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NFSD: Optimize nfsd4_encode_readv()

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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: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Chuck Lever 2022-07-22 16:09:04 -04:00
parent 24c7fb8549
commit 28d5bc468e
1 changed files with 6 additions and 12 deletions
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18
fs/nfsd/nfs4xdr.c
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@ -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,
@ -4008,11 +3999,14 @@ 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;
}
return nfserr;
p = xdr_encode_bool(p, read->rd_eof);
*p = cpu_to_be32(read->rd_length);
return nfs_ok;
}
static __be32