xen/blkback: Copy id field when doing BLKIF_DISCARD.

We weren't copying the id field so when we sent the response
back to the frontend (especially with a 64-bit host and 32-bit
guest), we ended up using a random value. This lead to the
frontend crashing as it would try to pass to __blk_end_request_all
a NULL 'struct request' (b/c it would use the 'id' to find the
proper 'struct request' in its shadow array) and end up crashing:

BUG: unable to handle kernel NULL pointer dereference at 000000e4
IP: [<c0646d4c>] __blk_end_request_all+0xc/0x40
.. snip..
EIP is at __blk_end_request_all+0xc/0x40
.. snip..
 [<ed95db72>] blkif_interrupt+0x172/0x330 [xen_blkfront]

This fixes the bug by passing in the proper id for the response.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=824641

CC: stable@kernel.org
Tested-by: William Dauchy <wdauchy@gmail.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
mtip32xx: Remove version.h header file inclusion

version.h header file inclusion is no longer required.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
block: fix return value on cfq_init() failure

cfq_init() would return zero after kmem cache creation failure.  Fix
so that it returns -ENOMEM.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block: blkcg_policy_cfq shouldn't be used if !CONFIG_CFQ_GROUP_IOSCHED

cfq may be built w/ or w/o blkcg support depending on
CONFIG_CFQ_CGROUP_IOSCHED.  If blkcg support is disabled, most of
related code is ifdef'd out but some part is left dangling -
blkcg_policy_cfq is left zero-filled and blkcg_policy_[un]register()
calls are made on it.

Feeding zero filled policy to blkcg_policy_register() is incorrect and
triggers the following WARN_ON() if CONFIG_BLK_CGROUP &&
!CONFIG_CFQ_GROUP_IOSCHED.

 ------------[ cut here ]------------
 WARNING: at block/blk-cgroup.c:867
 Modules linked in:
 Modules linked in:
 CPU: 3 Not tainted 3.4.0-09547-gfb21aff #1
 Process swapper/0 (pid: 1, task: 000000003ff80000, ksp: 000000003ff7f8b8)
 Krnl PSW : 0704100180000000 00000000003d76ca (blkcg_policy_register+0xca/0xe0)
	    R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:1 PM:0 EA:3
 Krnl GPRS: 0000000000000000 00000000014b85ec 00000000014b85b0 0000000000000000
	    000000000096fb60 0000000000000000 00000000009a8e78 0000000000000048
	    000000000099c070 0000000000b6f000 0000000000000000 000000000099c0b8
	    00000000014b85b0 0000000000667580 000000003ff7fd98 000000003ff7fd70
 Krnl Code: 00000000003d76be: a7280001           lhi     %r2,1
	    00000000003d76c2: a7f4ffdf           brc     15,3d7680
	   #00000000003d76c6: a7f40001           brc     15,3d76c8
	   >00000000003d76ca: a7c8ffea           lhi     %r12,-22
	    00000000003d76ce: a7f4ffce           brc     15,3d766a
	    00000000003d76d2: a7f40001           brc     15,3d76d4
	    00000000003d76d6: a7c80000           lhi     %r12,0
	    00000000003d76da: a7f4ffc2           brc     15,3d765e
 Call Trace:
 ([<0000000000b6f000>] initcall_debug+0x0/0x4)
  [<0000000000989e8a>] cfq_init+0x62/0xd4
  [<00000000001000ba>] do_one_initcall+0x3a/0x170
  [<000000000096fb60>] kernel_init+0x214/0x2bc
  [<0000000000623202>] kernel_thread_starter+0x6/0xc
  [<00000000006231fc>] kernel_thread_starter+0x0/0xc
 no locks held by swapper/0/1.
 Last Breaking-Event-Address:
  [<00000000003d76c6>] blkcg_policy_register+0xc6/0xe0
 ---[ end trace b8ef4903fcbf9dd3 ]---

This patch fixes the problem by ensuring all blkcg support code is
inside CONFIG_CFQ_GROUP_IOSCHED.

* blkcg_policy_cfq declaration and blkg_to_cfqg() definition are moved
  inside the first CONFIG_CFQ_GROUP_IOSCHED block.  __maybe_unused is
  dropped from blkcg_policy_cfq decl.

