linux-toradex.git/drivers/block, branch v3.5.2

virtio-blk: Use block layer provided spinlock

2012-08-15T14:52:30+00:00

commit 2c95a3290919541b846bee3e0fbaa75860929f53 upstream.

Block layer will allocate a spinlock for the queue if the driver does
not provide one in blk_init_queue().

The reason to use the internal spinlock is that blk_cleanup_queue() will
switch to use the internal spinlock in the cleanup code path.

        if (q->queue_lock != &q->__queue_lock)
                q->queue_lock = &q->__queue_lock;

However, processes which are in D state might have taken the driver
provided spinlock, when the processes wake up, they would release the
block provided spinlock.

=====================================
[ BUG: bad unlock balance detected! ]
3.4.0-rc7+ #238 Not tainted
-------------------------------------
fio/3587 is trying to release lock (&(&q->__queue_lock)->rlock) at:
[] blk_queue_bio+0x2a2/0x380
but there are no more locks to release!

other info that might help us debug this:
1 lock held by fio/3587:
 #0:  (&(&vblk->lock)->rlock){......}, at:
[] get_request_wait+0x19a/0x250

Other drivers use block layer provided spinlock as well, e.g. SCSI.

Switching to the block layer provided spinlock saves a bit of memory and
does not increase lock contention. Performance test shows no real
difference is observed before and after this patch.

Changes in v2: Improve commit log as Michael suggested.

Signed-off-by: Asias He 
Cc: virtualization@lists.linux-foundation.org
Cc: kvm@vger.kernel.org
Acked-by: Michael S. Tsirkin 
Signed-off-by: Rusty Russell 
Signed-off-by: Greg Kroah-Hartman

virtio-blk: Reset device after blk_cleanup_queue()

2012-08-15T14:52:30+00:00

commit 483001c765af6892b3fc3726576cb42f17d1d6b5 upstream.

blk_cleanup_queue() will call blk_drian_queue() to drain all the
requests before queue DEAD marking. If we reset the device before
blk_cleanup_queue() the drain would fail.

1) if the queue is stopped in do_virtblk_request() because device is
full, the q->request_fn() will not be called.

blk_drain_queue() {
   while(true) {
      ...
      if (!list_empty(&q->queue_head))
        __blk_run_queue(q) {
	    if (queue is not stoped)
		q->request_fn()
	}
      ...
   }
}

Do no reset the device before blk_cleanup_queue() gives the chance to
start the queue in interrupt handler blk_done().

2) In commit b79d866c8b7014a51f611a64c40546109beaf24a, We abort requests
dispatched to driver before blk_cleanup_queue(). There is a race if
requests are dispatched to driver after the abort and before the queue
DEAD mark. To fix this, instead of aborting the requests explicitly, we
can just reset the device after after blk_cleanup_queue so that the
device can complete all the requests before queue DEAD marking in the
drain process.

Signed-off-by: Asias He 
Cc: Rusty Russell 
Cc: virtualization@lists.linux-foundation.org
Cc: kvm@vger.kernel.org
Acked-by: Michael S. Tsirkin 
Signed-off-by: Rusty Russell 
Signed-off-by: Greg Kroah-Hartman

virtio-blk: Call del_gendisk() before disable guest kick

2012-08-15T14:52:30+00:00

commit 02e2b124943648fba0a2ccee5c3656a5653e0151 upstream.

del_gendisk() might not return due to failing to remove the
/sys/block/vda/serial sysfs entry when another thread (udev) is
trying to read it.

virtblk_remove()
  vdev->config->reset() : guest will not kick us through interrupt
    del_gendisk()
      device_del()
        kobject_del(): got stuck, sysfs entry ref count non zero

sysfs_open_file(): user space process read /sys/block/vda/serial
   sysfs_get_active() : got sysfs entry ref count
      dev_attr_show()
        virtblk_serial_show()
           blk_execute_rq() : got stuck, interrupt is disabled
                              request cannot be finished

This patch fixes it by calling del_gendisk() before we disable guest's
interrupt so that the request sent in virtblk_serial_show() will be
finished and del_gendisk() will success.

This fixes another race in hot-unplug process.

It is save to call del_gendisk(vblk->disk) before
flush_work(&vblk->config_work) which might access vblk->disk, because
vblk->disk is not freed until put_disk(vblk->disk).

Signed-off-by: Asias He 
Cc: virtualization@lists.linux-foundation.org
Cc: kvm@vger.kernel.org
Acked-by: Michael S. Tsirkin 
Signed-off-by: Rusty Russell 
Signed-off-by: Greg Kroah-Hartman

rbd: endian bug in rbd_req_cb()

2012-07-18T04:30:31+00:00

Sparse complains about this because:
drivers/block/rbd.c:996:20: warning: cast to restricted __le32
drivers/block/rbd.c:996:20: warning: cast from restricted __le16

These are set in osd_req_encode_op() and they are le16.

Signed-off-by: Dan Carpenter 
Reviewed-by: Alex Elder 
(cherry picked from commit 895cfcc810e53d7d36639969c71efb9087221167)

rbd: Fix ceph_snap_context size calculation

2012-07-18T04:30:19+00:00

ceph_snap_context->snaps is an u64 array

Signed-off-by: Zheng Yan 
Reviewed-by: Alex Elder 
(cherry picked from commit f9f9a1904467816452fc70740165030e84c2c659)

blk: fix wrong idr_pre_get() error check in loop.c

2012-07-14T22:39:58+00:00

The idr_pre_get() function never returns a value < 0.  It returns 0 (no
memory) or 1 (OK).

Reported-by: Silva Paulo 
[ Rewrote Silva's patch, but attributing it to Silva anyway  - Linus ]
Signed-off-by: Linus Torvalds

floppy: cancel any pending fd_timeouts before adding a new one

2012-07-03T22:51:22+00:00

In commit 070ad7e793dc ("floppy: convert to delayed work and
single-thread wq") the 'fd_timeout' timer was converted to a delayed
work.  However, the "del_timer(&fd_timeout)" was lost in the process,
and any previous pending timeouts would stay active when we then
re-queued the timeout.

This resulted in the floppy probe sequence having a (stale) 20s timeout
rather than the intended 3s timeout, and thus made booting with the
floppy driver (but no actual floppy controller) take much longer than it
should.

Of course, there's little reason for most people to compile the floppy
driver into the kernel at all, which is why most people never noticed.

Canceling the delayed work where we used to do the del_timer() fixes the
issue, and makes the floppy probing use the proper new timeout instead.
The three second timeout is still very wasteful, but better than the 20s
one.

Reported-and-tested-by: Andi Kleen 
Reported-and-tested-by: Calvin Walton 
Cc: Jiri Kosina 
Signed-off-by: Linus Torvalds

Merge branch 'for-jens' of git://git.drbd.org/linux-drbd into for-linus

2012-06-13T19:19:42+00:00

Merge branch 'stable/for-jens-3.5' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-linus

2012-06-13T19:19:06+00:00

umem: fix up unplugging

2012-06-13T19:17:21+00:00

Fix a regression introduced by 7eaceaccab5f40 ("block: remove per-queue
plugging").  In that patch, Jens removed the whole mm_unplug_device()
function, which used to be the trigger to make umem start to work.

We need to implement unplugging to make umem start to work, or I/O will
never be triggered.

Signed-off-by: Tao Guo 
Cc: Neil Brown 
Cc: Jens Axboe 
Cc: Shaohua Li 
Cc: 
Acked-by: NeilBrown 
Signed-off-by: Jens Axboe