linux/net/sunrpc
Chuck Lever 8154ef2776 NFSD: Clean up legacy NFS WRITE argument XDR decoders
Move common code in NFSD's legacy NFS WRITE decoders into a helper.
The immediate benefit is reduction of code duplication and some nice
micro-optimizations (see below).

In the long term, this helper can perform a per-transport call-out
to fill the rq_vec (say, using RDMA Reads).

The legacy WRITE decoders and procs are changed to work like NFSv4,
which constructs the rq_vec just before it is about to call
vfs_writev.

Why? Calling a transport call-out from the proc instead of the XDR
decoder means that the incoming FH can be resolved to a particular
filesystem and file. This would allow pages from the backing file to
be presented to the transport to be filled, rather than presenting
anonymous pages and copying or flipping them into the file's page
cache later.

I also prefer using the pages in rq_arg.pages, instead of pulling
the data pages directly out of the rqstp::rq_pages array. This is
currently the way the NFSv3 write decoder works, but the other two
do not seem to take this approach. Fixing this removes the only
reference to rq_pages found in NFSD, eliminating an NFSD assumption
about how transports use the pages in rq_pages.

Lastly, avoid setting up the first element of rq_vec as a zero-
length buffer. This happens with an RDMA transport when a normal
Read chunk is present because the data payload is in rq_arg's
page list (none of it is in the head buffer).

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-04-03 15:08:16 -04:00
..
auth_gss sunrpc: Fix unaligned access on sparc64 2018-03-19 16:38:12 -04:00
xprtrdma sunrpc: Save remote presentation address in svc_xprt for trace events 2018-04-03 15:08:11 -04:00
Kconfig svcrdma: Introduce local rdma_rw API helpers 2017-04-25 17:25:55 -04:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
addr.c replace strict_strto calls 2014-07-12 18:45:49 -04:00
auth.c sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
auth_generic.c NFS client updates for Linux 4.9 2016-10-13 21:28:20 -07:00
auth_null.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
auth_unix.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
backchannel_rqst.c SUNRPC: Don't hold the transport lock when receiving backchannel data 2017-08-16 15:10:16 -04:00
cache.c SUNRPC: cache: ignore timestamp written to 'flush' file. 2018-03-19 16:38:12 -04:00
clnt.c SUNRPC: Remove rpc_protocol() 2018-01-14 23:06:30 -05:00
debugfs.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
netns.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rpc_pipe.c vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
rpcb_clnt.c sunrpc: remove net pointer from messages 2017-11-17 16:43:51 -05:00
sched.c fix parallelism for rpc tasks 2018-02-08 16:24:35 -05:00
socklib.c sunrpc: do not pull udp headers on receive 2016-04-11 15:31:33 -04:00
stats.c sunrpc: move pc_count out of struct svc_procinfo 2017-07-13 15:58:02 -04:00
sunrpc.h SUNRPC: track whether a request is coming from a loop-back interface. 2014-05-22 15:59:18 -04:00
sunrpc_syms.c sunrpc: exit_net cleanup check added 2017-11-17 16:43:50 -05:00
svc.c NFSD: Clean up legacy NFS WRITE argument XDR decoders 2018-04-03 15:08:16 -04:00
svc_xprt.c svc: Report xprt dequeue latency 2018-04-03 15:08:13 -04:00
svcauth.c locking/atomic, kref: Implement kref_put_lock() 2017-01-18 10:03:29 +01:00
svcauth_unix.c kernel: make groups_sort calling a responsibility group_info allocators 2017-12-14 16:00:49 -08:00
svcsock.c sunrpc: Save remote presentation address in svc_xprt for trace events 2018-04-03 15:08:11 -04:00
sysctl.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
timer.c net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
xdr.c sunrpc: Fix xdr_init_decode_pages() documenting comment 2017-04-25 16:12:34 -04:00
xprt.c SUNRPC: Queue latency-sensitive socket tasks to xprtiod 2018-02-07 09:25:52 -05:00
xprtmultipath.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xprtsock.c SUNRPC: Don't call __UDPX_INC_STATS() from a preemptible context 2018-02-09 09:39:42 -05:00