This is a note to let you know that I've just added the patch titled
NFSD: Optimize nfsd4_encode_readv()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsd-optimize-nfsd4_encode_readv.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 60f24b2e65ec9cdea86e569a6187566894b3b631
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date: Fri Jul 22 16:09:04 2022 -0400
NFSD: Optimize nfsd4_encode_readv()
[ Upstream commit 28d5bc468efe74b790e052f758ce083a5015c665 ]
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@xxxxxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index b31103221fee9..b7a3c770d436b 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3888,7 +3888,6 @@ 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)
@@ -3907,9 +3906,6 @@ 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)
@@ -3970,11 +3966,6 @@ 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,
@@ -4016,11 +4007,14 @@ 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
