Now that svc_rdma_sendto has been renovated, svc_rdma_send_error can
be refactored to reduce code duplication and remove C structure-
based XDR encoding. It is also relocated to the source file that
contains its only caller.

This is a refactoring change only.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The current svcrdma sendto code path posts one RDMA Write WR at a
time. Each of these Writes typically carries a small number of pages
(for instance, up to 30 pages for mlx4 devices). That means a 1MB
NFS READ reply requires 9 ib_post_send() calls for the Write WRs,
and one for the Send WR carrying the actual RPC Reply message.

Instead, use the new rdma_rw API. The details of Write WR chain
construction and memory registration are taken care of in the RDMA
core. svcrdma can focus on the details of the RPC-over-RDMA
protocol. This gives three main benefits:

1. All Write WRs for one RDMA segment are posted in a single chain.
As few as one ib_post_send() for each Write chunk.

2. The Write path can now use FRWR to register the Write buffers.
If the device's maximum page list depth is large, this means a
single Write WR is needed for each RPC's Write chunk data.

3. The new code introduces support for RPCs that carry both a Write
list and a Reply chunk. This combination can be used for an NFSv4
READ where the data payload is large, and thus is removed from the
Payload Stream, but the Payload Stream is still larger than the
inline threshold.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The plan is to replace the local bespoke code that constructs and
posts RDMA Read and Write Work Requests with calls to the rdma_rw
API. This shares code with other RDMA-enabled ULPs that manages the
gory details of buffer registration and posting Work Requests.

Some design notes:

 o The structure of RPC-over-RDMA transport headers is flexible,
   allowing multiple segments per Reply with arbitrary alignment,
   each with a unique R_key. Write and Send WRs continue to be
   built and posted in separate code paths. However, one whole
   chunk (with one or more RDMA segments apiece) gets exactly
   one ib_post_send and one work completion.

 o svc_xprt reference counting is modified, since a chain of
   rdma_rw_ctx structs generates one completion, no matter how
   many Write WRs are posted.

 o The current code builds the transport header as it is construct-
   ing Write WRs. I've replaced that with marshaling of transport
   header data items in a separate step. This is because the exact
   structure of client-provided segments may not align with the
   components of the server's reply xdr_buf, or the pages in the
   page list. Thus parts of each client-provided segment may be
   written at different points in the send path.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The Send Queue depth is temporarily reduced to 1 SQE per credit. The
new rdma_rw API does an internal computation, during QP creation, to
increase the depth of the Send Queue to handle RDMA Read and Write
operations.

This change has to come before the NFSD code paths are updated to
use the rdma_rw API. Without this patch, rdma_rw_init_qp() increases
the size of the SQ too much, resulting in memory allocation failures
during QP creation.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Introduce a helper to DMA-map a reply's transport header before
sending it. This will in part replace the map vector cache.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Clean up: Move the ib_send_wr off the stack, and move common code
to post a Send Work Request into a helper.

This is a refactoring change only.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

A client can append random data to the end of an NFSv2 or NFSv3 RPC call
without our complaining; we'll just stop parsing at the end of the
expected data and ignore the rest.

Encoded arguments and replies are stored together in an array of pages,
and if a call is too large it could leave inadequate space for the
reply.  This is normally OK because NFS RPC's typically have either
short arguments and long replies (like READ) or long arguments and short
replies (like WRITE).  But a client that sends an incorrectly long reply
can violate those assumptions.  This was observed to cause crashes.

So, insist that the argument not be any longer than we expect.

Also, several operations increment rq_next_page in the decode routine
before checking the argument size, which can leave rq_next_page pointing
well past the end of the page array, causing trouble later in
svc_free_pages.

As followup we may also want to rewrite the encoding routines to check
more carefully that they aren't running off the end of the page array.
Reported-by: NTuomas Haanpää <thaan@synopsys.com>
Reported-by: NAri Kauppi <ari@synopsys.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Certain 64-bit systems (e.g. Amlogic Meson GX) require buffers to be
used for DMA to be 8-byte-aligned. struct sdio_func has an embedded
small DMA buffer not meeting this requirement.
When testing switching to descriptor chain mode in meson-gx driver
SDIO is broken therefore. Fix this by allocating the small DMA buffer
separately as kmalloc ensures that the returned memory area is
properly aligned for every basic data type.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Tested-by: NHelmut Klein <hgkr.klein@gmail.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Commit 729204ef("block: relax check on sg gap") allows us to merge
bios, if both are physically contiguous.  This change can merge a huge
number of small bios, through mkfs for example, mkfs.ntfs running time
can be decreased to ~1/10.

But if one rq starts with a non-aligned buffer (the 1st bvec's bv_offset
is non-zero) and if we allow the merge, it is quite difficult to respect
sg gap limit, especially the max segment size, or we risk having an
unaligned virtual boundary.  This patch tries to avoid the issue by
disallowing a merge, if the req starts with an unaligned buffer.

Also add comments to explain why the merged segment can't end in
unaligned virt boundary.

Fixes: 729204ef ("block: relax check on sg gap")
Tested-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NMing Lei <ming.lei@redhat.com>

Rewrote parts of the commit message and comments.
Signed-off-by: NJens Axboe <axboe@fb.com>

Dave noticed that after fixing MADV_DONTNEED vs numa balancing race the
last pmdp_huge_get_and_clear_notify() user is gone.

Let's drop the helper.

Link: http://lkml.kernel.org/r/20170306112047.24809-1-kirill.shutemov@linux.intel.comSigned-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

To improve scalability, if hardware queues are shared, restart
a single hardware queue in round-robin fashion. Rename
blk_mq_sched_restart_queues() to reflect the new semantics.
Remove blk_mq_sched_mark_restart_queue() because this function
has no callers. Remove flag QUEUE_FLAG_RESTART because this
patch removes the code that uses this flag.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Introduce a function that runs a hardware queue unconditionally
after a delay. Note: there is already a function that stops and
restarts a hardware queue after a delay, namely blk_mq_delay_queue().

This function will be used in the next patch in this series.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Long Li <longli@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

In elevator_switch(), if blk_mq_init_sched() fails, we attempt to fall
back to the original scheduler. However, at this point, we've already
torn down the original scheduler's tags, so this causes a crash. Doing
the fallback like the legacy elevator path is much harder for mq, so fix
it by just falling back to none, instead.
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Some drivers can't support all features in all configurations.  At the
moment we blindly set FEATURES_OK and later FAILED.  Support this better
by adding a callback drivers can use to do some early checks.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Recent pinctrl changes to allow dynamic allocation of pins exposed one
more issue with the pinctrl pins claimed early by the controller itself.
This caused a regression for IMX6 pinctrl hogs.

Before enabling the pin controller driver we need to wait until it has
been properly initialized, then claim the hogs, and only then enable it.

To fix the regression, split the code into pinctrl_claim_hogs() and
pinctrl_enable(). And then let's require that pinctrl_enable() is always
called by the pin controller driver when ready after calling
pinctrl_register_and_init().

Depends-on: 950b0d91 ("pinctrl: core: Fix regression caused by delayed
work for hogs")
Fixes: df61b366af26 ("pinctrl: core: Use delayed work for hogs")
Fixes: e566fc11 ("pinctrl: imx: use generic pinctrl helpers for
managing groups")
Cc: Haojian Zhuang <haojian.zhuang@linaro.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Mika Penttilä <mika.penttila@nextfour.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Nishanth Menon <nm@ti.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Stefan Agner <stefan@agner.ch>
Tested-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Tested-by: NGary Bisson <gary.bisson@boundarydevices.com>
Tested-by: NFabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

For SPI, we can get up to 32 additional bytes for response preamble.
The current overhead (2 bytes) may cause problems when we try to receive
a big response. Update it to 32 bytes.

Without this fix we could see a kernel BUG when we receive a big response
from the Chrome EC when is connected via SPI.
Signed-off-by: NVic Yang <victoryang@google.com>
Tested-by: Enric Balletbo i Serra <enric.balletbo.collabora.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

Rename the internal __reset_control_get/put functions to
__reset_control_get/put_internal and add an exported
__reset_control_get equivalent to __of_reset_control_get
that takes a struct device parameter.
This avoids the confusing call to __of_reset_control_get in
the non-DT case and fixes the devm_reset_control_get_optional
function to return NULL if RESET_CONTROLLER is enabled but
dev->of_node == NULL.

Fixes: bb475230 ("reset: make optional functions really optional")
Reported-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
Signed-off-by: NPhilipp Zabel <p.zabel@pengutronix.de>

As an oversight, for GICv2, we accidentally export the GICC_PMR register
in the format of the GICH_VMCR.VMPriMask field in the lower 5 bits of a
word, meaning that userspace must always use the lower 5 bits to
communicate with the KVM device and must shift the value left by 3
places to obtain the actual priority mask level.

Since GICv3 supports the full 8 bits of priority masking in the ICH_VMCR,
we have to fix the value we export when emulating a GICv2 on top of a
hardware GICv3 and exporting the emulated GICv2 state to userspace.

Take the chance to clarify this aspect of the ABI.
Reviewed-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NChristoffer Dall <cdall@linaro.org>

Include a mask in struct stat to indicate which bits of stx_attributes the
filesystem actually supports.

This would also be useful if we add another system call that allows you to
do a 'bulk attribute set' and pass in a statx struct with the masks
appropriately set to say what you want to set.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

opposite to iov_iter_advance(); the caller is responsible for never
using it to move back past the initial position.

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The enum values for QPTYPE, PRTYPE and CMS are off by 1 from the
values defined in figure 42 of the NVM Express over Fabrics 1.0:

    http://www.nvmexpress.org/wp-content/uploads/NVMe_over_Fabrics_1_0_Gold_20160605-1.pdf

Fix our enums to match the final spec.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>

Disable kasan after the first report.  There are several reasons for
this:

 - Single bug quite often has multiple invalid memory accesses causing
   storm in the dmesg.

 - Write OOB access might corrupt metadata so the next report will print
   bogus alloc/free stacktraces.

 - Reports after the first easily could be not bugs by itself but just
   side effects of the first one.

Given that multiple reports usually only do harm, it makes sense to
disable kasan after the first one.  If user wants to see all the
reports, the boot-time parameter kasan_multi_shot must be used.

[aryabinin@virtuozzo.com: wrote changelog and doc, added missing include]
Link: http://lkml.kernel.org/r/20170323154416.30257-1-aryabinin@virtuozzo.comSigned-off-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Huge pages are accounted as single units in the memcg's "file_mapped"
counter.  Account the correct number of base pages, like we do in the
corresponding node counter.

Link: http://lkml.kernel.org/r/20170322005111.3156-1-hannes@cmpxchg.orgSigned-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <stable@vger.kernel.org>	[4.8+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Yang Li has reported that drain_all_pages triggers a WARN_ON which means
that this function is called earlier than the mm_percpu_wq is
initialized on arm64 with CMA configured:

  WARNING: CPU: 2 PID: 1 at mm/page_alloc.c:2423 drain_all_pages+0x244/0x25c
  Modules linked in:
  CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.11.0-rc1-next-20170310-00027-g64dfbc5 #127
  Hardware name: Freescale Layerscape 2088A RDB Board (DT)
  task: ffffffc07c4a6d00 task.stack: ffffffc07c4a8000
  PC is at drain_all_pages+0x244/0x25c
  LR is at start_isolate_page_range+0x14c/0x1f0
  [...]
   drain_all_pages+0x244/0x25c
   start_isolate_page_range+0x14c/0x1f0
   alloc_contig_range+0xec/0x354
   cma_alloc+0x100/0x1fc
   dma_alloc_from_contiguous+0x3c/0x44
   atomic_pool_init+0x7c/0x208
   arm64_dma_init+0x44/0x4c
   do_one_initcall+0x38/0x128
   kernel_init_freeable+0x1a0/0x240
   kernel_init+0x10/0xfc
   ret_from_fork+0x10/0x20

Fix this by moving the whole setup_vmstat which is an initcall right now
to init_mm_internals which will be called right after the WQ subsystem
is initialized.

