Commit graph

388407 commits

Author SHA1 Message Date
Peter Hurley 809850b7a5 tty: Use lockless flip buffer free list
In preparation for lockless flip buffers, make the flip buffer
free list lockless.

NB: using llist is not the optimal solution, as the driver and
buffer work may contend over the llist head unnecessarily. However,
test measurements indicate this contention is low.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:47:08 -07:00
Peter Hurley 2cf7b67e87 tty: Use generic names for flip buffer list cursors
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:47:08 -07:00
Peter Hurley 11b9faa44d tty: Merge tty_buffer_find() into tty_buffer_alloc()
tty_buffer_find() implements a simple free list lookaside cache.
Merge this functionality into tty_buffer_alloc() to reflect the
more traditional alloc/free symmetry.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:47:08 -07:00
Peter Hurley 9dd5139f97 tty: Factor flip buffer initialization into helper function
Factor shared code; prepare for adding 0-sized sentinel flip buffer.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:47:07 -07:00
Peter Hurley 1cef50e317 tty: Fix flip buffer free list
Since flip buffers are size-aligned to 256 bytes and all flip
buffers 512-bytes or larger are not added to the free list, the
free list only contains 256-byte flip buffers.

Remove the list search when allocating a new flip buffer.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:47:07 -07:00
Peter Hurley 1fc359fc3e tty: Compute flip buffer ptrs
The char_buf_ptr and flag_buf_ptr values are trivially derived from
the .data field offset; compute values as needed.

Fixes a long-standing type-mismatch with the char and flag ptrs.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:47:07 -07:00
Peter Hurley f0f947c124 n_tty: Queue buffer work on any available cpu
Scheduling buffer work on the same cpu as the read() thread
limits the parallelism now possible between the receive_buf path
and the n_tty_read() path.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:03 -07:00
Peter Hurley 3afb1b394a n_tty: Special case pty flow control
The pty driver forces ldisc flow control on, regardless of available
receive buffer space, so the writer can be woken whenever unthrottle
is called. However, this 'forced throttle' has performance
consequences, as multiple atomic operations are necessary to
unthrottle and perform the write wakeup for every input line (in
canonical mode).

Instead, short-circuit the unthrottle if the tty is a pty and perform
the write wakeup directly.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:03 -07:00
Peter Hurley ee0bab83ce n_tty: Move n_tty_write_wakeup() to avoid forward declaration
Prepare to special case pty flow control; avoid forward declaration.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:02 -07:00
Peter Hurley 6367ca72f1 n_tty: Factor throttle/unthrottle into helper functions
Prepare for special handling of pty throttle/unthrottle; factor
flow control into helper functions.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:02 -07:00
Peter Hurley 9a4aec2dd5 n_tty: Move chars_in_buffer() to factor throttle/unthrottle
Prepare to factor throttle and unthrottle into helper functions;
relocate chars_in_buffer() to avoid forward declaration.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:02 -07:00
Peter Hurley d8c1f929aa tty: Only guarantee termios read safety for throttle/unthrottle
No tty driver modifies termios during throttle() or unthrottle().
Therefore, only read safety is required.

However, tty_throttle_safe and tty_unthrottle_safe must still be
mutually exclusive; introduce throttle_mutex for that purpose.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:02 -07:00
Peter Hurley fb7aa03db6 n_tty: Separate buffer indices to prevent cache-line sharing
If the read buffer indices are in the same cache-line, cpus will
contended over the cache-line (so called 'false sharing').

Separate the producer-published fields from the consumer-published
fields; document the locks relevant to each field.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:02 -07:00
Peter Hurley f95499c303 n_tty: Don't wait for buffer work in read() loop
User-space read() can run concurrently with receiving from device;
waiting for receive_buf() to complete is not required.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:02 -07:00
Peter Hurley d1913e3916 n_tty: Fix type mismatches in receive_buf raw copy
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:01 -07:00
Peter Hurley 6f9b028a8f n_tty: Reset lnext if canonical mode changes
lnext escapes the next input character as a literal, and must
be reset when canonical mode changes (to avoid misinterpreting
a special character as a literal if canonical mode is changed
back again).

lnext is specifically not reset on a buffer flush so as to avoid
misinterpreting the next input character as a special character.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:01 -07:00
Peter Hurley 6d76bd2618 n_tty: Make N_TTY ldisc receive path lockless
n_tty has a single-producer/single-consumer input model;
use lockless publish instead.

