Remove unreachable code from RC ack handling to fix an
smatch error.

Fixes: 633d2739 ("staging/rdma/hfi1: use mod_timer when appropriate")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The function refresh_qsfp_cache() acquires the i2c chain resource,
but one caller already holds the resource.  Change the acquire so
all calls to refresh_qsfp_cache() are covered by the acquire and
remove the acquire within refresh_qsfp_cache().
Reviewed-by: Easwar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The discrete ASIC board design makes the two I2C chains not
independent of each other.  That is, only one chain can safely
be accessed at a time.  For discrete ASIC devices, adjust the
resource locking so that access to one I2C chain will lock both
of the chains.
Reviewed-by: Easwar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The pre-LNI SerDes and channel tuning algorithm already checks for
module presence assertion for the relevant port types. The extraneous
check removed in this patch blocks link up for port types for which
the module presence assertion is not relevant.
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Easwar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

Clock and data recovery mechanisms (CDRs) in active QSFP modules
can be turned on or off to improve the bit error rate observed on
the channel. Signal integrity and bit error rate requirements require
us to always turn on any CDRs present in low power cables (power
dissipation 2.5W or lower). However, we adhere to the platform
designer's settings (provided in the platform configuration) for
higher power cables (dissipation 3.5W or higher) if the platform
designer has determined that the platform requires the CDRs to be
turned on (or off) and is capable of supplying and cooling the higher
power modules.

This patch also introduces the get_qsfp_power_class function to
centralize the bit twiddling required to determine the QSFP power class
across the code. Reusing this function improves the readability of code
that depends on knowing the power class of the cable, such as the
active and optical channel tuning algorithm.
Reviewed-by: Dean Luick <dean.luick@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Easwar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

Add the P_KEY check for user-context mechanism for
both PIO and SDMA. For PIO, the
SendCtxtCheckEnable.DisallowKDETHPackets is set by
default. When the P_KEY is set,
SendCtxtCheckEnable.DisallowKDETHPackets is cleared.
For SDMA, a software check was included. This change
requires user processes to set the P_KEY before sending
any packets, otherwise, the sent packet will fail. The
original submission didn't have this check but it's
required.
Reviewed-by: Dean Luick <dean.luick@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Mikto Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Sebastian Sanchez <sebastian.sanchez@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

Increasing the default MTU size to 10KB improves performance
for PSM. Change the default MTU to 10KB but constrain
Verbs MTU to 8KB. Also update default MTU module parameter
description to be HFI1_DEFAULT_MAX_MTU.
Reviewed-by: Dean Luick <dean.luick@intel.com>
Reviewed-by: Mitko Haralanov <mitko.haralanov@intel.com>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Sebastian Sanchez <sebastian.sanchez@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

Make init_qpmap_table() easier to understand by simplifying
the loop indexing and writing each register when it is "full",
removing the need for a follow-on register write.
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The function hdr2sc was using an unshifted mask to obtain
the 5th bit of the service class.  Correct the issue by using
the shifted mask.
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The QOS RSM rule mappings are off by one, referencing a kernel receive
context that does not exist.

Correctly start the QOS RSM map entries at FIRST_KERNEL_CONTEXT rather
than MIN_KERNEL_KCTXTS.  Remove the cruft that hid this.

Change the QP map table so all traffic not caught by QOS RSM goes to
the control context rather than the first QOS context.

