svcrdma: Fix double svc_rdma_send_ctxt_put() in an error path

This error path is almost never executed. Found by code inspection.

Fixes: 99722fe4d5a6 ("svcrdma: Persistently allocate and DMA-map Se

svcrdma: Fix double svc_rdma_send_ctxt_put() in an error path

This error path is almost never executed. Found by code inspection.

Fixes: 99722fe4d5a6 ("svcrdma: Persistently allocate and DMA-map Send buffers")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

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nfsd: Fix NFSv4 READ on RDMA when using readv

svcrdma expects that the payload falls precisely into the xdr_buf
page vector. This does not seem to be the case for
nfsd4_encode_readv().

This code is

nfsd: Fix NFSv4 READ on RDMA when using readv

svcrdma expects that the payload falls precisely into the xdr_buf
page vector. This does not seem to be the case for
nfsd4_encode_readv().

This code is called only when fops->splice_read is missing or when
RQ_SPLICE_OK is clear, so it's not a noticeable problem in many
common cases.

Add new transport method: ->xpo_read_payload so that when a READ
payload does not fit exactly in rq_res's page vector, the XDR
encoder can inform the RPC transport exactly where that payload is,
without the payload's XDR pad.

That way, when a Write chunk is present, the transport knows what
byte range in the Reply message is supposed to be matched with the
chunk.

Note that the Linux NFS server implementation of NFS/RDMA can
currently handle only one Write chunk per RPC-over-RDMA message.
This simplifies the implementation of this fix.

Fixes: b04209806384 ("nfsd4: allow exotic read compounds")
Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=198053
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

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svcrdma: Improve DMA mapping trace points

Capture the total size of Sends, the size of DMA map and the
matching DMA unmap to ensure operation is correct.

Signed-off-by: Chuck Lever <chuck.lever@ora

svcrdma: Improve DMA mapping trace points

Capture the total size of Sends, the size of DMA map and the
matching DMA unmap to ensure operation is correct.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Remove syslog warnings in work completion handlers

These can result in a lot of log noise, and are able to be triggered
by client misbehavior. Since there are trace points in these
handlers

svcrdma: Remove syslog warnings in work completion handlers

These can result in a lot of log noise, and are able to be triggered
by client misbehavior. Since there are trace points in these
handlers now, there's no need to spam the log.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Remove max_sge check at connect time

Two and a half years ago, the client was changed to use gathered
Send for larger inline messages, in commit 655fec6987b ("xprtrdma:
Use gathered Send fo

svcrdma: Remove max_sge check at connect time

Two and a half years ago, the client was changed to use gathered
Send for larger inline messages, in commit 655fec6987b ("xprtrdma:
Use gathered Send for large inline messages"). Several fixes were
required because there are a few in-kernel device drivers whose
max_sge is 3, and these were broken by the change.

Apparently my memory is going, because some time later, I submitted
commit 25fd86eca11c ("svcrdma: Don't overrun the SGE array in
svc_rdma_send_ctxt"), and after that, commit f3c1fd0ee294 ("svcrdma:
Reduce max_send_sges"). These too incorrectly assumed in-kernel
device drivers would have more than a few Send SGEs available.

The fix for the server side is not the same. This is because the
fundamental problem on the server is that, whether or not the client
has provisioned a chunk for the RPC reply, the server must squeeze
even the most complex RPC replies into a single RDMA Send. Failing
in the send path because of Send SGE exhaustion should never be an
option.

Therefore, instead of failing when the send path runs out of SGEs,
switch to using a bounce buffer mechanism to handle RPC replies that
are too complex for the device to send directly. That allows us to
remove the max_sge check to enable drivers with small max_sge to
work again.

Reported-by: Don Dutile <ddutile@redhat.com>
Fixes: 25fd86eca11c ("svcrdma: Don't overrun the SGE array in ...")
Cc: stable@vger.kernel.org
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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sunrpc: remove unused xpo_prep_reply_hdr callback

xpo_prep_reply_hdr are not used now.

It was defined for tcp transport only, however it cannot be
called indirectly, so let's move it to its caller

sunrpc: remove unused xpo_prep_reply_hdr callback

xpo_prep_reply_hdr are not used now.