* blkcg_deactivate_poilcy() invocation is moved inside ifdef.  This
  also makes the activation logic match cfq_init_queue().

* All blkcg_policy_[un]register() invocations are moved inside ifdef.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
LKML-Reference: <20120601112954.GC3535@osiris.boeblingen.de.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blkcg: fix blkg_alloc() failure path

When policy data allocation fails in the middle, blkg_alloc() invokes
blkg_free() to destroy the half constructed blkg.  This ends up
calling pd_exit_fn() on policy datas which didn't go through
pd_init_fn().  Fix it by making blkg_alloc() call pd_init_fn()
immediately after each policy data allocation.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
mtip32xx: Remove 'registers' and 'flags' from sysfs

This patch removes entries 'registers' and 'flags' from sysfs. Updated ABI file
to reflect this change.

Reported-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
mtip32xx: Create debugfs entries for troubleshooting

On module load, creates a debugfs parent 'rssd' in debugfs root. Then for each
device, create a new node with corresponding disk name. Under the new node, two
entries 'registers' and 'flags' are created.

NOTE: These entries were removed from sysfs in the previous patch

Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blkcg: drop local variable @q from blkg_destroy()

blkg_destroy() caches @blkg->q in local variable @q.  While there are
two places which needs @blkg->q, only lockdep_assert_held() used the
local variable leading to unused local variable warning if lockdep is
configured out.  Drop the local variable and just use @blkg->q
directly.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Rakesh Iyer <rni@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
xen/blkfront: Add WARN to deal with misbehaving backends.

Part of the ring structure is the 'id' field which is under
control of the frontend. The frontend stamps it with "some"
value (this some in this implementation being a value less
than BLK_RING_SIZE), and when it gets a response expects
said value to be in the response structure. We have a check
for the id field when spolling new requests but not when
de-spolling responses.

We also add an extra check in add_id_to_freelist to make
sure that the 'struct request' was not NULL - as we cannot
pass a NULL to __blk_end_request_all, otherwise that crashes
(and all the operations that the response is dealing with
end up with __blk_end_request_all).

Lastly we also print the name of the operation that failed.

[v1: s/BUG/WARN/ suggested by Stefano]
[v2: Add extra check in add_id_to_freelist]
[v3: Redid op_name per Jan's suggestion]
[v4: add const * and add WARN on failure returns]
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
drbd: fix access of unallocated pages and kernel panic

BUG: unable to handle kernel NULL pointer dereference at (null)
...
 [<d1e17561>] ? _drbd_bm_set_bits+0x151/0x240 [drbd]
 [<d1e236f8>] ? receive_bitmap+0x4f8/0xbc0 [drbd]

This fixes an off-by-one error in the receive_bitmap() path,
if run-length encoded bitmap transfer is enabled.

If the bitmap is an exact multiple of PAGE_SIZE, which means the visible
capacity of the drbd device is an exact multiple of 128 MiB (for 4k page
size), and bitmap compression (use-rle) is enabled (which became default
with 8.4), and the very last bit is dirty and reported in an rle
comressed bitmap packet, we ended up trying to kmap_atomic a page pointer
that does not exist (bitmap->bm_pages[last index + 1]).

bug introduced by:
    Date:   Fri Jul 24 15:33:24 2009 +0200
    set bits: optimize for complete last word, fix off-by-one-word corner case

made effective by:
    Date:   Thu Dec 16 00:32:38 2010 +0100
    drbd: get rid of unused debug code

    Long time ago, we had paranoia code in the bitmap that allocated one
    extra word, assigned a magic value, and checked on every occasion that
    the magic value was still unchanged.

    That debug code is unused, the extra long word complicates code a bit.
    Get rid of it.