Link: http://lkml.kernel.org/r/20170315164021.28532-1-mhocko@kernel.orgSigned-off-by: NMichal Hocko <mhocko@suse.com>
Reported-by: NYang Li <pku.leo@gmail.com>
Tested-by: NYang Li <pku.leo@gmail.com>
Tested-by: NXiaolong Ye <xiaolong.ye@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The patch fix syntax errors introduced by commit 0c8893c9095d
("clockevents: Add a clkevt-of mechanism like clksrc-of").

Fixes: 0c8893c9095d ("clockevents: Add a clkevt-of mechanism like clksrc-of")
Signed-off-by: NAlexander Kochetkov <al.kochet@gmail.com>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

No caller currently checks the return value of
kvm_io_bus_unregister_dev(). This is evil, as all callers silently go on
freeing their device. A stale reference will remain in the io_bus,
getting at least used again, when the iobus gets teared down on
kvm_destroy_vm() - leading to use after free errors.

There is nothing the callers could do, except retrying over and over
again.

So let's simply remove the bus altogether, print an error and make
sure no one can access this broken bus again (returning -ENOMEM on any
attempt to access it).

Fixes: e93f8a0f ("KVM: convert io_bus to SRCU")
Cc: stable@vger.kernel.org # 3.4+
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

People reported that commit:

  5680d809 ("sched/clock: Provide better clock continuity")

broke "perf test tsc".

That commit added another offset to the reported clock value; so
take that into account when computing the provided offset values.
Reported-by: NAdrian Hunter <adrian.hunter@intel.com>
Reported-by: NArnaldo Carvalho de Melo <acme@kernel.org>
Tested-by: NAlexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 5680d809 ("sched/clock: Provide better clock continuity")
Signed-off-by: NIngo Molnar <mingo@kernel.org>

The introduction of reserved regions has left a couple of rough edges
which we could do with sorting out sooner rather than later. Since we
are not yet addressing the potential dynamic aspect of software-managed
reservations and presenting them at arbitrary fixed addresses, it is
incongruous that we end up displaying hardware vs. software-managed MSI
regions to userspace differently, especially since ARM-based systems may
actually require one or the other, or even potentially both at once,
(which iommu-dma currently has no hope of dealing with at all). Let's
resolve the former user-visible inconsistency ASAP before the ABI has
been baked into a kernel release, in a way that also lays the groundwork
for the latter shortcoming to be addressed by follow-up patches.

For clarity, rename the software-managed type to IOMMU_RESV_SW_MSI, use
IOMMU_RESV_MSI to describe the hardware type, and document everything a
little bit. Since the x86 MSI remapping hardware falls squarely under
this meaning of IOMMU_RESV_MSI, apply that type to their regions as well,
so that we tell the same story to userspace across all platforms.

Secondly, as the various region types require quite different handling,
and it really makes little sense to ever try combining them, convert the
bitfield-esque #defines to a plain enum in the process before anyone
gets the wrong impression.

Fixes: d30ddcaa ("iommu: Add a new type field in iommu_resv_region")
Reviewed-by: NEric Auger <eric.auger@redhat.com>
CC: Alex Williamson <alex.williamson@redhat.com>
CC: David Woodhouse <dwmw2@infradead.org>
CC: kvm@vger.kernel.org
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

Unfortunately the HWMON_T_ALARM define was missing,
although the associated entry was present in hwmon_temp_attributes.
This is needed to convert drivers to the new interface which use channel
based alarms.
Signed-off-by: NPeter Huewe <peterhuewe@gmx.de>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

SOF_TIMESTAMPING_OPT_STATS can be enabled and disabled
while packets are collected on the error queue.
So, checking SOF_TIMESTAMPING_OPT_STATS in sk->sk_tsflags
is not enough to safely assume that the skb contains
OPT_STATS data.

