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| author | Chuck Lever <chuck.lever@oracle.com> | 2016-09-15 10:55:37 -0400 |
|---|---|---|
| committer | Anna Schumaker <Anna.Schumaker@Netapp.com> | 2016-09-19 13:08:37 -0400 |
| commit | 68778945e46f143ed7974b427a8065f69a4ce944 (patch) | |
| tree | a513ebe3eb2dd881a67bd55a3a0aa3d525eb4463 /net/sunrpc/xprtrdma | |
| parent | 3435c74aed2d7b743ccbf34616c523ebee7be943 (diff) | |
| download | linux-stable-68778945e46f143ed7974b427a8065f69a4ce944.tar.gz linux-stable-68778945e46f143ed7974b427a8065f69a4ce944.tar.bz2 linux-stable-68778945e46f143ed7974b427a8065f69a4ce944.zip | |
SUNRPC: Separate buffer pointers for RPC Call and Reply messages
For xprtrdma, the RPC Call and Reply buffers are involved in real
I/O operations.
To start with, the DMA direction of the I/O for a Call is opposite
that of a Reply.
In the current arrangement, the Reply buffer address is on a
four-byte alignment just past the call buffer. Would be friendlier
on some platforms if that was at a DMA cache alignment instead.
Because the current arrangement allocates a single memory region
which contains both buffers, the RPC Reply buffer often contains a
page boundary in it when the Call buffer is large enough (which is
frequent).
It would be a little nicer for setting up DMA operations (and
possible registration of the Reply buffer) if the two buffers were
separated, well-aligned, and contained as few page boundaries as
possible.
Now, I could just pad out the single memory region used for the pair
of buffers. But frequently that would mean a lot of unused space to
ensure the Reply buffer did not have a page boundary.
Add a separate pointer to rpc_rqst that points right to the RPC
Reply buffer. This makes no difference to xprtsock, but it will help
xprtrdma in subsequent patches.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Diffstat (limited to 'net/sunrpc/xprtrdma')
| -rw-r--r-- | net/sunrpc/xprtrdma/transport.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c index ebf14ba437c6..136caf3dd299 100644 --- a/net/sunrpc/xprtrdma/transport.c +++ b/net/sunrpc/xprtrdma/transport.c @@ -524,6 +524,7 @@ out: dprintk("RPC: %s: size %zd, request 0x%p\n", __func__, size, req); req->rl_connect_cookie = 0; /* our reserved value */ rqst->rq_buffer = req->rl_sendbuf->rg_base; + rqst->rq_rbuffer = (char *)rqst->rq_buffer + rqst->rq_rcvsize; return 0; out_rdmabuf: |