No-one triggered this bug in the last few years, because a large subset
of our userbase is unaffected:
 * typically the last few blocks of a device are not modified
   frequently, and remain unset
 * use-rle was disabled by default in drbd < 8.4
 * those with slightly "odd" device sizes, or
 * drbd internal meta data (which will skew the device size slightly,
   thus makes it harder to have a bug relevant device size)

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
drbd: fix list corruption by failing but already aborted reads

If a read is aborted due to force-detach of a supposedly unresponsive
local backing device, and retried on the peer, it can happen that the
local request later still completes (hopefully with an error).
As it may already have been completed to upper layers meanwhile,
it must not be retried again now.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
drbd: fix null pointer dereference with on-congestion policy when diskless

We must not look at mdev->actlog, unless we have a get_ldev() reference.
It also does not make much sense to try to disconnect or pull-ahead of
the peer, if we don't have good local data.

Only even consider congestion policies, if our local disk is D_UP_TO_DATE.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
splice: fix racy pipe->buffers uses

Dave Jones reported a kernel BUG at mm/slub.c:3474! triggered
by splice_shrink_spd() called from vmsplice_to_pipe()

commit 35f3d14dbbc5 (pipe: add support for shrinking and growing pipes)
added capability to adjust pipe->buffers.

Problem is some paths don't hold pipe mutex and assume pipe->buffers
doesn't change for their duration.

Fix this by adding nr_pages_max field in struct splice_pipe_desc, and
use it in place of pipe->buffers where appropriate.

splice_shrink_spd() loses its struct pipe_inode_info argument.

Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Tom Herbert <therbert@google.com>
Cc: stable <stable@vger.kernel.org> # 2.6.35
Tested-by: Dave Jones <davej@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
umem: fix up unplugging

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 <Tao.Guo@emc.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Shaohua Li <shli@kernel.org>
Cc: <stable@vger.kernel.org>
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Merge branch 'stable/for-jens-3.5' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-linus
Merge branch 'for-jens' of git://git.drbd.org/linux-drbd into for-linus
block: Avoid missed wakeup in request waitqueue

After hot-unplug a stressed disk, I found that rl->wait[] is not empty
while rl->count[] is empty and there are theads still sleeping on
get_request after the queue cleanup. With simple debug code, I found
there are exactly nr_sleep - nr_wakeup of theads in D state. So there
are missed wakeup.

  $ dmesg | grep nr_sleep
  [   52.917115] ---> nr_sleep=1046, nr_wakeup=873, delta=173
  $ vmstat 1
  1 173  0 712640  24292  96172 0 0  0  0  419  757  0  0  0 100  0

To quote Tejun:

  Ah, okay, freed_request() wakes up single waiter with the assumption
  that after the wakeup there will at least be one successful allocation
  which in turn will continue the wakeup chain until the wait list is
  empty - ie. waiter wakeup is dependent on successful request
  allocation happening after each wakeup.  With queue marked dead, any
  woken up waiter fails the allocation path, so the wakeup chaining is
  lost and we're left with hung waiters. What we need is wake_up_all()
  after drain completion.

This patch fixes the missed wakeup by waking up all the theads which
are sleeping on wait queue after queue drain.

Changes in v2: Drop waitqueue_active() optimization

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Asias He <asias@redhat.com>

Fixed a bug by me, where stacked devices would oops on calling
blk_drain_queue() since ->rq.wait[] do not get initialized unless
it's a full queue setup.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
block: Mitigate lock unbalance caused by lock switching

Commit 777eb1bf15b8532c396821774bf6451e563438f5 disconnects externally
supplied queue_lock before blk_drain_queue(). Switching the lock would
introduce lock unbalance because theads which have taken the external
lock might unlock the internal lock in the during the queue drain. This
patch mitigate this by disconnecting the lock after the queue draining
since queue draining makes a lot of request_queue users go away.

However, please note, this patch only makes the problem less likely to
happen. Anyone who still holds a ref might try to issue a new request on
a dead queue after the blk_cleanup_queue() finishes draining, the lock
unbalance might still happen in this case.

