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455659 commits

Author SHA1 Message Date
Lars Ellenberg e334f55095 drbd: make sure disk cleanup happens in worker context
The recent fix to put_ldev() (correct ordering of access to local_cnt
and state.disk; memory barrier in __drbd_set_state) guarantees
that the cleanup happens exactly once.

However it does not yet guarantee that the cleanup happens from worker
context, the last put_ldev() may still happen from atomic context,
which must not happen: blkdev_put() may sleep.

Fix this by scheduling the cleanup to the worker instead,
using a couple more bits in device->flags and a new helper,
drbd_device_post_work().

Generalized the "resync progress" work to cover these new work bits.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 18:34:55 +02:00
Lars Ellenberg ba3c6fb87d drbd: close race when detaching from disk
BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
IP: bd_release+0x21/0x70
Process drbd_w_t7146
Call Trace:
 close_bdev_exclusive
 drbd_free_ldev		[drbd]
 drbd_ldev_destroy	[drbd]
 w_after_state_ch	[drbd]

Race probably went like this:
  state.disk = D_FAILED

... first one to hit zero during D_FAILED:
   put_ldev() /* ----------------> 0 */
     i = atomic_dec_return()
     if (i == 0)
       if (state.disk == D_FAILED)
         schedule_work(go_diskless)
                                /* 1 <------ */ get_ldev_if_state()
   go_diskless()
      do_some_pre_cleanup()                     corresponding put_ldev():
      force_state(D_DISKLESS)   /* 0 <------ */ i = atomic_dec_return()
                                                if (i == 0)
        atomic_inc() /* ---------> 1 */
        state.disk = D_DISKLESS
        schedule_work(after_state_ch)           /* execution pre-empted by IRQ ? */

   after_state_ch()
     put_ldev()
       i = atomic_dec_return()  /* 0 */
       if (i == 0)
         if (state.disk == D_DISKLESS)            if (state.disk == D_DISKLESS)
           drbd_ldev_destroy()                      drbd_ldev_destroy();

Trying to fix this by checking the disk state *before* the
atomic_dec_return(), which implies memory barriers, and by inserting
extra memory barriers around the state assignment in __drbd_set_state().

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 18:34:54 +02:00
Lars Ellenberg 2ed912e9d3 drbd: explicitly submit meta data requests with REQ_NOIDLE
For some reason we have assumed NOIDLE was implied
by one of the other flags we set. It is not (anymore?).
Explicitly set REQ_NOIDLE for synchronous meta data updates,
or we can seriously starve random writes when using CFQ.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 18:34:54 +02:00
Lars Ellenberg 720979fb90 drbd: move set_disk_ro() to after we persisted the new role
This probably does not have any real life impact,
but we should first persist any potentially new UUID
and other meta data flags, as well as our new role,
before we allow/disallow write access.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 18:34:53 +02:00
Lars Ellenberg 123ff122ad drbd: trigger tcp_push_pending_frames() for PING and PING_ACK
This should reduce latency for such in-DRBD-protocol "pings",
and may help reduce spurious disconnect/reconnect cycles due to
 "PingAck did not arrive in time."

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 18:34:52 +02:00
Lars Ellenberg 66ce6dbce2 drbd: re-add lost conf_mutex protection in drbd_set_role
The conf_update mutex used to be held while clearing the
net_conf->discard_my_data flag inside drbd_set_role.

It was moved into drbd_adm_set_role with
    drbd: allow parallel promote/demote actions
but then replaced at that location by the newly introduced adm_mutex with
    drbd: Fix a potential deadlock in drbdsetup, introduce resource->adm_mutex

And I simply forgot to put it back in at the original location.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 18:34:52 +02:00
Lars Ellenberg fcb096740a drbd: stop the meta data sync timer before open coded meta data sync
If we re-write all meta data due to resize, we have open-coded write-out
of our meta data super block. Stop the md_sync_timer, it would just
trigger scary but in this case spurious "timer expired" messages.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 18:34:51 +02:00
Lars Ellenberg 5ab7d2c005 drbd: fix resync finished detection
This fixes one recent regresion,
and one long existing bug.

The bug:
drbd_try_clear_on_disk_bm() assumed that all "count" bits have to be
accounted in the resync extent corresponding to the start sector.