Add a bit in sock_exterr_skb to indicate whether the
skb contains opt_stats data.

Fixes: 1c885808 ("tcp: SOF_TIMESTAMPING_OPT_STATS option for SO_TIMESTAMPING")
Reported-by: NJongHwan Kim <zzoru007@gmail.com>
Signed-off-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

So that we can cancel a queued pkt later if necessary.
Signed-off-by: NPeng Tao <bergwolf@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When RESET_CONTROLLER is not enabled, the optional reset_control_get
stubs should now also return NULL.

Since it is now valid for reset_control_assert/deassert/reset/status/put
to be called unconditionally, with NULL as an argument for optional
resets, the stubs are not allowed to warn anymore.

Fixes: bb475230 ("reset: make optional functions really optional")
Reported-by: NAndrzej Hajda <a.hajda@samsung.com>
Tested-by: NAndrzej Hajda <a.hajda@samsung.com>
Reviewed-by: NAndrzej Hajda <a.hajda@samsung.com>
Cc: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
Signed-off-by: NPhilipp Zabel <p.zabel@pengutronix.de>

Creation of a kthread goes through a couple interlocked stages between
the kthread itself and its creator.  Once the new kthread starts
running, it initializes itself and wakes up the creator.  The creator
then can further configure the kthread and then let it start doing its
job by waking it up.

In this configuration-by-creator stage, the creator is the only one
that can wake it up but the kthread is visible to userland.  When
altering the kthread's attributes from userland is allowed, this is
fine; however, for cases where CPU affinity is critical,
kthread_bind() is used to first disable affinity changes from userland
and then set the affinity.  This also prevents the kthread from being
migrated into non-root cgroups as that can affect the CPU affinity and
many other things.

Unfortunately, the cgroup side of protection is racy.  While the
PF_NO_SETAFFINITY flag prevents further migrations, userland can win
the race before the creator sets the flag with kthread_bind() and put
the kthread in a non-root cgroup, which can lead to all sorts of
problems including incorrect CPU affinity and starvation.

This bug got triggered by userland which periodically tries to migrate
all processes in the root cpuset cgroup to a non-root one.  Per-cpu
workqueue workers got caught while being created and ended up with
incorrected CPU affinity breaking concurrency management and sometimes
stalling workqueue execution.

This patch adds task->no_cgroup_migration which disallows the task to
be migrated by userland.  kthreadd starts with the flag set making
every child kthread start in the root cgroup with migration
disallowed.  The flag is cleared after the kthread finishes
initialization by which time PF_NO_SETAFFINITY is set if the kthread
should stay in the root cgroup.

It'd be better to wait for the initialization instead of failing but I
couldn't think of a way of implementing that without adding either a
new PF flag, or sleeping and retrying from waiting side.  Even if
userland depends on changing cgroup membership of a kthread, it either
has to be synchronized with kthread_create() or periodically repeat,
so it's unlikely that this would break anything.

v2: Switch to a simpler implementation using a new task_struct bit
    field suggested by Oleg.
Signed-off-by: NTejun Heo <tj@kernel.org>
Suggested-by: NOleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reported-and-debugged-by: NChris Mason <clm@fb.com>
Cc: stable@vger.kernel.org # v4.3+ (we can't close the race on < v4.3)
Signed-off-by: NTejun Heo <tj@kernel.org>

Some Hypervisors detach VFs from VMs by instantly causing an FLR event
to be generated for a VF.

In the mlx4 case, this will cause that VF's comm channel to be disabled
before the VM has an opportunity to invoke the VF device's "shutdown"
method.

For such Hypervisors, there is a race condition between the VF's
shutdown method and its internal-error detection/reset thread.

The internal-error detection/reset thread (which runs every 5 seconds) also
detects a disabled comm channel. If the internal-error detection/reset
flow wins the race, we still get delays (while that flow tries repeatedly
to detect comm-channel recovery).

The cited commit fixed the command timeout problem when the
internal-error detection/reset flow loses the race.

