This is a note to let you know that I've just added the patch titled
NFSD: Optimize nfsd4_encode_fattr()
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_fattr.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 26bd1fbe732c3f43804e067da3ad29ba42af25cc
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date: Fri Jul 22 16:08:45 2022 -0400
NFSD: Optimize nfsd4_encode_fattr()
[ Upstream commit ab04de60ae1cc64ae16b77feae795311b97720c7 ]
write_bytes_to_xdr_buf() is a generic way to place a variable-length
data item in an already-reserved spot in the encoding buffer.
However, it is costly. In nfsd4_encode_fattr(), it is unnecessary
because the data item is fixed in size and the buffer destination
address is always word-aligned.
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 9eba9afe13794..d5a4aa0da32be 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2825,10 +2825,9 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
struct kstat stat;
struct svc_fh *tempfh = NULL;
struct kstatfs statfs;
- __be32 *p;
+ __be32 *p, *attrlen_p;
int starting_len = xdr->buf->len;
int attrlen_offset;
- __be32 attrlen;
u32 dummy;
u64 dummy64;
u32 rdattr_err = 0;
@@ -2916,10 +2915,9 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
goto out;
attrlen_offset = xdr->buf->len;
- p = xdr_reserve_space(xdr, 4);
- if (!p)
+ attrlen_p = xdr_reserve_space(xdr, XDR_UNIT);
+ if (!attrlen_p)
goto out_resource;
- p++; /* to be backfilled later */
if (bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
u32 supp[3];
@@ -3341,8 +3339,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
*p++ = cpu_to_be32(err == 0);
}
- attrlen = htonl(xdr->buf->len - attrlen_offset - 4);
- write_bytes_to_xdr_buf(xdr->buf, attrlen_offset, &attrlen, 4);
+ *attrlen_p = cpu_to_be32(xdr->buf->len - attrlen_offset - XDR_UNIT);
status = nfs_ok;
out:
