NFS: NFS over RDMA Client Side Changes

These patches improve both client performance and scalability, most notably
by increasing the maixmum allowed rsize and wsize and by increasing the number
of RDMA "credits".  There are also several bugfixes, such as correcting how
WRITE compounds are encoded and fixing large NFS symlink operations.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

And call nfs_file_clear_open_context() directly.  This makes it obvious
that nfs_file_release() will always return 0.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

All nfs_write_inode() does is pass its arguments to
nfs_commit_unstable_pages().  Let's cut out the middle man and have
nfs_write_pages() do the work directly.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

All these functions do is call nfs41_ping_server() without adding
anything.  Let's remove them and give nfs41_ping_server() a better name
instead.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The idmap_init() and idmap_quit() functions only exist to call the
_keyring() version.  Let's just call the keyring() functions directly.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

They already exist and do the exact same thing.  Let's save ourselves
several lines of code!
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This function is to help determine if two sockaddrs are really the same
socket.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

I'm planning on using these functions inside the client, so remove the
underscores to make it feel like I'm using a public interface.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

nfs_readdir_xdr_to_array() uses both a cache array and an array of
pages, so I rename these functions to make it clearer how the code
works.  nfs_readdir_large_page() becomes nfs_readdir_alloc_pages()
because this function has absolutely nothing to do with setting up a
large page.  nfs_readdir_free_pagearray() becomes
nfs_readdir_free_pages() to stay consistent with the new alloc_pages()
function.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This variable is initialized to NULL and is never modified before being
passed to nfs_readdir_free_large_page().  But that's okay, because
nfs_readdir_free_large_page() only seems to exist as a way of calling
nfs_readdir_free_pagearray() without this parameter.  Let's simplify by
removing pages_ptr and nfs_readdir_free_pagearray().
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

We already know that pg_lseg is NULL here.
Signed-off-by: NJeff Layton <jeff.layton@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

We generally want to read and write to a block device that's used by
the pNFS block layout client (and even if it's read only the server
has no way of telling us).  Add FMODE_WRITE to the mode argument
so that we don't incorrectly tell the block driver that we want a
read-only open.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Instead of overwriting kernel memory reject too long signatures.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

We need to replace the __be32 with a void pointer to do proper arithmentics
on the virtual addresses so that we can get the right page pointers.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

We need to include the first u32 for the number of entries.  Add a helper
for the calculation instead of opencoding it so that it's in one place.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

---Steps to Reproduce--
<nfs-server>
# cat /etc/exports
/nfs/referal  *(rw,insecure,no_subtree_check,no_root_squash,crossmnt)
/nfs/old      *(ro,insecure,subtree_check,root_squash,crossmnt)

<nfs-client>
# mount -t nfs nfs-server:/nfs/ /mnt/
# ll /mnt/*/

<nfs-server>
# cat /etc/exports
/nfs/referal   *(rw,insecure,no_subtree_check,no_root_squash,crossmnt,refer=/nfs/old/@nfs-server)
/nfs/old       *(ro,insecure,subtree_check,root_squash,crossmnt)
# service nfs restart