This commit avoids the unneeded delays when the internal-error
detection/reset flow wins.

Fixes: d585df1c ("net/mlx4_core: Avoid command timeouts during VF driver device shutdown")
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Reported-by: NSimon Xiao <sixiao@microsoft.com>
Signed-off-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The last caller of assert_held_device_hotplug() is gone, so remove it again.

Link: http://lkml.kernel.org/r/20170314125226.16779-3-heiko.carstens@de.ibm.comSigned-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: NDan Williams <dan.j.williams@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a prototype of task_struct to fix below warning on arm64.

  In file included from arch/arm64/kernel/probes/kprobes.c:19:0:
  include/linux/kasan.h:81:132: error: 'struct task_struct' declared inside parameter list will not be visible outside of this definition or declaration [-Werror]
   static inline void kasan_unpoison_task_stack(struct task_struct *task) {}

As same as other types (kmem_cache, page, and vm_struct) this adds a
prototype of task_struct data structure on top of kasan.h.

[arnd] A related warning was fixed before, but now appears in a
different line in the same file in v4.11-rc2.  The patch from Masami
Hiramatsu still seems appropriate, so let's take his version.

Fixes: 71af2ed5 ("kasan, sched/headers: Remove <linux/sched.h> from <linux/kasan.h>")
Link: https://patchwork.kernel.org/patch/9569839/
Link: http://lkml.kernel.org/r/20170313141517.3397802-1-arnd@arndb.deSigned-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NMasami Hiramatsu <mhiramat@kernel.org>
Acked-by: NAlexander Potapenko <glider@google.com>
Acked-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The CCP driver generally uses a round-robin approach when
assigning operations to available CCPs. For the DMA engine,
however, the DMA mappings of the SGs are associated with a
specific CCP. When an IOMMU is enabled, the IOMMU is
programmed based on this specific device.

If the DMA operations are not performed by that specific
CCP then addressing errors and I/O page faults will occur.

Update the CCP driver to allow a specific CCP device to be
requested for an operation and use this in the DMA engine
support.

Cc: <stable@vger.kernel.org> # 4.9.x-
Signed-off-by: NGary R Hook <gary.hook@amd.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

With the recent introduction of per-channel tasklet, we need to update
the way we handle the 3 concurrency issues:

1. hv_process_channel_removal -> percpu_channel_deq vs.
   vmbus_chan_sched -> list_for_each_entry(..., percpu_list);

2. vmbus_process_offer -> percpu_channel_enq/deq vs. vmbus_chan_sched.

3. vmbus_close_internal vs. the per-channel tasklet vmbus_on_event;

The first 2 issues can be handled by Stephen's recent patch
"vmbus: use rcu for per-cpu channel list", and the third issue
can be handled by calling tasklet_disable in vmbus_close_internal here.

We don't need the original hv_event_tasklet_disable/enable since we
now use per-channel tasklet instead of the previous per-CPU tasklet,
and actually we must remove them due to the side effect now:
vmbus_process_offer -> hv_event_tasklet_enable -> tasklet_schedule will
start the per-channel callback prematurely, cauing NULL dereferencing
(the channel may haven't been properly configured to run the callback yet).

Fixes: 631e63a9 ("vmbus: change to per channel tasklet")
Signed-off-by: NDexuan Cui <decui@microsoft.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Tested-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The per-cpu channel list is now referred to in the interrupt
routine. This is mostly safe since the host will not normally generate
an interrupt when channel is being deleted but if it did then there
would be a use after free problem.

To solve, this use RCU protection on ther per-cpu list.

Fixes: 631e63a9 ("vmbus: change to per channel tasklet")
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The only use of the ->prepare_context() fscrypt operation was to allow
ext4 to evict inline data from the inode before ->set_context().
However, there is no reason why this cannot be done as simply the first
step in ->set_context(), and in fact it makes more sense to do it that
way because then the policy modes and flags get validated before any
real work is done.  Therefore, merge ext4_prepare_context() into
ext4_set_context(), and remove ->prepare_context().
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>