Since we allow application requests to cross our "extent" boundaries,
this assumption is no longer true, resulting in possible misaccounting,
scary messages
("BAD! sector=12345s enr=6 rs_left=-7 rs_failed=0 count=58 cstate=..."),
and potentially, if the last bit to be cleared during resync would
reside in previously misaccounted resync extent, the resync would never
be recognized as finished, but would be "stalled" forever, even though
all blocks are in sync again and all bits have been cleared...

The regression was introduced by
    drbd: get rid of atomic update on disk bitmap works

For an "empty" resync (rs_total == 0), we must not "finish" the
resync on the SyncSource before the SyncTarget knows all relevant
information (sync uuid).  We need to wait for the full round-trip,
the SyncTarget will then explicitly notify us.

Also for normal, non-empty resyncs (rs_total > 0), the resync-finished
condition needs to be tested before the schedule() in wait_for_work, or
it is likely to be missed.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 18:34:50 +02:00
Lars Ellenberg a80ca1ae81 drbd: fix a race stopping the worker thread
We may implicitly call drbd_send() from inside wait_for_work(),
via maybe_send_barrier().

If the "stop" signal was send just before that, drbd_send() would call
flush_signals(), and we would run an unbounded schedule() afterwards.

Fix: check for thread_state == RUNNING before we schedule()

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 18:34:50 +02:00
Lars Ellenberg c7a58db4e9 drbd: get rid of atomic update on disk bitmap works
Just trigger the occasional lazy bitmap write-out during resync
from the central wait_for_work() helper.

Previously, during resync, bitmap pages would be written out separately,
synchronously, one at a time, at least 8 times each (every 512 bytes
worth of bitmap cleared).

Now we trigger "merge friendly" bulk write out of all cleared pages
every two seconds during resync, and once the resync is finished.
Most pages will be written out only once.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 18:34:49 +02:00
Lars Ellenberg 70df70927b drbd: allow write-ordering policy to be bumped up again
Previously, once you disabled flushes as a means of enforcing
write-ordering, you'd need to detach/re-attach to enable them again.

Allow drbdsetup disk-options to re-enable previously disabled
write-ordering policy options at runtime.

While at it fix RCU in drbd_bump_write_ordering()
max_allowed_wo() uses rcu_dereference, therefore it must
be called within rcu_read_lock()/rcu_read_unlock()

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 15:22:22 +02:00
Lars Ellenberg 44a4d55184 drbd: refactor use of first_peer_device()
Reduce the number of calls to first_peer_device(). Instead, call
first_peer_device() just once to assign a local variable peer_device.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 15:22:22 +02:00
Lars Ellenberg 35b5ed5bba drbd: reduce number of spinlock drop/re-aquire cycles
Instead of dropping and re-aquiring the spinlock around the submit,
just remember that we want to submit, and do that only once we have
dropped the spinlock for good.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 15:22:21 +02:00
Philipp Reisner 28995af5cf drbd: rename drbd_free_bc() to drbd_free_ldev()
Since the member of drbd_device is called ldev

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 15:22:21 +02:00
Philipp Reisner 8fe39aac05 drbd: device->ldev is not guaranteed on an D_ATTACHING disk
Some parts of the code assumed that get_ldev_if_state(device, D_ATTACHING)
is sufficient to access the ldev member of the device object. That was
wrong. ldev may not be there or might be freed at any time if the device
has a disk state of D_ATTACHING.

bm_rw()
  Documented that drbd_bm_read() is only called from drbd_adm_attach.
  drbd_bm_write() is only called when a reference is held, and it is
  documented that a caller has to hold a reference before calling
  drbd_bm_write()

drbd_bm_write_page()
  Use get_ldev() instead of get_ldev_if_state(device, D_ATTACHING)

drbd_bmio_set_n_write()
  No longer use get_ldev_if_state(device, D_ATTACHING). All callers
  hold a reference to ldev now.

drbd_bmio_clear_n_write()
  All callers where holding a reference of ldev anyways. Remove the
  misleading get_ldev_if_state(device, D_ATTACHING)

drbd_reconsider_max_bio_size()
  Removed the get_ldev_if_state(device, D_ATTACHING). All callers
  now pass a struct drbd_backing_dev* when they have a proper
  reference, or a NULL pointer.
  Before this fix, the receiver could trigger a NULL pointer
  deref when in drbd_reconsider_max_bio_size()

drbd_bump_write_ordering()
  Used get_ldev_if_state(device, D_ATTACHING) with the wrong assumption.
  Remove it, and allow the caller to pass in a struct drbd_backing_dev*
  when the caller knows that accessing this bdev is safe.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 15:22:20 +02:00
Philipp Reisner e952658020 drbd: Move write_ordering from connection to resource
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10 15:22:19 +02:00
Ming Lei 6a27b656fc block: virtio-blk: support multi virt queues per virtio-blk device
Firstly this patch supports more than one virtual queues for virtio-blk
device.

Secondly this patch maps the virtual queue to blk-mq's hardware queue.

With this approach, both scalability and performance can be improved.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-01 10:51:03 -06:00
Ming Lei cb553215d5 include/uapi/linux/virtio_blk.h: introduce feature of VIRTIO_BLK_F_MQ
Current virtio-blk spec only supports one virtual queue for transfering
data between VM and host, and inside VM all kinds of operations on
the virtual queue needs to hold one lock, so cause below problems:

	- bad scalability
	- bad throughput

This patch requests to introduce feature of VIRTIO_BLK_F_MQ
so that more than one virtual queues can be used to virtio-blk
device, then above problems can be solved or eased.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-01 10:51:01 -06:00
Douglas Gilbert d15156138d block SG_IO: add SG_FLAG_Q_AT_HEAD flag
After the SG_IO ioctl was copied into the block layer and
later into the bsg driver, subtle differences emerged.

One difference is the way injected commands are queued through
the block layer (i.e. this is not SCSI device queueing nor SATA
NCQ). Summarizing:
  - SG_IO on block layer device: blk_exec*(at_head=false)
  - sg device SG_IO: at_head=true
  - bsg device SG_IO: at_head=true

Some time ago Boaz Harrosh introduced a sg v4 flag called
BSG_FLAG_Q_AT_TAIL to override the bsg driver default. A
recent patch titled: "sg: add SG_FLAG_Q_AT_TAIL flag"
allowed the sg driver default to be overridden. This patch
allows a SG_IO ioctl sent to a block layer device to have
its default overridden.

ChangeLog:
    - introduce SG_FLAG_Q_AT_HEAD flag in sg.h to cause
      commands that are injected via a block layer
      device SG_IO ioctl to set at_head=true
    - make comments clearer about queueing in sg.h since the
      header is used both by the sg device and block layer
      device implementations of the SG_IO ioctl.
    - introduce BSG_FLAG_Q_AT_HEAD in bsg.h for compatibility
      (it does nothing) and update comments.

Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-01 10:48:05 -06:00
Akinobu Mita 9b4231bf99 block: fix SG_[GS]ET_RESERVED_SIZE ioctl when max_sectors is huge
SG_GET_RESERVED_SIZE and SG_SET_RESERVED_SIZE ioctls access a reserved
buffer in bytes as int type.  The value needs to be capped at the request
queue's max_sectors.  But integer overflow is not correctly handled in
the calculation when converting max_sectors from sectors to bytes.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: linux-scsi@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-01 10:43:09 -06:00
Akinobu Mita 63f2649659 block: fix BLKSECTGET ioctl when max_sectors is greater than USHRT_MAX
BLKSECTGET ioctl loads the request queue's max_sectors as unsigned
short value to the argument pointer.  So if the max_sector is greater
than USHRT_MAX, the upper 16 bits of that is just discarded.

In such case, USHRT_MAX is more preferable than the lower 16 bits of
max_sectors.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: linux-scsi@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-01 10:43:07 -06:00
Fabian Frederick 16e1556526 block/partitions/efi.c: kerneldoc fixing
Adding function documentation and fixing kerneldoc warnings
('field: description' uniformization).

Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-01 10:40:05 -06:00
Fabian Frederick dce14c239a block/partitions/msdos.c: code clean-up
checkpatch fixing:
WARNING: Missing a blank line after declarations
WARNING: space prohibited between function name and open parenthesis '('
ERROR: spaces required around that '<' (ctx:VxV)

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-01 10:40:03 -06:00
Fabian Frederick 600ffc5ead block/partitions/amiga.c: replace nolevel printk by pr_err
Also add no prefix pr_fmt to avoid any future default format update

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-01 10:40:02 -06:00
Fabian Frederick 472d5e2af2 block/partitions/aix.c: replace count*size kzalloc by kcalloc
kcalloc manages count*sizeof overflow.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-01 10:40:00 -06:00
Gu Zheng cbcd1054a1 bio-integrity: add "bip_max_vcnt" into struct bio_integrity_payload
Commit 08778795 ("block: Fix nr_vecs for inline integrity vectors") from
Martin introduces the function bip_integrity_vecs(get the useful vectors)
to fix the issue about nr_vecs for inline integrity vectors that reported
by David Milburn.

But it seems that bip_integrity_vecs() will return the wrong number if the
bio is not based on any bio_set for some reason(bio->bi_pool == NULL),
because in that case, the bip_inline_vecs[0] is malloced directly.  So
here we add the bip_max_vcnt to record the count of vector slots, and
cleanup the function bip_integrity_vecs().

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-01 10:36:47 -06:00
Tejun Heo add703fda9 blk-mq: use percpu_ref for mq usage count
Currently, blk-mq uses a percpu_counter to keep track of how many
usages are in flight.  The percpu_counter is drained while freezing to
ensure that no usage is left in-flight after freezing is complete.
blk_mq_queue_enter/exit() and blk_mq_[un]freeze_queue() implement this
per-cpu gating mechanism.

This type of code has relatively high chance of subtle bugs which are
extremely difficult to trigger and it's way too hairy to be open coded
in blk-mq.  percpu_ref can serve the same purpose after the recent
changes.  This patch replaces the open-coded per-cpu usage counting
and draining mechanism with percpu_ref.

blk_mq_queue_enter() performs tryget_live on the ref and exit()
performs put.  blk_mq_freeze_queue() kills the ref and waits until the
reference count reaches zero.  blk_mq_unfreeze_queue() revives the ref
and wakes up the waiters.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
Cc: Kent Overstreet <kmo@daterainc.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-01 10:34:38 -06:00
Tejun Heo 72d6f02a8d blk-mq: collapse __blk_mq_drain_queue() into blk_mq_freeze_queue()
Keeping __blk_mq_drain_queue() as a separate function doesn't buy us
anything and it's gonna be further simplified.  Let's flatten it into
its caller.

This patch doesn't make any functional change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-01 10:33:02 -06:00
Tejun Heo 780db2071a blk-mq: decouble blk-mq freezing from generic bypassing
blk_mq freezing is entangled with generic bypassing which bypasses
blkcg and io scheduler and lets IO requests fall through the block
layer to the drivers in FIFO order.  This allows forward progress on
IOs with the advanced features disabled so that those features can be
configured or altered without worrying about stalling IO which may
lead to deadlock through memory allocation.

However, generic bypassing doesn't quite fit blk-mq.  blk-mq currently
doesn't make use of blkcg or ioscheds and it maps bypssing to
freezing, which blocks request processing and drains all the in-flight
ones.  This causes problems as bypassing assumes that request
processing is online.  blk-mq works around this by conditionally
allowing request processing for the problem case - during queue
initialization.

Another weirdity is that except for during queue cleanup, bypassing
started on the generic side prevents blk-mq from processing new
requests but doesn't drain the in-flight ones.  This shouldn't break
anything but again highlights that something isn't quite right here.

The root cause is conflating blk-mq freezing and generic bypassing
which are two different mechanisms.  The only intersecting purpose
that they serve is during queue cleanup.  Let's properly separate
blk-mq freezing from generic bypassing and simply use it where
necessary.

* request_queue->mq_freeze_depth is added and
  blk_mq_[un]freeze_queue() now operate on this counter instead of
  ->bypass_depth.  The replacement for QUEUE_FLAG_BYPASS isn't added
  but the counter is tested directly.  This will be further updated by
  later changes.

* blk_mq_drain_queue() is dropped and "__" prefix is dropped from
  blk_mq_freeze_queue().  Queue cleanup path now calls
  blk_mq_freeze_queue() directly.

* blk_queue_enter()'s fast path condition is simplified to simply
  check @q->mq_freeze_depth.  Previously, the condition was

	!blk_queue_dying(q) &&
	    (!blk_queue_bypass(q) || !blk_queue_init_done(q))

  mq_freeze_depth is incremented right after dying is set and
  blk_queue_init_done() exception isn't necessary as blk-mq doesn't
  start frozen, which only leaves the blk_queue_bypass() test which
  can be replaced by @q->mq_freeze_depth test.

This change simplifies the code and reduces confusion in the area.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-01 10:31:13 -06:00
Tejun Heo 776687bce4 block, blk-mq: draining can't be skipped even if bypass_depth was non-zero
Currently, both blk_queue_bypass_start() and blk_mq_freeze_queue()
skip queue draining if bypass_depth was already above zero.  The
assumption is that the one which bumped the bypass_depth should have
performed draining already; however, there's nothing which prevents a
new instance of bypassing/freezing from starting before the previous
one finishes draining.  The current code may allow the later
bypassing/freezing instances to complete while there still are
in-flight requests which haven't finished draining.

Fix it by draining regardless of bypass_depth.  We still skip draining
from blk_queue_bypass_start() while the queue is initializing to avoid
introducing excessive delays during boot.  INIT_DONE setting is moved
above the initial blk_queue_bypass_end() so that bypassing attempts
can't slip inbetween.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-01 10:29:17 -06:00
Tejun Heo 531ed6261e blk-mq: fix a memory ordering bug in blk_mq_queue_enter()
blk-mq uses a percpu_counter to keep track of how many usages are in
flight.  The percpu_counter is drained while freezing to ensure that
no usage is left in-flight after freezing is complete.

blk_mq_queue_enter/exit() and blk_mq_[un]freeze_queue() implement this
per-cpu gating mechanism; unfortunately, it contains a subtle bug -
smp_wmb() in blk_mq_queue_enter() doesn't prevent prevent the cpu from
fetching @q->bypass_depth before incrementing @q->mq_usage_counter and
if freezing happens inbetween the caller can slip through and freezing
can be complete while there are active users.

Use smp_mb() instead so that bypass_depth and mq_usage_counter
modifications and tests are properly interlocked.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-01 10:27:06 -06:00
Jens Axboe 17737d3b59 Merge branch 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu into for-3.17/core
Merge the percpu_ref changes from Tejun, he says they are stable now.
2014-07-01 10:19:04 -06:00
Linus Torvalds 4c834452aa Linux 3.16-rc3 2014-06-29 14:11:36 -07:00
Linus Torvalds ef2e0391e5 Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
Pull ARM fixes from Russell King:
 "Another round of ARM fixes.  The largest change here is the L2 changes
  to work around problems for the Armada 37x/380 devices, where most of
  the size comes down to comments rather than code.

  The other significant fix here is for the ptrace code, to ensure that
  rewritten syscalls work as intended.  This was pointed out by Kees
  Cook, but Will Deacon reworked the patch to be more elegant.

  The remainder are fairly trivial changes"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8087/1: ptrace: reload syscall number after secure_computing() check
  ARM: 8086/1: Set memblock limit for nommu
  ARM: 8085/1: sa1100: collie: add top boot mtd partition
  ARM: 8084/1: sa1100: collie: revert back to cfi_probe
  ARM: 8080/1: mcpm.h: remove unused variable declaration
  ARM: 8076/1: mm: add support for HW coherent systems in PL310 cache
2014-06-29 13:40:08 -07:00
Randy Dunlap 97be078b87 MAINTAINERS: exceptions for Documentation maintainer
Note that I don't maintain Documentation/ABI/,
Documentation/devicetree/, or the language translation files.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-29 13:38:33 -07:00
Dan Carpenter 7d19e91b52 Documentation: add section about git to email-clients.txt
These days most people use git to send patches so I have added a section
about that.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-29 13:38:33 -07:00
Will Deacon 42309ab450 ARM: 8087/1: ptrace: reload syscall number after secure_computing() check
On the syscall tracing path, we call out to secure_computing() to allow
seccomp to check the syscall number being attempted. As part of this, a
SIGTRAP may be sent to the tracer and the syscall could be re-written by
a subsequent SET_SYSCALL ptrace request. Unfortunately, this new syscall
is ignored by the current code unless TIF_SYSCALL_TRACE is also set on
the current thread.

This patch slightly reworks the enter path of the syscall tracing code
so that we always reload the syscall number from
current_thread_info()->syscall after the potential ptrace traps.

Acked-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-06-29 10:29:35 +01:00
Laura Abbott 6980c3e251 ARM: 8086/1: Set memblock limit for nommu
Commit 1c2f87c (ARM: 8025/1: Get rid of meminfo) changed find_limits
to use memblock_get_current_limit for calculating the max_low pfn.
nommu targets never actually set a limit on memblock though which
means memblock_get_current_limit will just return the default
value. Set the memblock_limit to be the end of DDR to make sure
bounds are calculated correctly.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-06-29 10:29:34 +01:00
Andrea Adami 3abe742339 ARM: 8085/1: sa1100: collie: add top boot mtd partition
The CFI mapping is now perfect so we can expose the top block, read only.
There isn't much to read, though, just the sharpsl_params values.

