Commit Graph

632261 Commits

Author SHA1 Message Date
Ursula Braun
baac789832 s390/netiucv: get rid of one memcpy in netiucv_printuser
Save a memcpy in netiucv_printuser().

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-13 10:59:45 -04:00
Roopa Prabhu
de1dfeefef bridge: add address and vlan to fdb warning messages
This patch adds vlan and address to warning messages printed
in the bridge fdb code for debuggability.

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-13 10:49:54 -04:00
Xin Long
8ae808eb85 sctp: remove the old ttl expires policy
The prsctp polices include ttl expires policy already, we should remove
the old ttl expires codes, and just adjust the new polices' codes to be
compatible with the old one for users.

This patch is to remove all the old expires codes, and if prsctp polices
are not set, it will still set msg's expires_at and check the expires in
sctp_check_abandoned.

Note that asoc->prsctp_enable is set by default, so users can't feel any
difference even if they use the old expires api in userspace.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-13 09:44:14 -04:00
Xin Long
cc6ac9bccf sctp: reuse sent_count to avoid retransmitted chunks for RTT measurements
Now sctp uses chunk->resent to record if a chunk is retransmitted, for
RTT measurements with retransmitted DATA chunks. chunk->sent_count was
introduced to record how many times one chunk has been sent for prsctp
RTX policy before. We actually can know if one chunk is retransmitted
by checking chunk->sent_count is greater than 1.

This patch is to remove resent from sctp_chunk and reuse sent_count
to avoid retransmitted chunks for RTT measurements.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-13 09:44:13 -04:00
David S. Miller
0f505b1ae6 Merge branch 'centralize-netdevice-mtu-bounds-checking'
Jarod Wilson says:

====================
net: centralize net_device MTU bounds checking

While looking into an MTU issue with sfc, I started noticing that almost
every NIC driver with an ndo_change_mtu function implemented almost
exactly the same range checks, and in many cases, that was the only
practical thing their ndo_change_mtu function was doing. Quite a few
drivers have either 68, 64, 60 or 46 as their minimum MTU value checked,
and then various sizes from 1500 to 65535 for their maximum MTU value. We
can remove a whole lot of redundant code here if we simple store min_mtu
and max_mtu in net_device, and check against those in net/core/dev.c's
dev_set_mtu().

This pair of patches looks to introduce centralized MTU range checking
infrastructure, while maintaining compatibility with all existing drivers,
and start to make use of it, converting all eth_change_mtu/ether_setup users
over to this new infra.

Assuming these pass review muster, I've got a ton of follow-on patches to
clean up MTU settings for everything in the kernel with an ndo_change_mtu.

This work is all staged in a (rebasing) git tree here:

https://github.com/jarodwilson/linux-muck

The master branch is based on net-next from Oct 7, and carries these two
patches, plus a ton of follow-on patches to eliminate MTU range checks
and change_mtu functions where possible. All patches were successfully
built across 160 various arch and config combos by the 0-day folks.
(Thanks to Andrew Lunn for the suggestion to get that going).
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-13 09:36:58 -04:00
Jarod Wilson
a52ad514fd net: deprecate eth_change_mtu, remove usage
With centralized MTU checking, there's nothing productive done by
eth_change_mtu that isn't already done in dev_set_mtu, so mark it as
deprecated and remove all usage of it in the kernel. All callers have been
audited for calls to alloc_etherdev* or ether_setup directly, which means
they all have a valid dev->min_mtu and dev->max_mtu. Now eth_change_mtu
prints out a netdev_warn about being deprecated, for the benefit of
out-of-tree drivers that might be utilizing it.

Of note, dvb_net.c actually had dev->mtu = 4096, while using
eth_change_mtu, meaning that if you ever tried changing it's mtu, you
couldn't set it above 1500 anymore. It's now getting dev->max_mtu also set
to 4096 to remedy that.

v2: fix up lantiq_etop, missed breakage due to drive not compiling on x86

CC: netdev@vger.kernel.org
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-13 09:36:57 -04:00
Jarod Wilson
61e84623ac net: centralize net_device min/max MTU checking
While looking into an MTU issue with sfc, I started noticing that almost
every NIC driver with an ndo_change_mtu function implemented almost
exactly the same range checks, and in many cases, that was the only
practical thing their ndo_change_mtu function was doing. Quite a few
drivers have either 68, 64, 60 or 46 as their minimum MTU value checked,
and then various sizes from 1500 to 65535 for their maximum MTU value. We
can remove a whole lot of redundant code here if we simple store min_mtu
and max_mtu in net_device, and check against those in net/core/dev.c's
dev_set_mtu().

In theory, there should be zero functional change with this patch, it just
puts the infrastructure in place. Subsequent patches will attempt to start
using said infrastructure, with theoretically zero change in
functionality.

