Commit Graph

1516 Commits

Author SHA1 Message Date
Jeff Layton
cf619507ae SUNRPC: add a new svc_find_listener helper
svc_find_listener will return the transport instance pointer for the
endpoint accepting connections/peer traffic from the specified transport
class and matching sockaddr.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-05-06 09:07:22 -04:00
Lorenzo Bianconi
a79ec2aecb SUNRPC: introduce svc_xprt_create_from_sa utility routine
Add svc_xprt_create_from_sa utility routine and refactor
svc_xprt_create() codebase in order to introduce the capability to
create a svc port from socket address.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-05-06 09:07:22 -04:00
Linus Torvalds
1c582ec142 nfsd-6.9 fixes:
- Fix an NFS/RDMA performance regression in v6.9-rc
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEEKLLlsBKG3yQ88j7+M2qzM29mf5cFAmYmrs4ACgkQM2qzM29m
 f5c39Q/9HiozR34Dr/5X+7DaVJNhMAhz1li6uu1EbXlNPJHRuacJl7UH+Li3+5mB
 ozoZhIwcSjmAP9wAMFEFkBUI3ddCYoKT+PcJmrvpAoR9NHxeLz2hGU2nPvt2s4na
 JiKKV+uM8YLNK9bJxWSe2rrOmcEIuA8jJn7dnURuBBVgFFRHKmNE2WUdJrAGmIzv
 ph/+6Gjxrw83UyEs6KwV5SSaC7WuGQEph1otNzjQ8DgImvN/4zyQek4yqe7bt8FS
 0OnJtoM9ubIryiUfR4ZxrIk9xCGsgh2csEZsSbqFx2ECwoBrCR4RkKue+jHQSVON
 OV35+b1CxdVdYChjmdYWz63P/fkyMC9iNGces/WRZmoD6x9mn5OErCrsDFJDEbD/
 lf+2xS+ky8M6pb7TMzUwiYtYu9yJL8N4yUPZUbWQGwb4c2oKXJ+6SoxD+4aWi2xw
 9Is9tGcbr3fNJLw5/j5y30tVE4x80EuuV4xCxHSayqlKiD40OXkztKBFwnbugEqJ
 mD77L2PVhU7ozfwwIDtvrxqDsITbVB877Bu1CCvlWpUnq8YFWaA8CuQXNuYeQHR6
 KgVuYZfvn5oYXC+9b9EBiIkObatzU8VUsdstjx8aulceIG92rZrRsg56TrUq9teV
 IMBJCneg9iqzQJQVSgQ9wcqv+EUVfnpSehzo5vWdh/Hz1DlyOEA=
 =l92Y
 -----END PGP SIGNATURE-----

Merge tag 'nfsd-6.9-4' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

Pull nfsd fix from Chuck Lever:

 - Fix an NFS/RDMA performance regression in v6.9-rc

* tag 'nfsd-6.9-4' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  Revert "svcrdma: Add Write chunk WRs to the RPC's Send WR chain"
2024-04-22 12:20:09 -07:00
Chuck Lever
32cf5a4eda Revert "svcrdma: Add Write chunk WRs to the RPC's Send WR chain"
Performance regression reported with NFS/RDMA using Omnipath,
bisected to commit e084ee673c ("svcrdma: Add Write chunk WRs to
the RPC's Send WR chain").

Tracing on the server reports:

  nfsd-7771  [060]  1758.891809: svcrdma_sq_post_err:
	cq.id=205 cid=226 sc_sq_avail=13643/851 status=-12

sq_post_err reports ENOMEM, and the rdma->sc_sq_avail (13643) is
larger than rdma->sc_sq_depth (851). The number of available Send
Queue entries is always supposed to be smaller than the Send Queue
depth. That seems like a Send Queue accounting bug in svcrdma.

As it's getting to be late in the 6.9-rc cycle, revert this commit.
It can be revisited in a subsequent kernel release.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=218743
Fixes: e084ee673c ("svcrdma: Add Write chunk WRs to the RPC's Send WR chain")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-04-20 11:20:41 -04:00
Linus Torvalds
c1f10ac840 NFS client updates for Linux 6.9
Highlights include:
 
 Bugfixes:
  - Fix for an Oops in the NFSv4.2 listxattr handler
  - Correct an incorrect buffer size in listxattr
  - Fix for an Oops in the pNFS flexfiles layout
  - Fix a refcount leak in NFS O_DIRECT writes
  - Fix missing locking in NFS O_DIRECT
  - Avoid an infinite loop in pnfs_update_layout
  - Fix an overflow in the RPC waitqueue queue length counter
  - Ensure that pNFS I/O is also protected by TLS when xprtsec
    is specified by the mount options
  - Fix a leaked folio lock in the netfs read code
  - Fix a potential deadlock in fscache
  - Allow setting the fscache uniquifier in NFSv4
  - Fix an off by one in root_nfs_cat()
  - Fix another off by one in rpc_sockaddr2uaddr()
  - nfs4_do_open() can incorrectly trigger state recovery.
  - Various fixes for connection shutdown
 
