> On Jul 22, 2022, at 4:08 PM, Chuck Lever <chuck.lever@xxxxxxxxxx> wrote: > > 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, and here, it is unnecessary because the > data item is fixed in size, the buffer destination address is > always word-aligned, and the destination location is already in > @p. > > Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> > --- > fs/nfsd/nfs4xdr.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c > index 2acea7792bb2..b52ea7d8313a 100644 > --- a/fs/nfsd/nfs4xdr.c > +++ b/fs/nfsd/nfs4xdr.c > @@ -5373,8 +5373,7 @@ nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op) > so->so_replay.rp_buf, len); > } > status: > - /* Note that op->status is already in network byte order: */ > - write_bytes_to_xdr_buf(xdr->buf, post_err_offset - 4, &op->status, 4); > + *p = op->status; > } > > /* I hit "Send" too soon. Here's the cover letter for this series. write_bytes_to_xdr_buf() is a generic mechanism by which to push an arbitrary set of bytes to an arbitrary alignment within an xdr_buf. It's expensive to use, though. I found several hot paths in the server's NFSv4 reply encoders that write a 4-byte XDR data item on a 4-byte alignment, and thus can use the classic "*p = cpu_to_be32(yada)" form instead of write_bytes_to_xdr_buf(). This series replaces some write_bytes_to_xdr_buf() call sites. -- Chuck Lever
