Commit graph

1190 commits

Author SHA1 Message Date
Linus Torvalds 0961f0c00e NFS Client Updates for Linux 5.15
- New Features:
   - Better client responsiveness when server isn't replying
   - Use refcount_t in sunrpc rpc_client refcount tracking
   - Add srcaddr and dst_port to the sunrpc sysfs info files
   - Add basic support for connection sharing between servers with multiple NICs`
 
 - Bugfixes and Cleanups:
   - Sunrpc tracepoint cleanups
   - Disconnect after ib_post_send() errors to avoid deadlocks
   - Fix for tearing down rpcrdma_reps
   - Fix a potential pNFS layoutget livelock loop
   - pNFS layout barrier fixes
   - Fix a potential memory corruption in rpc_wake_up_queued_task_set_status()
   - Fix reconnection locking
   - Fix return value of get_srcport()
   - Remove rpcrdma_post_sends()
   - Remove pNFS dead code
   - Remove copy size restriction for inter-server copies
   - Overhaul the NFS callback service
   - Clean up sunrpc TCP socket shutdowns
   - Always provide aligned buffers to RPC read layers
 -----BEGIN PGP SIGNATURE-----
 
 iQIyBAABCAAdFiEEnZ5MQTpR7cLU7KEp18tUv7ClQOsFAmExP7AACgkQ18tUv7Cl
 QOshTg/zBz7OfrS23CcLLgNidTJ6S7JOuj1DShG+YzsYXT8f9Nl1DadLM7yAEyok
 6JZzC8rXYzJcmYztHZzRyTuzj1+tGGb0u/MrD0bBk42VEel6eOjH/Y9ybn12Gf/E
 aqlcJh8hPx44U8oo5EFjRJsg2h28O06vywqhJz+sTbkqKN4hlAgMOo5ysAB+1thg
 BrTlR84EKBw5QqxPJ1WPmq9tEyGebU9Yrj1p8f0Uf015IeRNeTOXx3NzmdPshphf
 2yJvjumwEzqkcHXTJFDfP6ikIcGPPMNVAOK8DHb+vDGzNsOXW7dDM7GuWA3U8DlU
 ZHvyyb05Wwe6Wwg8xwx90FEXcYZFfZbSKmI9z2uoOuGFzNG07zWzPDzRft+qrOvU
 VMMwP9oEh71+qesmWTvqIbR2RjxqbCYlTcc8mBrD66DROi6jZ2jznraNC85sxG0Q
 b8GE+2SnYr2Q25yehj2xrRlOXyiYNkeeYmIpIquEqH9o7cSyDNJhBWbzIv6x+ith
 O/S06ZVKMc9X1nH5t5121XcHrSTMMVA/67WMyKfKMxWnrADAWPQALG+ttoTcbRu7
 Txew3Jb+hB8+ZdHAqbPf1l1i+7USQl1CRHMw3GRvNjCL2qcjZb1R7eyJRSQQtUyw
 q6SJRGe6Sn1FTUnn96Hv15Zy8VHx+q0cOL/EQVzL1RzJIXYcag==
 =Ad/3
 -----END PGP SIGNATURE-----

Merge tag 'nfs-for-5.15-1' of git://git.linux-nfs.org/projects/anna/linux-nfs

Pull NFS client updates from Anna Schumaker:
 "New Features:
   - Better client responsiveness when server isn't replying
   - Use refcount_t in sunrpc rpc_client refcount tracking
   - Add srcaddr and dst_port to the sunrpc sysfs info files
   - Add basic support for connection sharing between servers with multiple NICs`

  Bugfixes and Cleanups:
   - Sunrpc tracepoint cleanups
   - Disconnect after ib_post_send() errors to avoid deadlocks
   - Fix for tearing down rpcrdma_reps
   - Fix a potential pNFS layoutget livelock loop
   - pNFS layout barrier fixes
   - Fix a potential memory corruption in rpc_wake_up_queued_task_set_status()
   - Fix reconnection locking
   - Fix return value of get_srcport()
   - Remove rpcrdma_post_sends()
   - Remove pNFS dead code
   - Remove copy size restriction for inter-server copies
   - Overhaul the NFS callback service
   - Clean up sunrpc TCP socket shutdowns
   - Always provide aligned buffers to RPC read layers"

* tag 'nfs-for-5.15-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (39 commits)
  NFS: Always provide aligned buffers to the RPC read layers
  NFSv4.1 add network transport when session trunking is detected
  SUNRPC enforce creation of no more than max_connect xprts
  NFSv4 introduce max_connect mount options
  SUNRPC add xps_nunique_destaddr_xprts to xprt_switch_info in sysfs
  SUNRPC keep track of number of transports to unique addresses
  NFSv3: Delete duplicate judgement in nfs3_async_handle_jukebox
  SUNRPC: Tweak TCP socket shutdown in the RPC client
  SUNRPC: Simplify socket shutdown when not reusing TCP ports
  NFSv4.2: remove restriction of copy size for inter-server copy.
  NFS: Clean up the synopsis of callback process_op()
  NFS: Extract the xdr_init_encode/decode() calls from decode_compound
  NFS: Remove unused callback void decoder
  NFS: Add a private local dispatcher for NFSv4 callback operations
  SUNRPC: Eliminate the RQ_AUTHERR flag
  SUNRPC: Set rq_auth_stat in the pg_authenticate() callout
  SUNRPC: Add svc_rqst::rq_auth_stat
  SUNRPC: Add dst_port to the sysfs xprt info file
  SUNRPC: Add srcaddr as a file in sysfs
  sunrpc: Fix return value of get_srcport()
  ...
2021-09-04 10:25:26 -07:00
Chuck Lever 729580ddc5 svcrdma: xpt_bc_xprt is already clear in __svc_rdma_free()
svc_xprt_free() already "puts" the bc_xprt before calling the
transport's "free" method. No need to do it twice.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-08-19 08:29:32 -04:00
Chuck Lever 07a92d009f svcrdma: Convert rdma->sc_rw_ctxts to llist
Relieve contention on sc_rw_ctxt_lock by converting rdma->sc_rw_ctxts
to an llist.