Correct comments to match the actual code operation and intent.
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

Remove an invalid compare of the number of QOS RSM map table entries
against the number of physical receive contexts.  The RSM map table
has its own size and has no relation to the number of physical receive
contexts.
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The bit width for num_vls, n, needs to be calculated based on
the pow2 rounded up of the number of vls.  Otherwise num_vls of 3,
5, 6, and 7 will have misplaced QOS RSM map entries.
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The i2c and qsfp read/write routines should check for the resource
reservation of the incoming argument target rather than the implicit
target of the hardware HFI.
Reviewed-by: Easwar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

Two sysfs files do not pay attention to the file offset when
reading data. Fix that.
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

rdi->ports has memory allocated in rvt_alloc_device(), but does not get
freed because the hfi1 and qib drivers drivers call ib_dealloc_device()
directly instead of going through rdmavt. Add a rvt_dealloc_device()
that frees rdi->ports and then calls ib_dealloc_device(). Switch hfi1
and qib drivers to calling rvt_dealloc_device() instead of
ib_dealloc_device() directly.
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Brian Welty <brian.welty@intel.com>
Signed-off-by: Jubin John <jubin.john@intel.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

There are two possible causes for node/memory corruption both
of which are related to the cache eviction algorithm. One way
to cause corruption is due to the asynchronous nature of the
MMU invalidation and the locking used when invalidating node.

The MMU invalidation routine would temporarily release the
RB tree lock to avoid a deadlock. However, this would allow
the eviction function to take the lock resulting in the removal
of cache nodes.

If the node being removed by the eviction code is the same as
the node being invalidated, the result is use after free.

The same is true in the other direction due to the temporary
release of the eviction list lock in the eviction loop.

Another corner case exists when dealing with the SDMA buffer
cache that could cause memory corruption of kernel memory.
The most common way, in which this corruption exhibits itself
is a linked list node corruption. In that case, the kernel will
complain that a node with poisoned pointers is being removed.
The fact that the pointers are already poisoned means that the
node has already been removed from the list.

To root cause of this corruption was a mishandling of the
eviction list maintained by the driver. In order for this
to happen four conditions need to be satisfied:

   1. A node describing a user buffer already exists in the
      interval RB tree,
   2. The beginning of the current user buffer matches that
      node but is bigger. This will cause the node to be
      extended.
   3. The amount of cached buffers is close or at the limit
      of the buffer cache size.
   4. The node has dropped close to the end of the eviction
      list. This will cause the node to be considered for
      eviction.

If all of the above conditions have been satisfied, it is
possible for the eviction algorithm to evict the current node,
which will free the node without the driver knowing.

To solve both issues described above:
   - the locking around the MMU invalidation loop and cache
     eviction loop has been improved so locks are not released in
     the loop body,
   - a new RB function is introduced which will "atomically" find
     and remove the matching node from the RB tree, preventing the
     MMU invalidation loop from touching it, and
   - the node being extended by the pin_vector_pages() function is
     removed from the eviction list prior to calling the eviction
     function.
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The page pinning function, which also maintains the pin cache,
behaves one of two ways when an exact buffer match is not found:
  1. If no node is not found (a buffer with the same starting address
     is not found in the cache), a new node is created, the buffer
     pages are pinned, and the node is inserted into the RB tree, or
  2. If a node is found but the buffer in that node is a subset of
     the new user buffer, the node is extended with the new buffer
     pages.

Both modes of operation require (re-)insertion into the interval RB
tree.

When the node being inserted is a new node, the operations are pretty
simple. However, when the node is already existing and is being
extended, special care must be taken.

First, we want to guard against an asynchronous attempt to
delete the node by the MMU invalidation notifier. The simplest way to
do this is to remove the node from the RB tree, preventing the search
algorithm from finding it.

Second, the node needs to be re-inserted so it lands in the proper place
in the tree and the tree is correctly re-balanced. This also requires
the node to be removed from the RB tree.

This commit adds the hfi1_mmu_rb_extract() function, which will search
for a node in the interval RB tree matching an address and length and
remove it from the RB tree if found. This allows for both of the above
special cases be handled in a single step.
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The computation of the interval of an interval RB node
was incorrect leading to data corruption due to the RB
search algorithm not properly finding the all RB nodes
in an MMU invalidation interval.

The problem stemmed from the fact that the beginning
address of the node's range was being aligned to a page
boundary. For certain buffer sizes, this would lead to
a end address calculation that was off by 1 page.