It was defined for tcp transport only, however it cannot be
called indirectly, so let's move it to its caller and
remove unused callback.

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Optimize the logic that selects the R_key to invalidate

o Select the R_key to invalidate while the CPU cache still contains
the received RPC Call transport header, rather than waiting unt

svcrdma: Optimize the logic that selects the R_key to invalidate

o Select the R_key to invalidate while the CPU cache still contains
the received RPC Call transport header, rather than waiting until
we're about to send the RPC Reply.

o Choose Send With Invalidate if there is exactly one distinct R_key
in the received transport header. If there's more than one, the
client will have to perform local invalidation after it has
already waited for remote invalidation.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Avoid releasing a page in svc_xprt_release()

svc_xprt_release() invokes svc_free_res_pages(), which releases
pages between rq_respages and rq_next_page.

Historically, the RPC/RDMA transpor

svcrdma: Avoid releasing a page in svc_xprt_release()

svc_xprt_release() invokes svc_free_res_pages(), which releases
pages between rq_respages and rq_next_page.

Historically, the RPC/RDMA transport has set these two pointers to
be different by one, which means:

- one page gets released when svc_recv returns 0. This normally
happens whenever one or more RDMA Reads need to be dispatched to
complete construction of an RPC Call.

- one page gets released after every call to svc_send.

In both cases, this released page is immediately refilled by
svc_alloc_arg. There does not seem to be a reason for releasing this
page.

To avoid this unnecessary memory allocator traffic, set rq_next_page
more carefully.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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net/xprtrdma: Simplify ib_post_(send|recv|srq_recv)() calls

Instead of declaring and passing a dummy 'bad_wr' pointer, pass NULL
as third argument to ib_post_(send|recv|srq_recv)().

Signed-off-by:

net/xprtrdma: Simplify ib_post_(send|recv|srq_recv)() calls

Instead of declaring and passing a dummy 'bad_wr' pointer, pass NULL
as third argument to ib_post_(send|recv|srq_recv)().

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Anna Schumaker <Anna.Schumaker@netapp.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

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svcrdma: Persistently allocate and DMA-map Send buffers

While sending each RPC Reply, svc_rdma_sendto allocates and DMA-
maps a separate buffer where the RPC/RDMA transport header is
constructed. Th

svcrdma: Persistently allocate and DMA-map Send buffers

While sending each RPC Reply, svc_rdma_sendto allocates and DMA-
maps a separate buffer where the RPC/RDMA transport header is
constructed. The buffer is unmapped and released in the Send
completion handler. This is significant per-RPC overhead,
especially for small RPCs.

Instead, allocate and DMA-map a buffer, and cache it in each
svc_rdma_send_ctxt. This buffer and its mapping can be re-used
for each RPC, saving the cost of memory allocation and DMA
mapping.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Simplify svc_rdma_send()

Clean up: No current caller of svc_rdma_send's passes in a chained
WR. The logic that counts the chain length can be replaced with a
constant (1).

Signed-off-by: C

svcrdma: Simplify svc_rdma_send()

Clean up: No current caller of svc_rdma_send's passes in a chained
WR. The logic that counts the chain length can be replaced with a
constant (1).

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Remove post_send_wr

Clean up: Now that the send_wr is part of the svc_rdma_send_ctxt,
svc_rdma_post_send_wr is nearly empty.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-

svcrdma: Remove post_send_wr

Clean up: Now that the send_wr is part of the svc_rdma_send_ctxt,
svc_rdma_post_send_wr is nearly empty.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Don't overrun the SGE array in svc_rdma_send_ctxt

Receive buffers are always the same size, but each Send WR has a
variable number of SGEs, based on the contents of the xdr_buf being
sent.

svcrdma: Don't overrun the SGE array in svc_rdma_send_ctxt

Receive buffers are always the same size, but each Send WR has a
variable number of SGEs, based on the contents of the xdr_buf being
sent.

While assembling a Send WR, keep track of the number of SGEs so that
we don't exceed the device's maximum, or walk off the end of the
Send SGE array.

