Persuant to Liran's comments on node_type on linux-rdma
mailing list:

In an effort to reform the RDMA core and ULPs to minimize use of
node_type in struct ib_device, an additional bit is added to
struct ib_device for is_switch (IB switch). This is needed
to be initialized by any IB switch device driver. This is a
NEW requirement on such device drivers which are all
"out of tree".

In addition, an ib_switch helper was added to ib_verbs.h
based on the is_switch device bit rather than node_type
(although those should be consistent).

The RDMA core (MAD, SMI, agent, sa_query, multicast, sysfs)
as well as (IPoIB and SRP) ULPs are updated where
appropriate to use this new helper. In some cases,
the helper is now used under the covers of using
rdma_[start end]_port rather than the open coding
previously used.
Reviewed-by: NSean Hefty <sean.hefty@intel.com>
Reviewed-By: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: NIra Weiny <ira.weiny@intel.com>
Tested-by: NIra Weiny <ira.weiny@intel.com>
Signed-off-by: NHal Rosenstock <hal@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Currently, ib_create_cq uses cqe and comp_vecotr instead
of the extendible ib_cq_init_attr struct.

Earlier patches already changed the vendors to work with
ib_cq_init_attr. This patch changes the consumers too.
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Most code already uses consts for the struct kernel_param_ops,
sweep the kernel for the last offending stragglers. Other than
include/linux/moduleparam.h and kernel/params.c all other changes
were generated with the following Coccinelle SmPL patch. Merge
conflicts between trees can be handled with Coccinelle.

In the future git could get Coccinelle merge support to deal with
patch --> fail --> grammar --> Coccinelle --> new patch conflicts
automatically for us on patches where the grammar is available and
the patch is of high confidence. Consider this a feature request.

Test compiled on x86_64 against:

	* allnoconfig
	* allmodconfig
	* allyesconfig

@ const_found @
identifier ops;
@@

const struct kernel_param_ops ops = {
};

@ const_not_found depends on !const_found @
identifier ops;
@@

-struct kernel_param_ops ops = {
+const struct kernel_param_ops ops = {
};

Generated-by: Coccinelle SmPL
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Junio C Hamano <gitster@pobox.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: cocci@systeme.lip6.fr
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NLuis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

The SCSI standard defines 64-bit values for LUNs. Large arrays
employing large or hierarchical LUN numbers become more and more
common. So update the SRP initiator to use 64-bit LUN numbers.
See also Hannes Reinecke, commit 9cb78c16 ("scsi: use 64-bit LUNs"),
June 2014.

The largest LUN number that has been tested is 0xd2003fff00000000.

Checked the following structure sizes with gdb:
* sizeof(struct srp_cmd) = 48
* sizeof(struct srp_tsk_mgmt) = 48
* sizeof(struct srp_aer_req) = 36

The ibmvscsi changes have been compile tested only (on a PPC system).
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Reviewed-by: NYann Droneaud <ydroneaud@opteya.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: Brian King <brking@linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Remove the !ch->target tests from the reconnect code. These
tests are not needed: upon entry of srp_rport_reconnect()
it is guaranteed that all ch->target pointers are non-NULL.
None of the functions srp_new_cm_id(), srp_finish_req(),
srp_create_ch_ib() nor srp_connect_ch() modifies this pointer.
srp_free_ch_ib() is never called concurrently with
srp_rport_reconnect().
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

The function srp_free_req_data() does not use ch->target.
Hence remove the ch->target != NULL check.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Move the module version and release date into separate fields.
This makes the modinfo output easier to read.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

A long time ago the data type int64_t was declared as long long
on x86 systems and as long on PPC systems. Today that data type
is declared as long long on all Linux architectures. This means
that the casts from uint64_t into unsigned long long are
superfluous. Remove these superfluous casts.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Although it is possible to let SRP I/O continue if a reconnect
results in a reduction of the number of channels, the current
code does not handle this scenario correctly. Instead of making
the reconnect code more complex, consider this as a reconnection
failure.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: <stable@vger.kernel.org> #v3.19
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Reception of a DREQ message only causes the state of a single
channel to change. Hence move the 'connected' member variable
from the target to the channel data structure. This patch
avoids that following false positive warning can be reported
by srp_destroy_qp():