An important aspect of keeping the RB same is also
updating the node's range in the case it's being extended.
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The current implementation of the clean up function for
the interval RB trees has two flaws which may cause
problems in cases of concurrent executing of the function
and MMU notifier.

The flaws were due to the fact that deregistration of the
MMU callbacks was done after the tree was emptied and,
furthermore, the tree was not being locked.

This commit fixes both of these flaws by, first, switch the
order of operations, and, second, locking the tree while
traversing it to prevent any other operations.
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The driver had two memory leaks - one in the user
expected receive code and one in SDMA buffer cache.

The leak in the expected receive code only showed up
when the user/admin had set ulimit sufficiently low
and the driver did not have enough room in the cache
before hitting the limit of allowed cachable memory.

When this condition occurred, the driver returned
early signaling userland that it needed to free some
buffers to free up room in the cache.

The bug was that the driver was not cleaning up
allocated memory prior to returning early.

The leak in the SDMA buffer cache could occur (even
though it never did), when the insertion of a buffer
node in the interval RB tree failed. In this case, the
driver failed to unpin the pages of the node instead
erroneously returning success.
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The SDMA cache logic maintains an eviction list which is ordered
by most recently used user buffers. Upon errors or buffer freeing,
the list nodes were unconditionally being deleted. This would lead
to list corruption warnings if the nodes were never inserted in the
eviction list to begin with.

This commit prevents this by checking that the nodes are already
part of the eviction list.
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The dual lock patch moved locking around and missed an issue
with handling irq flags when processing UD loopback
packets.  This issue was revealed by smatch.

Fix for both qib and hfi1 to pass the saved flags to the UD request
builder and handle the changes correctly.

Fixes: 46a80d62 ("IB/qib, staging/rdma/hfi1: add s_hlock for use in post send")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The RVT_S_WAIT_PIO_DRAIN flag was missing from
the set of flags indicating a qp is waiting
on a resource.

This caused the sleep/wakeup for adaptive pio
drain to lose a wakeup "hanging" a QP.
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into testing/4.6

The drivers/infiniband stack uses write() as a replacement for
bi-directional ioctl().  This is not safe. There are ways to
trigger write calls that result in the return structure that
is normally written to user space being shunted off to user
specified kernel memory instead.

For the immediate repair, detect and deny suspicious accesses to
the write API.

For long term, update the user space libraries and the kernel API
to something that doesn't present the same security vulnerabilities
(likely a structured ioctl() interface).

The impacted uAPI interfaces are generally only available if
hardware from drivers/infiniband is installed in the system.
Reported-by: Jann Horn <jann@thejh.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
[ Expanded check to all known write() entry points ]
Cc: stable@vger.kernel.org
Signed-off-by: Doug Ledford <dledford@redhat.com>

The ui device llseek had a mistake with SEEK_END and did
not fully follow seek semantics.  Correct all this by
using a kernel supplied function for fixed size devices.

Cc: Al Viro <viro@ZenIV.linux.org.uk>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

Attempting to free resources which have not been allocated and
initialized properly led to the following kernel backtrace:

    BUG: unable to handle kernel NULL pointer dereference at           (null)
    IP: [<ffffffffa09658fe>] unlock_exp_tids.isra.8+0x2e/0x120 [hfi1]
    PGD 852a43067 PUD 85d4a6067 PMD 0
    Oops: 0000 [#1] SMP
    CPU: 0 PID: 2831 Comm: osu_bw Tainted: G          IO 3.12.18-wfr+ #1
    task: ffff88085b15b540 ti: ffff8808588fe000 task.ti: ffff8808588fe000
    RIP: 0010:[<ffffffffa09658fe>]  [<ffffffffa09658fe>] unlock_exp_tids.isra.8+0x2e/0x120 [hfi1]
    RSP: 0018:ffff8808588ffde0  EFLAGS: 00010282
    RAX: 0000000000000000 RBX: ffff880858a31800 RCX: 0000000000000000
    RDX: ffff88085d971bc0 RSI: ffff880858a318f8 RDI: ffff880858a318c0
    RBP: ffff8808588ffe20 R08: 0000000000000000 R09: 0000000000000000
    R10: ffff88087ffd6f40 R11: 0000000001100348 R12: ffff880852900000
    R13: ffff880858a318c0 R14: 0000000000000000 R15: ffff88085d971be8
    FS:  00007f4674e83740(0000) GS:ffff88087f400000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 0000000000000000 CR3: 000000085c377000 CR4: 00000000001407f0
    Stack:
     ffffffffa0941a71 ffff880858a318f8 ffff88085d971bc0 ffff880858a31800
     ffff880852900000 ffff880858a31800 00000000003ffff7 ffff88085d971bc0
     ffff8808588ffe60 ffffffffa09663fc ffff8808588ffe60 ffff880858a31800
    Call Trace:
     [<ffffffffa0941a71>] ? find_mmu_handler+0x51/0x70 [hfi1]
     [<ffffffffa09663fc>] hfi1_user_exp_rcv_free+0x6c/0x120 [hfi1]
     [<ffffffffa0932809>] hfi1_file_close+0x1a9/0x340 [hfi1]
     [<ffffffff8116c189>] __fput+0xe9/0x270
     [<ffffffff8116c35e>] ____fput+0xe/0x10
     [<ffffffff81065707>] task_work_run+0xa7/0xe0
     [<ffffffff81002969>] do_notify_resume+0x59/0x80
     [<ffffffff814ffc1a>] int_signal+0x12/0x17

This commit re-arranges the context initialization code in a way that
would allow for context event flags to be used to determine whether
the context has been successfully initialized.

In turn, this can be used to skip the resource de-allocation if they
were never allocated in the first place.

Fixes: 3abb33ac ("staging/hfi1: Add TID cache receive init and free funcs")
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com.
Signed-off-by: Doug Ledford <dledford@redhat.com>

The iowait_sdma_drained() callback lacked locking to
protect the qp s_flags field.

This causes the s_flags to be out of sync
on multiple CPUs, potentially corrupting the s_flags.

Fixes: a545f530 ("staging/rdma/hfi: fix CQ completion order issue")
Reviewed-by: Sebastian Sanchez <sebastian.sanchez@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

call_send is used to determine whether to send immediately or schedule
a send for later. The current logic in rdmavt is inverted and has a
negative impact on the latency of the hfi1 and qib drivers. Fix this
regression by correctly calling send immediately when call_send is set.
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The routine used by the SDMA cache to handle already
cached nodes can extend an already existing node.

In its error handling code, the routine will unpin pages
when not all pages of the buffer extension were pinned.

There was a bug in that part of the routine, which would
mistakenly unpin pages from the original set rather than
the newly pinned pages.

This commit fixes that bug by offsetting the page array
to the proper place pointing at the beginning of the newly
pinned pages.
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

The locking around the interval RB tree is designed to prevent
access to the tree while it's being modified. The locking in its
current form is too overzealous, which is causing a deadlock in
certain cases with the following backtrace:

    Kernel panic - not syncing: Watchdog detected hard LOCKUP on cpu 0
    CPU: 0 PID: 5836 Comm: IMB-MPI1 Tainted: G           O 3.12.18-wfr+ #1
     0000000000000000 ffff88087f206c50 ffffffff814f1caa ffffffff817b53f0
     ffff88087f206cc8 ffffffff814ecd56 0000000000000010 ffff88087f206cd8
     ffff88087f206c78 0000000000000000 0000000000000000 0000000000001662
    Call Trace:
     <NMI>  [<ffffffff814f1caa>] dump_stack+0x45/0x56
     [<ffffffff814ecd56>] panic+0xc2/0x1cb
     [<ffffffff810d4370>] ? restart_watchdog_hrtimer+0x50/0x50
     [<ffffffff810d4432>] watchdog_overflow_callback+0xc2/0xd0
     [<ffffffff81109b4e>] __perf_event_overflow+0x8e/0x2b0
     [<ffffffff8110a714>] perf_event_overflow+0x14/0x20
     [<ffffffff8101c906>] intel_pmu_handle_irq+0x1b6/0x390
     [<ffffffff814f927b>] perf_event_nmi_handler+0x2b/0x50
     [<ffffffff814f8ad8>] nmi_handle.isra.3+0x88/0x180
     [<ffffffff814f8d39>] do_nmi+0x169/0x310
     [<ffffffff814f8177>] end_repeat_nmi+0x1e/0x2e
     [<ffffffff81272600>] ? unmap_single+0x30/0x30
     [<ffffffff814f780d>] ? _raw_spin_lock_irqsave+0x2d/0x40
     [<ffffffff814f780d>] ? _raw_spin_lock_irqsave+0x2d/0x40
     [<ffffffff814f780d>] ? _raw_spin_lock_irqsave+0x2d/0x40
     <<EOE>>  <IRQ>  [<ffffffffa056c4a8>] hfi1_mmu_rb_search+0x38/0x70 [hfi1]
     [<ffffffffa05919cb>] user_sdma_free_request+0xcb/0x120 [hfi1]
     [<ffffffffa0593393>] user_sdma_txreq_cb+0x263/0x350 [hfi1]
     [<ffffffffa057fad7>] ? sdma_txclean+0x27/0x1c0 [hfi1]
     [<ffffffffa0593130>] ? user_sdma_send_pkts+0x1710/0x1710 [hfi1]
     [<ffffffffa057fdd6>] sdma_make_progress+0x166/0x480 [hfi1]
     [<ffffffff810762c9>] ? ttwu_do_wakeup+0x19/0xd0
     [<ffffffffa0581c7e>] sdma_engine_interrupt+0x8e/0x100 [hfi1]
     [<ffffffffa0546bdd>] sdma_interrupt+0x5d/0xa0 [hfi1]
     [<ffffffff81097e57>] handle_irq_event_percpu+0x47/0x1d0
     [<ffffffff81098017>] handle_irq_event+0x37/0x60
     [<ffffffff8109aa5f>] handle_edge_irq+0x6f/0x120
     [<ffffffff810044af>] handle_irq+0xbf/0x150
     [<ffffffff8104c9b7>] ? irq_enter+0x17/0x80
     [<ffffffff8150168d>] do_IRQ+0x4d/0xc0
     [<ffffffff814f7c6a>] common_interrupt+0x6a/0x6a
     <EOI>  [<ffffffff81073524>] ? finish_task_switch+0x54/0xe0
     [<ffffffff814f56c6>] __schedule+0x3b6/0x7e0
     [<ffffffff810763a6>] __cond_resched+0x26/0x30
     [<ffffffff814f5eda>] _cond_resched+0x3a/0x50
     [<ffffffff814f4f82>] down_write+0x12/0x30
     [<ffffffffa0591619>] hfi1_release_user_pages+0x69/0x90 [hfi1]
     [<ffffffffa059173a>] sdma_rb_remove+0x9a/0xc0 [hfi1]
     [<ffffffffa056c00d>] __mmu_rb_remove.isra.5+0x5d/0x70 [hfi1]
     [<ffffffffa056c536>] hfi1_mmu_rb_remove+0x56/0x70 [hfi1]
     [<ffffffffa059427b>] hfi1_user_sdma_process_request+0x74b/0x1160 [hfi1]
     [<ffffffffa055c763>] hfi1_aio_write+0xc3/0x100 [hfi1]
     [<ffffffff8116a14c>] do_sync_readv_writev+0x4c/0x80
     [<ffffffff8116b58b>] do_readv_writev+0xbb/0x230
     [<ffffffff811a9da1>] ? fsnotify+0x241/0x320
     [<ffffffff81073524>] ? finish_task_switch+0x54/0xe0
     [<ffffffff8116b795>] vfs_writev+0x35/0x60
     [<ffffffff8116b8c9>] SyS_writev+0x49/0xc0
     [<ffffffff810cd876>] ? __audit_syscall_exit+0x1f6/0x2a0
     [<ffffffff814ff992>] system_call_fastpath+0x16/0x1b

As evident from the backtrace above, the process was being put to sleep
while holding the lock.

