   [BLOCK] noop-iosched: reimplementation of request dispatching ... Browse Code »

    The original implementation directly used dispatch queue. As new
    generic dispatch queue imposes stricter rules over ioscheds and
    dispatch queue usage, this direct use becomes somewhat problematic.
    This patch reimplements noop-iosched such that it complies to generic
    iosched model better. Request merging with q->last_merge and
    rq->queuelist.prev/next work again now.

    Signed-off-by: Tejun Heo
    Signed-off-by: Jens Axboe <axboe@suse.de

    Tejun Heo
     

04 Nov, 2005

1 commit