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From:   "NeilBrown" <neilb@suse.de>
To:     "Chuck Lever" <chuck.lever@oracle.com>
Cc:     linux-nfs@vger.kernel.org
Subject: Re: [PATCH v1 4/5] SUNRPC: Clean up xdr_get_next_encode_buffer()
In-reply-to: <165445912444.1664.7733109680322574177.stgit@bazille.1015granger.net>
References: <165445865736.1664.4497130284832282034.stgit@bazille.1015granger.net>,
 <165445912444.1664.7733109680322574177.stgit@bazille.1015granger.net>
Date:   Tue, 07 Jun 2022 11:07:13 +1000
Message-id: <165456403303.22243.14012939379410947473@noble.neil.brown.name>
Precedence: bulk

On Mon, 06 Jun 2022, Chuck Lever wrote:
> The value of @p is not used until the "location of the next item" is
> computed. Help human readers by moving its initial assignment to the
> paragraph where that value is used and by clarifying the antecedents
> in the documenting comment.
>=20
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Reviewed-by: NeilBrown <neilb@suse.com>


> ---
>  net/sunrpc/xdr.c |    8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>=20
> diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
> index de8f71468637..89cb48931a1f 100644
> --- a/net/sunrpc/xdr.c
> +++ b/net/sunrpc/xdr.c
> @@ -971,6 +971,7 @@ static noinline __be32 *xdr_get_next_encode_buffer(stru=
ct xdr_stream *xdr,
>  		xdr->buf->page_len +=3D frag1bytes;
>  	xdr->page_ptr++;
>  	xdr->iov =3D NULL;
> +
>  	/*
>  	 * If the last encode didn't end exactly on a page boundary, the
>  	 * next one will straddle boundaries.  Encode into the next
> @@ -979,11 +980,12 @@ static noinline __be32 *xdr_get_next_encode_buffer(st=
ruct xdr_stream *xdr,
>  	 * space at the end of the previous buffer:
>  	 */
>  	xdr_set_scratch_buffer(xdr, xdr->p, frag1bytes);
> -	p =3D page_address(*xdr->page_ptr);
> +
>  	/*
> -	 * Note this is where the next encode will start after we've
> -	 * shifted this one back:
> +	 * xdr->p is where the next encode will start after
> +	 * xdr_commit_encode() has shifted this one back:
>  	 */
> +	p =3D page_address(*xdr->page_ptr);
>  	xdr->p =3D (void *)p + frag2bytes;
>  	space_left =3D xdr->buf->buflen - xdr->buf->len;
>  	if (space_left - nbytes >=3D PAGE_SIZE)
>=20
>=20
>=20