From 68778945e46f143ed7974b427a8065f69a4ce944 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Thu, 15 Sep 2016 10:55:37 -0400 Subject: 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 Signed-off-by: Anna Schumaker --- include/linux/sunrpc/xprt.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux/sunrpc/xprt.h') diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index 72c2aebc592b..46f069efa056 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -84,8 +84,9 @@ struct rpc_rqst { struct list_head rq_list; void *rq_buffer; /* Call XDR encode buffer */ - size_t rq_callsize, - rq_rcvsize; + size_t rq_callsize; + void *rq_rbuffer; /* Reply XDR decode buffer */ + size_t rq_rcvsize; size_t rq_xmit_bytes_sent; /* total bytes sent */ size_t rq_reply_bytes_recvd; /* total reply bytes */ /* received */ -- cgit v1.2.3-59-g8ed1b