The goal is to reduce the average overhead of Send completions,
because a transport's completion handlers are single-threaded on
one CPU core. This change reduces CPU utilization of each Send
completion by 2-3% on my server.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-By: Tom Talpey <tom@talpey.com>
2021-08-17 11:47:53 -04:00
Chuck Lever b6c2bfea09 svcrdma: Relieve contention on sc_send_lock.
/proc/lock_stat indicates the the sc_send_lock is heavily
contended when the server is under load from a single client.

To address this, convert the send_ctxt free list to an llist.
Returning an item to the send_ctxt cache is now waitless, which
reduces the instruction path length in the single-threaded Send
handler (svc_rdma_wc_send).

The goal is to enable the ib_comp_wq worker to handle a higher
RPC/RDMA Send completion rate given the same CPU resources. This
change reduces CPU utilization of Send completion by 2-3% on my
server.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-By: Tom Talpey <tom@talpey.com>
2021-08-17 11:47:53 -04:00
Chuck Lever 6c8c84f525 svcrdma: Fewer calls to wake_up() in Send completion handler
Because wake_up() takes an IRQ-safe lock, it can be expensive,
especially to call inside of a single-threaded completion handler.
What's more, the Send wait queue almost never has waiters, so
most of the time, this is an expensive no-op.

As always, the goal is to reduce the average overhead of each
completion, because a transport's completion handlers are single-
threaded on one CPU core. This change reduces CPU utilization of
the Send completion thread by 2-3% on my server.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-By: Tom Talpey <tom@talpey.com>
2021-08-17 11:47:53 -04:00
Trond Myklebust f99fa50880 SUNRPC/xprtrdma: Fix reconnection locking
The xprtrdma client code currently relies on the task that initiated the
connect to hold the XPRT_LOCK for the duration of the connection
attempt. If the task is woken early, due to some other event, then that
lock could get released early.
Avoid races by using the same mechanism that the socket code uses of
transferring lock ownership to the RDMA connect worker itself. That
frees us to call rpcrdma_xprt_disconnect() directly since we're now
guaranteed exclusion w.r.t. other callers.

Fixes: 4cf44be6f1 ("xprtrdma: Fix recursion into rpcrdma_xprt_disconnect()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-08-09 16:57:05 -04:00
Chuck Lever 8d863b1f05 xprtrdma: Eliminate rpcrdma_post_sends()
Clean up.

Now that there is only one registration mode, there is only one
target "post_send" method: frwr_send(). rpcrdma_post_sends() no
longer adds much value, especially since all of its call sites
ignore the return code value except to check if it's non-zero.

Just have them call frwr_send() directly instead.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-08-09 16:42:25 -04:00
Chuck Lever d9ae8134f2 xprtrdma: Add an xprtrdma_post_send_err tracepoint
Unlike xprtrdma_post_send(), this one can be left enabled all the
time, and should almost never fire. But we do want to know about
immediate errors when they happen.

Note that there is already a similar post_linv_err tracepoint.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-08-09 16:42:18 -04:00
Chuck Lever 683f31c3ab xprtrdma: Add xprtrdma_post_recvs_err() tracepoint
In the vast majority of cases, rc=0. Don't record that in the
post_recvs tracepoint. Instead, add a separate tracepoint that can
be left enabled all the time to capture the very rare immediate
errors returned by ib_post_recv().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-08-09 16:42:10 -04:00
Chuck Lever 97480cae13 xprtrdma: Put rpcrdma_reps before waking the tear-down completion
Ensure the tear-down completion is awoken only /after/ we've stopped
fiddling with rpcrdma_rep objects in rpcrdma_post_recvs().

Fixes: 15788d1d10 ("xprtrdma: Do not refresh Receive Queue while it is draining")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-08-09 16:42:02 -04:00
Chuck Lever 1143129e4d xprtrdma: Disconnect after an ib_post_send() immediate error
ib_post_send() does not disconnect the QP when it returns an
immediate error. Thus, the code that posts LocalInv has to
explicitly disconnect after an immediate error. This is just
like the frwr_send() callers handle it.

If a disconnect isn't done here, the transport deadlocks.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-08-09 16:40:51 -04:00
Linus Torvalds 96890bc2ea NFS client updates for Linux 5.14
Highlights include:
 
 Stable fixes:
 - Two sunrpc fixes for deadlocks involving privileged rpc_wait_queues
 
 Bugfixes
 - SUNRPC: Avoid a KASAN slab-out-of-bounds bug in xdr_set_page_base()
 - SUNRPC: prevent port reuse on transports which don't request it.
 - NFSv3: Fix memory leak in posix_acl_create()
 - NFS: Various fixes to attribute revalidation timeouts
 - NFSv4: Fix handling of non-atomic change attribute updates
 - NFSv4: If a server is down, don't cause mounts to other servers to
   hang as well
 - pNFS: Fix an Oops in pnfs_mark_request_commit() when doing O_DIRECT
 - NFS: Fix mount failures due to incorrect setting of the has_sec_mnt_opts
   filesystem flag
  - NFS: Ensure nfs_readpage returns promptly when an internal error occurs
  - NFS: Fix fscache read from NFS after cache error
  - pNFS: Various bugfixes around the LAYOUTGET operation
 