Use termios_rwsem to exclude both consumer and producer while
changing or resetting buffer indices, eg., when flushing. Also,
claim exclusive termios_rwsem to safely retrieve the buffer
indices from a thread other than consumer or producer
(eg., TIOCINQ ioctl).

Note the read_tail is published _after_ clearing the newline
indicator in read_flags to avoid racing the producer.

Drop read_lock spinlock.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:01 -07:00
Peter Hurley a73d3d6987 n_tty: Replace canon_data with index comparison
canon_data represented the # of lines which had been copied
to the receive buffer but not yet copied to the user buffer.
The value was tested to determine if input was available in
canonical mode (and also to force input overrun if the
receive buffer was full but a newline had not been received).

However, the actual count was irrelevent; only whether it was
non-zero (meaning 'is there any input to transfer?'). This
shared count is unnecessary and unsafe with a lockless algorithm.
The same check is made by comparing canon_head with read_tail instead.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:01 -07:00
Peter Hurley 9356b535fc n_tty: Access termios values safely
Use termios_rwsem to guarantee safe access to the termios values.
This is particularly important for N_TTY as changing certain termios
settings alters the mode of operation.

termios_rwsem must be dropped across throttle/unthrottle since
those functions claim the termios_rwsem exclusively (to guarantee
safe access to the termios and for mutual exclusion).

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:01 -07:00
Peter Hurley 6a1c0680cf tty: Convert termios_mutex to termios_rwsem
termios is commonly accessed unsafely (especially by N_TTY)
because the existing mutex forces exclusive access.
Convert existing usage.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:01 -07:00
Peter Hurley a2f73be8ee n_tty: Remove read_cnt
Storing the read_cnt creates an unnecessary shared variable
between the single-producer (n_tty_receive_buf()) and the
single-consumer (n_tty_read()).

Compute read_cnt from head & tail instead of storing.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:00 -07:00
Peter Hurley bc5a5e3f45 n_tty: Don't wrap input buffer indices at buffer size
Wrap read_buf indices (read_head, read_tail, canon_head) at
max representable value, instead of at the N_TTY_BUF_SIZE. This step
is necessary to allow lockless reads of these shared variables
(by updating the variables atomically).

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:00 -07:00
Peter Hurley ce74117a18 n_tty: Get read_cnt through accessor
Prepare for replacing read_cnt field with computed value.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:00 -07:00
Peter Hurley 475340846f tty: Deprecate ldisc .chars_in_buffer() method
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:00 -07:00
Peter Hurley a19d0c6a91 n_tty: Split n_tty_chars_in_buffer() for reader-only interface
N_TTY .chars_in_buffer() method requires serialized access if
the current thread is not the single-consumer, n_tty_read().

Separate the internal interface; prepare for lockless read-side.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:00 -07:00
Peter Hurley 32f13521ca n_tty: Line copy to user buffer in canonical mode
Instead of pushing one char per loop, pre-compute the data length
to copy and copy all at once.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:42:59 -07:00
Peter Hurley 88bb0de389 n_tty: Factor canonical mode copy from n_tty_read()
Simplify n_tty_read(); extract complex copy algorithm
into separate function, canon_copy_to_user().

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:42:59 -07:00
Peter Hurley 24a89d1cb6 tty: Make ldisc input flow control concurrency-friendly
Although line discipline receiving is single-producer/single-consumer,
using tty->receive_room to manage flow control creates unnecessary
critical regions requiring additional lock use.

Instead, introduce the optional .receive_buf2() ldisc method which
returns the # of bytes actually received. Serialization is guaranteed
by the caller.

In turn, the line discipline should schedule the buffer work item
whenever space becomes available; ie., when there is room to receive
data and receive_room() previously returned 0 (the buffer work
item stops processing if receive_buf2() returns 0). Note the
'no room' state need not be atomic despite concurrent use by two
threads because only the buffer work thread can set the state and
only the read() thread can clear the state.

Add n_tty_receive_buf2() as the receive_buf2() method for N_TTY.
Provide a public helper function, tty_ldisc_receive_buf(), to use
when directly accessing the receive_buf() methods.