WARNING: at drivers/infiniband/ulp/srp/ib_srp.c:617 srp_destroy_qp+0xa6/0x120 [ib_srp]()
Call Trace:
[<ffffffff8106e10f>] warn_slowpath_common+0x7f/0xc0
[<ffffffff8106e16a>] warn_slowpath_null+0x1a/0x20
[<ffffffffa0440226>] srp_destroy_qp+0xa6/0x120 [ib_srp]
[<ffffffffa0440322>] srp_free_ch_ib+0x82/0x1e0 [ib_srp]
[<ffffffffa044408b>] srp_create_target+0x7ab/0x998 [ib_srp]
[<ffffffff81346f60>] dev_attr_store+0x20/0x30
[<ffffffff811dd90f>] sysfs_write_file+0xef/0x170
[<ffffffff8116d248>] vfs_write+0xc8/0x190
[<ffffffff8116d411>] sys_write+0x51/0x90
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: <stable@vger.kernel.org> #v3.19
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Avoid that receiving a DREQ while RDMA channels are being
established causes target->qp_in_error to be reset.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: <stable@vger.kernel.org> #v3.19
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Fix a scsi_get_host() / scsi_host_put() imbalance in the error
path of srp_create_target(). See also patch "IB/srp: Avoid that
I/O hangs due to a cable pull during LUN scanning" (commit ID
34aa654e).
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: <stable@vger.kernel.org> #v3.19
Signed-off-by: NDoug Ledford <dledford@redhat.com>

This change slightly reduces the time needed to log in.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Reviewed-by: NDavid Dillow <dave@thedillows.org>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

In case the last argument of the connection string is processed as a
string (destination GID for example).
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Acked-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Since we got rid of ordered tag support in 2010 the prime use case of
switching on and off ordered tags has been obsolete.  The other function
of enabling/disabling tagging entirely has only been correctly implemented
by the 53c700 driver and isn't generally useful.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com
Reviewed-by: NHannes Reinecke <hare@suse.de>

Drop the now unused reason argument from the ->change_queue_depth method.
Also add a return value to scsi_adjust_queue_depth, and rename it to
scsi_change_queue_depth now that it can be used as the default
->change_queue_depth implementation.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NHannes Reinecke <hare@suse.de>

We won't ever queue more commands than the host allows.  Instead of
letting drivers either reject or ignore this case handle it in
common code.  Note that various driver use internal constant or
variables that are assigned to both shost->can_queue and checked
in ->change_queue_depth - I did remove those checks as well.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NHannes Reinecke <hare@suse.de>

All drivers use the implementation for ramping the queue up and down, so
instead of overloading the change_queue_depth method call the
implementation diretly if the driver opts into it by setting the
track_queue_depth flag in the host template.

Note that a few drivers validated the new queue depth in their
change_queue_depth method, but as we never go over the queue depth
set during slave_configure or the sysfs file this isn't nessecary
and can safely be removed.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NVenkatesh Srinivas <venkateshs@google.com>

At least LID reassignment can trigger a race condition in the SRP
initiator driver, namely the receive completion handler trying to
post a request on a QP during or after QP destruction and before
the CQ's have been destroyed. Avoid this race by modifying a QP
into the error state and by waiting until all receive completions
have been processed before destroying a QP.
Reported-by: NMax Gurtuvoy <maxg@mellanox.com>
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Improve performance by using multiple RDMA/RC channels per SCSI
host for communication with an SRP target. About the
implementation:
- Introduce a loop over all channels in the code that uses
  target->ch.
- Set the SRP_MULTICHAN_MULTI flag during login for the creation
  of the second and subsequent channels.
- RDMA completion vectors are chosen such that RDMA completion
  interrupts are handled by the CPU socket that submitted the I/O
  request. As one can see in this patch it has been assumed if a
  system contains n CPU sockets and m RDMA completion vectors
  have been assigned to an RDMA HCA that IRQ affinity has been
  configured such that completion vectors [i*m/n..(i+1)*m/n) are
  bound to CPU socket i with 0 <= i < n.
- Modify srp_free_ch_ib() and srp_free_req_data() such that it
  becomes safe to invoke these functions after the corresponding
  allocation function failed.
- Add a ch_count sysfs attribute per target port.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Since the block layer already contains functionality to assign
a tag to each request, use that functionality instead of
reimplementing that functionality in the SRP initiator driver.
This change makes the free_reqs list superfluous. Hence remove
that list.

[hch: updated to use .use_blk_tags instead scsi_activate_tcq]
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Changes in this patch:
- Move channel variables into a new structure (struct srp_rdma_ch).
- Add an srp_target_port pointer, 'lock' and 'comp_vector' members
  in struct srp_rdma_ch.
- Add code to initialize these three new member variables.
- Many boring "target->" into "ch->" changes.
- The cm_id and completion handler context pointers are now of type
  srp_rdma_ch * instead of srp_target_port *.
- Three kzalloc(a * b, f) calls have been changed into kcalloc(a, b, f)
  to avoid that this patch would trigger a checkpatch warning.
- Two casts from u64 into unsigned long long have been left out
  because these are superfluous. Since considerable time u64 is
  defined as unsigned long long for all architectures supported by
  the Linux kernel.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Acked-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Introduce the srp_target_port member variables 'sgid' and 'pkey'.
Change the type of 'orig_dgid' from __be16[8] into union ib_gid.
This patch does not change any functionality but makes the
"Separate target and channel variables" patch easier to verify.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

If a cable is pulled during LUN scanning it can happen that the
SRP rport and the SCSI host have been created but no LUNs have been
added to the SCSI host. Since multipathd only sends SCSI commands
to a SCSI target if one or more SCSI devices are present and since
there is no keepalive mechanism for IB queue pairs this means that
after a LUN scan failed and after a reconnect has succeeded no
data will be sent over the QP and hence that a subsequent cable
pull will not be detected. Avoid this by not creating an rport or
SCSI host if a cable is pulled during a SCSI LUN scan.

Note: so far the above behavior has only been observed with the
kernel module parameter ch_count set to a value >= 2.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Attempting to connect three times may be insufficient after an
initiator system tries to relogin, especially if the relogin
attempt occurs before the SRP target service ID has been
registered. Since the srp_daemon retries a failed login attempt
anyway, remove the stale connection retry mechanism.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The patch that adds multichannel support into the SRP initiator
driver introduces an additional call to srp_free_ch_ib(). This
patch helps to keep that later patch simple.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Remove the tagged argument from scsi_adjust_queue_depth, and just let it
handle the queue depth.  For most drivers those two are fairly separate,
given that most modern drivers don't care about the SCSI "tagged" status
of a command at all, and many old drivers allow queuing of multiple
untagged commands in the driver.

Instead we start out with the ->simple_tags flag set before calling
->slave_configure, which is how all drivers actually looking at
->simple_tags except for one worke anyway.  The one other case looks
broken, but I've kept the behavior as-is for now.

Except for that we only change ->simple_tags from the ->change_queue_type,
and when rejecting a tag message in a single driver, so keeping this
churn out of scsi_adjust_queue_depth is a clear win.

Now that the usage of scsi_adjust_queue_depth is more obvious we can
also remove all the trivial instances in ->slave_alloc or ->slave_configure
that just set it to the cmd_per_lun default.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>

Most drivers use exactly the same implementation, so provide it as a
library function.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>

In case of error, the function create_workqueue() returns NULL pointer
not ERR_PTR().  The IS_ERR() test in the return value check should be
replaced with NULL test.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

From Documentation/scsi/scsi_mid_low_api.txt: "resid - an LLD should
set this signed integer to the requested transfer length (i.e.
'request_bufflen') less the number of bytes that are actually
transferred."  This means that resid > 0 in case of an underrun and
also that resid < 0 in case of an overrun.  Modify the SRP initiator
code such that it matches this requirement.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Reviewed-by: NDavid Dillow <dave@thedillows.org>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

If scsi_remove_host() is invoked after a SCSI device has been blocked,
if the fast_io_fail_tmo or dev_loss_tmo work gets scheduled on the
workqueue executing srp_remove_work() and if an I/O request is
scheduled after the SCSI device had been blocked by e.g. multipathd
then the following deadlock can occur:

    kworker/6:1     D ffff880831f3c460     0   195      2 0x00000000
    Call Trace:
     [<ffffffff814aafd9>] schedule+0x29/0x70
     [<ffffffff814aa0ef>] schedule_timeout+0x10f/0x2a0
     [<ffffffff8105af6f>] msleep+0x2f/0x40
     [<ffffffff8123b0ae>] __blk_drain_queue+0x4e/0x180
     [<ffffffff8123d2d5>] blk_cleanup_queue+0x225/0x230
     [<ffffffffa0010732>] __scsi_remove_device+0x62/0xe0 [scsi_mod]
     [<ffffffffa000ed2f>] scsi_forget_host+0x6f/0x80 [scsi_mod]
     [<ffffffffa0002eba>] scsi_remove_host+0x7a/0x130 [scsi_mod]
     [<ffffffffa07cf5c5>] srp_remove_work+0x95/0x180 [ib_srp]
     [<ffffffff8106d7aa>] process_one_work+0x1ea/0x6c0
     [<ffffffff8106dd9b>] worker_thread+0x11b/0x3a0
     [<ffffffff810758bd>] kthread+0xed/0x110
     [<ffffffff814b972c>] ret_from_fork+0x7c/0xb0
    multipathd      D ffff880096acc460     0  5340      1 0x00000000
    Call Trace:
     [<ffffffff814aafd9>] schedule+0x29/0x70
     [<ffffffff814aa0ef>] schedule_timeout+0x10f/0x2a0
     [<ffffffff814ab79b>] io_schedule_timeout+0x9b/0xf0
     [<ffffffff814abe1c>] wait_for_completion_io_timeout+0xdc/0x110
     [<ffffffff81244b9b>] blk_execute_rq+0x9b/0x100
     [<ffffffff8124f665>] sg_io+0x1a5/0x450
     [<ffffffff8124fd21>] scsi_cmd_ioctl+0x2a1/0x430
     [<ffffffff8124fef2>] scsi_cmd_blk_ioctl+0x42/0x50
     [<ffffffffa00ec97e>] sd_ioctl+0xbe/0x140 [sd_mod]
     [<ffffffff8124bd04>] blkdev_ioctl+0x234/0x840
     [<ffffffff811cb491>] block_ioctl+0x41/0x50
     [<ffffffff811a0df0>] do_vfs_ioctl+0x300/0x520
     [<ffffffff811a1051>] SyS_ioctl+0x41/0x80
     [<ffffffff814b9962>] tracesys+0xd0/0xd5

Fix this by scheduling removal work on another workqueue than the
transport layer timers.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Reviewed-by: NDavid Dillow <dave@thedillows.org>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

SRP defines pr_fmt(fmt) to be "PFX fmt", and then includes a bunch of
header files before it gets around to defining PFX.  This causes
problems if any of the header files do a pr_... and use pr_fmt().

Fix this by using KBUILD_MODNAME instead of the private PFX.
Acked-by: NChris Metcalf <cmetcalf@tilera.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Certain HCA types (e.g. Connect-IB) and certain configurations (e.g.
ConnectX VF) support fast registration but not FMR. Hence add fast
registration support.

In function srp_rport_reconnect(), move the the srp_finish_req()
loop from after to before the srp_create_target_ib() call. This is
needed to avoid that srp_finish_req() tries to queue any
invalidation requests for rkeys associated with the old queue pair
on the newly allocated queue pair. Invoking srp_finish_req() before
the queue pair has been reallocated is safe since srp_claim_req()
handles completions correctly that arrive after srp_finish_req()
has been invoked.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

The next patch will cause the renamed variables to be shared between
the code for FMR and for FR memory registration. Make the names of
these variables independent of the memory registration mode. This
patch does not change any functionality. The start of this patch was
the changes applied via the following shell command:

sed -i.orig 's/SRP_FMR_SIZE/SRP_MAX_PAGES_PER_MR/g; \
    s/fmr_page_mask/mr_page_mask/g;s/fmr_page_size/mr_page_size/g; \
    s/fmr_page_shift/mr_page_shift/g;s/fmr_max_size/mr_max_size/g; \
    s/max_pages_per_fmr/max_pages_per_mr/g;s/nfmr/nmdesc/g; \
    s/fmr_len/dma_len/g' drivers/infiniband/ulp/srp/ib_srp.[ch]
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Allocate one FMR pool per SRP connection instead of one SRP pool
per HCA. This improves scalability of the SRP initiator.

Only request the SCSI mid-layer to retry a SCSI command after a
temporary mapping failure (-ENOMEM) but not after a permanent
mapping failure. This avoids that SCSI commands are retried
indefinitely if a permanent memory mapping failure occurs.

Tell the SCSI mid-layer to reduce queue depth temporarily in the
unlikely case where an application is queuing many requests with
more than max_pages_per_fmr sg-list elements.

For FMR pool allocation, base the max_pages_per_fmr parameter on
the HCA memory registration limit. Only try to allocate an FMR
pool if FMR is supported.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Add a kernel module parameter that enables memory registration also for SG-lists
that can be processed without memory registration. This makes it easier for kernel
developers to test the memory registration code.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

This patch does not change any functionality.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

This patch does not change any functionality.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

This patch does not change any functionality.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>