For now the Send path just fails if it exceeds the maximum.

The current logic in svc_rdma_accept bases the maximum number of
Send SGEs on the largest NFS request that can be sent or received.
In the transport layer, the limit is actually based on the
capabilities of the underlying device, not on properties of the
Upper Layer Protocol.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Introduce svc_rdma_send_ctxt

svc_rdma_op_ctxt's are pre-allocated and maintained on a per-xprt
free list. This eliminates the overhead of calling kmalloc / kfree,
both of which grab a globa

svcrdma: Introduce svc_rdma_send_ctxt

svc_rdma_op_ctxt's are pre-allocated and maintained on a per-xprt
free list. This eliminates the overhead of calling kmalloc / kfree,
both of which grab a globally shared lock that disables interrupts.
Introduce a replacement to svc_rdma_op_ctxt's that is built
especially for the svcrdma Send path.

Subsequent patches will take advantage of this new structure by
allocating real resources which are then cached in these objects.
The allocations are freed when the transport is torn down.

I've renamed the structure so that static type checking can be used
to ensure that uses of op_ctxt and send_ctxt are not confused. As an
additional clean up, structure fields are renamed to conform with
kernel coding conventions.

Additional clean ups:
- Handle svc_rdma_send_ctxt_get allocation failure at each call
site, rather than pre-allocating and hoping we guessed correctly
- All send_ctxt_put call-sites request page freeing, so remove
the @free_pages argument
- All send_ctxt_put call-sites unmap SGEs, so fold that into
svc_rdma_send_ctxt_put

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Clean up Send SGE accounting

Clean up: Since there's already a svc_rdma_op_ctxt being passed
around with the running count of mapped SGEs, drop unneeded
parameters to svc_rdma_post_send_wr(

svcrdma: Clean up Send SGE accounting

Clean up: Since there's already a svc_rdma_op_ctxt being passed
around with the running count of mapped SGEs, drop unneeded
parameters to svc_rdma_post_send_wr().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Refactor svc_rdma_dma_map_buf

Clean up: svc_rdma_dma_map_buf does mostly the same thing as
svc_rdma_dma_map_page, so let's fold these together.

Signed-off-by: Chuck Lever <chuck.lever@orac

svcrdma: Refactor svc_rdma_dma_map_buf

Clean up: svc_rdma_dma_map_buf does mostly the same thing as
svc_rdma_dma_map_page, so let's fold these together.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Persistently allocate and DMA-map Receive buffers

The current Receive path uses an array of pages which are allocated
and DMA mapped when each Receive WR is posted, and then handed off
to t

svcrdma: Persistently allocate and DMA-map Receive buffers

The current Receive path uses an array of pages which are allocated
and DMA mapped when each Receive WR is posted, and then handed off
to the upper layer in rqstp::rq_arg. The page flip releases unused
pages in the rq_pages pagelist. This mechanism introduces a
significant amount of overhead.

So instead, kmalloc the Receive buffer, and leave it DMA-mapped
while the transport remains connected. This confers a number of
benefits:

* Each Receive WR requires only one receive SGE, no matter how large
the inline threshold is. This helps the server-side NFS/RDMA
transport operate on less capable RDMA devices.

* The Receive buffer is left allocated and mapped all the time. This
relieves svc_rdma_post_recv from the overhead of allocating and
DMA-mapping a fresh buffer.

* svc_rdma_wc_receive no longer has to DMA unmap the Receive buffer.
It has to DMA sync only the number of bytes that were received.

* svc_rdma_build_arg_xdr no longer has to free a page in rq_pages
for each page in the Receive buffer, making it a constant-time
function.

* The Receive buffer is now plugged directly into the rq_arg's
head[0].iov_vec, and can be larger than a page without spilling
over into rq_arg's page list. This enables simplification of
the RDMA Read path in subsequent patches.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Preserve Receive buffer until svc_rdma_sendto

Rather than releasing the incoming svc_rdma_recv_ctxt at the end of
svc_rdma_recvfrom, hold onto it until svc_rdma_sendto.

This permits the co

svcrdma: Preserve Receive buffer until svc_rdma_sendto

Rather than releasing the incoming svc_rdma_recv_ctxt at the end of
svc_rdma_recvfrom, hold onto it until svc_rdma_sendto.

This permits the contents of the Receive buffer to be preserved
through svc_process and then referenced directly in sendto as it
constructs Write and Reply chunks to return to the client.

The real changes will come in subsequent patches.

Note: I cannot use ->xpo_release_rqst for this purpose because that
is called _before_ ->xpo_sendto. svc_rdma_sendto uses information in
the received Call transport header to construct the Reply transport
header, which is preserved in the RPC's Receive buffer.

The historical comment in svc_send() isn't helpful: it is already
obvious that ->xpo_release_rqst is being called before ->xpo_sendto,
but there is no explanation for this ordering going back to the
beginning of the git era.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Introduce svc_rdma_recv_ctxt

svc_rdma_op_ctxt's are pre-allocated and maintained on a per-xprt
free list. This eliminates the overhead of calling kmalloc / kfree,
both of which grab a globa

svcrdma: Introduce svc_rdma_recv_ctxt

svc_rdma_op_ctxt's are pre-allocated and maintained on a per-xprt
free list. This eliminates the overhead of calling kmalloc / kfree,
both of which grab a globally shared lock that disables interrupts.
To reduce contention further, separate the use of these objects in
the Receive and Send paths in svcrdma.

Subsequent patches will take advantage of this separation by
allocating real resources which are then cached in these objects.
The allocations are freed when the transport is torn down.

I've renamed the structure so that static type checking can be used
to ensure that uses of op_ctxt and recv_ctxt are not confused. As an
additional clean up, structure fields are renamed to conform with
kernel coding conventions.

As a final clean up, helpers related to recv_ctxt are moved closer
to the functions that use them.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Trace key RDMA API events

This includes:
* Posting on the Send and Receive queues
* Send, Receive, Read, and Write completion
* Connect upcalls
* QP errors

Signed-off-by: Chuck Lev

svcrdma: Trace key RDMA API events

This includes:
* Posting on the Send and Receive queues
* Send, Receive, Read, and Write completion
* Connect upcalls
* QP errors

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Trace key RPC/RDMA protocol events

This includes:
* Transport accept and tear-down
* Decisions about using Write and Reply chunks
* Each RDMA segment that is handled
* Whenever an R

svcrdma: Trace key RPC/RDMA protocol events

This includes:
* Transport accept and tear-down
* Decisions about using Write and Reply chunks
* Each RDMA segment that is handled
* Whenever an RDMA_ERR is sent

As a clean-up, I've standardized the order of the includes, and
removed some now redundant dprintk call sites.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Add proper SPDX tags for NetApp-contributed source

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Post Receives in the Receive completion handler

This change improves Receive efficiency by posting Receives only
on the same CPU that handles Receive completion. Improved latency
and throug

svcrdma: Post Receives in the Receive completion handler

This change improves Receive efficiency by posting Receives only
on the same CPU that handles Receive completion. Improved latency
and throughput has been noted with this change.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: fix an incorrect check on -E2BIG and -EINVAL

The current check will always be true and will always jump to
err1, this looks dubious to me. I believe && should be used
instead of ||.

Detect

svcrdma: fix an incorrect check on -E2BIG and -EINVAL

The current check will always be true and will always jump to
err1, this looks dubious to me. I believe && should be used
instead of ||.

Detected by CoverityScan, CID#1450120 ("Logically Dead Code")

Fixes: 107c1d0a991a ("svcrdma: Avoid Send Queue overflow")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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svcrdma: Avoid Send Queue overflow

Sanity case: Catch the case where more Work Requests are being
posted to the Send Queue than there are Send Queue Entries.

This might happen if a client sends a c

svcrdma: Avoid Send Queue overflow

Sanity case: Catch the case where more Work Requests are being
posted to the Send Queue than there are Send Queue Entries.

This might happen if a client sends a chunk with more segments than
there are SQEs for the transport. The server can't send that reply,
so the transport will deadlock unless the client drops the RPC.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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