 Features and cleanups:
  - Ensure that containers only see their own RPC and NFS stats
  - Enable nconnect for RDMA
  - Remove dead code from nfs_writepage_locked()
  - Various tracepoint additions to track EXCHANGE_ID, GETDEVICEINFO, and
    mount options.
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEESQctxSBg8JpV8KqEZwvnipYKAPIFAmX14K0ACgkQZwvnipYK
 APLCeg/7Bdah7158TdNxSQAHPo3jzDqZmc933eZC0H8C9whNlu6XIa9fyT6ZrsQr
 qkQ/ztSwsB6yp6vLPSnVdDh5KsndwrInTB874H8y6+8x+KwwuhSQ7Uy8epg5wrO0
 kgiaRYSH7HB7EgUdNY14fHNXkA/DMLHz1F1aw2NVGCYmVCMg7kGV4wYCOH6bI2Ea
 Wu8amZce6D1AbktbdSZcEz2ricR3lGXjCUPMnzRCaSpUmdd2t7d/rsnjTeKU1gb4
 p9zLlOZs9Xe2vMT0ZQI8SEI+Scze82LBy7ykSKyhOjOt4AurVpzQFAvK+3dFZoIq
 lzIHJwabBGNui26CR1k90ZqERLkkk+24i3ccT28HwhTqe5eM/qDCKOVQmuP0F1F8
 QYsnIM+NnmPZveSGAMdOQwlGFQTyJbT5Na1blHTW2R2rjqBzgvfn8fR0vV4L5P7B
 0J8ShmZKVkvb7mtJJhaaI4LF41ciCF8+I5zwpnYQi0tsX370XPNNFbzS3BmPUVFL
 k0uEMVfNy69PkaH4DJWQT9GoE3qiAamkO+EdAlPad6b8QMdJJZxXOmaUzL8YsCHV
 sX5ugsih/Hf5/+QFBCbHEy7G3oeeHsT80yO8nvGT+yy94bv4F+WcM/tviyRbKrls
 t5audBDNRfrAeUlqAQkXfFmAyqP2CGNr29oL62cXL2muFG7d7ys=
 =5n+X
 -----END PGP SIGNATURE-----

Merge tag 'nfs-for-6.9-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

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

  Bugfixes:
   - Fix for an Oops in the NFSv4.2 listxattr handler
   - Correct an incorrect buffer size in listxattr
   - Fix for an Oops in the pNFS flexfiles layout
   - Fix a refcount leak in NFS O_DIRECT writes
   - Fix missing locking in NFS O_DIRECT
   - Avoid an infinite loop in pnfs_update_layout
   - Fix an overflow in the RPC waitqueue queue length counter
   - Ensure that pNFS I/O is also protected by TLS when xprtsec is
     specified by the mount options
   - Fix a leaked folio lock in the netfs read code
   - Fix a potential deadlock in fscache
   - Allow setting the fscache uniquifier in NFSv4
   - Fix an off by one in root_nfs_cat()
   - Fix another off by one in rpc_sockaddr2uaddr()
   - nfs4_do_open() can incorrectly trigger state recovery
   - Various fixes for connection shutdown

  Features and cleanups:
   - Ensure that containers only see their own RPC and NFS stats
   - Enable nconnect for RDMA
   - Remove dead code from nfs_writepage_locked()
   - Various tracepoint additions to track EXCHANGE_ID, GETDEVICEINFO,
     and mount options"

* tag 'nfs-for-6.9-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (29 commits)
  nfs: fix panic when nfs4_ff_layout_prepare_ds() fails
  NFS: trace the uniquifier of fscache
  NFS: Read unlock folio on nfs_page_create_from_folio() error
  NFS: remove unused variable nfs_rpcstat
  nfs: fix UAF in direct writes
  nfs: properly protect nfs_direct_req fields
  NFS: enable nconnect for RDMA
  NFSv4: nfs4_do_open() is incorrectly triggering state recovery
  NFS: avoid infinite loop in pnfs_update_layout.
  NFS: remove sync_mode test from nfs_writepage_locked()
  NFSv4.1/pnfs: fix NFS with TLS in pnfs
  NFS: Fix an off by one in root_nfs_cat()
  nfs: make the rpc_stat per net namespace
  nfs: expose /proc/net/sunrpc/nfs in net namespaces
  sunrpc: add a struct rpc_stats arg to rpc_create_args
  nfs: remove unused NFS_CALL macro
  NFSv4.1: add tracepoint to trunked nfs4_exchange_id calls
  NFS: Fix nfs_netfs_issue_read() xarray locking for writeback interrupt
  SUNRPC: increase size of rpc_wait_queue.qlen from unsigned short to unsigned int
  nfs: fix regression in handling of fsc= option in NFSv4
  ...
2024-03-16 11:44:00 -07:00
Josef Bacik
2057a48d0d sunrpc: add a struct rpc_stats arg to rpc_create_args
We want to be able to have our rpc stats handled in a per network
namespace manner, so add an option to rpc_create_args to specify a
different rpc_stats struct instead of using the one on the rpc_program.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2024-03-09 09:14:50 -05:00
Chuck Lever
e084ee673c svcrdma: Add Write chunk WRs to the RPC's Send WR chain
Chain RDMA Writes that convey Write chunks onto the local Send
chain. This means all WRs for an RPC Reply are now posted with a
single ib_post_send() call, and there is a single Send completion
when all of these are done. That reduces both the per-transport
doorbell rate and completion rate.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-03-01 09:12:30 -05:00
Chuck Lever
d2727cefff svcrdma: Post WRs for Write chunks in svc_rdma_sendto()
Refactor to eventually enable svcrdma to post the Write WRs for each
RPC response using the same ib_post_send() as the Send WR (ie, as a
single WR chain).

svc_rdma_result_payload (originally svc_rdma_read_payload) was added
so that the upper layer XDR encoder could identify a range of bytes
to be possibly conveyed by RDMA (if a Write chunk was provided by
the client).

The purpose of commit f6ad77590a ("svcrdma: Post RDMA Writes while
XDR encoding replies") was to post as much of the result payload
outside of svc_rdma_sendto() as possible because svc_rdma_sendto()
used to be called with the xpt_mutex held.

However, since commit ca4faf543a ("SUNRPC: Move xpt_mutex into
socket xpo_sendto methods"), the xpt_mutex is no longer held when
calling svc_rdma_sendto(). Thus, that benefit is no longer an issue.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-03-01 09:12:29 -05:00
Chuck Lever
10e6fc1054 svcrdma: Post the Reply chunk and Send WR together
Reduce the doorbell and Send completion rates when sending RPC/RDMA
replies that have Reply chunks. NFS READDIR procedures typically
return their result in a Reply chunk, for example.

Instead of calling ib_post_send() to post the Write WRs for the
Reply chunk, and then calling it again to post the Send WR that
conveys the transport header, chain the Write WRs to the Send WR
and call ib_post_send() only once.

Thanks to the Send Queue completion ordering rules, when the Send
WR completes, that guarantees that Write WRs posted before it have
also completed successfully. Thus all Write WRs for the Reply chunk
can remain unsignaled. Instead of handling a Write completion and
then a Send completion, only the Send completion is seen, and it
handles clean up for both the Writes and the Send.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-03-01 09:12:29 -05:00
Chuck Lever
a1f5788a0c svcrdma: Move write_info for Reply chunks into struct svc_rdma_send_ctxt
Since the RPC transaction's svc_rdma_send_ctxt will stay around for
the duration of the RDMA Write operation, the write_info structure
for the Reply chunk can reside in the request's svc_rdma_send_ctxt
instead of being allocated separately.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-03-01 09:12:28 -05:00
Chuck Lever
71b43531ee svcrdma: Post Send WR chain
Eventually I'd like the server to post the reply's Send WR along
with any Write WRs using only a single call to ib_post_send(), in
order to reduce the NIC's doorbell rate.

To do this, add an anchor for a WR chain to svc_rdma_send_ctxt, and
refactor svc_rdma_send() to post this WR chain to the Send Queue. For
the moment, the posted chain will continue to contain a single Send
WR.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-03-01 09:12:28 -05:00
Josef Bacik
3f6ef182f1 sunrpc: remove ->pg_stats from svc_program
Now that this isn't used anywhere, remove it.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-03-01 09:12:09 -05:00
Josef Bacik
f094323867 sunrpc: pass in the sv_stats struct through svc_create_pooled
Since only one service actually reports the rpc stats there's not much
of a reason to have a pointer to it in the svc_program struct.  Adjust
the svc_create_pooled function to take the sv_stats as an argument and
pass the struct through there as desired instead of getting it from the
svc_program->pg_stats.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-03-01 09:12:08 -05:00
Dai Ngo
2c35f43b5a SUNRPC: increase size of rpc_wait_queue.qlen from unsigned short to unsigned int
When the NFS client is under extreme load the rpc_wait_queue.qlen counter
can be overflowed. Here is an instant of the backlog queue overflow in a
real world environment shown by drgn helper:

rpc_task_stats(rpc_clnt):
-------------------------
rpc_clnt: 0xffff92b65d2bae00
rpc_xprt: 0xffff9275db64f000
  Queue:  sending[64887] pending[524] backlog[30441] binding[0]
XMIT task: 0xffff925c6b1d8e98
     WRITE: 750654
        __dta_call_status_580: 65463
        __dta_call_transmit_status_579: 1
        call_reserveresult: 685189
        nfs_client_init_is_complete: 1
    COMMIT: 584
        call_reserveresult: 573
        __dta_call_status_580: 11
    ACCESS: 1
        __dta_call_status_580: 1
   GETATTR: 10
        __dta_call_status_580: 4
        call_reserveresult: 6
751249 tasks for server 111.222.333.444
Total tasks: 751249

count_rpc_wait_queues(xprt):
----------------------------
**** rpc_xprt: 0xffff9275db64f000 num_reqs: 65511
wait_queue: xprt_binding[0] cnt: 0
wait_queue: xprt_binding[1] cnt: 0
wait_queue: xprt_binding[2] cnt: 0
wait_queue: xprt_binding[3] cnt: 0
rpc_wait_queue[xprt_binding].qlen: 0 maxpriority: 0
wait_queue: xprt_sending[0] cnt: 0
wait_queue: xprt_sending[1] cnt: 64887
wait_queue: xprt_sending[2] cnt: 0
wait_queue: xprt_sending[3] cnt: 0
rpc_wait_queue[xprt_sending].qlen: 64887 maxpriority: 3
wait_queue: xprt_pending[0] cnt: 524
wait_queue: xprt_pending[1] cnt: 0
wait_queue: xprt_pending[2] cnt: 0
wait_queue: xprt_pending[3] cnt: 0
rpc_wait_queue[xprt_pending].qlen: 524 maxpriority: 0
wait_queue: xprt_backlog[0] cnt: 0
wait_queue: xprt_backlog[1] cnt: 685801
wait_queue: xprt_backlog[2] cnt: 0
wait_queue: xprt_backlog[3] cnt: 0
rpc_wait_queue[xprt_backlog].qlen: 30441 maxpriority: 3 [task cnt mismatch]

There is no effect on operations when this overflow occurs. However
it causes confusion when trying to diagnose the performance problem.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2024-02-28 16:18:19 -05:00
Trond Myklebust
3f7edeac0b SUNRPC: Add a transport callback to handle dequeuing of an RPC request
Add a transport level callback to allow it to handle the consequences of
dequeuing the request that was in the process of being transmitted.
For something like a TCP connection, we may need to disconnect if the
request was partially transmitted.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2024-02-28 15:00:14 -05:00
Linus Torvalds
587217f970 NFS Client Updates for Linux 6.8
New Features:
   * Always ask for type with READDIR
   * Remove nfs_writepage()
 
 Bugfixes:
   * Fix a suspicious RCU usage warning
   * Fix a blocklayoutdriver reference leak
   * Fix the block driver's calculation of layoutget size
   * Fix handling NFS4ERR_RETURNCONFLICT
   * Fix _xprt_switch_find_current_entry()
   * Fix v4.1 backchannel request timeouts
   * Don't add zero-length pnfs block devices
   * Use the parent cred in nfs_access_login_time()
 
 Cleanups:
   * A few improvements when dealing with referring calls from the server
   * Clean up various unused variables, struct fields, and function calls
   * Various tracepoint improvements
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEEnZ5MQTpR7cLU7KEp18tUv7ClQOsFAmWfDp8ACgkQ18tUv7Cl
 QOsJ+Q/8DgrVmP3jwoM9Fu7JI/RnTQr9svk7zyrlyrQd3ywYqu6A1SC7lphcrzhy
 qxH55ykUuVgCB4kFqWPsU5yilJ8UzPncTOUObiBxN3pCU885Wckm4PJ9PNXtF9ct
 hc7+RpSTby/hYxiJABGVLgUADJ30rYBe6Y+KspSf+S1HvmgY1jbMPhEbVGpP2QBt
 zSF5pmnecZ748LGzSwSeW29WUZhvRPBL5B204EB4aq9SmPAhnAclnE7uhErQ1u8e
 Z6RVwSXv2j1FcM79F5xc/gAByCQhObGuMceFd0sAnx87RUttHi1fteVboz2gZxHB
 rawZQ9p9K9c7ayCu8disxKWTxNYAztvXDOs+Dnij+c3/2EpAmEUD53AXnXAz025b
 IbSnh6ggLlxoKLv1Lrwrli2d/Qi4TYTm2RSW/dY416pIhoO3aC6fv1a5tUnou9RX
 3XpiiFeNoTixWswmS23AMT7BrJTWXY/+NX7AxFZUyPyJ8y9F2Ug8BCam8uAvTluf
 80Dx0pB+7DRF19/ZkH0mUFU+2/+mlK/Ub0p+izSJhkhPSH5TwUTA7hvX6xb7yFtS
 OY4aTVD0rpTbSOvHOEI+F4tWBnw8onTobYMfRcuwNKYJCvuEh4mLLpn44QEJwW9M
 3nHIzdE75Nz3deO+gg6Jo5JuiMwqvh7AEGsxIA64FnAi/xRCDi0=
 =9hVw
 -----END PGP SIGNATURE-----

Merge tag 'nfs-for-6.8-1' of git://git.linux-nfs.org/projects/anna/linux-nfs

Pull nfs client updates from Anna Schumaker:
 "New Features:
   - Always ask for type with READDIR
   - Remove nfs_writepage()

  Bugfixes:
   - Fix a suspicious RCU usage warning
   - Fix a blocklayoutdriver reference leak
   - Fix the block driver's calculation of layoutget size
   - Fix handling NFS4ERR_RETURNCONFLICT
   - Fix _xprt_switch_find_current_entry()
   - Fix v4.1 backchannel request timeouts
   - Don't add zero-length pnfs block devices
   - Use the parent cred in nfs_access_login_time()

  Cleanups:
   - A few improvements when dealing with referring calls from the
     server
   - Clean up various unused variables, struct fields, and function
     calls
   - Various tracepoint improvements"

* tag 'nfs-for-6.8-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (21 commits)
  NFSv4.1: Use the nfs_client's rpc timeouts for backchannel
  SUNRPC: Fixup v4.1 backchannel request timeouts
  rpc_pipefs: Replace one label in bl_resolve_deviceid()
  nfs: Remove writepage
  NFS: drop unused nfs_direct_req bytes_left
  pNFS: Fix the pnfs block driver's calculation of layoutget size
  nfs: print fileid in lookup tracepoints
  nfs: rename the nfs_async_rename_done tracepoint
  nfs: add new tracepoint at nfs4 revalidate entry point
  SUNRPC: fix _xprt_switch_find_current_entry logic
  NFSv4.1/pnfs: Ensure we handle the error NFS4ERR_RETURNCONFLICT
  NFSv4.1: if referring calls are complete, trust the stateid argument
  NFSv4: Track the number of referring calls in struct cb_process_state
  NFS: Use parent's objective cred in nfs_access_login_time()
  NFSv4: Always ask for type with READDIR
  pnfs/blocklayout: Don't add zero-length pnfs_block_dev
  blocklayoutdriver: Fix reference leak of pnfs_device_node
  SUNRPC: Fix a suspicious RCU usage warning
  SUNRPC: Create a helper function for accessing the rpc_clnt's xprt_switch
  SUNRPC: Remove unused function rpc_clnt_xprt_switch_put()
  ...
2024-01-10 16:13:57 -08:00
NeilBrown
1e3577a452 SUNRPC: discard sv_refcnt, and svc_get/svc_put
sv_refcnt is no longer useful.
lockd and nfs-cb only ever have the svc active when there are a non-zero
number of threads, so sv_refcnt mirrors sv_nrthreads.

nfsd also keeps the svc active between when a socket is added and when
the first thread is started, but we don't really need a refcount for
that.  We can simply not destroy the svc while there are any permanent
sockets attached.

So remove sv_refcnt and the get/put functions.
Instead of a final call to svc_put(), call svc_destroy() instead.
This is changed to also store NULL in the passed-in pointer to make it
easier to avoid use-after-free situations.

Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:33 -05:00
NeilBrown
7b207ccd98 svc: don't hold reference for poolstats, only mutex.
A future patch will remove refcounting on svc_serv as it is of little
use.
It is currently used to keep the svc around while the pool_stats file is
open.
Change this to get the pointer, protected by the mutex, only in
seq_start, and the release the mutex in seq_stop.
This means that if the nfsd server is stopped and restarted while the
pool_stats file it open, then some pool stats info could be from the
first instance and some from the second.  This might appear odd, but is
unlikely to be a problem in practice.

Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:33 -05:00
Chuck Lever
d3dba53410 svcrdma: Implement multi-stage Read completion again
Having an nfsd thread waiting for an RDMA Read completion is
problematic if the Read responder (ie, the client) stops responding.
We need to go back to handling RDMA Reads by getting the svc scheduler
to call svc_rdma_recvfrom() a second time to finish building an RPC
message after a Read completion.

This is the final patch, and makes several changes that have to
happen concurrently:

1. svc_rdma_process_read_list no longer waits for a completion, but
   simply builds and posts the Read WRs.

2. svc_rdma_read_done() now queues a completed Read on
   sc_read_complete_q for later processing rather than calling
   complete().

3. The completed RPC message is no longer built in the
   svc_rdma_process_read_list() path. Finishing the message is now
   done in svc_rdma_recvfrom() when it notices work on the
   sc_read_complete_q. The "finish building this RPC message" code
   is removed from the svc_rdma_process_read_list() path.

This arrangement avoids the need for an nfsd thread to wait for an
RDMA Read non-interruptibly without a timeout. It's basically the
same code structure that Tom Tucker used for Read chunks along with
some clean-up and modernization.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:33 -05:00
Chuck Lever
a937693a82 svcrdma: Add back svcxprt_rdma::sc_read_complete_q
Having an nfsd thread waiting for an RDMA Read completion is
problematic if the Read responder (ie, the client) stops responding.
We need to go back to handling RDMA Reads by allowing the nfsd
thread to return to the svc scheduler, then waking a second thread
finish the RPC message once the Read completion fires.

As a next step, add a list_head upon which completed Reads are queued.
A subsequent patch will make use of this queue.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:32 -05:00
Chuck Lever
4d9d69db89 svcrdma: Add back svc_rdma_recv_ctxt::rc_pages
Having an nfsd thread waiting for an RDMA Read completion is
problematic if the Read responder (the client) stops responding. We
need to go back to handling RDMA Reads by allowing the nfsd thread
to return to the svc scheduler, then waking a second thread finish
the RPC message once the Read completion fires.

To start with, restore the rc_pages field so that RDMA Read pages
can be managed across calls to svc_rdma_recvfrom().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:32 -05:00
Chuck Lever
28ee0ec894 svcrdma: De-duplicate completion ID initialization helpers
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:31 -05:00
Chuck Lever
018f34051b svcrdma: Move the svc_rdma_cc_init() call
Now that the chunk_ctxt for Reads is no longer dynamically allocated
it can be initialized once for the life of the object that contains
it (struct svc_rdma_recv_ctxt).

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:31 -05:00
Chuck Lever
fc20f19b4d svcrdma: Update synopsis of svc_rdma_build_read_segment()
Since the RDMA Read I/O state is now contained in the recv_ctxt,
svc_rdma_build_read_segment() can use the recv_ctxt to derive that
information rather than the other way around. This removes one usage
of the ri_readctxt field, enabling its removal in a subsequent
patch.

At the same time, the use of ri_rqst can similarly be replaced with
a passed-in function parameter.

Start with build_read_segment() because it is a common utility
function at the bottom of the Read chunk path.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:30 -05:00
Chuck Lever
919f6e790a svcrdma: Move read_info::ri_pageoff into struct svc_rdma_recv_ctxt
Further clean up: move the starting byte offset field into
svc_rdma_recv_ctxt.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:30 -05:00
Chuck Lever
8e12258268 svcrdma: Move svc_rdma_read_info::ri_pageno to struct svc_rdma_recv_ctxt
Further clean up: move the page index field into svc_rdma_recv_ctxt.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:29 -05:00
Chuck Lever
b1818412d0 svcrdma: Start moving fields out of struct svc_rdma_read_info
Since the request's svc_rdma_recv_ctxt will stay around for the
duration of the RDMA Read operation, the contents of struct
svc_rdma_read_info can reside in the request's svc_rdma_recv_ctxt
rather than being allocated separately. This will eventually save a
call to kmalloc() in a hot path.

Start this clean-up by moving the Read chunk's svc_rdma_chunk_ctxt.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:29 -05:00
Chuck Lever
6a04a43493 svcrdma: Move struct svc_rdma_chunk_ctxt to svc_rdma.h
Prepare for nestling these into the send and recv ctxts so they
no longer have to be allocated dynamically.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:29 -05:00
Chuck Lever
ae225fe27b svcrdma: Add an async version of svc_rdma_send_ctxt_put()
DMA unmapping can take quite some time, so it should not be handled
in a single-threaded completion handler. Defer releasing send_ctxts
to the recently-added workqueue.

With this patch, DMA unmapping can be handled in parallel, and it
does not cause head-of-queue blocking of Send completions.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:27 -05:00
Chuck Lever
9c7e1a0658 svcrdma: Add a utility workqueue to svcrdma
To handle work in the background, set up an UNBOUND workqueue for
svcrdma. Subsequent patches will make use of it.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:26 -05:00
Chuck Lever
b541dd554b svcrdma: Eliminate allocation of recv_ctxt objects in backchannel
The svc_rdma_recv_ctxt free list uses a lockless list to avoid the
need for a spin lock in the fast path. llist_del_first(), which is
used by svc_rdma_recv_ctxt_get(), requires serialization, however,
when there are multiple list producers that are unserialized.

I mistakenly thought there was only one caller of
svc_rdma_recv_ctxt_get() (svc_rdma_refresh_recvs()), thus explicit
serialization would not be necessary. But there is another caller:
svc_rdma_bc_sendto(), and these two are not serialized against each
other. I haven't seen ill effects that I could directly ascribe to
a lack of serialization. It's just an observation based on code
audit.

When DMA-mapping before sending a Reply, the passed-in struct
svc_rdma_recv_ctxt is used only for its write and reply PCLs. These
are currently always empty in the backchannel case. So, instead of
passing a full svc_rdma_recv_ctxt object to
svc_rdma_map_reply_msg(), let's pass in just the Write and Reply
PCLs.