Limiting the scope of the lock only to the RB tree operation fixes the
above error allowing for proper locking and the process being put to
sleep when needed.
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

There is a potential kernel crash when the MMU notifier calls the
invalidation routines in the hfi1 pinned page caching code for sdma.

The invalidation routine could call the remove callback
for the node, which in turn ends up dereferencing the
current task_struct to get a pointer to the mm_struct.
However, the mm_struct pointer could be NULL resulting in
the following backtrace:

    BUG: unable to handle kernel NULL pointer dereference at 00000000000000a8
    IP: [<ffffffffa041f75a>] sdma_rb_remove+0xaa/0x100 [hfi1]
    15
    task: ffff88085e66e080 ti: ffff88085c244000 task.ti: ffff88085c244000
    RIP: 0010:[<ffffffffa041f75a>]  [<ffffffffa041f75a>] sdma_rb_remove+0xaa/0x100 [hfi1]
    RSP: 0000:ffff88085c245878  EFLAGS: 00010002
    RAX: 0000000000000000 RBX: ffff88105b9bbd40 RCX: ffffea003931a830
    RDX: 0000000000000004 RSI: ffff88105754a9c0 RDI: ffff88105754a9c0
    RBP: ffff88085c245890 R08: ffff88105b9bbd70 R09: 00000000fffffffb
    R10: ffff88105b9bbd58 R11: 0000000000000013 R12: ffff88105754a9c0
    R13: 0000000000000001 R14: 0000000000000001 R15: ffff88105b9bbd40
    FS:  0000000000000000(0000) GS:ffff88107ef40000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 00000000000000a8 CR3: 0000000001a0b000 CR4: 00000000001407e0
    Stack:
     ffff88105b9bbd40 ffff88080ec481a8 ffff88080ec481b8 ffff88085c2458c0
     ffffffffa03fa00e ffff88080ec48190 ffff88080ed9cd00 0000000001024000
     0000000000000000 ffff88085c245920 ffffffffa03fa0e7 0000000000000282
    Call Trace:
     [<ffffffffa03fa00e>] __mmu_rb_remove.isra.5+0x5e/0x70 [hfi1]
     [<ffffffffa03fa0e7>] mmu_notifier_mem_invalidate+0xc7/0xf0 [hfi1]
     [<ffffffffa03fa143>] mmu_notifier_page+0x13/0x20 [hfi1]
     [<ffffffff81156dd0>] __mmu_notifier_invalidate_page+0x50/0x70
     [<ffffffff81140bbb>] try_to_unmap_one+0x20b/0x470
     [<ffffffff81141ee7>] try_to_unmap_anon+0xa7/0x120
     [<ffffffff81141fad>] try_to_unmap+0x4d/0x60
     [<ffffffff8111fd7b>] shrink_page_list+0x2eb/0x9d0
     [<ffffffff81120ab3>] shrink_inactive_list+0x243/0x490
     [<ffffffff81121491>] shrink_lruvec+0x4c1/0x640
     [<ffffffff81121641>] shrink_zone+0x31/0x100
     [<ffffffff81121b0f>] kswapd_shrink_zone.constprop.62+0xef/0x1c0
     [<ffffffff811229e3>] kswapd+0x403/0x7e0
     [<ffffffff811225e0>] ? shrink_all_memory+0xf0/0xf0
     [<ffffffff81068ac0>] kthread+0xc0/0xd0
     [<ffffffff81068a00>] ? insert_kthread_work+0x40/0x40
     [<ffffffff814ff8ec>] ret_from_fork+0x7c/0xb0
     [<ffffffff81068a00>] ? insert_kthread_work+0x40/0x40

