Clean up: Pass in just the piece of the svc_rqst that is needed
here.

While we're in the area, add an informative documenting comment.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Calling ib_poll_cq() to sort through WCs during a completion is a
common pattern amongst RDMA consumers. Since commit 14d3a3b2
("IB: add a proper completion queue abstraction"), WC sorting can
be handled by the IB core.

By converting to this new API, svcrdma is made a better neighbor to
other RDMA consumers, as it allows the core to schedule the delivery
of completions more fairly amongst all active consumers.

This new API also aims each completion at a function that is
specific to the WR's opcode. Thus the ctxt->wr_op field and the
switch in process_context is replaced by a set of methods that
handle each completion type.

Because each ib_cqe carries a pointer to a completion method, the
core can now post operations on a consumer's QP, and handle the
completions itself.

The server's rdma_stat_sq_poll and rdma_stat_sq_prod metrics are no
longer updated.

As a clean up, the cq_event_handler, the dto_tasklet, and all
associated locking is removed, as they are no longer referenced or
used.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Tested-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Calling ib_poll_cq() to sort through WCs during a completion is a
common pattern amongst RDMA consumers. Since commit 14d3a3b2
("IB: add a proper completion queue abstraction"), WC sorting can
be handled by the IB core.

By converting to this new API, svcrdma is made a better neighbor to
other RDMA consumers, as it allows the core to schedule the delivery
of completions more fairly amongst all active consumers.

Because each ib_cqe carries a pointer to a completion method, the
core can now post operations on a consumer's QP, and handle the
completions itself.

svcrdma receive completions no longer use the dto_tasklet. Each
polled Receive WC is now handled individually in soft IRQ context.

The server transport's rdma_stat_rq_poll and rdma_stat_rq_prod
metrics are no longer updated.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

When constructing an error reply, svc_rdma_xdr_encode_error()
needs to view the client's request message so it can get the
failing request's XID.

svc_rdma_xdr_decode_req() is supposed to return a pointer to the
client's request header. But if it fails to decode the client's
message (and thus an error reply is needed) it does not return the
pointer. The server then sends a bogus XID in the error reply.

Instead, unconditionally generate the pointer to the client's header
in svc_rdma_recvfrom(), and pass that pointer to both functions.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NDevesh Sharma <devesh.sharma@broadcom.com>
Tested-by: NDevesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Fix several issues with svc_rdma_send_error():

 - Post a receive buffer to replace the one that was consumed by
   the incoming request
 - Posting a send should use DMA_TO_DEVICE, not DMA_FROM_DEVICE
 - No need to put_page _and_ free pages in svc_rdma_put_context
 - Make sure the sge is set up completely in case the error
   path goes through svc_rdma_unmap_dma()
 - Replace the use of ENOSYS, which has a reserved meaning

Related fixes in svc_rdma_recvfrom():

 - Don't leak the ctxt associated with the incoming request
 - Don't close the connection after sending an error reply
 - Let svc_rdma_send_error() figure out the right header error code

As a last clean up, move svc_rdma_send_error() to svc_rdma_sendto.c
with other similar functions. There is some common logic in these
functions that could someday be combined to reduce code duplication.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NDevesh Sharma <devesh.sharma@broadcom.com>
Tested-by: NDevesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Clean up: Most svc_rdma_post_recv() call sites close the transport
connection when a receive cannot be posted. Wrap that in a common
helper.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NDevesh Sharma <devesh.sharma@broadcom.com>
Tested-by: NDevesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The NFS server's XDR encoders adds an XDR pad for content in the
xdr_buf page list at the beginning of the xdr_buf's tail buffer.

On RDMA transports, Write chunks are sent separately and without an
XDR pad.

If a Write chunk is being sent, strip off the pad in the tail buffer
so that inline content following the Write chunk remains XDR-aligned
when it is sent to the client.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=294Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

We now alwasy have a per-PD local_dma_lkey available.  Make use of that
fact in svc_rdma and stop registering our own MR.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Reviewed-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NSteve Wise <swise@opengridcomputing.com>
Acked-by: NJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

To support the server-side of an NFSv4.1 backchannel on RDMA
connections, add a transport class that enables backward
direction messages on an existing forward channel connection.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Acked-by: NBruce Fields <bfields@fieldses.org>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Extra resources for handling backchannel requests have to be
pre-allocated when a transport instance is created. Set up
additional fields in svcxprt_rdma to track these resources.