Signed-off-by: Andrea Adami <andrea.adami@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-06-29 10:29:34 +01:00
Andrea Adami 92183103d8 ARM: 8084/1: sa1100: collie: revert back to cfi_probe
Reverts commit d26b17edaf
ARM: sa1100: collie.c: fall back to jedec_probe flash detection

Unfortunately the detection was challenged on the defective unit used for tests:
one of the NOR chips did not respond to the CFI query.
Moreover that bad device needed extra delays on erase-suspend/resume cycles.

Tested personally on 3 different units and with feedback of two other users.

Signed-off-by: Andrea Adami <andrea.adami@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-06-29 10:29:33 +01:00
Nicolas Pitre d0ba7cc02c ARM: 8080/1: mcpm.h: remove unused variable declaration
The sync_phys variable has been replaced by link time computation in
mcpm_head.S before the code was submitted upstream.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-06-29 10:29:32 +01:00
Thomas Petazzoni 98ea2dba65 ARM: 8076/1: mm: add support for HW coherent systems in PL310 cache
When a PL310 cache is used on a system that provides hardware
coherency, the outer cache sync operation is useless, and can be
skipped. Moreover, on some systems, it is harmful as it causes
deadlocks between the Marvell coherency mechanism, the Marvell PCIe
controller and the Cortex-A9.

To avoid this, this commit introduces a new Device Tree property
'arm,io-coherent' for the L2 cache controller node, valid only for the
PL310 cache. It identifies the usage of the PL310 cache in an I/O
coherent configuration. Internally, it makes the driver disable the
outer cache sync operation.

Note that technically speaking, a fully coherent system wouldn't
require any of the other .outer_cache operations. However, in
practice, when booting secondary CPUs, these are not yet coherent, and
therefore a set of cache maintenance operations are necessary at this
point. This explains why we keep the other .outer_cache operations and
only ->sync is disabled.

While in theory any write to a PL310 register could cause the
deadlock, in practice, disabling ->sync is sufficient to workaround
the deadlock, since the other cache maintenance operations are only
used in very specific situations.

Contrary to previous versions of this patch, this new version does not
simply NULL-ify the ->sync member, because the l2c_init_data
structures are now 'const' and therefore cannot be modified, which is
a good thing. Therefore, this patch introduces a separate
l2c_init_data instance, called of_l2c310_coherent_data.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-06-29 10:26:37 +01:00
Linus Torvalds 24b414d5a7 spi: Fixes for v3.16
A few driver specific fixes, the biggest one being a fix for the newly
 added Qualcomm SPI controller driver to make it not use its internal
 chip select due to hardware bugs, replacing it with GPIOs.
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Merge tag 'spi-v3.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi

Pull spi fixes from Mark Brown:
 "A few driver specific fixes, the biggest one being a fix for the newly
  added Qualcomm SPI controller driver to make it not use its internal
  chip select due to hardware bugs, replacing it with GPIOs"

* tag 'spi-v3.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
  spi: qup: Remove chip select function
  spi: qup: Fix order of spi_register_master
  spi: sh-sci: fix use-after-free in sh_sci_spi_remove()
  spi/pxa2xx: fix incorrect SW mode chipselect setting for BayTrail LPSS SPI
2014-06-28 11:32:32 -07:00
Linus Torvalds 4194976b09 regulator: Fixes for v3.16
Several driver specific fixes here, the palmas fixes being especially
 important for a range of boards - the recent updates to support new
 devices have introduced several regressions.
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Merge tag 'regulator-v3.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator

Pull regulator fixes from Mark Brown:
 "Several driver specific fixes here, the palmas fixes being especially
  important for a range of boards - the recent updates to support new
  devices have introduced several regressions"

* tag 'regulator-v3.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
  regulator: tps65218: Correct the the config register for LDO1
  regulator: tps65218: Add the missing of_node assignment in probe
  regulator: palmas: fix typo in enable_reg calculation
  regulator: bcm590xx: fix vbus name
  regulator: palmas: Fix SMPS enable/disable/is_enabled
2014-06-28 11:31:58 -07:00
Linus Torvalds eb477e03fe Merge git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending
Pull SCSI target fixes from Nicholas Bellinger:
 "Mostly minor fixes this time around.  The highlights include:

   - iscsi-target CHAP authentication fixes to enforce explicit key
     values (Tejas Vaykole + rahul.rane)
   - fix a long-standing OOPs in target-core when a alua configfs
     attribute is accessed after port symlink has been removed.
     (Sebastian Herbszt)
   - fix a v3.10.y iscsi-target regression causing the login reject
     status class/detail to be ignored (Christoph Vu-Brugier)
   - fix a v3.10.y iscsi-target regression to avoid rejecting an
     existing ITT during Data-Out when data-direction is wrong (Santosh
     Kulkarni + Arshad Hussain)
   - fix a iscsi-target related shutdown deadlock on UP kernels (Mikulas
     Patocka)
   - fix a v3.16-rc1 build issue with vhost-scsi + !CONFIG_NET (MST)"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  iscsi-target: fix iscsit_del_np deadlock on unload
  iovec: move memcpy_from/toiovecend to lib/iovec.c
  iscsi-target: Avoid rejecting incorrect ITT for Data-Out
  tcm_loop: Fix memory leak in tcm_loop_submission_work error path
  iscsi-target: Explicily clear login response PDU in exception path
  target: Fix left-over se_lun->lun_sep pointer OOPs
  iscsi-target; Enforce 1024 byte maximum for CHAP_C key value
  iscsi-target: Convert chap_server_compute_md5 to use kstrtoul
2014-06-28 09:43:58 -07:00
Mark Brown 7216a41839 Merge remote-tracking branches 'spi/fix/pxa2xx', 'spi/fix/qup' and 'spi/fix/sh-sci' into spi-linus 2014-06-28 14:01:23 +01:00
Mark Brown 11767484b8 Merge remote-tracking branches 'regulator/fix/bcm590xx', 'regulator/fix/palmas' and 'regulator/fix/tps65218' into regulator-linus 2014-06-28 14:01:04 +01:00
Tejun Heo 2d7227828e percpu-refcount: implement percpu_ref_reinit() and percpu_ref_is_zero()
Now that explicit invocation of percpu_ref_exit() is necessary to free
the percpu counter, we can implement percpu_ref_reinit() which
reinitializes a released percpu_ref.  This can be used implement
scalable gating switch which can be drained and then re-opened without
worrying about memory allocation failures.

percpu_ref_is_zero() is added to be used in a sanity check in
percpu_ref_exit().  As this function will be useful for other purposes
too, make it a public interface.

v2: Use smp_read_barrier_depends() instead of smp_load_acquire().  We
    only need data dep barrier and smp_load_acquire() is stronger and
    heavier on some archs.  Spotted by Lai Jiangshan.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
2014-06-28 08:10:14 -04:00
Tejun Heo 9a1049da9b percpu-refcount: require percpu_ref to be exited explicitly
Currently, a percpu_ref undoes percpu_ref_init() automatically by
freeing the allocated percpu area when the percpu_ref is killed.
While seemingly convenient, this has the following niggles.

* It's impossible to re-init a released reference counter without
  going through re-allocation.

* In the similar vein, it's impossible to initialize a percpu_ref
  count with static percpu variables.

* We need and have an explicit destructor anyway for failure paths -
  percpu_ref_cancel_init().

This patch removes the automatic percpu counter freeing in
percpu_ref_kill_rcu() and repurposes percpu_ref_cancel_init() into a
generic destructor now named percpu_ref_exit().  percpu_ref_destroy()
is considered but it gets confusing with percpu_ref_kill() while
"exit" clearly indicates that it's the counterpart of
percpu_ref_init().

All percpu_ref_cancel_init() users are updated to invoke
percpu_ref_exit() instead and explicit percpu_ref_exit() calls are
added to the destruction path of all percpu_ref users.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Benjamin LaHaise <bcrl@kvack.org>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
Cc: Li Zefan <lizefan@huawei.com>
2014-06-28 08:10:14 -04:00
Tejun Heo 7d74207512 percpu-refcount: use unsigned long for pcpu_count pointer
percpu_ref->pcpu_count is a percpu pointer with a status flag in its
lowest bit.  As such, it always goes through arithmetic operations
which is very cumbersome to do on a pointer.  It has to be first
casted to unsigned long and then back.

Let's just make the field unsigned long so that we can skip the first
casts.  While at it, rename it to pcpu_counter_ptr to clarify that
it's a pointer value.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
2014-06-28 08:10:13 -04:00