This change makes it unnecessary for the backchannel to acquire a
dummy svc_rdma_recv_ctxt object when sending an RPC Call. The need
for svc_rdma_recv_ctxt free list serialization is now completely
avoided.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:26 -05:00
Chuck Lever
3587b5c753 SUNRPC: Remove RQ_SPLICE_OK
This flag is no longer used.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:26 -05:00
Chuck Lever
deb704281f SUNRPC: Add a server-side API for retrieving an RPC's pseudoflavor
NFSD will use this new API to determine whether nfsd_splice_read is
safe to use. This avoids the need to add a dependency to NFSD for
CONFIG_SUNRPC_GSS.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-07 17:54:25 -05:00
Benjamin Coddington
57331a59ac NFSv4.1: Use the nfs_client's rpc timeouts for backchannel
For backchannel requests that lookup the appropriate nfs_client, use the
state-management rpc_clnt's rpc_timeout parameters for the backchannel's
response.  When the nfs_client cannot be found, fall back to using the
xprt's default timeout parameters.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2024-01-04 17:01:01 -05:00
Anna Schumaker
5f1e77b228 SUNRPC: Remove unused function rpc_clnt_xprt_switch_put()
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2024-01-04 10:47:56 -05:00
Linus Torvalds
6bc986ab83 NFS client updates for Linux 6.7
Highlights include:
 
 Bugfixes:
  - SUNRPC: A fix to re-probe the target RPC port after an ECONNRESET error
  - SUNRPC: Handle allocation errors from rpcb_call_async()
  - SUNRPC: Fix a use-after-free condition in rpc_pipefs
  - SUNRPC: fix up various checks for timeouts
  - NFSv4.1: Handle NFS4ERR_DELAY errors during session trunking
  - NFSv4.1: fix SP4_MACH_CRED protection for pnfs IO
  - NFSv4: Ensure that we test all delegations when the server notifies
    us that it may have revoked some of them
 
 Features:
  - Allow knfsd processes to break out of NFS4ERR_DELAY loops when
    re-exporting NFSv4.x by setting appropriate values for the
    'delay_retrans' module parameter.
  - nfs: Convert nfs_symlink() to use a folio
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEESQctxSBg8JpV8KqEZwvnipYKAPIFAmVL62IACgkQZwvnipYK
 API4Ww/+I75hmEdI4i/6v8WnrLWLWzmCgybez2AfrKYtuYmEcDZTf2K4pNVEJxFG
 PJ4TYRpaSgwxCXqoup5INOdL5gS8g3JbAlTqrDQ8nYGeBXETN9tN5n2Xj8liHk2l
 OrnYzgTjC2pwpWDZq/W1LCQMatCbs9XhpmyBvqZH5r7tAOVGkrk1ICZ/r+/nGiN8
 LAbm/I0M1Jp0iJisN/i/0CsEgLQMCfeQVrtEMCZGsoVS79Mr/W1hF3KiGognI/xz
 FvEXnZKauw9npu7U7ckhHZcHd8oQxby0Q0Xny/IpgiO2Z1YqfKCvJSK1sjBt/lFu
 7fe2HGMFfcTMx/bn/qdUJR351607rBi4h3t1OfK4KIxV1gSLUyS/RR7ayFx5A0gM
 pFJcC0ZnKoiVr2vSNMMguennbyjScqNOC5ECb+bpMAyDV7suF9e/khK12CdYwqFm
 cpeUUD35GZT+RjP3htI92Pj0bqBOHx+o7qEi+MEel3t90us8PPBrWywHk7Tw40vJ
 eUxH0XQtZVswH6TvekNdoMXx8TXSAbx4I6Hw3fmNGWLRp494p3GVSmWQmctcvCi7
 Y6E1P3YT8G1OeI9+fIQr5Wp2F9sOdFPrb3BrAojj9ndJ3ZqQAcx+gY5z2RVnvvur
 PTsLInFxS8+WvvqPtQCZZ5UxnrcPFCk1js0rg6EqdjZmq6+OqJU=
 =TNRl
 -----END PGP SIGNATURE-----

Merge tag 'nfs-for-6.7-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client updates from Trond Myklebust:
 "Bugfixes:

   - SUNRPC:
       - re-probe the target RPC port after an ECONNRESET error
       - handle allocation errors from rpcb_call_async()
       - fix a use-after-free condition in rpc_pipefs
       - fix up various checks for timeouts

   - NFSv4.1:
       - Handle NFS4ERR_DELAY errors during session trunking
       - fix SP4_MACH_CRED protection for pnfs IO

   - NFSv4:
       - Ensure that we test all delegations when the server notifies
         us that it may have revoked some of them

  Features:

   - Allow knfsd processes to break out of NFS4ERR_DELAY loops when
     re-exporting NFSv4.x by setting appropriate values for the
     'delay_retrans' module parameter

   - nfs: Convert nfs_symlink() to use a folio"

* tag 'nfs-for-6.7-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  nfs: Convert nfs_symlink() to use a folio
  SUNRPC: Fix RPC client cleaned up the freed pipefs dentries
  NFSv4.1: fix SP4_MACH_CRED protection for pnfs IO
  SUNRPC: Add an IS_ERR() check back to where it was
  NFSv4.1: fix handling NFS4ERR_DELAY when testing for session trunking
  nfs41: drop dependency between flexfiles layout driver and NFSv3 modules
  NFSv4: fairly test all delegations on a SEQ4_ revocation
  SUNRPC: SOFTCONN tasks should time out when on the sending list
  SUNRPC: Force close the socket when a hard error is reported
  SUNRPC: Don't skip timeout checks in call_connect_status()
  SUNRPC: ECONNRESET might require a rebind
  NFSv4/pnfs: Allow layoutget to return EAGAIN for softerr mounts
  NFSv4: Add a parameter to limit the number of retries after NFS4ERR_DELAY
2023-11-08 13:39:16 -08:00
felix
bfca5fb4e9 SUNRPC: Fix RPC client cleaned up the freed pipefs dentries
RPC client pipefs dentries cleanup is in separated rpc_remove_pipedir()
workqueue,which takes care about pipefs superblock locking.
In some special scenarios, when kernel frees the pipefs sb of the
current client and immediately alloctes a new pipefs sb,
rpc_remove_pipedir function would misjudge the existence of pipefs
sb which is not the one it used to hold. As a result,
the rpc_remove_pipedir would clean the released freed pipefs dentries.

