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authorChuck Lever <chuck.lever@oracle.com>2016-09-15 10:55:37 -0400
committerAnna Schumaker <Anna.Schumaker@Netapp.com>2016-09-19 13:08:37 -0400
commit68778945e46f143ed7974b427a8065f69a4ce944 (patch)
treea513ebe3eb2dd881a67bd55a3a0aa3d525eb4463 /net/sunrpc/xprtrdma
parent3435c74aed2d7b743ccbf34616c523ebee7be943 (diff)
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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.c1
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: