ib_send_cm_drep() calls cm_enter_timewait() while holding a spinlock
that can be locked from inside an interrupt handler. Hence do not
enable interrupts inside cm_enter_timewait() if called with interrupts
disabled.

This patch fixes e.g. the following deadlock:
Acked-by: NErez Shitrit <erezsh@mellanox.com>

=================================
[ INFO: inconsistent lock state ]
4.4.0-rc7+ #1 Tainted: G            E
---------------------------------
inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
swapper/8/0 [HC1[1]:SC0[0]:HE0:SE1] takes:
(&(&cm_id_priv->lock)->rlock){?.+...}, at: [<ffffffffa036eec4>] cm_establish+0x
74/0x1b0 [ib_cm]
{HARDIRQ-ON-W} state was registered at:
  [<ffffffff810a3c11>] mark_held_locks+0x71/0x90
  [<ffffffff810a3e87>] trace_hardirqs_on_caller+0xa7/0x1c0
  [<ffffffff810a3fad>] trace_hardirqs_on+0xd/0x10
  [<ffffffff8151c40b>] _raw_spin_unlock_irq+0x2b/0x40
  [<ffffffffa036ea8e>] cm_enter_timewait+0xae/0x100 [ib_cm]
  [<ffffffffa036ff76>] ib_send_cm_drep+0xb6/0x190 [ib_cm]
  [<ffffffffa052ed08>] srp_cm_handler+0x128/0x1a0 [ib_srp]
  [<ffffffffa0370340>] cm_process_work+0x20/0xf0 [ib_cm]
  [<ffffffffa0371335>] cm_dreq_handler+0x135/0x2c0 [ib_cm]
  [<ffffffffa03733c5>] cm_work_handler+0x75/0xd0 [ib_cm]
  [<ffffffff8107184d>] process_one_work+0x1bd/0x460
  [<ffffffff81073148>] worker_thread+0x118/0x420
  [<ffffffff81078454>] kthread+0xe4/0x100
  [<ffffffff8151cbbf>] ret_from_fork+0x3f/0x70
irq event stamp: 1672286
hardirqs last  enabled at (1672283): [<ffffffff81408ec0>] poll_idle+0x10/0x80
hardirqs last disabled at (1672284): [<ffffffff8151d304>] common_interrupt+0x84/0x89
softirqs last  enabled at (1672286): [<ffffffff8105b4dc>] _local_bh_enable+0x1c/0x50
softirqs last disabled at (1672285): [<ffffffff8105b697>] irq_enter+0x47/0x70

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&cm_id_priv->lock)->rlock);
  <Interrupt>
    lock(&(&cm_id_priv->lock)->rlock);

 *** DEADLOCK ***

no locks held by swapper/8/0.

stack backtrace:
CPU: 8 PID: 0 Comm: swapper/8 Tainted: G            E   4.4.0-rc7+ #1
Hardware name: Dell Inc. PowerEdge R430/03XKDV, BIOS 1.0.2 11/17/2014
 ffff88045af5e950 ffff88046e503a88 ffffffff81251c1b 0000000000000007
 0000000000000006 0000000000000003 ffff88045af5ddc0 ffff88046e503ad8
 ffffffff810a32f4 0000000000000000 0000000000000000 0000000000000001
Call Trace:
 <IRQ>  [<ffffffff81251c1b>] dump_stack+0x4f/0x74
 [<ffffffff810a32f4>] print_usage_bug+0x184/0x190
 [<ffffffff810a36e2>] mark_lock_irq+0xf2/0x290
 [<ffffffff810a3995>] mark_lock+0x115/0x1b0
 [<ffffffff810a3b8c>] mark_irqflags+0x15c/0x170
 [<ffffffff810a4fef>] __lock_acquire+0x1ef/0x560
 [<ffffffff810a53c2>] lock_acquire+0x62/0x80
 [<ffffffff8151bd33>] _raw_spin_lock_irqsave+0x43/0x60
 [<ffffffffa036eec4>] cm_establish+0x74/0x1b0 [ib_cm]
 [<ffffffffa036f031>] ib_cm_notify+0x31/0x100 [ib_cm]
 [<ffffffffa0637f24>] srpt_qp_event+0x54/0xd0 [ib_srpt]
 [<ffffffffa0196052>] mlx4_ib_qp_event+0x72/0xc0 [mlx4_ib]
 [<ffffffffa00775b9>] mlx4_qp_event+0x69/0xd0 [mlx4_core]
 [<ffffffffa006000e>] mlx4_eq_int+0x51e/0xd50 [mlx4_core]
 [<ffffffffa006084f>] mlx4_msi_x_interrupt+0xf/0x20 [mlx4_core]
 [<ffffffff810b67b0>] handle_irq_event_percpu+0x40/0x110
 [<ffffffff810b68bf>] handle_irq_event+0x3f/0x70
 [<ffffffff810ba7f9>] handle_edge_irq+0x79/0x120
 [<ffffffff81007f3d>] handle_irq+0x5d/0x130
 [<ffffffff810071fd>] do_IRQ+0x6d/0x130
 [<ffffffff8151d309>] common_interrupt+0x89/0x89
 <EOI>  [<ffffffff8140895f>] cpuidle_enter_state+0xcf/0x200
 [<ffffffff81408aa2>] cpuidle_enter+0x12/0x20
 [<ffffffff810990d6>] call_cpuidle+0x36/0x60
 [<ffffffff81099163>] cpuidle_idle_call+0x63/0x110
 [<ffffffff8109930a>] cpu_idle_loop+0xfa/0x130
 [<ffffffff8109934e>] cpu_startup_entry+0xe/0x10
 [<ffffffff8103c443>] start_secondary+0x83/0x90

Fixes: commit be4b4993 ("IB/cm: Do not queue work to a device that's going away")
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Erez Shitrit <erezsh@mellanox.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Sparse complains about dereference before check. Fixing this by
moving the check before the dereference.

Fixes: 20029832 ('IB/core: Validate route when we init ah')
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

When write_gid function needs to do a sleep-able operation, it unlocks
table->rwlock and then relocks it. Sparse complains about context
imbalance.

This is safe as write_gid is always called with table->rwlock.
write_gid protects from simultaneous writes to this GID entry
by setting the GID_TABLE_ENTRY_INVALID flag.

Fixes: 9c584f04 ('IB/core: Change per-entry lock in RoCE GID table to
		     one lock')
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Port number is not part of ClassPortInfo attribute but is
still needed as a parameter when invoking process_mad.

To properly handle this attribute, port_num is added as a
parameter to get_counter_table and get_perf_mad was changed
not to store port_num in the attribute itself when it's
querying the ClassPortInfo attribute.

This handles issue pointed out by Matan Barak <matanb@dev.mellanox.co.il>

Fixes: 145d9c54 ('IB/core: Display extended counter set if available')
Signed-off-by: NHal Rosenstock <hal@mellanox.com>
Acked-by: NMatan Barak <matanb@mellanox.com>
Acked-by: NIra Weiny <ira.weiny@intel.com>
Reviewed-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Detected this by building the IB core with W=1. See also patch
"IB core: Fix ib_sg_to_pages()" (commit 8f5ba10e).
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: NLeon Romanovsky <leon.romanovsky@mellanox.com>
Acked-by: NSagi Grimberg <sagig@mellanox.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Remove the local workqueue to process mad completions and use the CQ API
instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHal Rosenstock <hal@mellanox.com>
Reviewed-by: NIra Weiny <ira.weiny@intel.com>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Stop abusing wr_id and just pass the parameter explicitly.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHal Rosenstock <hal@mellanox.com>
Reviewed-by: NIra Weiny <ira.weiny@intel.com>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

The issue here is that there is a cut and paste bug.  When we allocate
cma_dev_group->default_ports_group we use "sizeof(*cma_dev_group->ports)"
instead of "sizeof(*cma_dev_group->default_ports_group)".

We're bumping up against the 80 character limit so I introduced a new
local pointer "ports_group" to get around that.

Fixes: 045959db ('IB/cma: Add configfs for rdma_cm')
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Attributed ID was declared as an int while the value should really be big
endian 16.

Fixes: 35c4cbb1 ("IB/core: Create get_perf_mad function in sysfs.c")
Reported-by: NBart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: NIra Weiny <ira.weiny@intel.com>
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NChristoph Lameter <cl@linux.com>
Reviewed-by: NHal Rosenstock <hal@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

cma_validate_port wrongly assumed that Ethernet devices are RoCE
devices and thus their ndev should be matched in the GID table.
This broke the iWarp support. Fixing that matching the ndev only if
we work on a RoCE port.

Cc: <stable@vger.kernel.org> # 4.4.x-
Fixes: abae1b71 ('IB/cma: cma_validate_port should verify the port
		     and netdevice')
Reported-by: NHariprasad Shenai <hariprasad@chelsio.com>
Tested-by: NHariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Reviewed-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

This mmu_notifier_ops structure is never modified, so declare it as
const, like the other mmu_notifier_ops structures.

Done with the help of Coccinelle.
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Reviewed-by: NHaggai Eran <haggaie@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

It was found that when a process was rapidly sending MADs other processes could
be hung in their unregister calls.

This would happen when process A was injecting packets fast enough that the
single threaded workqueue was never exiting ib_mad_completion_handler.
Therefore when process B called flush_workqueue via the unregister call it
would hang until process A stopped sending MADs.

The fix is to periodically reschedule ib_mad_completion_handler after
processing a large number of completions.  The number of completions chosen was
decided based on the defaults for the recv queue size.  However, it was kept
fixed such that increasing those queue sizes would not adversely affect
fairness in the future.
Reviewed-by: NIra Weiny <ira.weiny@intel.com>
Signed-off-by: NDean Luick <dean.luick@intel.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

The cross-channel feature allows to execute WQEs that involve
synchronization of I/O operations’ on different QPs.

This capability enables to program complex flows with a single
function call, hereby significantly reducing overhead associated
with I/O processing.

Cross-channel operations support is indicated by HCA capability
information.

The queue pairs can be configured to work as a “sync master queue”
or “sync slave queues”.

The added flags are:

1. Device capability flag IB_DEVICE_CROSS_CHANNEL for the
   devices that can perform cross-channel operations.

2. CQ property flag IB_CQ_FLAGS_IGNORE_OVERRUN to disable CQ overrun
   check. This check is useless in cross-channel scenario.

3. QP property flags to indicate if queues are slave or master:
   * IB_QP_CREATE_MANAGED_SEND indicates that posted send work requests
     will not be executed immediately and requires enabling.
   * IB_QP_CREATE_MANAGED_RECV indicates that posted receive work
     requests will not be executed immediately and requires enabling.
   * IB_QP_CREATE_CROSS_CHANNEL declares the QP to work in cross-channel
     mode. If IB_QP_CREATE_MANAGED_SEND and IB_QP_CREATE_MANAGED_RECV are
     not provided, this QP will be sync master queue, else it will be sync
     slave.
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Check if the extended counters are available and if so
create the proper extended and additional counters.
Signed-off-by: NChristoph Lameter <cl@linux.com>
Reviewed-by: NIra Weiny <ira.weiny@intel.com>
Reviewed-by: NHal Rosenstock <hal@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Add the attr_id on port_table_attribute since we will have to add
a different port_table_attribute for the extended attribute soon.
Reviewed-by: NHal Rosenstock <hal@mellanox.com>
Signed-off-by: NChristoph Lameter <cl@linux.com>
Reviewed-by: NIra Weiny <ira.weiny@intel.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Create a new function to retrieve performance management
data from the existing code in get_pma_counter().
Reviewed-by: NHal Rosenstock <hal@mellanox.com>
Signed-off-by: NChristoph Lameter <cl@linux.com>
Reviewed-by: NIra Weiny <ira.weiny@intel.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBart Van Assche <bvanassche@sandisk.com>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Remove the unused ib_allow_mw and ib_bind_mw functions, remove the
unused IB_WR_BIND_MW and IB_WC_BIND_MW opcodes and move ib_dealloc_mw
into the uverbs module.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> [core]
Reviewed-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

This functionality has no users and was only supported by the staged out
EHCA driver.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> [core]
Reviewed-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Since RoCEv2 is a protocol over IP header it is required to send IGMP
join and leave requests to the network when joining and leaving
multicast groups.
Signed-off-by: NMoni Shoua <monis@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

ib_ud_header_init() is used to format InfiniBand headers
in a buffer up to (but not with) BTH. For RoCE UDP ENCAP it is
required that this function would be able to build also IP and UDP
headers.
Signed-off-by: NMoni Shoua <monis@mellanox.com>
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Users would like to control the behaviour of rdma_cm.
For example, old applications which don't set the
required RoCE gid type could be executed on RoCE V2
network types. In order to support this configuration,
we implement a configfs for rdma_cm.

In order to use the configfs, one needs to mount it and
mkdir <IB device name> inside rdma_cm directory.

The patch adds support for a single configuration file,
default_roce_mode. The mode can either be "IB/RoCE v1" or
"RoCE v2".
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Currently, cma users can't increase or decrease the cma reference
count. This is necassary when setting cma attributes (like the
default GID type) in order to avoid use-after-free errors.
Adding cma_ref_dev and cma_deref_dev APIs.
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

In order to make sure API users don't try to use SGIDs which don't
conform to the routing table, validate the route before searching
the RoCE GID table.
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

In order to validate the route, we need an easy way to check if a
net-device belongs to our RDMA device. Move this helper function
to a header file in order to make this check easier.
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Reviewed-by: NHaggai Eran <haggaie@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Providers should tell IB core the wc's network type.
This is used in order to search for the proper GID in the
GID table. When using HCAs that can't provide this info,
IB core tries to deep examine the packet and extract
the GID type by itself.

We choose sgid_index and type from all the matching entries in
RDMA-CM based on hint from the IP stack and we set hop_limit for
the IP packet based on above hint from IP stack.
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NSomnath Kotur <Somnath.Kotur@Avagotech.Com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Adding RoCE v2 GID type and port type. Vendors
which support this type will get their GID table
populated with RoCE v2 GIDs automatically.
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

This patch set adds attributes of net device and gid type to each GID
in the GID table. Users that use verbs directly need to specify
the GID index. Since the same GID could have different types or
associated net devices, users should have the ability to query the
associated GID attributes. Adding these attributes to sysfs.
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Previosuly, cm and cma modules supported only IB and RoCE v1 GID type.
In order to support multiple GID types, the gid_type is passed to
cm_init_av_by_path and stored in the path record.

The rdma cm client would use a default GID type that will be saved in
rdma_id_private.
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

In order to support multiple GID types, we need to store the gid_type
with each GID. This is also aligned with the RoCE v2 annex "RoCEv2 PORT
GID table entries shall have a "GID type" attribute that denotes the L3
Address type". The currently supported GID is IB_GID_TYPE_IB which is
also RoCE v1 GID type.