To fix this issue, rpc_remove_pipedir should check whether the
current pipefs sb is consistent with the original pipefs sb.

This error can be catched by KASAN:
=========================================================
[  250.497700] BUG: KASAN: slab-use-after-free in dget_parent+0x195/0x200
[  250.498315] Read of size 4 at addr ffff88800a2ab804 by task kworker/0:18/106503
[  250.500549] Workqueue: events rpc_free_client_work
[  250.501001] Call Trace:
[  250.502880]  kasan_report+0xb6/0xf0
[  250.503209]  ? dget_parent+0x195/0x200
[  250.503561]  dget_parent+0x195/0x200
[  250.503897]  ? __pfx_rpc_clntdir_depopulate+0x10/0x10
[  250.504384]  rpc_rmdir_depopulate+0x1b/0x90
[  250.504781]  rpc_remove_client_dir+0xf5/0x150
[  250.505195]  rpc_free_client_work+0xe4/0x230
[  250.505598]  process_one_work+0x8ee/0x13b0
...
[   22.039056] Allocated by task 244:
[   22.039390]  kasan_save_stack+0x22/0x50
[   22.039758]  kasan_set_track+0x25/0x30
[   22.040109]  __kasan_slab_alloc+0x59/0x70
[   22.040487]  kmem_cache_alloc_lru+0xf0/0x240
[   22.040889]  __d_alloc+0x31/0x8e0
[   22.041207]  d_alloc+0x44/0x1f0
[   22.041514]  __rpc_lookup_create_exclusive+0x11c/0x140
[   22.041987]  rpc_mkdir_populate.constprop.0+0x5f/0x110
[   22.042459]  rpc_create_client_dir+0x34/0x150
[   22.042874]  rpc_setup_pipedir_sb+0x102/0x1c0
[   22.043284]  rpc_client_register+0x136/0x4e0
[   22.043689]  rpc_new_client+0x911/0x1020
[   22.044057]  rpc_create_xprt+0xcb/0x370
[   22.044417]  rpc_create+0x36b/0x6c0
...
[   22.049524] Freed by task 0:
[   22.049803]  kasan_save_stack+0x22/0x50
[   22.050165]  kasan_set_track+0x25/0x30
[   22.050520]  kasan_save_free_info+0x2b/0x50
[   22.050921]  __kasan_slab_free+0x10e/0x1a0
[   22.051306]  kmem_cache_free+0xa5/0x390
[   22.051667]  rcu_core+0x62c/0x1930
[   22.051995]  __do_softirq+0x165/0x52a
[   22.052347]
[   22.052503] Last potentially related work creation:
[   22.052952]  kasan_save_stack+0x22/0x50
[   22.053313]  __kasan_record_aux_stack+0x8e/0xa0
[   22.053739]  __call_rcu_common.constprop.0+0x6b/0x8b0
[   22.054209]  dentry_free+0xb2/0x140
[   22.054540]  __dentry_kill+0x3be/0x540
[   22.054900]  shrink_dentry_list+0x199/0x510
[   22.055293]  shrink_dcache_parent+0x190/0x240
[   22.055703]  do_one_tree+0x11/0x40
[   22.056028]  shrink_dcache_for_umount+0x61/0x140
[   22.056461]  generic_shutdown_super+0x70/0x590
[   22.056879]  kill_anon_super+0x3a/0x60
[   22.057234]  rpc_kill_sb+0x121/0x200

Fixes: 0157d021d2 ("SUNRPC: handle RPC client pipefs dentries by network namespace aware routines")
Signed-off-by: felix <fuzhen5@huawei.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2023-11-01 15:40:44 -04:00
Lorenzo Bianconi
bd9d6a3efa NFSD: add rpc_status netlink support
Introduce rpc_status netlink support for NFSD in order to dump pending
RPC requests debugging information from userspace.

Closes: https://bugzilla.linux-nfs.org/show_bug.cgi?id=366
Tested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:09 -04:00
NeilBrown
15d39883ee SUNRPC: change the back-channel queue to lwq
This removes the need to store and update back-links in the list.
It also remove the need for the _bh version of spin_lock().

Signed-off-by: NeilBrown <neilb@suse.de>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:08 -04:00
NeilBrown
580a25756a SUNRPC: discard sp_lock
sp_lock is now only used to protect sp_all_threads.  This isn't needed
as sp_all_threads is only manipulated through svc_set_num_threads(),
which is already serialized.  Read-acccess only requires rcu_read_lock().
So no more locking is needed.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:08 -04:00
NeilBrown
2e8fc923fe SUNRPC: change sp_nrthreads to atomic_t
Using an atomic_t avoids the need to take a spinlock (which can soon be
removed).

Choosing a thread to kill needs to be careful as we cannot set the "die
now" bit atomically with the test on the count.  Instead we temporarily
increase the count.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:07 -04:00
NeilBrown
9a0e6accc0 SUNRPC: use lwq for sp_sockets - renamed to sp_xprts
lwq avoids using back pointers in lists, and uses less locking.
This introduces a new spinlock, but the other one will be removed in a
future patch.