 Features
 - Multiple patches to add support for fcntl() leases over NFSv4.
 - A sysfs interface to display more information about the various
   transport connections used by the RPC client
 - A sysfs interface to allow a suitably privileged user to offline a
   transport that may no longer point to a valid server
 - A sysfs interface to allow a suitably privileged user to change the
   server IP address used by the RPC client
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEESQctxSBg8JpV8KqEZwvnipYKAPIFAmDnPrkACgkQZwvnipYK
 APKGAw/9EjdGoic6VpShQyb5uxaRoDd4uwWgFLBOfPhIWC7qNMtkj49wHIOEUm7e
 YfdF5RlCdmshaoMxjY84wjl8NTMwHbPahgooDd4+UsZUs2qxZ8dBsr0itfbFsJv8
 BpaCYKQt6XGQngGrWfC7SiCETnMej2YsmjDfHvhD58TxnRfPWexHUvx9xi9uGRCS
 sIWRA2QMNs7LwdShkkRotagodRLhu/zo4g0lon5lI8D/SRg6o8RoO4YP6oKH1FN4
 OyVzy1aWZGocgwCMUtNeuigJSRyDa+bJTfJ2c27uw5g18s0XWZ3j2DxD5I+HCEuE
 B4rhg+ujtPIifYLHf2Aj3nlxdBePZ5L67a2MOOUo+wSD+nPmNMZF1eIT/3Jsg/HA
 Z8gqcBiTIkBfVGJxWWbrbHfxPXQiK1IRGQx9acyhLCN9M6Kv5bbkn4R4dnronvJR
 g6O968fgC5uvl60CXdc8NCpWtSitXB/nH8pn7MbJ8JBGq7QIYNkS0d4E8ePhYwxk
 sRYJt21O+ryjodfQDHaUxodzCKGcpRoknpirMmgoAp4zdkva4ltViNsQvHa7jFh8
 HIuhU6Aia1xVYpUMDEXf2WMXCT9yLa2TyMDuS5KDfb69wBkQJWeKNkebf+1k03wQ
 saEmdoP4aEEujimkA7rqyOlI8XhsudKvBd3HXg+w9+xIt4yoie0=
 =NaOI
 -----END PGP SIGNATURE-----

Merge tag 'nfs-for-5.14-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client updates from Trond Myklebust:
 "Highlights include:

  Features:

   - Multiple patches to add support for fcntl() leases over NFSv4.

   - A sysfs interface to display more information about the various
     transport connections used by the RPC client

   - A sysfs interface to allow a suitably privileged user to offline a
     transport that may no longer point to a valid server

   - A sysfs interface to allow a suitably privileged user to change the
     server IP address used by the RPC client

  Stable fixes:

   - Two sunrpc fixes for deadlocks involving privileged rpc_wait_queues

  Bugfixes:

   - SUNRPC: Avoid a KASAN slab-out-of-bounds bug in xdr_set_page_base()

   - SUNRPC: prevent port reuse on transports which don't request it.

   - NFSv3: Fix memory leak in posix_acl_create()

   - NFS: Various fixes to attribute revalidation timeouts

   - NFSv4: Fix handling of non-atomic change attribute updates

   - NFSv4: If a server is down, don't cause mounts to other servers to
     hang as well

   - pNFS: Fix an Oops in pnfs_mark_request_commit() when doing O_DIRECT

   - NFS: Fix mount failures due to incorrect setting of the
     has_sec_mnt_opts filesystem flag

   - NFS: Ensure nfs_readpage returns promptly when an internal error
     occurs

   - NFS: Fix fscache read from NFS after cache error

   - pNFS: Various bugfixes around the LAYOUTGET operation"

* tag 'nfs-for-5.14-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (46 commits)
  NFSv4/pNFS: Return an error if _nfs4_pnfs_v3_ds_connect can't load NFSv3
  NFSv4/pNFS: Don't call _nfs4_pnfs_v3_ds_connect multiple times
  NFSv4/pnfs: Clean up layout get on open
  NFSv4/pnfs: Fix layoutget behaviour after invalidation
  NFSv4/pnfs: Fix the layout barrier update
  NFS: Fix fscache read from NFS after cache error
  NFS: Ensure nfs_readpage returns promptly when internal error occurs
  sunrpc: remove an offlined xprt using sysfs
  sunrpc: provide showing transport's state info in the sysfs directory
  sunrpc: display xprt's queuelen of assigned tasks via sysfs
  sunrpc: provide multipath info in the sysfs directory
  NFSv4.1 identify and mark RPC tasks that can move between transports
  sunrpc: provide transport info in the sysfs directory
  SUNRPC: take a xprt offline using sysfs
  sunrpc: add dst_attr attributes to the sysfs xprt directory
  SUNRPC for TCP display xprt's source port in sysfs xprt_info
  SUNRPC query transport's source port
  SUNRPC display xprt's main value in sysfs's xprt_info
  SUNRPC mark the first transport
  sunrpc: add add sysfs directory per xprt under each xprt_switch
  ...
2021-07-09 09:43:57 -07:00
Olga Kornievskaia d3abc73987 sunrpc: keep track of the xprt_class in rpc_xprt structure
We need to keep track of the type for a given transport.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-07-08 14:03:23 -04:00
Linus Torvalds 0cc2ea8ceb Some highlights:
- add tracepoints for callbacks and for client creation and
 	  destruction
 	- cache the mounts used for server-to-server copies
 	- expose callback information in /proc/fs/nfsd/clients/*/info
 	- don't hold locks unnecessarily while waiting for commits
 	- update NLM to use xdr_stream, as we have for NFSv2/v3/v4
 -----BEGIN PGP SIGNATURE-----
 