Line disciplines not using input flow control can continue to set
tty->receive_room to a fixed value and only provide the receive_buf()
method.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:42:59 -07:00
Peter Hurley da261e7fe7 tty: Simplify tty buffer/ldisc interface with helper function
Ldisc interface functions must be called with interrupts enabled.
Separating the ldisc calls into a helper function simplies the
eventual removal of the spinlock.

Note that access to the buf->head ptr outside the spinlock is
safe here because;
* __tty_buffer_flush() is prevented from running while buffer work
  performs i/o,
* tty_buffer_find() only assigns buf->head if the flip buffer list
  is empty (which is never the case in flush_to_ldisc() since at
  least one buffer is always left in the list after use)
Access to the read index outside the spinlock is safe here for the
same reasons.

Update the buffer's read index _after_ the data has been received
by the ldisc.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:42:59 -07:00
Peter Hurley 3b80df7ca7 tty: Don't change receive_room for ioctl(TIOCSETD)
tty_set_ldisc() is guaranteed exclusive use of the line discipline
by tty_ldisc_lock_pair_timeout(); shutting off input by resetting
receive_room is unnecessary.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:42:59 -07:00
Peter Hurley b0e9585823 tty: Clarify multiple-references comment in TIOCSETD ioctl
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:38:35 -07:00
Peter Hurley e97733ca67 tty: Fix hangup race with TIOCSETD ioctl
The hangup may already have happened; check for that state also.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:38:35 -07:00
Peter Hurley 9fbfa34c18 tty: Clarify ldisc variable
Rename o_ldisc to avoid confusion with the ldisc of the
'other' tty.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:38:35 -07:00
Peter Hurley 36697529b5 tty: Replace ldisc locking with ldisc_sem
Line discipline locking was performed with a combination of
a mutex, a status bit, a count, and a waitqueue -- basically,
a rw semaphore.

Replace the existing combination with an ld_semaphore.

Fixes:
 1) the 'reference acquire after ldisc locked' bug
 2) the over-complicated halt mechanism
 3) lock order wrt. tty_lock()
 4) dropping locks while changing ldisc
 5) previously unidentified deadlock while locking ldisc from
    both linked ttys concurrently
 6) previously unidentified recursive deadlocks

Adds much-needed lockdep diagnostics.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:38:34 -07:00
Peter Hurley d2c438905f tty: Add lock/unlock ldisc pair functions
Just as the tty pair must be locked in a stable sequence
(ie, independent of which is consider the 'other' tty), so must
the ldisc pair be locked in a stable sequence as well.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:38:34 -07:00
Peter Hurley 137084bbad tty: Fix tty_ldisc_lock name collision
The file scope spinlock identifier, tty_ldisc_lock, will collide
with the file scope lock function tty_ldisc_lock() so rename it.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:38:34 -07:00
Bjørn Mork 94190301ff usb: option: add TP-LINK MA260
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:07:51 -07:00
Linus Torvalds a474902cf5 Device tree bug fixes and maintainership updates for v3.11-rc2
This branch contains a couple of minor bug fixes and documentation
 additions, but the bulk of it are several changes to the MAINTAINERS
 file regarding the subsystems I've been involved with.
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Merge tag 'devicetree-for-linus' of git://git.secretlab.ca/git/linux

Pull device tree bug fixes and maintainership updates from Grant Likely:
 "This branch contains a couple of minor bug fixes and documentation
  additions, but the bulk of it are several changes to the MAINTAINERS
  file regarding the subsystems I've been involved with"

* tag 'devicetree-for-linus' of git://git.secretlab.ca/git/linux:
  of/irq: init struct resource to 0 in of_irq_to_resource()
  of/irq: Avoid calling list_first_entry() for empty list
  of: add vendor prefixes for hisilicon
  of: add vendor prefix for Qualcomm Atheros, Inc.
  MAINTAINERS: Fix incorrect status tag
  MAINTAINERS: Refactor device tree maintainership
  MAINTAINERS: Change device tree mailing list
  MAINTAINERS: Remove Grant Likely
2013-07-23 16:04:07 -07:00
Borislav Petkov 88d84ac973 EDAC: Fix lockdep splat
Fix the following:

BUG: key ffff88043bdd0330 not in .data!
------------[ cut here ]------------
WARNING: at kernel/lockdep.c:2987 lockdep_init_map+0x565/0x5a0()
DEBUG_LOCKS_WARN_ON(1)
Modules linked in: glue_helper sb_edac(+) edac_core snd acpi_cpufreq lrw gf128mul ablk_helper iTCO_wdt evdev i2c_i801 dcdbas button cryptd pcspkr iTCO_vendor_support usb_common lpc_ich mfd_core soundcore mperf processor microcode
CPU: 2 PID: 599 Comm: modprobe Not tainted 3.10.0 #1
Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A08 01/24/2013
 0000000000000009 ffff880439a1d920 ffffffff8160a9a9 ffff880439a1d958
 ffffffff8103d9e0 ffff88043af4a510 ffffffff81a16e11 0000000000000000
 ffff88043bdd0330 0000000000000000 ffff880439a1d9b8 ffffffff8103dacc
Call Trace:
  dump_stack
  warn_slowpath_common
  warn_slowpath_fmt
  lockdep_init_map
  ? trace_hardirqs_on_caller
  ? trace_hardirqs_on
  debug_mutex_init
  __mutex_init
  bus_register
  edac_create_sysfs_mci_device
  edac_mc_add_mc
  sbridge_probe
  pci_device_probe
  driver_probe_device
  __driver_attach
  ? driver_probe_device
  bus_for_each_dev
  driver_attach
  bus_add_driver
  driver_register
  __pci_register_driver
  ? 0xffffffffa0010fff
  sbridge_init
  ? 0xffffffffa0010fff
  do_one_initcall
  load_module
  ? unset_module_init_ro_nx
  SyS_init_module
  tracesys
---[ end trace d24a70b0d3ddf733 ]---
EDAC MC0: Giving out device to 'sbridge_edac.c' 'Sandy Bridge Socket#0': DEV 0000:3f:0e.0
EDAC sbridge: Driver loaded.

What happens is that bus_register needs a statically allocated lock_key
because the last is handed in to lockdep. However, struct mem_ctl_info
embeds struct bus_type (the whole struct, not a pointer to it) and the
whole thing gets dynamically allocated.

Fix this by using a statically allocated struct bus_type for the MC bus.

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: stable@kernel.org # v3.10
Signed-off-by: Tony Luck <tony.luck@intel.com>
2013-07-23 16:01:28 -07:00
Linus Torvalds c2468d32f5 Merge branch 'for-3.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup changes from Tejun Heo:
 "This contains two patches, both of which aren't fixes per-se but I
  think it'd be better to fast-track them.

  One removes bcache_subsys_id which was added without proper review
  through the block tree.  Fortunately, bcache cgroup code is
  unconditionally disabled, so this was never exposed to userland.  The
  cgroup subsys_id is removed.  Kent will remove the affected (disabled)
  code through bcache branch.

  The other simplifies task_group_path_from_hierarchy().  The function
  doesn't currently have in-kernel users but there are external code and
  development going on dependent on the function and making the function
  available for 3.11 would make things go smoother"

* 'for-3.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: replace task_cgroup_path_from_hierarchy() with task_cgroup_path()
  cgroup: remove bcache_subsys_id which got added stealthily
2013-07-23 15:48:35 -07:00
Linus Torvalds 549f3a1218 Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linux
Pull drm fixes from Dave Airlie:
 "This is just a regular fixes pull, mostly nouveau and i915, the i915
  ones fix RC6 on Sandybridge after suspend/resume, which I think people
  have be wanting for quite a while!

  Now you shouldn't wish for more patches, as the new mutex/reservation
  code found a number of problems with the qxl driver, and it currently
  makes lockdep angry, I'm working on a set of fixes for it, but its a
  bit large, I'll submit them separately later today or tomorrow once
  I've banged on them a bit more, just warning you in advance :-)"

Yeah, I'm definitely over the whole "wish for more patches" thing.