 =====================================
 [ BUG: bad unlock balance detected! ]
 3.4.0+ #288 Not tainted
 -------------------------------------
 fio/17706 is trying to release lock (&(&q->__queue_lock)->rlock) at:
 [<ffffffff81329372>] 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/17706:
  #0:  (&(&vblk->lock)->rlock){......}, at: [<ffffffff81327f1a>]
 get_request_wait+0x19a/0x250

 stack backtrace:
 Pid: 17706, comm: fio Not tainted 3.4.0+ #288
 Call Trace:
  [<ffffffff81329372>] ? blk_queue_bio+0x2a2/0x380
  [<ffffffff810dea49>] print_unlock_inbalance_bug+0xf9/0x100
  [<ffffffff810dfe4f>] lock_release_non_nested+0x1df/0x330
  [<ffffffff811dae24>] ? dio_bio_end_aio+0x34/0xc0
  [<ffffffff811d6935>] ? bio_check_pages_dirty+0x85/0xe0
  [<ffffffff811daea1>] ? dio_bio_end_aio+0xb1/0xc0
  [<ffffffff81329372>] ? blk_queue_bio+0x2a2/0x380
  [<ffffffff81329372>] ? blk_queue_bio+0x2a2/0x380
  [<ffffffff810e0079>] lock_release+0xd9/0x250
  [<ffffffff81a74553>] _raw_spin_unlock_irq+0x23/0x40
  [<ffffffff81329372>] blk_queue_bio+0x2a2/0x380
  [<ffffffff81328faa>] generic_make_request+0xca/0x100
  [<ffffffff81329056>] submit_bio+0x76/0xf0
  [<ffffffff8115470c>] ? set_page_dirty_lock+0x3c/0x60
  [<ffffffff811d69e1>] ? bio_set_pages_dirty+0x51/0x70
  [<ffffffff811dd1a8>] do_blockdev_direct_IO+0xbf8/0xee0
  [<ffffffff811d8620>] ? blkdev_get_block+0x80/0x80
  [<ffffffff811dd4e5>] __blockdev_direct_IO+0x55/0x60
  [<ffffffff811d8620>] ? blkdev_get_block+0x80/0x80
  [<ffffffff811d92e7>] blkdev_direct_IO+0x57/0x60
  [<ffffffff811d8620>] ? blkdev_get_block+0x80/0x80
  [<ffffffff8114c6ae>] generic_file_aio_read+0x70e/0x760
  [<ffffffff810df7c5>] ? __lock_acquire+0x215/0x5a0
  [<ffffffff811e9924>] ? aio_run_iocb+0x54/0x1a0
  [<ffffffff8114bfa0>] ? grab_cache_page_nowait+0xc0/0xc0
  [<ffffffff811e82cc>] aio_rw_vect_retry+0x7c/0x1e0
  [<ffffffff811e8250>] ? aio_fsync+0x30/0x30
  [<ffffffff811e9936>] aio_run_iocb+0x66/0x1a0
  [<ffffffff811ea9b0>] do_io_submit+0x6f0/0xb80
  [<ffffffff8134de2e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
  [<ffffffff811eae50>] sys_io_submit+0x10/0x20
  [<ffffffff81a7c9e9>] system_call_fastpath+0x16/0x1b

Changes since v2: Update commit log to explain how the code is still
                  broken even if we delay the lock switching after the drain.
Changes since v1: Update commit log as Tejun suggested.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block: Drop dead function blk_abort_queue()

This function was only used by btrfs code in btrfs_abort_devices()
(seems in a wrong way).

It was removed in commit d07eb9117050c9ed3f78296ebcc06128b52693be,
So, Let's remove the dead code to avoid any confusion.

Changes in v2: update commit log, btrfs_abort_devices() was removed
already.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-kernel@vger.kernel.org
Cc: Chris Mason <chris.mason@oracle.com>
Cc: linux-btrfs@vger.kernel.org
Cc: David Sterba <dave@jikos.cz>
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
scsi: Silence unnecessary warnings about ioctl to partition

Sometimes, warnings about ioctls to partition happen often enough that they
form majority of the warnings in the kernel log and users complain. In some
cases warnings are about ioctls such as SG_IO so it's not good to get rid of
the warnings completely as they can ease debugging of userspace problems
when ioctl is refused.

Since I have seen warnings from lots of commands, including some proprietary
userspace applications, I don't think disallowing the ioctls for processes
with CAP_SYS_RAWIO will happen in the near future if ever. So lets just
stop warning for processes with CAP_SYS_RAWIO for which ioctl is allowed.

CC: Paolo Bonzini <pbonzini@redhat.com>
CC: James Bottomley <JBottomley@parallels.com>
CC: linux-scsi@vger.kernel.org
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>