This implies that gid_type should be added to roce_gid_table meta-data.
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Previously, we've searched the GID table twice: first when we searched
the table for a GID matching the proposed new one, and second when we
didn't find a match, we searched again for an empty GID slot in the
table.  Instead, search the table once noting the first empty slot as
we search for our target GID.
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Reviewed-by: NHaggai Eran <haggaie@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Previously, IB GID cached used a lock per entry. This could result
in spending a lot of CPU cycles for locking and unlocking just
in order to find a GID. Changing this in favor of one lock per
a GID table.
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Reviewed-by: NHaggai Eran <haggaie@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Refactor ib_dispatch_event into a new function in order to avoid
duplicating code in the next patch.
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Reviewed-by: NHaggai Eran <haggaie@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

The copy of the attributes present on the device is now used by all consumers
except for uverbs in case of serving user-space query, where dev->query_device
is called.
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Use the cached copy of the attributes present on the device, except for
the case of a query originating from user-space, where we have to invoke
the driver query_device entry, so they can fill in their udata.
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

This way both the IB core and upper level drivers can access these cached
device attributes rather than querying or caching them on their own.
Signed-off-by: NIra Weiny <ira.weiny@intel.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

This adds an abstraction that allows ULPs to simply pass a completion
object and completion callback with each submitted WR and let the RDMA
core handle the nitty gritty details of how to handle completion
interrupts and poll the CQ.

In detail there is a new ib_cqe structure which just contains the
completion callback, and which can be used to get at the containing
object using container_of.  It is pointed to by the WR and WC as an
alternative to the wr_id field, similar to how many ULPs already use
the field to store a pointer using casts.

A driver using the new completion callbacks allocates it's CQs using
the new ib_create_cq API, which in addition to the number of CQEs and
the completion vectors also takes a mode on how we poll for CQEs.
Three modes are available: direct for drivers that never take CQ
interrupts and just poll for them, softirq to poll from softirq context
using the to be renamed blk-iopoll infrastructure which takes care of
rearming and budgeting, or a workqueue for consumer who want to be
called from user context.

Thanks a lot to Sagi Grimberg who helped reviewing the API, wrote
the current version of the workqueue code because my two previous
attempts sucked too much and converted the iSER initiator to the new
API.
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Receipt of CM MAD with other than the Send method for an attribute
other than the ClassPortInfo attribute is invalid.

CM attributes other than ClassPortInfo only use the send method.

The SRP initiator does not maintain a timeout policy for CM connect
requests relies on the CM layer to do that. The result was that
the SRP initiator hung as the connect request never completed.

A new SRP target has been observed to respond to Send CM REQ
with GetResp of CM REQ with bad status. This is non conformant
with IBA spec but exposes a vulnerability in the current MAD/CM
code which will respond to the incoming GetResp of CM REQ as if
it was a valid incoming Send of CM REQ rather than tossing
this on the floor. It also causes the MAD layer not to
retransmit the original REQ even though it has not received a REP.
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NHal Rosenstock <hal@mellanox.com>
Reviewed-by: NIra Weiny <ira.weiny@intel.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Ensure that validate_ipv4_net_dev() calls rcu_read_unlock() if
fib_lookup() fails. Detected by sparse. Compile-tested only.

Fixes: "IB/cma: Validate routing of incoming requests" (commit f887f2ac).
Cc: Haggai Eran <haggaie@mellanox.com>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Reviewed-by: NHaggai Eran <haggaie@mellanox.com>
Reviewed-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

On 12/03/2015 01:18 AM, Christoph Hellwig wrote:
> The patch looks good to me, but while we touch this area, how about
> throwing in a few cosmetic fixes as well?

How about the patch below ? In that version of the ib_sg_to_pages() fix
these concerns have been addressed and additionally to more bugs have been fixed.

------------

[PATCH] IB core: Fix ib_sg_to_pages()

Fix the code for detecting gaps. A gap occurs not only if the
second or later scatterlist element is not aligned but also if
any scatterlist element other than the last does not end at a
page boundary.

In the code for coalescing contiguous elements, ensure that
mr->length is correct and that last_page_addr is up-to-date.

Ensure that this function returns a negative
error code instead of zero if the first set_page() call fails.

Fixes: commit 4c67e2bf ("IB/core: Introduce new fast registration API")
Reported-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDoug Ledford <dledford@redhat.com>