Interrupt is only queued after the request has been sent to userspace.
This is either done in request_wait_answer() or fuse_dev_do_read()
depending on which state the request is in at the time of the interrupt.
If it's not yet sent, then queuing the interrupt is postponed until the
request is read.  Otherwise (the request has already been read and is
waiting for an answer) the interrupt is queued immedidately.

We want to call queue_interrupt() without fc->lock protection, in which
case there can be a race between the two functions:

 - neither of them queue the interrupt (thinking the other one has already
   done it).

 - both of them queue the interrupt

The first one is prevented by adding memory barriers, the second is
prevented by checking (under fiq->waitq.lock) if the interrupt has already
been queued.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Use fiq->waitq.lock for protecting members of struct fuse_iqueue and
FR_PENDING request flag, previously protected by fc->lock.

Following patches will remove fc->lock protection from these members.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

Different lists will need different locks.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

Rearrange fuse_abort_conn() so that input queue accesses are grouped
together.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

This will allow checking ->connected just with the input queue lock.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

The input queue contains normal requests (fc->pending), forgets
(fc->forget_*) and interrupts (fc->interrupts).  There's also fc->waitq and
fc->fasync for waking up the readers of the fuse device when a request is
available.

The fc->reqctr is also moved to the input queue (assigned to the request
when the request is added to the input queue.

This patch just rearranges the fields, no functional change.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

Use flags for representing the state in fuse_req.  This is needed since
req->list will be protected by different locks in different states, hence
we'll want the state itself to be split into distinct bits, each protected
with the relevant lock in that state.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

FUSE_REQ_INIT is actually the same state as FUSE_REQ_PENDING and
FUSE_REQ_READING and FUSE_REQ_WRITING can be merged into a common
FUSE_REQ_IO state.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

Only hold fc->lock over sections of request_wait_answer() that actually
need it.  If wait_event_interruptible() returns zero, it means that the
request finished.  Need to add memory barriers, though, to make sure that
all relevant data in the request is synchronized.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Since it's a 64bit counter, it's never gonna wrap around.  Remove code
dealing with that possibility.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

Splice fc->pending and fc->processing lists into a common kill list while
holding fc->lock.

By the time we release fc->lock, pending and processing lists are empty and
the io list contains only locked requests.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

Fold end_io_requests() and end_queued_requests() into fuse_abort_conn().
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

Reuse req->waitq.lock for protecting FR_ABORTED and FR_LOCKED flags.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

Finer grained locking will mean there's no single lock to protect
modification of bitfileds in fuse_req.

So move to using bitops.  Can use the non-atomic variants for those which
happen while the request definitely has only one reference.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

 - don't end the request while req->locked is true

 - make unlock_request() return an error if the connection was aborted
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

fuse_abort_conn() does all the work done by fuse_dev_release() and more.
"More" consists of:

	end_io_requests(fc);
	wake_up_all(&fc->waitq);
	kill_fasync(&fc->fasync, SIGIO, POLL_IN);

All of which should be no-op (WARN_ON's added).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

And the same with fuse_request_send_nowait_locked().
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

fc->conn_error is set once in FUSE_INIT reply and never cleared.  Check it
in request allocation, there's no sense in doing all the preparation if
sending will surely fail.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

Move accounting of fc->num_waiting to the point where the request actually
starts waiting.  This is earlier than the current queue_request() for
background requests, since they might be waiting on the fc->bg_queue before
being queued on fc->pending.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

Reset req->waiting in fuse_put_request().  This is needed for correct
accounting in fc->num_waiting for reserved requests.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

request_end() expects fc->num_background and fc->active_background to have
been incremented, which is not the case in fuse_request_send_nowait()
failure path.  So instead just call the ->end() callback (which is actually
set by all callers).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

fc->release is called from fuse_conn_put() which was used in the error
cleanup before fc->release was initialized.

[Jeremiah Mahler <jmmahler@gmail.com>: assign fc->release after calling
fuse_conn_init(fc) instead of before.]
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Fixes: a325f9b9 ("fuse: update fuse_conn_init() and separate out fuse_conn_kill()")
Cc: <stable@vger.kernel.org> #v2.6.31+

Pull scsi target fixes from Nicholas Bellinger:
 "Apologies for the late pull request.

  Here are the outstanding target-pending fixes for v4.1 code.

  The series contains three patches from Sagi + Co that address a few
  iser-target issues that have been uncovered during recent testing at
  Mellanox.