 iQJJBAABCAAzFiEEYtFWavXG9hZotryuJ5vNeUKO4b4FAmDlvjIVHGJmaWVsZHNA
 ZmllbGRzZXMub3JnAAoJECebzXlCjuG+0MoP/RJ8Q7zwIz6WFHn3bCRaEXpnnkAH
 mmMfELhmgvH0V5nXWbb2rAfhllY+/zeWtf8QHSEKUPCnVLmB7WeXKdjXSy7EnYJ8
 R8DuuuII85McIrg93nJ8hxm4wXTaTZKXpS4Vxkuxc6YKxoeJoXOaTjbgRLIw8mfX
 w4wPfjAsnROboVxvDHUmBS9zNKaAi2dZ0jH2x2eS7eZSWzoJC30yd+pFSxyYoOac
 3fZUntDskQDGIpXHuTf53WcaK7h1bUHrwS7Joez8Z0ctg4vcbJsfdhKZUZwAxOZh
 3xWAgm3PFcze5xqHuX8BYBThHfB3uTeygZQRb3zI9sG2UQtQfundrtlxZRSjMMkC
 cwlSi2SQNL66EBIgOcS3U/9OeorLALnnRax1KWMWjpFzaBJJQTJDumwLRx4zogI1
 Ouiu0fI+hApck+L+qCzJMidA2wxOBsDzH471YiGiqQSmgNZc6wBc+aC/JKN8QAWb
 jG53vvpa3gCZa8Rs3KyOoUvtcCCdiQc+nljbzqtVfIvvGa9MSixufa+U5fojLEO7
 i8aangK+mteMxrrejEKvRu1efDIfpFq0HW7ev1mzW2Jl/AguDXM5XUeGK2mMMPtc
 WqT3arbtGVcXJN+Oh5TzTVuED/DecyO0Fig77G+WJTiWONgoHfs+E5nC4aHSpohn
 bMpmQMIOmTa5zgQP
 =BQyR
 -----END PGP SIGNATURE-----

Merge tag 'nfsd-5.14' of git://linux-nfs.org/~bfields/linux

Pull nfsd updates from Bruce Fields:

 - add tracepoints for callbacks and for client creation and destruction

 - cache the mounts used for server-to-server copies

 - expose callback information in /proc/fs/nfsd/clients/*/info

 - don't hold locks unnecessarily while waiting for commits

 - update NLM to use xdr_stream, as we have for NFSv2/v3/v4

* tag 'nfsd-5.14' of git://linux-nfs.org/~bfields/linux: (69 commits)
  nfsd: fix NULL dereference in nfs3svc_encode_getaclres
  NFSD: Prevent a possible oops in the nfs_dirent() tracepoint
  nfsd: remove redundant assignment to pointer 'this'
  nfsd: Reduce contention for the nfsd_file nf_rwsem
  lockd: Update the NLMv4 SHARE results encoder to use struct xdr_stream
  lockd: Update the NLMv4 nlm_res results encoder to use struct xdr_stream
  lockd: Update the NLMv4 TEST results encoder to use struct xdr_stream
  lockd: Update the NLMv4 void results encoder to use struct xdr_stream
  lockd: Update the NLMv4 FREE_ALL arguments decoder to use struct xdr_stream
  lockd: Update the NLMv4 SHARE arguments decoder to use struct xdr_stream
  lockd: Update the NLMv4 SM_NOTIFY arguments decoder to use struct xdr_stream
  lockd: Update the NLMv4 nlm_res arguments decoder to use struct xdr_stream
  lockd: Update the NLMv4 UNLOCK arguments decoder to use struct xdr_stream
  lockd: Update the NLMv4 CANCEL arguments decoder to use struct xdr_stream
  lockd: Update the NLMv4 LOCK arguments decoder to use struct xdr_stream
  lockd: Update the NLMv4 TEST arguments decoder to use struct xdr_stream
  lockd: Update the NLMv4 void arguments decoder to use struct xdr_stream
  lockd: Update the NLMv1 SHARE results encoder to use struct xdr_stream
  lockd: Update the NLMv1 nlm_res results encoder to use struct xdr_stream
  lockd: Update the NLMv1 TEST results encoder to use struct xdr_stream
  ...
2021-07-07 12:50:08 -07:00
Zheng Yongjun d50295255e xprtrdma: Fix spelling mistakes
Fix some spelling mistakes in comments:
succes  ==> success

Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2021-07-06 20:14:41 -04:00
Chuck Lever ae605ee983 xprtrdma: Revert 586a0787ce
Commit 9ed5af268e ("SUNRPC: Clean up the handling of page padding
in rpc_prepare_reply_pages()") [Dec 2020] affects RPC Replies that
have a data payload (i.e., Write chunks).

rpcrdma_prepare_readch(), as its name suggests, sets up Read chunks
which are data payloads within RPC Calls. Those payloads are
constructed by xdr_write_pages(), which continues to stuff the call
buffer's tail kvec with the payload's XDR roundup. Thus removing
the tail buffer logic in rpcrdma_prepare_readch() was the wrong
thing to do.