CC: netdev@vger.kernel.org
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-13 09:36:56 -04:00
David S. Miller
1b830996c1 Merge branch 's390-net'
Ursula Braun says:

====================
s390: af_iucv patches

here are 2 patches for the s390-only af_iucv socket family code.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-12 01:56:10 -04:00
Ursula Braun
8c68b1a0e9 Subject: [PATCH] af_iucv: drop skbs rejected by filter
A packet filter might be installed for instance with setsockopt
SO_ATTACH_FILTER. af_iucv currently queues skbs rejected by filter
into the backlog queue. This does not make sense, since packets
rejected by filter can be dropped immediately. This patch adds
separate sk_filter return code checking, and dropping of packets
if applicable.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Reported-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-12 01:56:04 -04:00
Ursula Braun
4e0ad32216 Subject: [PATCH] af_iucv: enable control sends in case of SEND_SHUTDOWN
If a socket program has shut down the socket for sending, it can still
receive an undetermined number of packets. The AF_IUCV protocol for
HIPER transport requires sending of a WIN flag from time to time
from the receiver to the sender, otherwise the peer cannot continue
sending. That means sending of control flags must still work, even
though the AF_IUCV socket is shutdown for sending data.
sock_alloc_send_skb() returns with error EPIPE, if socket sk_shutdown
is SEND_SHUTDOWN. Thus this patch temporarily removes the send
shutdown attribute from the socket to enable transfer of control
flags.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-12 01:56:04 -04:00
David S. Miller
b07bf5fa32 Merge branch 'xgene-gpio'
Iyappan Subramanian says:

====================
drivers: net: xgene: fix: Use GPIO to get link status

Since the link value reported by the link status register is not
reliable if no SPF module inserted, this patchset fixes the issue by
using GPIO to determine the link status when no module inserted.
====================

Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Signed-off-by: Quan Nguyen <qnguyen@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-12 01:54:03 -04:00
Iyappan Subramanian
d2561ed389 arm64: xgene: defconfig: Enable Standby GPIO
Enable CONFIG_GPIO_XGENE_SB.

Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Signed-off-by: Quan Nguyen <qnguyen@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-12 01:53:55 -04:00
Iyappan Subramanian
751d6fd18f drivers: net: xgene: fix: Use GPIO to get link status
The link value reported by the link status register is not
reliable when no SPF module inserted. This patchset fixes this
issue by using GPIO to determine the link status.

Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Signed-off-by: Quan Nguyen <qnguyen@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-12 01:53:55 -04:00
Jiri Benc
c66549ffd6 openvswitch: correctly fragment packet with mpls headers
If mpls headers were pushed to a defragmented packet, the refragmentation no
longer works correctly after 48d2ab609b ("net: mpls: Fixups for GSO"). The
network header has to be shifted after the mpls headers for the
fragmentation and restored afterwards.

Fixes: 48d2ab609b ("net: mpls: Fixups for GSO")
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-12 01:42:52 -04:00
Philippe Reynes
bb10bb3ea8 net: dsa: slave: use new api ethtool_{get|set}_link_ksettings
The ethtool api {get|set}_settings is deprecated.
We move this driver to new api {get|set}_link_ksettings.

Signed-off-by: Philippe Reynes <tremyfr@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-12 01:40:25 -04:00
Philippe Reynes
6e76510e7e net: usb: lan78xx: use new api ethtool_{get|set}_link_ksettings
The ethtool api {get|set}_settings is deprecated.
We move this driver to new api {get|set}_link_ksettings.

Signed-off-by: Philippe Reynes <tremyfr@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-12 01:40:25 -04:00
Philippe Reynes
86e3a04002 net: ti: netcp_ethss: use new api ethtool_{get|set}_link_ksettings
The ethtool api {get|set}_settings is deprecated.
We move this driver to new api {get|set}_link_ksettings.

Signed-off-by: Philippe Reynes <tremyfr@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-12 01:40:25 -04:00
Philippe Reynes
2479876d46 net: ti: cpsw: use new api ethtool_{get|set}_link_ksettings
The ethtool api {get|set}_settings is deprecated.
We move this driver to new api {get|set}_link_ksettings.

Signed-off-by: Philippe Reynes <tremyfr@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-12 01:40:25 -04:00
Philippe Reynes
1685e785cc net: stmmac: use new api ethtool_{get|set}_link_ksettings
The ethtool api {get|set}_settings is deprecated.
We move this driver to new api {get|set}_link_ksettings.

Signed-off-by: Philippe Reynes <tremyfr@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-12 01:40:25 -04:00
Philippe Reynes
d6d50c7ea4 net: stmmac: use phydev from struct net_device
The private structure contain a pointer to phydev, but the structure
net_device already contain such pointer. So we can remove the pointer
phydev in the private structure, and update the driver to use the
one contained in struct net_device.

Signed-off-by: Philippe Reynes <tremyfr@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-12 01:40:25 -04:00
Philippe Reynes
a54e1612bc net: mv643xx_eth: use new api ethtool_{get|set}_link_ksettings
The ethtool api {get|set}_settings is deprecated.
We move this driver to new api {get|set}_link_ksettings.

Signed-off-by: Philippe Reynes <tremyfr@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-12 01:40:25 -04:00
Philippe Reynes
1e8a655db2 net: mv643xx_eth: use phydev from struct net_device
The private structure contain a pointer to phydev, but the structure
net_device already contain such pointer. So we can remove the pointer
phydev in the private structure, and update the driver to use the
one contained in struct net_device.

Signed-off-by: Philippe Reynes <tremyfr@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-12 01:40:24 -04:00
Linus Torvalds
6b25e21fa6 Merge tag 'drm-for-v4.9' of git://people.freedesktop.org/~airlied/linux
Pull drm updates from Dave Airlie:
 "Core:
   - Fence destaging work
   - DRIVER_LEGACY to split off legacy drm drivers
   - drm_mm refactoring
   - Splitting drm_crtc.c into chunks and documenting better
   - Display info fixes
   - rbtree support for prime buffer lookup
   - Simple VGA DAC driver

  Panel:
   - Add Nexus 7 panel
   - More simple panels

  i915:
   - Refactoring GEM naming
   - Refactored vma/active tracking
   - Lockless request lookups
   - Better stolen memory support
   - FBC fixes
   - SKL watermark fixes
   - VGPU improvements
   - dma-buf fencing support
   - Better DP dongle support

  amdgpu:
   - Powerplay for Iceland asics
   - Improved GPU reset support
   - UVD/VEC powergating support for CZ/ST
   - Preinitialised VRAM buffer support
   - Virtual display support
   - Initial SI support
   - GTT rework
   - PCI shutdown callback support
   - HPD IRQ storm fixes

  amdkfd:
   - bugfixes

  tilcdc:
   - Atomic modesetting support

  mediatek:
   - AAL + GAMMA engine support
   - Hook up gamma LUT
   - Temporal dithering support

  imx:
   - Pixel clock from devicetree
   - drm bridge support for LVDS bridges
   - active plane reconfiguration
   - VDIC deinterlacer support
   - Frame synchronisation unit support
   - Color space conversion support

  analogix:
   - PSR support
   - Better panel on/off support

  rockchip:
   - rk3399 vop/crtc support
   - PSR support

  vc4:
   - Interlaced vblank timing
   - 3D rendering CPU overhead reduction
   - HDMI output fixes

  tda998x:
   - HDMI audio ASoC support

  sunxi:
   - Allwinner A33 support
   - better TCON support

  msm:
   - DT binding cleanups
   - Explicit fence-fd support

  sti:
   - remove sti415/416 support

  etnaviv:
   - MMUv2 refactoring
   - GC3000 support

  exynos:
   - Refactoring HDMI DCC/PHY
   - G2D pm regression fix
   - Page fault issues with wait for vblank

  There is no nouveau work in this tree, as Ben didn't get a pull
  request in, and he was fighting moving to atomic and adding mst
  support, so maybe best it waits for a cycle"

* tag 'drm-for-v4.9' of git://people.freedesktop.org/~airlied/linux: (1412 commits)
  drm/crtc: constify drm_crtc_index parameter
  drm/i915: Fix conflict resolution from backmerge of v4.8-rc8 to drm-next
  drm/i915/guc: Unwind GuC workqueue reservation if request construction fails
  drm/i915: Reset the breadcrumbs IRQ more carefully
  drm/i915: Force relocations via cpu if we run out of idle aperture
  drm/i915: Distinguish last emitted request from last submitted request
  drm/i915: Allow DP to work w/o EDID
  drm/i915: Move long hpd handling into the hotplug work
  drm/i915/execlists: Reinitialise context image after GPU hang
  drm/i915: Use correct index for backtracking HUNG semaphores
  drm/i915: Unalias obj->phys_handle and obj->userptr
  drm/i915: Just clear the mmiodebug before a register access
  drm/i915/gen9: only add the planes actually affected by ddb changes
  drm/i915: Allow PCH DPLL sharing regardless of DPLL_SDVO_HIGH_SPEED
  drm/i915/bxt: Fix HDMI DPLL configuration
  drm/i915/gen9: fix the watermark res_blocks value
  drm/i915/gen9: fix plane_blocks_per_line on watermarks calculations
  drm/i915/gen9: minimum scanlines for Y tile is not always 4
  drm/i915/gen9: fix the WaWmMemoryReadLatency implementation
  drm/i915/kbl: KBL also needs to run the SAGV code
  ...
2016-10-11 18:12:22 -07:00
Linus Torvalds
a379f71a30 Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:

 - a few block updates that fell in my lap

 - lib/ updates

 - checkpatch

 - autofs

 - ipc

 - a ton of misc other things

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (100 commits)
  mm: split gfp_mask and mapping flags into separate fields
  fs: use mapping_set_error instead of opencoded set_bit
  treewide: remove redundant #include <linux/kconfig.h>
  hung_task: allow hung_task_panic when hung_task_warnings is 0
  kthread: add kerneldoc for kthread_create()
  kthread: better support freezable kthread workers
  kthread: allow to modify delayed kthread work
  kthread: allow to cancel kthread work
  kthread: initial support for delayed kthread work
  kthread: detect when a kthread work is used by more workers
  kthread: add kthread_destroy_worker()
  kthread: add kthread_create_worker*()
  kthread: allow to call __kthread_create_on_node() with va_list args
  kthread/smpboot: do not park in kthread_create_on_cpu()
  kthread: kthread worker API cleanup
  kthread: rename probe_kthread_data() to kthread_probe_data()
  scripts/tags.sh: enable code completion in VIM
  mm: kmemleak: avoid using __va() on addresses that don't have a lowmem mapping
  kdump, vmcoreinfo: report memory sections virtual addresses
  ipc/sem.c: add cond_resched in exit_sme
  ...
2016-10-11 17:34:10 -07:00
Michal Hocko
9c5d760b8d mm: split gfp_mask and mapping flags into separate fields
mapping->flags currently encodes two different things into a single flag.
It contains sticky gfp_mask for page cache allocations and AS_ codes used
to report errors/enospace and other states which are mapping specific.
Condensing the two semantically unrelated things saves few bytes but it
also complicates other things.  For one thing the gfp flags space is
reduced and in fact we are already running out of available bits.  It can
be assumed that more gfp flags will be necessary later on.

To not introduce the address_space grow (at least on x86_64) we can stick
it right after private_lock because we have a hole there.

struct address_space {
        struct inode *             host;                 /*     0     8 */
        struct radix_tree_root     page_tree;            /*     8    16 */
        spinlock_t                 tree_lock;            /*    24     4 */
        atomic_t                   i_mmap_writable;      /*    28     4 */
        struct rb_root             i_mmap;               /*    32     8 */
        struct rw_semaphore        i_mmap_rwsem;         /*    40    40 */
        /* --- cacheline 1 boundary (64 bytes) was 16 bytes ago --- */
        long unsigned int          nrpages;              /*    80     8 */
        long unsigned int          nrexceptional;        /*    88     8 */
        long unsigned int          writeback_index;      /*    96     8 */
        const struct address_space_operations  * a_ops;  /*   104     8 */
        long unsigned int          flags;                /*   112     8 */
        spinlock_t                 private_lock;         /*   120     4 */

        /* XXX 4 bytes hole, try to pack */

        /* --- cacheline 2 boundary (128 bytes) --- */
        struct list_head           private_list;         /*   128    16 */
        void *                     private_data;         /*   144     8 */

        /* size: 152, cachelines: 3, members: 14 */
        /* sum members: 148, holes: 1, sum holes: 4 */
        /* last cacheline: 24 bytes */
};

Link: http://lkml.kernel.org/r/20160912114852.GI14524@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:34 -07:00
Michal Hocko
5114a97a8b fs: use mapping_set_error instead of opencoded set_bit
The mapping_set_error() helper sets the correct AS_ flag for the mapping
so there is no reason to open code it.  Use the helper directly.

[akpm@linux-foundation.org: be honest about conversion from -ENXIO to -EIO]
Link: http://lkml.kernel.org/r/20160912111608.2588-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Masahiro Yamada
97139d4a6f treewide: remove redundant #include <linux/kconfig.h>
Kernel source files need not include <linux/kconfig.h> explicitly
because the top Makefile forces to include it with:

  -include $(srctree)/include/linux/kconfig.h

This commit removes explicit includes except the following:

  * arch/s390/include/asm/facilities_src.h
  * tools/testing/radix-tree/linux/kernel.h

These two are used for host programs.

Link: http://lkml.kernel.org/r/1473656164-11929-1-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
John Siddle
48a6d64eda hung_task: allow hung_task_panic when hung_task_warnings is 0
Previously hung_task_panic would not be respected if enabled after
hung_task_warnings had already been decremented to 0.

Permit the kernel to panic if hung_task_panic is enabled after
hung_task_warnings has already been decremented to 0 and another task
hangs for hung_task_timeout_secs seconds.

Check if hung_task_panic is enabled so we don't return prematurely, and
check if hung_task_warnings is non-zero so we don't print the warning
unnecessarily.

[akpm@linux-foundation.org: fix off-by-one]
Link: http://lkml.kernel.org/r/1473450214-4049-1-git-send-email-jsiddle@redhat.com
Signed-off-by: John Siddle <jsiddle@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Jonathan Corbet
e154ccc831 kthread: add kerneldoc for kthread_create()
This macro is referenced in other kerneldoc comments, but lacks one of its
own; fix that.

Link: http://lkml.kernel.org/r/20160826072313.726a3485@lwn.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Reported-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Petr Mladek
dbf52682cb kthread: better support freezable kthread workers
This patch allows to make kthread worker freezable via a new @flags
parameter. It will allow to avoid an init work in some kthreads.

It currently does not affect the function of kthread_worker_fn()
but it might help to do some optimization or fixes eventually.

I currently do not know about any other use for the @flags
parameter but I believe that we will want more flags
in the future.

Finally, I hope that it will not cause confusion with @flags member
in struct kthread. Well, I guess that we will want to rework the
basic kthreads implementation once all kthreads are converted into
kthread workers or workqueues. It is possible that we will merge
the two structures.

Link: http://lkml.kernel.org/r/1470754545-17632-12-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Petr Mladek
9a6b06c8d9 kthread: allow to modify delayed kthread work
There are situations when we need to modify the delay of a delayed kthread
work. For example, when the work depends on an event and the initial delay
means a timeout. Then we want to queue the work immediately when the event
happens.

