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From:   Olga Kornievskaia <olga.kornievskaia@gmail.com>
To:     trond.myklebust@hammerspace.com, anna.schumaker@netapp.com,
        chuck.level@oracle.com
Cc:     linux-nfs@vger.kernel.org
Subject: [RFC 1/2] xprtrdma: xdr pad optimization revisted again
Date:   Mon, 30 Aug 2021 12:53:01 -0400
Message-Id: <20210830165302.60225-2-olga.kornievskaia@gmail.com>
In-Reply-To: <20210830165302.60225-1-olga.kornievskaia@gmail.com>
References: <20210830165302.60225-1-olga.kornievskaia@gmail.com>
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From: Olga Kornievskaia <kolga@netapp.com>

Given the patch "Always provide aligned buffers to the RPC read layers",
RPC over RDMA doesn't need to look at the tail page and add that space
to the write chunk.

For the RFC 8166 compliant server, it must not write an XDR padding
into the write chunk (even if space was provided). Historically
(before RFC 8166) Solaris RDMA server has been requiring the client
to provide space for the XDR padding and thus this client code has
existed.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
---
 net/sunrpc/xprtrdma/rpc_rdma.c | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index c335c1361564..2c4146bcf2a8 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -255,21 +255,6 @@ rpcrdma_convert_iovs(struct rpcrdma_xprt *r_xprt, struct xdr_buf *xdrbuf,
 		page_base = 0;
 	}
 
-	if (type == rpcrdma_readch)
-		goto out;
-
-	/* When encoding a Write chunk, some servers need to see an
-	 * extra segment for non-XDR-aligned Write chunks. The upper
-	 * layer provides space in the tail iovec that may be used
-	 * for this purpose.
-	 */
-	if (type == rpcrdma_writech && r_xprt->rx_ep->re_implicit_roundup)
-		goto out;
-
-	if (xdrbuf->tail[0].iov_len)
-		rpcrdma_convert_kvec(&xdrbuf->tail[0], seg, &n);
-
-out:
 	if (unlikely(n > RPCRDMA_MAX_SEGS))
 		return -EIO;
 	return n;
-- 
2.27.0