Fixes: 586a0787ce ("xprtrdma: Clean up rpcrdma_prepare_readch()")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-05-27 08:46:19 -04:00
Trond Myklebust e86be3a04b SUNRPC: More fixes for backlog congestion
Ensure that we fix the XPRT_CONGESTED starvation issue for RDMA as well
as socket based transports.
Ensure we always initialise the request after waking up from the backlog
list.

Fixes: e877a88d1f ("SUNRPC in case of backlog, hand free slots directly to waiting task")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-05-26 06:36:13 -04:00
Linus Torvalds a647034fe2 NFS client updates for Linux 5.13
Highlights include:
 
 Stable fixes:
 - Add validation of the UDP retrans parameter to prevent shift out-of-bounds
 - Don't discard pNFS layout segments that are marked for return
 
 Bugfixes:
 - Fix a NULL dereference crash in xprt_complete_bc_request() when the
   NFSv4.1 server misbehaves.
 - Fix the handling of NFS READDIR cookie verifiers
 - Sundry fixes to ensure attribute revalidation works correctly when the
   server does not return post-op attributes.
 - nfs4_bitmask_adjust() must not change the server global bitmasks
 - Fix major timeout handling in the RPC code.
 - NFSv4.2 fallocate() fixes.
 - Fix the NFSv4.2 SEEK_HOLE/SEEK_DATA end-of-file handling
 - Copy offload attribute revalidation fixes
 - Fix an incorrect filehandle size check in the pNFS flexfiles driver
 - Fix several RDMA transport setup/teardown races
 - Fix several RDMA queue wrapping issues
 - Fix a misplaced memory read barrier in sunrpc's call_decode()
 
 Features:
 - Micro optimisation of the TCP transmission queue using TCP_CORK
 - statx() performance improvements by further splitting up the tracking
   of invalid cached file metadata.
 - Support the NFSv4.2 "change_attr_type" attribute and use it to
   optimise handling of change attribute updates.
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEESQctxSBg8JpV8KqEZwvnipYKAPIFAmCVLooACgkQZwvnipYK
 APJB5BAAtIJyhx40ooMBzcucDmXd1qovlKsb8ZlvnSI6c7wvHhFPNk9z4zwThnjL
 FpVYzJzK6XzAQY/PtgbrPwnSUmW925ngPWYR/hiYe+OGPBnYV+tXP8izCyEkNgMg
 45goDOxojGWl7AGTuAJiKcDSdH9PyIrbvt28iwcNSGjslasGSbAoL/836l4OIGr1
 Ymxs/NDML11dPco8GIKLGtHd8leFGleDx089VeNsgud8MdaFErp16O5Iz8DdzRKd
 W1l2zDMb05j8eDZIfy3w3FyrLkDXA+KgLSADiC8TcpxoadPaQJMeCvoIq8oqVndn
 bZBoxduXdLgf54Aec0WnNKFAOyc7pGvZoSNmFouT7EGV73g+g1LQ+ZbEE1bb8fCQ
 XHqCVaBt2+47NiTUgdxjXlZRfcn8fYKx0tVxfG3mQVMXUAWfsjmMyQMNgijDRJI2
 8Wz3lZMRGMILbR9j4QpP1biVy/2zGNWG/TB5ZZyZMSY4uT+aOpzlqdknb4UsRaSp
 f7MfmB7xEWpS4DJr9RIBrJ/hIdnMu1mNInxDPFo5Kl5HNp4TaPm2dPir2ZD2wMZI
 daURTX7giUhpE15ZebQDBqWD+mTR0bVDqLLeo131JRmMfMEHugNrr49xe+NkBu/R
 QWnFzgkGdQsOeiKRRwEUuhsi74JspqfwzdZzHqcRM5WuXVvBLcA=
 =h01b
 -----END PGP SIGNATURE-----

Merge tag 'nfs-for-5.13-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client updates from Trond Myklebust:
 "Highlights include:

  Stable fixes:

   - Add validation of the UDP retrans parameter to prevent shift
     out-of-bounds

   - Don't discard pNFS layout segments that are marked for return

  Bugfixes:

   - Fix a NULL dereference crash in xprt_complete_bc_request() when the
     NFSv4.1 server misbehaves.

   - Fix the handling of NFS READDIR cookie verifiers

   - Sundry fixes to ensure attribute revalidation works correctly when
     the server does not return post-op attributes.

   - nfs4_bitmask_adjust() must not change the server global bitmasks

   - Fix major timeout handling in the RPC code.

   - NFSv4.2 fallocate() fixes.

   - Fix the NFSv4.2 SEEK_HOLE/SEEK_DATA end-of-file handling

   - Copy offload attribute revalidation fixes

   - Fix an incorrect filehandle size check in the pNFS flexfiles driver

   - Fix several RDMA transport setup/teardown races

   - Fix several RDMA queue wrapping issues

   - Fix a misplaced memory read barrier in sunrpc's call_decode()

  Features:

   - Micro optimisation of the TCP transmission queue using TCP_CORK

   - statx() performance improvements by further splitting up the
     tracking of invalid cached file metadata.

   - Support the NFSv4.2 'change_attr_type' attribute and use it to
     optimise handling of change attribute updates"

* tag 'nfs-for-5.13-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (85 commits)
  xprtrdma: Fix a NULL dereference in frwr_unmap_sync()
  sunrpc: Fix misplaced barrier in call_decode
  NFSv4.2: Remove ifdef CONFIG_NFSD from NFSv4.2 client SSC code.
  xprtrdma: Move fr_mr field to struct rpcrdma_mr
  xprtrdma: Move the Work Request union to struct rpcrdma_mr
  xprtrdma: Move fr_linv_done field to struct rpcrdma_mr
  xprtrdma: Move cqe to struct rpcrdma_mr
  xprtrdma: Move fr_cid to struct rpcrdma_mr
  xprtrdma: Remove the RPC/RDMA QP event handler
  xprtrdma: Don't display r_xprt memory addresses in tracepoints
  xprtrdma: Add an rpcrdma_mr_completion_class
  xprtrdma: Add tracepoints showing FastReg WRs and remote invalidation
  xprtrdma: Avoid Send Queue wrapping
  xprtrdma: Do not wake RPC consumer on a failed LocalInv
  xprtrdma: Do not recycle MR after FastReg/LocalInv flushes
  xprtrdma: Clarify use of barrier in frwr_wc_localinv_done()
  xprtrdma: Rename frwr_release_mr()
  xprtrdma: rpcrdma_mr_pop() already does list_del_init()
  xprtrdma: Delete rpcrdma_recv_buffer_put()
  xprtrdma: Fix cwnd update ordering
  ...
2021-05-07 11:23:41 -07:00
Chuck Lever 9e895cd964 xprtrdma: Fix a NULL dereference in frwr_unmap_sync()
The normal mechanism that invalidates and unmaps MRs is
frwr_unmap_async(). frwr_unmap_sync() is used only when an RPC
Reply bearing Write or Reply chunks has been lost (ie, almost
never).

Coverity found that after commit 9a301cafc8 ("xprtrdma: Move
fr_linv_done field to struct rpcrdma_mr"), the while() loop in
frwr_unmap_sync() exits only once @mr is NULL, unconditionally
causing subsequent dereferences of @mr to Oops.

I've tested this fix by creating a client that skips invoking
frwr_unmap_async() when RPC Replies complete. That forces all
invalidation tasks to fall upon frwr_unmap_sync(). Simple workloads
with this fix applied to the adulterated client work as designed.

Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1504556 ("Null pointer dereferences")
Fixes: 9a301cafc8 ("xprtrdma: Move fr_linv_done field to struct rpcrdma_mr")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-05-01 19:42:22 -04:00
Chuck Lever 13bcf7e32a xprtrdma: Move fr_mr field to struct rpcrdma_mr
Clean up: The last remaining field in struct rpcrdma_frwr has been
removed, so the struct can be eliminated.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:27:23 -04:00
Chuck Lever dcff9ed209 xprtrdma: Move the Work Request union to struct rpcrdma_mr
Clean up.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:27:13 -04:00
Chuck Lever 9a301cafc8 xprtrdma: Move fr_linv_done field to struct rpcrdma_mr
Clean up: Move more of struct rpcrdma_frwr into its parent.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:27:06 -04:00
Chuck Lever e10fa96d34 xprtrdma: Move cqe to struct rpcrdma_mr
Clean up.

- Simplify variable initialization in the completion handlers.

- Move another field out of struct rpcrdma_frwr.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:27:00 -04:00
Chuck Lever 0a26d10e30 xprtrdma: Move fr_cid to struct rpcrdma_mr
Clean up (for several purposes):

- The MR's cid is initialized sooner so that tracepoints can show
  something reasonable even if the MR is never posted.
- The MR's res.id doesn't change so the cid won't change either.
  Initializing the cid once is sufficient.
- struct rpcrdma_frwr is going away soon.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:26:53 -04:00
Chuck Lever e1648eb23d xprtrdma: Remove the RPC/RDMA QP event handler
Clean up: The handler only recorded a trace event. If indeed no
action is needed by the RPC/RDMA consumer, then the event can be
ignored.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:26:31 -04:00
Chuck Lever 4ddd0fc32c xprtrdma: Add tracepoints showing FastReg WRs and remote invalidation
The Send signaling logic is a little subtle, so add some
observability around it. For every xprtrdma_mr_fastreg event, there
should be an xprtrdma_mr_localinv or xprtrdma_mr_reminv event.

When these tracepoints are enabled, we can see exactly when an MR is
DMA-mapped, registered, invalidated (either locally or remotely) and
then DMA-unmapped.

   kworker/u25:2-190   [000]   787.979512: xprtrdma_mr_map:      task:351@5 mr.id=4 nents=2 5608@0x8679e0c8f6f56000:0x00000503 (TO_DEVICE)
   kworker/u25:2-190   [000]   787.979515: xprtrdma_chunk_read:  task:351@5 pos=148 5608@0x8679e0c8f6f56000:0x00000503 (last)
   kworker/u25:2-190   [000]   787.979519: xprtrdma_marshal:     task:351@5 xid=0x8679e0c8: hdr=52 xdr=148/5608/0 read list/inline
   kworker/u25:2-190   [000]   787.979525: xprtrdma_mr_fastreg:  task:351@5 mr.id=4 nents=2 5608@0x8679e0c8f6f56000:0x00000503 (TO_DEVICE)
   kworker/u25:2-190   [000]   787.979526: xprtrdma_post_send:   task:351@5 cq.id=0 cid=73 (2 SGEs)

 ...

    kworker/5:1H-219   [005]   787.980567: xprtrdma_wc_receive:  cq.id=1 cid=161 status=SUCCESS (0/0x0) received=164
    kworker/5:1H-219   [005]   787.980571: xprtrdma_post_recvs:  peer=[192.168.100.55]:20049 r_xprt=0xffff8884974d4000: 0 new recvs, 70 active (rc 0)
    kworker/5:1H-219   [005]   787.980573: xprtrdma_reply:       task:351@5 xid=0x8679e0c8 credits=64
    kworker/5:1H-219   [005]   787.980576: xprtrdma_mr_reminv:   task:351@5 mr.id=4 nents=2 5608@0x8679e0c8f6f56000:0x00000503 (TO_DEVICE)
    kworker/5:1H-219   [005]   787.980577: xprtrdma_mr_unmap:    mr.id=4 nents=2 5608@0x8679e0c8f6f56000:0x00000503 (TO_DEVICE)

Note that I've moved the xprtrdma_post_send tracepoint so that event
always appears after the xprtrdma_mr_fastreg tracepoint. Otherwise
the event log looks counterintuitive (FastReg is always supposed to
happen before Send).