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/crtc-helper: explicit DPMS on after modeset
  drm/i915: fix up gt init sequence fallout
  drm/i915: Serialize almost all register access
  drm/i915: quirk no PCH_PWM_ENABLE for Dell XPS13 backlight
  drm/i915: correctly restore fences with objects attached
  drm/i915: Fix dereferencing invalid connectors in is_crtc_connector_off()
  drm/i915: Sanitize shared dpll state
  drm/i915: fix long-standing SNB regression in power consumption after resume v2
  drm/i915: Preserve the DDI_A_4_LANES bit from the bios
  drm/i915: fix pfit regression for non-autoscaled resolutions
  drm/i915: fix up readout of the lvds dither bit on gen2/3
  drm/nouveau: do not allow negative sizes for now
  drm/nouveau: add falcon interrupt handler
  drm/nouveau: use dedicated channel for async moves on GT/GF chipsets.
  drm/nouveau: bump fence timeout to 15 seconds
  drm/nouveau: do not unpin in nouveau_gem_object_del
  drm/nv50/kms: fix pin refcnt leaks
  drm/nouveau: fix some error-path leaks in fbcon handling code
  drm/nouveau: fix locking issues in page flipping paths
2013-07-23 15:47:08 -07:00
David Howells 42577ca8c3 Fix __wait_on_atomic_t() to call the action func if the counter != 0
Fix __wait_on_atomic_t() so that it calls the action func if the counter != 0
rather than if the counter is 0 so as to be analogous to __wait_on_bit().

Thanks to Yacine who found this by visual inspection.

This will affect FS-Cache in that it will could fail to sleep correctly when
trying to clean up after a netfs cookie is withdrawn.

Reported-by: Yacine Belkadi <yacine.belkadi.1@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: Milosz Tanski <milosz@adfin.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-23 15:46:48 -07:00
James Bottomley 53a983c4f8 [SCSI] mvsas: Fix kernel panic on tile due to unaligned data access
slot->response is a 64 bit quantity (and accessed as such), but its alignment
is only 32 bits.  This doesn't cause a problem on x86, but apparently causes a
kernel panic on Tile:

Stack dump complete Kernel panic - not syncing:
 Kernel unalign fault running the idle task!
 Starting stack dump of tid 0, pid 0 (swapper) on cpu 1 at cycle 341586172541
   frame 0: 0xfffffff700140ee0 dump_stack+0x0/0x20 (sp 0xfffffe43ffedf420)
   frame 1: 0xfffffff700283270 panic+0x150/0x3a0 (sp 0xfffffe43ffedf420)
   frame 2: 0xfffffff70012bff8 jit_bundle_gen+0xfd8/0x27e0 (sp 0xfffffe43ffedf4c8)
   frame 3: 0xfffffff7003b5b68 do_unaligned+0xc0/0x5a0 (sp 0xfffffe43ffedf710)
   frame 4: 0xfffffff70044ca78 handle_interrupt+0x270/0x278 (sp 0xfffffe43ffedf840)
   <interrupt 17 while in kernel mode>
   frame 5: 0xfffffff7002ac370 mvs_slot_complete+0x5f0/0x12a0 (sp 0xfffffe43ffedfa90)
   frame 6: 0xfffffff7002abec0 mvs_slot_complete+0x140/0x12a0 (sp 0xfffffe43ffedfa90)
   frame 7: 0xfffffff7005cc840 mvs_int_rx+0x140/0x2a0 (sp 0xfffffe43ffedfb00)
   frame 8: 0xfffffff7005bbaf0 mvs_94xx_isr+0xd8/0x2b8 (sp 0xfffffe43ffedfb68)
   frame 9: 0xfffffff700658ba0 mvs_tasklet+0x128/0x1f8 (sp 0xfffffe43ffedfba8)
   frame 10: 0xfffffff7003e8230 tasklet_action+0x178/0x2c8 (sp 0xfffffe43ffedfbe0)
   frame 11: 0xfffffff700103850 __do_softirq+0x210/0x398 (sp 0xfffffe43ffedfc40)
   frame 12: 0xfffffff700180308 do_softirq+0xc8/0x140 (sp 0xfffffe43ffedfcd8)
   frame 13: 0xfffffff7000bd7f0 irq_exit+0xb0/0x158 (sp 0xfffffe43ffedfcf0)
   frame 14: 0xfffffff70013fa58 tile_dev_intr+0x1d8/0x2f0 (sp 0xfffffe43ffedfd00)
   frame 15: 0xfffffff70044ca78 handle_interrupt+0x270/0x278 (sp 0xfffffe43ffedfd40)
   <interrupt 30 while in kernel mode>
   frame 16: 0xfffffff700143e68 _cpu_idle_nap+0x0/0x18 (sp 0xfffffe43ffedffb0)
   frame 17: 0xfffffff700482480 cpu_idle+0x310/0x428 (sp 0xfffffe43ffedffb0)

Since the check is just for non-zero, split it to be two 32 bit accesses
(preserving speed in the fast path) and do a get_unaligned() in the slow path.