The max_requests fields are elements of the RPC-over-RDMA
protocol, so they should be u32. To ensure that unsigned
arithmetic is used everywhere, some other fields in the
svcxprt_rdma struct are updated.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Acked-by: NBruce Fields <bfields@fieldses.org>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Pre-requisite to use map_xdr in the backchannel code.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Acked-by: NBruce Fields <bfields@fieldses.org>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

svc_rdma_post_recv() allocates pages for receive buffers on-demand.
It uses GFP_KERNEL so the allocator tries hard, and may sleep. But
I'm about to add a call to svc_rdma_post_recv() from a function
that may not sleep.

Since all svc_rdma_post_recv() call sites can tolerate its failure,
allow it to fail if the page allocator returns nothing. Longer term,
receive buffers, being a finite resource per-connection, should be
pre-allocated and re-used.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Acked-by: NBruce Fields <bfields@fieldses.org>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Clean up.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Acked-by: NBruce Fields <bfields@fieldses.org>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

To ensure this allocation cannot fail and will not sleep,
pre-allocate the req_map structures per-connection.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Acked-by: NBruce Fields <bfields@fieldses.org>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

When the maximum payload size of NFS READ and WRITE was increased
by commit cc9a903d ("svcrdma: Change maximum server payload back
to RPCSVC_MAXPAYLOAD"), the size of struct svc_rdma_op_ctxt
increased to over 6KB (on x86_64). That makes allocating one of
these from a kmem_cache more likely to fail in situations when
system memory is exhausted.

Since I'm about to add a caller where this allocation must always
work _and_ it cannot sleep, pre-allocate ctxts for each connection.

Another motivation for this change is that NFSv4.x servers are
required by specification not to drop NFS requests. Pre-allocating
memory resources reduces the likelihood of a drop.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Acked-by: NBruce Fields <bfields@fieldses.org>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

On NFSv4.1 mount points, the Linux NFS client uses this transport
endpoint to receive backward direction calls and route replies back
to the NFSv4.1 server.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Acked-by: N"J. Bruce Fields" <bfields@fieldses.org>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Tested-By: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Instead of maintaining a fastreg page list, keep an sg table
and convert an array of pages to a sg list. Then call ib_map_mr_sg
and construct ib_reg_wr.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Acked-by: NChristoph Hellwig <hch@lst.de>
Tested-by: NSteve Wise <swise@opengridcomputing.com>
Tested-by: NSelvin Xavier <selvin.xavier@avagotech.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Both commit 0380a3f3 ("svcrdma: Add a separate "max data segs"
macro for svcrdma") and commit 7e5be288 ("svcrdma: advertise
the correct max payload") are incorrect. This commit reverts both
changes, restoring the server's maximum payload size to 1MB.

Commit 7e5be288 based the server's maximum payload on the
_client's_ RPCRDMA_MAX_DATA_SEGS value. That was wrong.

Commit 0380a3f3 tried to fix this so that the client maximum
payload size could be raised without affecting the server, but
managed to confuse matters more on the server side.

More importantly, limiting the advertised maximum payload size was
meant to be a workaround, not the actual fix. We need to revisit

  https://bugzilla.linux-nfs.org/show_bug.cgi?id=270

A Linux client on a platform with 64KB pages can overrun and crash
an x86_64 NFS/RDMA server when the r/wsize is 1MB. An x86/64 Linux
client seems to work fine using 1MB reads and writes when the Linux
server's maximum payload size is restored to 1MB.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=270
Fixes: 0380a3f3 ("svcrdma: Add a separate "max data segs" macro")
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Commit 0bf48289 ("svcrdma: refactor marshalling logic") removed
the last call site for svc_rdma_fastreg().
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Kernel coding conventions frown upon having large nontrivial
functions in header files, and the preference these days is to
allow the compiler to make inlining decisions if possible.

As these functions are re-homed into a .c file, be sure that
comparisons with fields in struct rpcrdma_msg are with be32
constants.

This is a refactoring change; no behavior change is intended.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The server and client maximum are architecturally independent.
Allow changing one without affecting the other.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

At the 2015 LSF/MM, it was requested that memory allocation
call sites that request GFP_KERNEL allocations in a loop should be
annotated with __GFP_NOFAIL.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Fields in struct rpcrdma_msg are __be32. Don't byte-swap these
fields when decoding RPC calls and then swap them back for the
reply. For the most part, they can be left alone.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

svc_rdma_xdr_decode_deferred_req() indexes an array with an
un-byte-swapped value off the wire. Fortunately this function
isn't used anywhere, so simply remove it.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Clean up: Replace htonl and ntohl with the be32 equivalents.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Currently the Linux server can not decode RDMA_NOMSG type requests.
Operations whose length exceeds the fixed size of RDMA SEND buffers,
like large NFSv4 CREATE(NF4LNK) operations, must be conveyed via
RDMA_NOMSG.

For an RDMA_MSG type request, the client sends the RPC/RDMA, RPC
headers, and some or all of the NFS arguments via RDMA SEND.

For an RDMA_NOMSG type request, the client sends just the RPC/RDMA
header via RDMA SEND. The request's read list contains elements for
the entire RPC message, including the RPC header.

NFSD expects the RPC/RMDA header and RPC header to be contiguous in
page zero of the XDR buffer. Add logic in the RDMA READ path to make
the read list contents land where the server prefers, when the
incoming message is a type RDMA_NOMSG message.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The RDMA reader function doesn't change once an svcxprt_rdma is
instantiated. Instead of checking sc_devcap during every incoming
RPC, set the reader function once when the connection is accepted.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The byte_count argument is not used, and the function is called
only from one place.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The RDMA credit limit controls how many concurrent RPCs are allowed
per connection.

An NFS/RDMA client and server exchange their credit limits in the
RPC/RDMA headers. The Linux client and the Solaris client and server
allow 32 credits. The Linux server allows only 16, which limits its
performance.

Set the server's default credit limit to 32, like the other well-
known implementations, so the out-of-the-shrinkwrap performance of
the Linux server is better.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

This patch refactors the NFSRDMA server marshalling logic to
remove the intermediary map structures.  It also fixes an existing bug
where the NFSRDMA server was not minding the device fast register page
list length limitations.
Signed-off-by: NTom Tucker <tom@opengridcomputing.com>
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>

Sparse complains that the definition function definition and the
implementation aren't anotated the same way.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NTom Tucker <tom@opengridcomputing.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The svcrdma transport was un-marshalling requests in-place. This resulted
in sparse warnings due to __beXX data containing both NBO and HBO data.

The code has been restructured to do byte-swapping as the header is
parsed instead of when the header is validated immediately after receipt.

Also moved extern declarations for the workqueue and memory pools to the
private header file.
Signed-off-by: NTom Tucker <tom@ogc.us>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

RPCRDMA requests that specify a read-list are fetched with RDMA_READ. Using
an FRMR to map the data sink improves NFSRDMA security on transports that
place the RDMA_READ data sink LKEY on the wire because the valid lifetime
of the MR is only the duration of the RDMA_READ. The LKEY is invalidated
when the last RDMA_READ WR completes.

Mapping the data sink also allows for very large amounts to data to be
fetched with a single WR, so if the client is also using FRMR, the entire
RPC read-list can be fetched with a single WR.
Signed-off-by: NTom Tucker <tom@opengridcomputing.com>

Fast Reg MR introduces a new WR type. Add a service to register the
region with the adapter and update the completion handling to support
completions with a NULL WR context.
Signed-off-by: NTom Tucker <tom@opengridcomputing.com>

Add services for the allocating, freeing, and unmapping Fast Reg MR. These
services will be used by the transport connection setup, send and receive
routines.
Signed-off-by: NTom Tucker <tom@opengridcomputing.com>

Add data types to track Fast Reg Memory Regions. The core data type is
svc_rdma_fastreg_mr that associates a device MR with a host kva and page
list. A field is added to the WR context to keep track of the FRMR
used to map the local memory for an RPC.

An FRMR list and spin lock are added to the transport instance to keep
track of all FRMR allocated for the transport. Also added are device
capability flags to indicate what the memory registration
capabilities are for the underlying device and whether or not fast
memory registration is supported.
Signed-off-by: NTom Tucker <tom@opengridcomputing.com>

RDMA_READ completions are kept on a separate queue from the general
I/O request queue. Since a separate lock is used to protect the RDMA_READ
completion queue, a race exists between the dto_tasklet and the
svc_rdma_recvfrom thread where the dto_tasklet sets the XPT_DATA
bit and adds I/O to the read-completion queue. Concurrently, the
recvfrom thread checks the generic queue, finds it empty and resets
the XPT_DATA bit. A subsequent svc_xprt_enqueue will fail to enqueue
the transport for I/O and cause the transport to "stall".

The fix is to protect both lists with the same lock and set the XPT_DATA
bit with this lock held.
Signed-off-by: NTom Tucker <tom@opengridcomputing.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Change the WR context pool to be shared across mount points. This
reduces the RDMA transport memory footprint significantly since
idle mounts don't consume WR context memory.
Signed-off-by: NTom Tucker <tom@opengridcomputing.com>

The sc_read_wait queue head is no longer used. Remove it.
Signed-off-by: NTom Tucker <tom@opengridcomputing.com>