This patch implements kthread_mod_delayed_work() as inspired workqueues.
It cancels the timer, removes the work from any worker list and queues it
again with the given timeout.

A very special case is when the work is being canceled at the same time.
It might happen because of the regular kthread_cancel_delayed_work_sync()
or by another kthread_mod_delayed_work(). In this case, we do nothing and
let the other operation win. This should not normally happen as the caller
is supposed to synchronize these operations a reasonable way.

Link: http://lkml.kernel.org/r/1470754545-17632-11-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Petr Mladek
37be45d49d kthread: allow to cancel kthread work
We are going to use kthread workers more widely and sometimes we will need
to make sure that the work is neither pending nor running.

This patch implements cancel_*_sync() operations as inspired by
workqueues.  Well, we are synchronized against the other operations via
the worker lock, we use del_timer_sync() and a counter to count parallel
cancel operations.  Therefore the implementation might be easier.

First, we check if a worker is assigned.  If not, the work has newer been
queued after it was initialized.

Second, we take the worker lock.  It must be the right one.  The work must
not be assigned to another worker unless it is initialized in between.

Third, we try to cancel the timer when it exists.  The timer is deleted
synchronously to make sure that the timer call back is not running.  We
need to temporary release the worker->lock to avoid a possible deadlock
with the callback.  In the meantime, we set work->canceling counter to
avoid any queuing.

Fourth, we try to remove the work from a worker list. It might be
the list of either normal or delayed works.

Fifth, if the work is running, we call kthread_flush_work().  It might
take an arbitrary time.  We need to release the worker-lock again.  In the
meantime, we again block any queuing by the canceling counter.

As already mentioned, the check for a pending kthread work is done under a
lock.  In compare with workqueues, we do not need to fight for a single
PENDING bit to block other operations.  Therefore we do not suffer from
the thundering storm problem and all parallel canceling jobs might use
kthread_flush_work().  Any queuing is blocked until the counter gets zero.

Link: http://lkml.kernel.org/r/1470754545-17632-10-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Petr Mladek
22597dc3d9 kthread: initial support for delayed kthread work
We are going to use kthread_worker more widely and delayed works
will be pretty useful.

The implementation is inspired by workqueues.  It uses a timer to queue
the work after the requested delay.  If the delay is zero, the work is
queued immediately.

In compare with workqueues, each work is associated with a single worker
(kthread).  Therefore the implementation could be much easier.  In
particular, we use the worker->lock to synchronize all the operations with
the work.  We do not need any atomic operation with a flags variable.

In fact, we do not need any state variable at all.  Instead, we add a list
of delayed works into the worker.  Then the pending work is listed either
in the list of queued or delayed works.  And the existing check of pending
works is the same even for the delayed ones.

A work must not be assigned to another worker unless reinitialized.
Therefore the timer handler might expect that dwork->work->worker is valid
and it could simply take the lock.  We just add some sanity checks to help
with debugging a potential misuse.

Link: http://lkml.kernel.org/r/1470754545-17632-9-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Petr Mladek
8197b3d43b kthread: detect when a kthread work is used by more workers
Nothing currently prevents a work from queuing for a kthread worker when
it is already running on another one.  This means that the work might run
in parallel on more than one worker.  Also some operations are not
reliable, e.g.  flush.

This problem will be even more visible after we add kthread_cancel_work()
function.  It will only have "work" as the parameter and will use
worker->lock to synchronize with others.

Well, normally this is not a problem because the API users are sane.
But bugs might happen and users also might be crazy.

This patch adds a warning when we try to insert the work for another
worker.  It does not fully prevent the misuse because it would make the
code much more complicated without a big benefit.

It adds the same warning also into kthread_flush_work() instead of the
repeated attempts to get the right lock.

A side effect is that one needs to explicitly reinitialize the work if it
must be queued into another worker.  This is needed, for example, when the
worker is stopped and started again.  It is a bit inconvenient.  But it
looks like a good compromise between the stability and complexity.

I have double checked all existing users of the kthread worker API and
they all seems to initialize the work after the worker gets started.

Just for completeness, the patch adds a check that the work is not already
in a queue.

The patch also puts all the checks into a separate function.  It will be
reused when implementing delayed works.

Link: http://lkml.kernel.org/r/1470754545-17632-8-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Petr Mladek
35033fe9cb kthread: add kthread_destroy_worker()
The current kthread worker users call flush() and stop() explicitly.
This function does the same plus it frees the kthread_worker struct
in one call.

It is supposed to be used together with kthread_create_worker*() that
allocates struct kthread_worker.

Link: http://lkml.kernel.org/r/1470754545-17632-7-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Petr Mladek
fbae2d44aa kthread: add kthread_create_worker*()
Kthread workers are currently created using the classic kthread API,
namely kthread_run().  kthread_worker_fn() is passed as the @threadfn
parameter.

This patch defines kthread_create_worker() and
kthread_create_worker_on_cpu() functions that hide implementation details.

They enforce using kthread_worker_fn() for the main thread.  But I doubt
that there are any plans to create any alternative.  In fact, I think that
we do not want any alternative main thread because it would be hard to
support consistency with the rest of the kthread worker API.

The naming and function of kthread_create_worker() is inspired by the
workqueues API like the rest of the kthread worker API.

The kthread_create_worker_on_cpu() variant is motivated by the original
kthread_create_on_cpu().  Note that we need to bind per-CPU kthread
workers already when they are created.  It makes the life easier.
kthread_bind() could not be used later for an already running worker.

This patch does _not_ convert existing kthread workers.  The kthread
worker API need more improvements first, e.g.  a function to destroy the
worker.

IMPORTANT:

kthread_create_worker_on_cpu() allows to use any format of the worker
name, in compare with kthread_create_on_cpu().  The good thing is that it
is more generic.  The bad thing is that most users will need to pass the
cpu number in two parameters, e.g.  kthread_create_worker_on_cpu(cpu,
"helper/%d", cpu).

To be honest, the main motivation was to avoid the need for an empty
va_list.  The only legal way was to create a helper function that would be
called with an empty list.  Other attempts caused compilation warnings or
even errors on different architectures.

There were also other alternatives, for example, using #define or
splitting __kthread_create_worker().  The used solution looked like the
least ugly.

Link: http://lkml.kernel.org/r/1470754545-17632-6-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Petr Mladek
255451e453 kthread: allow to call __kthread_create_on_node() with va_list args
kthread_create_on_node() implements a bunch of logic to create the
kthread.  It is already called by kthread_create_on_cpu().

We are going to extend the kthread worker API and will need to call
kthread_create_on_node() with va_list args there.

This patch does only a refactoring and does not modify the existing
behavior.

Link: http://lkml.kernel.org/r/1470754545-17632-5-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Petr Mladek
a65d40961d kthread/smpboot: do not park in kthread_create_on_cpu()
kthread_create_on_cpu() was added by the commit 2a1d446019
("kthread: Implement park/unpark facility").  It is currently used only
when enabling new CPU.  For this purpose, the newly created kthread has to
be parked.

The CPU binding is a bit tricky.  The kthread is parked when the CPU has
not been allowed yet.  And the CPU is bound when the kthread is unparked.

The function would be useful for more per-CPU kthreads, e.g.
bnx2fc_thread, fcoethread.  For this purpose, the newly created kthread
should stay in the uninterruptible state.

This patch moves the parking into smpboot.  It binds the thread already
when created.  Then the function might be used universally.  Also the
behavior is consistent with kthread_create() and kthread_create_on_node().

Link: http://lkml.kernel.org/r/1470754545-17632-4-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Petr Mladek
3989144f86 kthread: kthread worker API cleanup
A good practice is to prefix the names of functions by the name
of the subsystem.

The kthread worker API is a mix of classic kthreads and workqueues.  Each
worker has a dedicated kthread.  It runs a generic function that process
queued works.  It is implemented as part of the kthread subsystem.

This patch renames the existing kthread worker API to use
the corresponding name from the workqueues API prefixed by
kthread_:

__init_kthread_worker()		-> __kthread_init_worker()
init_kthread_worker()		-> kthread_init_worker()
init_kthread_work()		-> kthread_init_work()
insert_kthread_work()		-> kthread_insert_work()
queue_kthread_work()		-> kthread_queue_work()
flush_kthread_work()		-> kthread_flush_work()
flush_kthread_worker()		-> kthread_flush_worker()

Note that the names of DEFINE_KTHREAD_WORK*() macros stay
as they are. It is common that the "DEFINE_" prefix has
precedence over the subsystem names.

Note that INIT() macros and init() functions use different
naming scheme. There is no good solution. There are several
reasons for this solution:

  + "init" in the function names stands for the verb "initialize"
    aka "initialize worker". While "INIT" in the macro names
    stands for the noun "INITIALIZER" aka "worker initializer".

  + INIT() macros are used only in DEFINE() macros

  + init() functions are used close to the other kthread()
    functions. It looks much better if all the functions
    use the same scheme.

  + There will be also kthread_destroy_worker() that will
    be used close to kthread_cancel_work(). It is related
    to the init() function. Again it looks better if all
    functions use the same naming scheme.

  + there are several precedents for such init() function
    names, e.g. amd_iommu_init_device(), free_area_init_node(),
    jump_label_init_type(),  regmap_init_mmio_clk(),

  + It is not an argument but it was inconsistent even before.

[arnd@arndb.de: fix linux-next merge conflict]
 Link: http://lkml.kernel.org/r/20160908135724.1311726-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/1470754545-17632-3-git-send-email-pmladek@suse.com
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Petr Mladek
e700591ae0 kthread: rename probe_kthread_data() to kthread_probe_data()
Patch series "kthread: Kthread worker API improvements"

The intention of this patchset is to make it easier to manipulate and
maintain kthreads.  Especially, I want to replace all the custom main
cycles with a generic one.  Also I want to make the kthreads sleep in a
consistent state in a common place when there is no work.

This patch (of 11):

A good practice is to prefix the names of functions by the name of the
subsystem.

This patch fixes the name of probe_kthread_data().  The other wrong
functions names are part of the kthread worker API and will be fixed
separately.

