Commit 28d5bc46 authored by Chuck Lever's avatar Chuck Lever
Browse files

NFSD: Optimize nfsd4_encode_readv() 



write_bytes_to_xdr_buf() is pretty expensive to use for inserting
an XDR data item that is always 1 XDR_UNIT at an address that is
always XDR word-aligned.

Since both the readv and splice read paths encode EOF and maxcount
values, move both to a common code path.

Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 24c7fb85

fs/nfsd/nfs4xdr.c

+6 −12
Original line number Diff line number Diff line
@@ -3880,7 +3880,6 @@ static __be32 nfsd4_encode_splice_read( 
	struct xdr_buf *buf = xdr->buf;

	int status, space_left;

	__be32 nfserr;

	__be32 *p = xdr->p - 2;



	/* Make sure there will be room for padding if needed */

	if (xdr->end - xdr->p < 1)
@@ -3899,9 +3898,6 @@ static __be32 nfsd4_encode_splice_read( 
		goto out_err;

	}



	*(p++) = htonl(read->rd_eof);

	*(p++) = htonl(maxcount);



	buf->page_len = maxcount;

	buf->len += maxcount;

	xdr->page_ptr += (buf->page_base + maxcount + PAGE_SIZE - 1)
@@ -3962,11 +3958,6 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp, 
		return nfserr_io;

	xdr_truncate_encode(xdr, starting_len + 8 + xdr_align_size(maxcount));



	tmp = htonl(read->rd_eof);

	write_bytes_to_xdr_buf(xdr->buf, starting_len    , &tmp, 4);

	tmp = htonl(maxcount);

	write_bytes_to_xdr_buf(xdr->buf, starting_len + 4, &tmp, 4);



	tmp = xdr_zero;

	pad = (maxcount&3) ? 4 - (maxcount&3) : 0;

	write_bytes_to_xdr_buf(xdr->buf, starting_len + 8 + maxcount,
@@ -4008,13 +3999,16 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr, 
		nfserr = nfsd4_encode_splice_read(resp, read, file, maxcount);

	else

		nfserr = nfsd4_encode_readv(resp, read, file, maxcount);



	if (nfserr)

	if (nfserr) {

		xdr_truncate_encode(xdr, starting_len);



		return nfserr;

	}



	p = xdr_encode_bool(p, read->rd_eof);

	*p = cpu_to_be32(read->rd_length);

	return nfs_ok;

}



static __be32

nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_readlink *readlink)

{