<nfs-client>
# ll /mnt/*/    --->>>>> oops here

[ 5123.102925] BUG: unable to handle kernel NULL pointer dereference at           (null)
[ 5123.103363] IP: [<ffffffffa03ed38b>] nfs4_proc_get_locations+0x9b/0x120 [nfsv4]
[ 5123.103752] PGD 587b9067 PUD 3cbf5067 PMD 0
[ 5123.104131] Oops: 0000 [#1]
[ 5123.104529] Modules linked in: nfsv4(OE) nfs(OE) fscache(E) nfsd(OE) xfs libcrc32c iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi coretemp crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel ppdev vmw_balloon parport_pc parport i2c_piix4 shpchp auth_rpcgss nfs_acl vmw_vmci lockd grace sunrpc vmwgfx drm_kms_helper ttm drm mptspi serio_raw scsi_transport_spi e1000 mptscsih mptbase ata_generic pata_acpi [last unloaded: nfsd]
[ 5123.105887] CPU: 0 PID: 15853 Comm: ::1-manager Tainted: G           OE   4.2.0-rc6+ #214
[ 5123.106358] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/20/2014
[ 5123.106860] task: ffff88007620f300 ti: ffff88005877c000 task.ti: ffff88005877c000
[ 5123.107363] RIP: 0010:[<ffffffffa03ed38b>]  [<ffffffffa03ed38b>] nfs4_proc_get_locations+0x9b/0x120 [nfsv4]
[ 5123.107909] RSP: 0018:ffff88005877fdb8  EFLAGS: 00010246
[ 5123.108435] RAX: ffff880053f3bc00 RBX: ffff88006ce6c908 RCX: ffff880053a0d240
[ 5123.108968] RDX: ffffea0000e6d940 RSI: ffff8800399a0000 RDI: ffff88006ce6c908
[ 5123.109503] RBP: ffff88005877fe28 R08: ffffffff81c708a0 R09: 0000000000000000
[ 5123.110045] R10: 00000000000001a2 R11: ffff88003ba7f5c8 R12: ffff880054c55800
[ 5123.110618] R13: 0000000000000000 R14: ffff880053a0d240 R15: ffff880053a0d240
[ 5123.111169] FS:  0000000000000000(0000) GS:ffffffff81c27000(0000) knlGS:0000000000000000
[ 5123.111726] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 5123.112286] CR2: 0000000000000000 CR3: 0000000054cac000 CR4: 00000000001406f0
[ 5123.112888] Stack:
[ 5123.113458]  ffffea0000e6d940 ffff8800399a0000 00000000000167d0 0000000000000000
[ 5123.114049]  0000000000000000 0000000000000000 0000000000000000 00000000a7ec82c6
[ 5123.114662]  ffff88005877fe18 ffffea0000e6d940 ffff8800399a0000 ffff880054c55800
[ 5123.115264] Call Trace:
[ 5123.115868]  [<ffffffffa03fb44b>] nfs4_try_migration+0xbb/0x220 [nfsv4]
[ 5123.116487]  [<ffffffffa03fcb3b>] nfs4_run_state_manager+0x4ab/0x7b0 [nfsv4]
[ 5123.117104]  [<ffffffffa03fc690>] ? nfs4_do_reclaim+0x510/0x510 [nfsv4]
[ 5123.117813]  [<ffffffff810a4527>] kthread+0xd7/0xf0
[ 5123.118456]  [<ffffffff810a4450>] ? kthread_worker_fn+0x160/0x160
[ 5123.119108]  [<ffffffff816d9cdf>] ret_from_fork+0x3f/0x70
[ 5123.119723]  [<ffffffff810a4450>] ? kthread_worker_fn+0x160/0x160
[ 5123.120329] Code: 4c 8b 6a 58 74 17 eb 52 48 8d 55 a8 89 c6 4c 89 e7 e8 4a b5 ff ff 8b 45 b0 85 c0 74 1c 4c 89 f9 48 8b 55 90 48 8b 75 98 48 89 df <41> ff 55 00 3d e8 d8 ff ff 41 89 c6 74 cf 48 8b 4d c8 65 48 33
[ 5123.121643] RIP  [<ffffffffa03ed38b>] nfs4_proc_get_locations+0x9b/0x120 [nfsv4]
[ 5123.122308]  RSP <ffff88005877fdb8>
[ 5123.122942] CR2: 0000000000000000

Fixes: ec011fe8 ("NFS: Introduce a vector of migration recovery ops")
Cc: stable@vger.kernel.org # v3.13+
Signed-off-by: NKinglong Mee <kinglongmee@gmail.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The xprt created by svc_create_xprt have be added to serv->sv_permsocks.
So putting the xprt directly is useless.
Otherwise, there is a more svc_xprt_put after the xprt be freed.

v2, same as v1.
Signed-off-by: NKinglong Mee <kinglongmee@gmail.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Commit 1d3d4437 "vmscan: per-node deferred work" have made
register_shrinker can return an intergater error.

If register_shrinker() fail, the later unregister_shrinker() will
 cause a NULL pointer access.

v2, same as v1.
Signed-off-by: NKinglong Mee <kinglongmee@gmail.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

It is unusual to combine the open flags O_RDONLY and O_EXCL, but
it appears that libre-office does just that.

[pid  3250] stat("/home/USER/.config", {st_mode=S_IFDIR|0700, st_size=8192, ...}) = 0
[pid  3250] open("/home/USER/.config/libreoffice/4-suse/user/extensions/buildid", O_RDONLY|O_EXCL <unfinished ...>

NFSv4 takes O_EXCL as a sign that a setattr command should be sent,
probably to reset the timestamps.

When it was an O_RDONLY open, the SETATTR command does not
identify any actual attributes to change.
If no delegation was provided to the open, the SETATTR uses the
all-zeros stateid and the request is accepted (at least by the
Linux NFS server - no harm, no foul).

If a read-delegation was provided, this is used in the SETATTR
request, and a Netapp filer will justifiably claim
NFS4ERR_BAD_STATEID, which the Linux client takes as a sign
to retry - indefinitely.

So only treat O_EXCL specially if O_CREAT was also given.
Signed-off-by: NNeilBrown <neilb@suse.com>
Cc: stable@vger.kernel.org
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The current limit of 32 bytes artificially limits the name string that
we end up stuffing into NFSv4.x client ID blobs. If you have multiple
hosts with long hostnames that only differ near the end, then this can
cause NFSv4 client ID collisions.

Linux nodenames are actually limited to __NEW_UTS_LEN bytes (64), so use
that as the limit instead. Also, use XDR_QUADLEN to specify the slack
length, just for clarity and in case someone in the future changes this
to something not evenly divisible by 4.
Reported-by: NMichael Skralivetsky <michael.skralivetsky@primarydata.com>
Signed-off-by: NJeff Layton <jeff.layton@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Prevent a potential deadlock.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Turned out I misinterpreted the spec...

Cc: Tom Haynes <thomas.haynes@primarydata.com>
Reported-by: NJean Spector <jean@primarydata.com>
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

pnfs_layout_mark_request_commit() needs to ensure that it adds the
request to the commit list atomically with all the other updates
in order to prevent corruption to buckets[ds_commit_idx].wlseg
due to races with pnfs_generic_clear_request_commit().

Fixes: 338d00cf ("pnfs: Refactor the *_layout_mark_request_commit...")
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This is a rework of the following patch sent almost a year back:
http://www.mail-archive.com/linux-rdma%40vger.kernel.org/msg20730.html

In presence of active mount if someone tries to rmmod vendor-driver, the
command remains stuck forever waiting for destruction of all rdma-cm-id.
in worst case client can crash during shutdown with active mounts.

The existing code assumes that ia->ri_id->device cannot change during
the lifetime of a transport. xprtrdma do not have support for
DEVICE_REMOVAL event either. Lifting that assumption and adding support
for DEVICE_REMOVAL event is a long chain of work, and is in plan.

The community decided that preventing the hang right now is more
important than waiting for architectural changes.

Thus, this patch introduces a temporary workaround to acquire HCA driver
module reference count during the mount of a nfs-rdma mount point.
Signed-off-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NSagi Grimberg <sagig@dev.mellanox.co.il>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

The verbs are obsolete. The ib_rereg_phys_mr() verb is not used by
kernel ULPs, and the last ib_reg_phys_mr() call site in the kernel
tree has now been removed.

Two staging tree call sites remain in the Lustre client. The Lustre
team has been notified of the deprecation of reg_phys_mr.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Acked-by: NDoug Ledford <dledford@redhat.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

RDMA_NOMSG type calls are less efficient than RDMA_MSG. Count NOMSG
calls so administrators can tell if they happen to be used more than
expected.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Tested-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

checkpatch.pl complained about the seq_printf() format string split
across lines and the use of %Lu.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Tested-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Repair how rpcrdma_marshal_req() chooses which RDMA message type
to use for large non-WRITE operations so that it picks RDMA_NOMSG
in the correct situations, and sets up the marshaling logic to
SEND only the RPC/RDMA header.

Large NFSv2 SYMLINK requests now use RDMA_NOMSG calls. The Linux NFS
server XDR decoder for NFSv2 SYMLINK does not handle having the
pathname argument arrive in a separate buffer. The decoder could be
fixed, but this is simpler and RDMA_NOMSG can be used in a variety
of other situations.

Ensure that the Linux client continues to use "RDMA_MSG + read
list" when sending large NFSv3 SYMLINK requests, which is more
efficient than using RDMA_NOMSG.

Large NFSv4 CREATE(NF4LNK) requests are changed to use "RDMA_MSG +
read list" just like NFSv3 (see Section 5 of RFC 5667). Before,
these did not work at all.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Tested-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Currently xprtrdma appends an extra chunk element to the RPC/RDMA
read chunk list of each NFSv4 WRITE compound. The extra element
contains the final GETATTR operation in the compound.

The result is an extra RDMA READ operation to transfer a very short
piece of each NFS WRITE compound (typically 16 bytes). This is
inefficient.

It is also incorrect.

The client is sending the trailing GETATTR at the same Position as
the preceding WRITE data payload. Whether or not RFC 5667 allows
the GETATTR to appear in a read chunk, RFC 5666 requires that these
two separate RPC arguments appear at two distinct Positions.

It can also be argued that the GETATTR operation is not bulk data,
and therefore RFC 5667 forbids its appearance in a read chunk at
all.

Although RFC 5667 is not precise about when using a read list with
NFSv4 COMPOUND is allowed, the intent is that only data arguments
not touched by NFS (ie, read and write payloads) are to be sent
using RDMA READ or WRITE.

The NFS client constructs GETATTR arguments itself, and therefore is
required to send the trailing GETATTR operation as additional inline
content, not as a data payload.

NB: This change is not backwards compatible. Some older servers do
not accept inline content following the read list. The Linux NFS
server should handle this content correctly as of commit
a97c331f ("svcrdma: Handle additional inline content").
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Tested-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Currently Linux always offers a reply chunk, even when the reply
can be sent inline (ie. is smaller than 1KB).

On the client, registering a memory region can be expensive. A
server may choose not to use the reply chunk, wasting the cost of
the registration.

This is a change only for RPC replies smaller than 1KB which the
server constructs in the RPC reply send buffer. Because the elements
of the reply must be XDR encoded, a copy-free data transfer has no
benefit in this case.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Tested-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

The client has been setting up a reply chunk for NFS READs that are
smaller than the inline threshold. This is not efficient: both the
server and client CPUs have to copy the reply's data payload into
and out of the memory region that is then transferred via RDMA.

Using the write list, the data payload is moved by the device and no
extra data copying is necessary.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Reviewed-By: NSagi Grimberg <sagig@mellanox.com>
Tested-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

When the size of the RPC message is near the inline threshold (1KB),
the client would allow messages to be sent that were a few bytes too
large.

When marshaling RPC/RDMA requests, ensure the combined size of
RPC/RDMA header and RPC header do not exceed the inline threshold.
Endpoints typically reject RPC/RDMA messages that exceed the size
of their receive buffers.

The two server implementations I test with (Linux and Solaris) use
receive buffers that are larger than the client’s inline threshold.
Thus so far this has been benign, observed only by code inspection.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Tested-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

RDMA_MSGP type calls insert a zero pad in the middle of the RPC
message to align the RPC request's data payload to the server's
alignment preferences. A server can then "page flip" the payload
into place to avoid a data copy in certain circumstances. However:

1. The client has to have a priori knowledge of the server's
   preferred alignment

2. Requests eligible for RDMA_MSGP are requests that are small
   enough to have been sent inline, and convey a data payload
   at the _end_ of the RPC message

Today 1. is done with a sysctl, and is a global setting that is
copied during mount. Linux does not support CCP to query the
server's preferences (RFC 5666, Section 6).

A small-ish NFSv3 WRITE might use RDMA_MSGP, but no NFSv4
compound fits bullet 2.

Thus the Linux client currently leaves RDMA_MSGP disabled. The
Linux server handles RDMA_MSGP, but does not use any special
page flipping, so it confers no benefit.

Clean up the marshaling code by removing the logic that constructs
RDMA_MSGP type calls. This also reduces the maximum send iovec size
from four to just two elements.

/proc/sys/sunrpc/rdma_inline_write_padding is a kernel API, and
thus is left in place.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Tested-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Untangle the end of rpcrdma_ia_open() by moving DMA MR set-up, which
is different for each registration method, to the .ro_open functions.

This is refactoring only. No behavior change is expected.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Tested-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

All HCA providers have an ib_get_dma_mr() verb. Thus
rpcrdma_ia_open() will either grab the device's local_dma_key if one
is available, or it will call ib_get_dma_mr(). If ib_get_dma_mr()
fails, rpcrdma_ia_open() fails and no transport is created.

Therefore execution never reaches the ib_reg_phys_mr() call site in
rpcrdma_register_internal(), so it can be removed.

The remaining logic in rpcrdma_{de}register_internal() is folded
into rpcrdma_{alloc,free}_regbuf().

This is clean up only. No behavior change is expected.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Reviewed-By: NSagi Grimberg <sagig@mellanox.com>
Tested-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

PHYSICAL memory registration uses a single rkey for all of the
client's memory, thus is insecure. It is still useful in some cases
for testing.

Retain the ability to select PHYSICAL memory registration capability
via /proc/sys/sunrpc/rdma_memreg_strategy, but don't fall back to it
if the HCA does not support FRWR or FMR.

This means amso1100 no longer works out of the box with NFS/RDMA.
When using amso1100 HCAs, set the memreg_strategy sysctl to 6 before
performing NFS/RDMA mounts.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Tested-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

In preparation for similar increases on NFS/RDMA servers, bump the
advertised credit limit for RPC/RDMA to 128. This allocates some
extra resources, but the client will continue to allow only the
number of RPCs in flight that the server requests via its advertised
credit limit.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-By: NSagi Grimberg <sagig@mellanox.com>
Tested-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

The point of larger rsize and wsize is to reduce the per-byte cost
of memory registration and deregistration. Modern HCAs can typically
handle a megabyte or more with a single registration operation.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Reviewed-By: NSagi Grimberg <sagig@mellanox.com>
Tested-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

In particular, recognize when an IPv6 connection is bound.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Tested-by: NDevesh Sharma <devesh.sharma@avagotech.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>