Link: http://lkml.kernel.org/r/1470754545-17632-2-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Mathieu Maret
d0c75f33f0 scripts/tags.sh: enable code completion in VIM
Vim, with the omnicppcomplete(#1) plugin, can do code completion using
information build by ctags.  Add flags needed by omnicppcomplete(#2) to
have completion on member of structure.

1: https://github.com/vim-scripts/omnicppcomplete
2: https://github.com/vim-scripts/OmniCppComplete/blob/master/doc/omnicppcomplete.txt#L93

Link: http://lkml.kernel.org/r/20160830191546.4469-1-mathieu.maret@gmail.com
Signed-off-by: Mathieu Maret <mathieu.maret@gmail.com>
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Catalin Marinas
9099daed9c mm: kmemleak: avoid using __va() on addresses that don't have a lowmem mapping
Some of the kmemleak_*() callbacks in memblock, bootmem, CMA convert a
physical address to a virtual one using __va().  However, such physical
addresses may sometimes be located in highmem and using __va() is
incorrect, leading to inconsistent object tracking in kmemleak.

The following functions have been added to the kmemleak API and they take
a physical address as the object pointer.  They only perform the
corresponding action if the address has a lowmem mapping:

kmemleak_alloc_phys
kmemleak_free_part_phys
kmemleak_not_leak_phys
kmemleak_ignore_phys

The affected calling places have been updated to use the new kmemleak
API.

Link: http://lkml.kernel.org/r/1471531432-16503-1-git-send-email-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Thomas Garnier
0549a3c02e kdump, vmcoreinfo: report memory sections virtual addresses
KASLR memory randomization can randomize the base of the physical memory
mapping (PAGE_OFFSET), vmalloc (VMALLOC_START) and vmemmap
(VMEMMAP_START).  Adding these variables on VMCOREINFO so tools can easily
identify the base of each memory section.

Link: http://lkml.kernel.org/r/1471531632-23003-1-git-send-email-thgarnie@google.com
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Xunlei Pang <xlpang@redhat.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Eugene Surovegin <surovegin@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Nikolay Borisov
2a1613a586 ipc/sem.c: add cond_resched in exit_sme
In CONFIG_PREEMPT=n kernel a softlockup was observed while the for loop in
exit_sem.  Apparently it's possible for the loop to take quite a long time
and it doesn't have a scheduling point in it.  Since the codes is
executing under an rcu read section this may also cause rcu stalls, which
in turn block synchronize_rcu operations, which more or less de-stabilises
the whole system.

Fix this by introducing a cond_resched() at the beginning of the loop.

So this patch fixes the following:

  NMI watchdog: BUG: soft lockup - CPU#10 stuck for 23s! [httpd:18119]
  CPU: 10 PID: 18119 Comm: httpd Tainted: G           O    4.4.20-clouder2 #6
  Hardware name: Supermicro X10DRi/X10DRi, BIOS 1.1 04/14/2015
  task: ffff88348d695280 ti: ffff881c95550000 task.ti: ffff881c95550000
  RIP: 0010:[<ffffffff81614bc7>]  [<ffffffff81614bc7>] _raw_spin_lock+0x17/0x30
  RSP: 0018:ffff881c95553e40  EFLAGS: 00000246
  RAX: 0000000000000000 RBX: ffff883161b1eea8 RCX: 000000000000000d
  RDX: 0000000000000001 RSI: 000000000000000e RDI: ffff883161b1eea4
  RBP: ffff881c95553ea0 R08: ffff881c95553e68 R09: ffff883fef376f88
  R10: ffff881fffb58c20 R11: ffffea0072556600 R12: ffff883161b1eea0
  R13: ffff88348d695280 R14: ffff883dec427000 R15: ffff8831621672a0
  FS:  0000000000000000(0000) GS:ffff881fffb40000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f3b3723e020 CR3: 0000000001c0a000 CR4: 00000000001406e0
  Call Trace:
    ? exit_sem+0x7c/0x280
    do_exit+0x338/0xb40
    do_group_exit+0x43/0xd0
    SyS_exit_group+0x14/0x20
    entry_SYSCALL_64_fastpath+0x16/0x6e

Link: http://lkml.kernel.org/r/1475154992-6363-1-git-send-email-kernel@kyup.com
Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Cc: Herton R. Krzesinski <herton@redhat.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Davidlohr Bueso
ed27f9122c ipc/msg: avoid waking sender upon full queue
Blocked tasks queued in q_senders waiting for their message to fit in the
queue are blindly awoken every time we think there's a remote chance this
might happen.  This could cause numerous (and expensive -- thundering
herd-ish) bogus wakeups if the queue is still really full.  Adding to the
scheduling cost/overhead, there's also the fact that we need to take the
ipc object lock and requeue ourselves in the q_senders list.

By keeping track of the blocked sender's message size, we can know
previously if the wakeup ought to occur or not.  Otherwise, to maintain
the current wakeup order we just move it to the tail.  This is exactly
what occurs right now if the sender needs to go back to sleep.

The case of EIDRM is left completely untouched, as we need to wakeup all
the tasks, and shouldn't be playing games in the first place.