This is a modification of a wholly get_unaligned patch submitted by Paul Guo

Reported-by: Paul Guo <ggang@tilera.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-07-23 15:23:08 -07:00
Karlis Ogsts 72bb99cfe9 staging: android: logger: Correct write offset reset on error
In the situation that a writer fails to copy data from userspace it will reset
the write offset to the value it had before it went to sleep. This discarding
any messages written while aquiring the mutex.

Therefore the reset offset needs to be retrieved after acquiring the mutex.

Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 15:08:50 -07:00
Sergey Senozhatsky 644d478793 staging: zram: protect zram_reset_device() call
Commit 9b3bb7abcd (remove
zram_sysfs file (v2)) accidentally made zram_reset_device()
racy. Protect zram_reset_device() call with zram->lock.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Jerome Marchand <jmarchand@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 15:08:50 -07:00
Dan Carpenter f2a6fed1ce staging: gdm72xx: potential use after free in send_qos_list()
Sometimes free_qos_entry() sometimes frees its argument.  I have moved
the dereference of "entry" ahead on line to avoid a use after free.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 15:08:50 -07:00
Paul Bolle 3a349cee59 staging: drm/imx: drop "select OF_VIDEOMODE"
Commit ac4c1a9b33 ("staging: drm/imx: Add LDB support") added the
DRM_IMX_LDB Kconfig entry. That entry selects OF_VIDEOMODE. But there is
no Kconfig symbol named OF_VIDEOMODE. The select statement for that
symbol is a nop. Drop it.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 15:08:50 -07:00
Dan Carpenter c8145c5610 staging: frontier: use after free in disconnect()
usb_alphatrack_delete() frees "dev" so we can't use it on that path.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 15:08:50 -07:00
Linus Torvalds 7c6d4dca77 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha
Pull alpha architecture fixes from Matt Turner:
 "This contains mostly clean ups and fixes but also an implementation of
  atomic64_dec_if_positive() and a pair of new syscalls"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha:
  alpha: Use handle_percpu_irq for the timer interrupt
  alpha: Force the user-visible HZ to a constant 1024.
  alpha: Don't if-out dp264_device_interrupt.
  alpha: Use __builtin_alpha_rpcc
  alpha: Fix type compatibility warning for marvel_map_irq
  alpha: Generate dwarf2 unwind info for various kernel entry points.
  alpha: Implement atomic64_dec_if_positive
  alpha: Improve atomic_add_unless
  alpha: Modernize lib/mpi/longlong.h
  alpha: Add kcmp and finit_module syscalls
  alpha: locks: remove unused arch_*_relax operations
  alpha: kernel: typo issue, using '1' instead of '11'
  alpha: kernel: using memcpy() instead of strcpy()
  alpha: Convert print_symbol to %pSR
2013-07-23 14:39:57 -07:00
Linus Torvalds a030cbc350 vhost: more fixes for 3.11
This includes some fixes for vhost net and scsi drivers.
 The test module has already been reworked to avoid rcu
 usage, but the necessary core changes are missing,
 we fixed this.
 Unlikely to affect any real-world users, but it's
 early in the cycle so, let's merge them.
 
 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull vhost fixes from Michael Tsirkin:
 "vhost: more fixes for 3.11

  This includes some fixes for vhost net and scsi drivers.

  The test module has already been reworked to avoid rcu usage, but the
  necessary core changes are missing, we fixed this.

  Unlikely to affect any real-world users, but it's early in the cycle
  so, let's merge them"

(It was earlier when Michael originally sent the email, but it somehot
got missed in the flood, so here it is after -rc2)

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost: Remove custom vhost rcu usage
  vhost-scsi: Always access vq->private_data under vq mutex
  vhost-net: Always access vq->private_data under vq mutex
2013-07-23 14:38:20 -07:00