To correct this, the mm_struct passed to us by the MMU notifier is
used (which is what should have been done to begin with). This avoids
the broken derefences and ensures that the correct mm_struct is used.
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Acked-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

mlx5 devices (Connect-IB, ConnectX-4, ConnectX-4-LX) has a limitation
where rdma read work queue entries cannot exceed 512 bytes.
A rdma_read wqe needs to fit in 512 bytes:
- wqe control segment (16 bytes)
- rdma segment (16 bytes)
- scatter elements (16 bytes each)

So max_sge_rd should be: (512 - 16 - 16) / 16 = 30.

Cc: linux-stable@vger.kernel.org
Reported-by: Christoph Hellwig <hch@lst.de>
Tested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagig@grimberg.me>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

Pull workqueue fix from Tejun Heo:
 "So, it turns out we had a silly bug in the most fundamental part of
  workqueue for a very long time.  AFAICS, this dates back to pre-git
  era and has quite likely been there from the time workqueue was first
  introduced.

  A work item uses its PENDING bit to synchronize multiple queuers.
  Anyone who wins the PENDING bit owns the pending state of the work
  item.  Whether a queuer wins or loses the race, one thing should be
  guaranteed - there will soon be at least one execution of the work
  item - where "after" means that the execution instance would be able
  to see all the changes that the queuer has made prior to the queueing
  attempt.

  Unfortunately, we were missing a smp_mb() after clearing PENDING for
  execution, so nothing guaranteed visibility of the changes that a
  queueing loser has made, which manifested as a reproducible blk-mq
  stall.

  Lots of kudos to Roman for debugging the problem.  The patch for
  -stable is the minimal one.  For v3.7, Peter is working on a patch to
  make the code path slightly more efficient and less fragile"

* 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: fix ghost PENDING flag while doing MQ IO

Pull cgroup fixes from Tejun Heo:
 "Two patches to fix a deadlock which can be easily triggered if memcg
  charge moving is used.

  This bug was introduced while converting threadgroup locking to a
  global percpu_rwsem and is caused by cgroup controller task migration
  path depending on the ability to create new kthreads.  cpuset had a
  similar issue which was fixed by performing heavy-lifting operations
  asynchronous to task migration.  The two patches fix the same issue in
  memcg in a similar way.  The first patch makes the mechanism generic
  and the second relocates memcg charge moving outside the migration
  path.

  Given that we don't want to perform heavy operations while
  writelocking threadgroup lock anyway, moving them out of the way is a
  desirable solution.  One thing to note is that the problem was
  difficult to debug because lockdep couldn't figure out the deadlock
  condition.  Looking into how to improve that"

* 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  memcg: relocate charge moving from ->attach to ->post_attach
  cgroup, cpuset: replace cpuset_post_attach_flush() with cgroup_subsys->post_attach callback

Pull i2c fixes from Wolfram Sang:
 "I2C has one buildfix, one ABBA deadlock fix, and three simple 'add ID'
  patches"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: exynos5: Fix possible ABBA deadlock by keeping I2C clock prepared
  i2c: cpm: Fix build break due to incompatible pointer types
  i2c: ismt: Add Intel DNV PCI ID
  i2c: xlp9xx: add support for Broadcom Vulcan
  i2c: rk3x: add support for rk3228

Pull ARC fixes from Vineet Gupta:

 - lockdep now works for ARCv2 builds

 - enable DT reserved-memory binding (for forthcoming HDMI driver)

* tag 'arc-4.6-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: add support for reserved memory defined by device tree
  ARC: support generic per-device coherent dma mem
  Documentation: dt: arc: fix spelling mistakes
  ARCv2: Enable LOCKDEP

Pull arch/nios2 fix from Ley Foon Tan:
 "memset: use the right constraint modifier for the %4 output operand"

* tag 'nios2-v4.6-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/lftan/nios2:
  nios2: memset: use the right constraint modifier for the %4 output operand