For svc_clean_up_xprts(), we now dequeue the entire queue, walk it to
remove and process the xprts that need cleaning up, then re-enqueue the
remaining queue.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:07 -04:00
NeilBrown
5b80147e0c SUNRPC: only have one thread waking up at a time
Currently if several items of work become available in quick succession,
that number of threads (if available) will be woken.  By the time some
of them wake up another thread that was already cache-warm might have
come along and completed the work.  Anecdotal evidence suggests as many
as 15% of wakes find nothing to do once they get to the point of
looking.

This patch changes svc_pool_wake_idle_thread() to wake the first thread
on the queue but NOT remove it.  Subsequent calls will wake the same
thread.  Once that thread starts it will dequeue itself and after
dequeueing some work to do, it will wake the next thread if there is more
work ready.  This results in a more orderly increase in the number of
busy threads.

As a bonus, this allows us to reduce locking around the idle queue.
svc_pool_wake_idle_thread() no longer needs to take a lock (beyond
rcu_read_lock()) as it doesn't manipulate the queue, it just looks at
the first item.

The thread itself can avoid locking by using the new
llist_del_first_this() interface.  This will safely remove the thread
itself if it is the head.  If it isn't the head, it will do nothing.
If multiple threads call this concurrently only one will succeed.  The
others will do nothing, so no corruption can result.

If a thread wakes up and finds that it cannot dequeue itself that means
either
- that it wasn't woken because it was the head of the queue.  Maybe the
  freezer woke it.  In that case it can go back to sleep (after trying
  to freeze of course).
- some other thread found there was nothing to do very recently, and
  placed itself on the head of the queue in front of this thread.
  It must check again after placing itself there, so it can be deemed to
  be responsible for any pending work, and this thread can go back to
  sleep until woken.

No code ever tests for busy threads any more.  Only each thread itself
cares if it is busy.  So svc_thread_busy() is no longer needed.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:07 -04:00
NeilBrown
9bd4161c59 SUNRPC: change service idle list to be an llist
With an llist we don't need to take a lock to add a thread to the list,
though we still need a lock to remove it.  That will go in the next
patch.

Unlike double-linked lists, a thread cannot reliably remove itself from
the list.  Only the first thread can be removed, and that can change
asynchronously.  So some care is needed.

We already check if there is pending work to do, so we are unlikely to
add ourselves to the idle list and then want to remove ourselves again.

If we DO find something needs to be done after adding ourselves to the
list, we simply wake up the first thread on the list.  If that was us,
we successfully removed ourselves and can continue.  If it was some
other thread, they will do the work that needs to be done.  We can
safely sleep until woken.

We also remove the test on freezing() from rqst_should_sleep().  Instead
we set TASK_FREEZABLE before scheduling.  This makes is safe to
schedule() when a freeze is pending.  As we now loop waiting to be
removed from the idle queue, this is a cleaner way to handle freezing.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:05 -04:00
NeilBrown
2b65a22684 SUNRPC: discard SP_CONGESTED
We can tell if a pool is congested by checking if the idle list is
empty.  We don't need a separate flag.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:05 -04:00
NeilBrown
5ff817b235 SUNRPC: add list of idle threads
Rather than searching a list of threads to find an idle one, having a
list of idle threads allows an idle thread to be found immediately.

This adds some spin_lock calls which is not ideal, but as the hold-time
is tiny it is still faster than searching a list.  A future patch will
remove them using llist.h.  This involves some subtlety and so is left
to a separate patch.

This removes the need for the RQ_BUSY flag.  The rqst is "busy"
precisely when it is not on the "idle" list.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:04 -04:00
NeilBrown
fa341560ca SUNRPC: change how svc threads are asked to exit.
svc threads are currently stopped using kthread_stop().  This requires
identifying a specific thread.  However we don't care which thread
stops, just as long as one does.

So instead, set a flag in the svc_pool to say that a thread needs to
die, and have each thread check this flag instead of calling
kthread_should_stop().  The first thread to find and clear this flag
then moves towards exiting.

This removes an explicit dependency on sp_all_threads which will make a
future patch simpler.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:04 -04:00
NeilBrown
063ab935a4 SUNRPC: integrate back-channel processing with svc_recv()
Using svc_recv() for (NFSv4.1) back-channel handling means we have just
one mechanism for waking threads.

Also change kthread_freezable_should_stop() in nfs4_callback_svc() to
kthread_should_stop() as used elsewhere.
kthread_freezable_should_stop() effectively adds a try_to_freeze() call,
and svc_recv() already contains that at an appropriate place.

Signed-off-by: NeilBrown <neilb@suse.de>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:03 -04:00
Chuck Lever
6ed8cdf967 SUNRPC: Clean up bc_svc_process()
The test robot complained that, in some build configurations, the
@error variable in bc_svc_process's only caller is set but never
used. This happens because dprintk() is the only consumer of that
value.

 - Remove the dprintk() call sites in favor of the svc_process
   tracepoint
 - The @error variable and the return value of bc_svc_process() are
   now unused, so get rid of them.
 - The @serv parameter is set to rqstp->rq_serv by the only caller,
   and bc_svc_process() then uses it only to set rqstp->rq_serv. It
   can be removed.
 - Rename bc_svc_process() according to the convention that
   globally-visible RPC server functions have names that begin with
   "svc_"; and because it is globally-visible, give it a proper
   kdoc comment.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202308121314.HA8Rq2XG-lkp@intel.com/
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:03 -04:00
Trond Myklebust
993b5662f3 SUNRPC: Silence compiler complaints about tautological comparisons
On 64-bit systems, the compiler will complain that the comparison
between SIZE_MAX and the 32-bit unsigned int 'len' is unnecessary.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2023-09-15 15:50:39 -04:00