This patch was seen to save on the 'msgctl10' ltp testcase ~15% in context
switches (avg out of ten runs).  Although these tests are really about
functionality (as opposed to performance), is does show the direct
benefits of the optimization.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/1469748819-19484-6-git-send-email-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Davidlohr Bueso
d0d6a2a95e ipc/msg: make ss_wakeup() kill arg boolean
... 'tis annoying.

Link: http://lkml.kernel.org/r/1469748819-19484-4-git-send-email-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Davidlohr Bueso
e3658538bf ipc/msg: batch queue sender wakeups
Currently the use of wake_qs in sysv msg queues are only for the receiver
tasks that are blocked on the queue.  But blocked sender tasks (due to
queue size constraints) still are awoken with the ipc object lock held,
which can be a problem particularly for small sized queues and far from
gracious for -rt (just like it was for the receiver side).

The paths that actually wakeup a sender are obviously related to when we
are either getting rid of the queue or after (some) space is freed-up
after a receiver takes the msg (msgrcv).  Furthermore, with the exception
of msgrcv, we can always piggy-back on expunge_all that has its own tasks
lined-up for waking.  Finally, upon unlinking the message, it should be no
problem delaying the wakeups a bit until after we've released the lock.

Link: http://lkml.kernel.org/r/1469748819-19484-3-git-send-email-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Sebastian Andrzej Siewior
ee51636ca5 ipc/msg: implement lockless pipelined wakeups
This patch moves the wakeup_process() invocation so it is not done under
the ipc global lock by making use of a lockless wake_q.  With this change,
the waiter is woken up once the message has been assigned and it does not
need to loop on SMP if the message points to NULL.  In the signal case we
still need to check the pointer under the lock to verify the state.

This change should also avoid the introduction of preempt_disable() in -RT
which avoids a busy-loop which pools for the NULL -> !NULL change if the
waiter has a higher priority compared to the waker.

By making use of wake_qs, the logic of sysv msg queues is greatly
simplified (and very well suited as we can batch lockless wakeups),
particularly around the lockless receive algorithm.

This has been tested with Manred's pmsg-shared tool on a "AMD A10-7800
Radeon R7, 12 Compute Cores 4C+8G":

test             |   before   |   after    | diff
-----------------|------------|------------|----------
pmsg-shared 8 60 | 19,347,422 | 30,442,191 | + ~57.34 %
pmsg-shared 4 60 | 21,367,197 | 35,743,458 | + ~67.28 %
pmsg-shared 2 60 | 22,884,224 | 24,278,200 | +  ~6.09 %

Link: http://lkml.kernel.org/r/1469748819-19484-2-git-send-email-dave@stgolabs.net
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Manfred Spraul
5864a2fd30 ipc/sem.c: fix complex_count vs. simple op race
Commit 6d07b68ce1 ("ipc/sem.c: optimize sem_lock()") introduced a
race:

sem_lock has a fast path that allows parallel simple operations.
There are two reasons why a simple operation cannot run in parallel:
 - a non-simple operations is ongoing (sma->sem_perm.lock held)
 - a complex operation is sleeping (sma->complex_count != 0)

As both facts are stored independently, a thread can bypass the current
checks by sleeping in the right positions.  See below for more details
(or kernel bugzilla 105651).

The patch fixes that by creating one variable (complex_mode)
that tracks both reasons why parallel operations are not possible.

The patch also updates stale documentation regarding the locking.

With regards to stable kernels:
The patch is required for all kernels that include the
commit 6d07b68ce1 ("ipc/sem.c: optimize sem_lock()") (3.10?)

The alternative is to revert the patch that introduced the race.

The patch is safe for backporting, i.e. it makes no assumptions
about memory barriers in spin_unlock_wait().

Background:
Here is the race of the current implementation:

Thread A: (simple op)
- does the first "sma->complex_count == 0" test

Thread B: (complex op)
- does sem_lock(): This includes an array scan. But the scan can't
  find Thread A, because Thread A does not own sem->lock yet.
- the thread does the operation, increases complex_count,
  drops sem_lock, sleeps

Thread A:
- spin_lock(&sem->lock), spin_is_locked(sma->sem_perm.lock)
- sleeps before the complex_count test

Thread C: (complex op)
- does sem_lock (no array scan, complex_count==1)
- wakes up Thread B.
- decrements complex_count

Thread A:
- does the complex_count test

Bug:
Now both thread A and thread C operate on the same array, without
any synchronization.

Fixes: 6d07b68ce1 ("ipc/sem.c: optimize sem_lock()")
Link: http://lkml.kernel.org/r/1469123695-5661-1-git-send-email-manfred@colorfullife.com
Reported-by: <felixh@informatik.uni-bremen.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <1vier1@web.de>
Cc: <stable@vger.kernel.org>	[3.10+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Alexander Potapenko
65deb8af76 kcov: do not instrument lib/stackdepot.c
There's no point in collecting coverage from lib/stackdepot.c, as it is
not a function of syscall inputs.  Disabling kcov instrumentation for that
file will reduce the coverage noise level.

Link: http://lkml.kernel.org/r/1474640972-104131-1-git-send-email-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:32 -07:00