  Patch #1 has a v3.16+ stable tag, and #2-3 have v3.10+ stable tags"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  iser-target: Fix possible use-after-free
  iser-target: release stale iser connections
  iser-target: Fix variable-length response error completion

Pull drm fixes from Dave Airlie:
 "A smattering of fixes,

  mgag200:
      don't accept modes that aren't aligned properly as hw can't do it

  i915:
      two regression fixes

  radeon:
      one query to allow userspace fixes
      one oops fixer for older hw with new options enabled"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/radeon: don't probe MST on hw we don't support it on
  drm/radeon: Add RADEON_INFO_VA_UNMAP_WORKING query
  drm/mgag200: Reject non-character-cell-aligned mode widths
  Revert "drm/i915: Don't skip request retirement if the active list is empty"
  drm/i915: Always reset vma->ggtt_view.pages cache on unbinding

Pull clk fixes from Michael Turquette:
 "Very late clk regression fixes for the ARM-based AT91 platform.

  These went unnoticed by me until recently, hence the late pull
  request"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: at91: fix h32mx prototype inclusion in pmc header
  clk: at91: trivial: typo in peripheral clock description
  clk: at91: fix PERIPHERAL_MAX_SHIFT definition
  clk: at91: pll: fix input range validity check

Pull sound fixes from Takashi Iwai:
 "Nothing looks scary, just a few usual HD-audio regression fixes and
  fixup, in addition to a minor Kconfig dependency fix for the old MIPS
  drivers"

* tag 'sound-4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: hda - Fix unused label skip_i915
  ALSA: hda - Fix noisy outputs on Dell XPS13 (2015 model)
  ALSA: mips: let SND_SGI_O2 select SND_PCM
  ALSA: hda - Fix audio crackles on Dell Latitude E7x40
  ALSA: hda - adding a DAC/pin preference map for a HP Envy TS machine

Trivial fix that prevents to compile this pmc clock driver if h32mx clock is
present but smd clock isn't.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Fixes: bcc5fd49 ("clk: at91: add a driver for the h32mx clock")
Cc: <stable@vger.kernel.org> # 3.18+

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Fix the PERIPHERAL_MAX_SHIFT definition (3 instead of 4) and adapt the
round_rate and set_rate logic accordingly.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reported-by: "Wu, Songjun" <Songjun.Wu@atmel.com>

The PLL impose a certain input range to work correctly, but it appears that
this input range does not apply on the input clock (or parent clock) but
on the input clock after it has passed the PLL divisor.
Fix the implementation accordingly.

Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reported-by: Jonas Andersson <jonas@microbit.se>

Pull i2c documentation fix from Wolfram Sang:
 "Here is a small documentation fix for I2C.

  We already had a user who unsuccessfully tried to get the new slave
  framework running with the currently broken example.  So, before this
  happens again, I'd like to have this how-to-use section fixed for 4.1
  already.  So that no more hacking time is wasted"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: slave: fix the example how to instantiate from userspace

Revert commit 534b483a ("cpumask: don't perform while loop in
cpumask_next_and()").

This was a minor optimization, but it puts a `struct cpumask' on the
stack, which consumes too much stack space.

Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Amir Vadai <amirv@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

one fix, one revert
* tag 'drm-intel-fixes-2015-06-18' of git://anongit.freedesktop.org/drm-intel:
  Revert "drm/i915: Don't skip request retirement if the active list is empty"
  drm/i915: Always reset vma->ggtt_view.pages cache on unbinding

two radeon fixes
	one MST fix,
	one query addition, destined for stable, and to fix a regression
* 'drm-fixes-4.1' of git://people.freedesktop.org/~deathsimple/linux:
  drm/radeon: don't probe MST on hw we don't support it on
  drm/radeon: Add RADEON_INFO_VA_UNMAP_WORKING query

If you do radeon.mst=1 on a gpu without mst hw, and then
plug some mst hw it will oops instead of falling back.

So check we have DCE5 at least before proceeding.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Christian König <christian.koenig@amd.com>

This tells userspace that it's safe to use the RADEON_VA_UNMAP operation
of the DRM_RADEON_GEM_VA ioctl.

Cc: stable@vger.kernel.org
(NOTE: Backporting this commit requires at least backports of commits
26d4d129,
48afbd70 and
c29c0876 as well, otherwise using
RADEON_VA_UNMAP runs into trouble)
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>

Merge tag 'trace-fix-filter-4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing filter fix from Steven Rostedt:
 "Vince Weaver reported a warning when he added perf event filters into
  his fuzzer tests.  There's a missing check of balanced operations when
  parenthesis are used, and this triggers a WARN_ON() and when reading
  the failure, the filter reports no failure occurred.

  The operands were not being checked if they match, this adds that"

* tag 'trace-fix-filter-4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Have filter check for balanced ops

Pull kvm bugfix from Marcelo Tosatti:
 "Rrestore APIC migration functionality"

* git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: fix lapic.timer_mode on restore