Commit cfabe2c6 authored by Chuck Lever's avatar Chuck Lever Committed by Anna Schumaker
Browse files

xprtrdma: Update only specific fields in private receive buffer 



Now that rpcrdma_inline_fixup() updates only two fields in
rq_rcv_buf, a full memcpy of that structure to rq_private_buf is
unwarranted. Updating rq_private_buf fields only where needed also
better documents what is going on.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Tested-by: default avatarSteve Wise <swise@opengridcomputing.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent cb0ae1fb

net/sunrpc/xprtrdma/rpc_rdma.c

+9 −4
Original line number Diff line number Diff line
@@ -750,6 +750,11 @@ rpcrdma_count_chunks(struct rpcrdma_rep *rep, int wrchunk, __be32 **iptrp) 
 * The upper layer has set the maximum number of bytes it can

 * receive in each component of rq_rcv_buf. These values are set in

 * the head.iov_len, page_len, tail.iov_len, and buflen fields.

 *

 * Unlike the TCP equivalent (xdr_partial_copy_from_skb), in

 * many cases this function simply updates iov_base pointers in

 * rq_rcv_buf to point directly to the received reply data, to

 * avoid copying reply data.

 */

static void

rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
@@ -763,6 +768,7 @@ rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad) 
	 * in the receive buffer, to avoid a memcopy.

	 */

	rqst->rq_rcv_buf.head[0].iov_base = srcp;

	rqst->rq_private_buf.head[0].iov_base = srcp;



	/* The contents of the receive buffer that follow

	 * head.iov_len bytes are copied into the page list.
@@ -822,16 +828,15 @@ rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad) 
	/* The tail iovec is redirected to the remaining data

	 * in the receive buffer, to avoid a memcopy.

	 */

	if (copy_len || pad)

	if (copy_len || pad) {

		rqst->rq_rcv_buf.tail[0].iov_base = srcp;

		rqst->rq_private_buf.tail[0].iov_base = srcp;

	}



	if (copy_len)

		dprintk("RPC:       %s: %d bytes in"

			" %d extra segments (%d lost)\n",

			__func__, olen, i, copy_len);



	/* TBD avoid a warning from call_decode() */

	rqst->rq_private_buf = rqst->rq_rcv_buf;

}



void

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