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:25:58 -04:00
Chuck Lever b3ce7a25f4 xprtrdma: Avoid Send Queue wrapping
Send WRs can be signalled or unsignalled. A signalled Send WR
always has a matching Send completion, while a unsignalled Send
has a completion only if the Send WR fails.

xprtrdma has a Send account mechanism that is designed to reduce
the number of signalled Send WRs. This in turn mitigates the
interrupt rate of the underlying device.

RDMA consumers can't leave all Sends unsignaled, however, because
providers rely on Send completions to maintain their Send Queue head
and tail pointers. xprtrdma counts the number of unsignaled Send WRs
that have been posted to ensure that Sends are signalled often
enough to prevent the Send Queue from wrapping.

This mechanism neglected to account for FastReg WRs, which are
posted on the Send Queue but never signalled. As a result, the
Send Queue wrapped on occasion, resulting in duplication completions
of FastReg and LocalInv WRs.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:25:43 -04:00
Chuck Lever 8a053433de xprtrdma: Do not wake RPC consumer on a failed LocalInv
Throw away any reply where the LocalInv flushes or could not be
posted. The registered memory region is in an unknown state until
the disconnect completes.

rpcrdma_xprt_disconnect() will find and release the MR. No need to
put it back on the MR free list in this case.

The client retransmits pending RPC requests once it reestablishes a
fresh connection, so a replacement reply should be forthcoming on
the next connection instance.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:25:19 -04:00
Chuck Lever e4b52ca013 xprtrdma: Do not recycle MR after FastReg/LocalInv flushes
Better not to touch MRs involved in a flush or post error until the
Send and Receive Queues are drained and the transport is fully
quiescent. Simply don't insert such MRs back onto the free list.
They remain on mr_all and will be released when the connection is
torn down.

I had thought that recycling would prevent hardware resources from
being tied up for a long time. However, since v5.7, a transport
disconnect destroys the QP and other hardware-owned resources. The
MRs get cleaned up nicely at that point.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:25:12 -04:00
Chuck Lever 44438ad9ae xprtrdma: Clarify use of barrier in frwr_wc_localinv_done()
Clean up: The comment and the placement of the memory barrier is
confusing. Humans want to read the function statements from head
to tail.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:24:47 -04:00
Chuck Lever f912af77e2 xprtrdma: Rename frwr_release_mr()
Clean up: To be consistent with other functions in this source file,
follow the naming convention of putting the object being acted upon
before the action itself.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:24:29 -04:00
Chuck Lever 1363e6388c xprtrdma: rpcrdma_mr_pop() already does list_del_init()
The rpcrdma_mr_pop() earlier in the function has already cleared
out mr_list, so it must not be done again in the error path.

Fixes: 847568942f ("xprtrdma: Remove fr_state")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:24:22 -04:00
Chuck Lever c35ca60d49 xprtrdma: Delete rpcrdma_recv_buffer_put()
Clean up: The name recv_buffer_put() is a vestige of older code,
and the function is just a wrapper for the newer rpcrdma_rep_put().
In most of the existing call sites, a pointer to the owning
rpcrdma_buffer is already available.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:24:12 -04:00
Chuck Lever 35d8b10a25 xprtrdma: Fix cwnd update ordering
After a reconnect, the reply handler is opening the cwnd (and thus
enabling more RPC Calls to be sent) /before/ rpcrdma_post_recvs()
can post enough Receive WRs to receive their replies. This causes an
RNR and the new connection is lost immediately.

The race is most clearly exposed when KASAN and disconnect injection
are enabled. This slows down rpcrdma_rep_create() enough to allow
the send side to post a bunch of RPC Calls before the Receive
completion handler can invoke ib_post_recv().

Fixes: 2ae50ad68c ("xprtrdma: Close window between waking RPC senders and posting Receives")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:24:05 -04:00
Chuck Lever 9e3ca33b62 xprtrdma: Improve locking around rpcrdma_rep creation
Defensive clean up: Protect the rb_all_reps list during rep
creation.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:23:40 -04:00
Chuck Lever 8b5292be68 xprtrdma: Improve commentary around rpcrdma_reps_unmap()
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:23:19 -04:00
Chuck Lever eaf86e8cc8 xprtrdma: Improve locking around rpcrdma_rep destruction
Currently rpcrdma_reps_destroy() assumes that, at transport
tear-down, the content of the rb_free_reps list is the same as the
content of the rb_all_reps list. Although that is usually true,
using the rb_all_reps list should be more reliable because of
the way it's managed. And, rpcrdma_reps_unmap() uses rb_all_reps;
these two functions should both traverse the "all" list.

Ensure that all rpcrdma_reps are always destroyed whether they are
on the rep free list or not.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:22:29 -04:00
Chuck Lever 5030c9a938 xprtrdma: Put flushed Receives on free list instead of destroying them
Defer destruction of an rpcrdma_rep until transport tear-down to
preserve the rb_all_reps list while Receives flush.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Tom Talpey <tom@talpey.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:21:49 -04:00
Chuck Lever 15788d1d10 xprtrdma: Do not refresh Receive Queue while it is draining
Currently the Receive completion handler refreshes the Receive Queue
whenever a successful Receive completion occurs.

On disconnect, xprtrdma drains the Receive Queue. The first few
Receive completions after a disconnect are typically successful,
until the first flushed Receive.

This means the Receive completion handler continues to post more
Receive WRs after the drain sentinel has been posted. The late-
posted Receives flush after the drain sentinel has completed,
leading to a crash later in rpcrdma_xprt_disconnect().

To prevent this crash, xprtrdma has to ensure that the Receive
handler stops posting Receives before ib_drain_rq() posts its
drain sentinel.

Suggested-by: Tom Talpey <tom@talpey.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:21:44 -04:00
Chuck Lever 32e6b68167 xprtrdma: Avoid Receive Queue wrapping
Commit e340c2d6ef ("xprtrdma: Reduce the doorbell rate (Receive)")
increased the number of Receive WRs that are posted by the client,
but did not increase the size of the Receive Queue allocated during
transport set-up.

This is usually not an issue because RPCRDMA_BACKWARD_WRS is defined
as (32) when SUNRPC_BACKCHANNEL is defined. In cases where it isn't,
there is a real risk of Receive Queue wrapping.

Fixes: e340c2d6ef ("xprtrdma: Reduce the doorbell rate (Receive)")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Tom Talpey <tom@talpey.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-26 09:21:36 -04:00
Chuck Lever 8727f78855 svcrdma: Pass a useful error code to the send_err tracepoint
Capture error codes in @ret, which is passed to the send_err
tracepoint, so that they can be logged when something goes awry.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-04-14 12:09:27 -04:00
Chuck Lever c7731d5e05 svcrdma: Rename goto labels in svc_rdma_sendto()
Clean up: Make the goto labels consistent with other similar
functions.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-04-14 12:09:27 -04:00
Chuck Lever 351461f332 svcrdma: Don't leak send_ctxt on Send errors
Address a rare send_ctxt leak in the svc_rdma_sendto() error paths.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-04-14 12:09:27 -04:00
Chuck Lever 7638e0bfae SUNRPC: Move fault injection call sites
I've hit some crashes that occur in the xprt_rdma_inject_disconnect
path. It appears that, for some provides, rdma_disconnect() can
take so long that the transport can disconnect and release its
hardware resources while rdma_disconnect() is still running,
resulting in a UAF in the provider.

The transport's fault injection method may depend on the stability
of transport data structures. That means it needs to be invoked
only from contexts that hold the transport write lock.

Fixes: 4a06825839 ("SUNRPC: Transport fault injection")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-14 09:36:29 -04:00
Chuck Lever e3eded5e81 svcrdma: Clean up dto_q critical section in svc_rdma_recvfrom()
This, to me, seems less cluttered and less redundant. I was hoping
it could help reduce lock contention on the dto_q lock by reducing
the size of the critical section, but alas, the only improvement is
readability.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-03-31 15:58:48 -04:00
Chuck Lever 5533c4f4b9 svcrdma: Remove svc_rdma_recv_ctxt::rc_pages and ::rc_arg
These fields are no longer used.

The size of struct svc_rdma_recv_ctxt is now less than 300 bytes on
x86_64, down from 2440 bytes.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-03-31 15:57:48 -04:00
Chuck Lever 9af723be86 svcrdma: Remove sc_read_complete_q
Now that svc_rdma_recvfrom() waits for Read completion,
sc_read_complete_q is no longer used.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-03-31 15:57:48 -04:00
Chuck Lever 7d81ee8722 svcrdma: Single-stage RDMA Read
Currently the generic RPC server layer calls svc_rdma_recvfrom()
twice to retrieve an RPC message that uses Read chunks. I'm not
exactly sure why this design was chosen originally.

Instead, let's wait for the Read chunk completion inline in the
first call to svc_rdma_recvfrom().

The goal is to eliminate some page allocator churn.
rdma_read_complete() replaces pages in the second svc_rqst by
calling put_page() repeatedly while the upper layer waits for the
request to be constructed, which adds unnecessary NFS WRITE round-
trip latency.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Tom Talpey <tom@talpey.com>
2021-03-31 15:57:39 -04:00
Chuck Lever 82011c80b3 SUNRPC: Move svc_xprt_received() call sites
Currently, XPT_BUSY is not cleared until xpo_recvfrom returns.
That effectively blocks the receipt and handling of the next RPC
message until the current one has been taken off the transport.
This strict ordering is a requirement for socket transports.

For our kernel RPC/RDMA transport implementation, however, dequeuing
an ingress message is nothing more than a list_del(). The transport
can safely be marked un-busy as soon as that is done.

To keep the changes simpler, this patch just moves the
svc_xprt_received() call site from svc_handle_xprt() into the
transports, so that the actual optimization can be done in a
subsequent patch.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-03-22 13:22:13 -04:00
Chuck Lever cc93ce9529 svcrdma: Retain the page backing rq_res.head[0].iov_base
svc_rdma_sendto() now waits for the NIC hardware to finish with
the pages backing rq_res. We still have to release the page array
in some cases, but now it's always safe to immediately re-use the
page backing rq_res's head buffer.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-03-22 13:22:13 -04:00