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SubjectRe: [PATCH v4 09/16] block: sed-opal: split generation of bytestring header and content
Date
Looks good

Reviewed-by Jon Derrick <jonathan.derrick@intel.com>

On Fri, 2019-02-01 at 21:50 +0100, David Kozub wrote:
> From: Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de>
>
> Split the header generation from the (normal) memcpy part if a
> bytestring is copied into the command buffer. This allows in-place
> generation of the bytestring content. For example, copy_from_user may be
> used without an intermediate buffer.
>
> Signed-off-by: Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de>
> Reviewed-by: Scott Bauer <sbauer@plzdonthack.me>
> ---
> block/sed-opal.c | 23 +++++++++++++++--------
> 1 file changed, 15 insertions(+), 8 deletions(-)
>
> diff --git a/block/sed-opal.c b/block/sed-opal.c
> index 4225f23b2165..4b0a63b9d7c9 100644
> --- a/block/sed-opal.c
> +++ b/block/sed-opal.c
> @@ -586,14 +586,11 @@ static void add_token_u64(int *err, struct opal_dev *cmd, u64 number)
> add_token_u8(err, cmd, number >> (len * 8));
> }
>
> -static void add_token_bytestring(int *err, struct opal_dev *cmd,
> - const u8 *bytestring, size_t len)
> +static u8 *add_bytestring_header(int *err, struct opal_dev *cmd, size_t len)
> {
> size_t header_len = 1;
> bool is_short_atom = true;
> -
> - if (*err)
> - return;
> + char *start;
>
> if (len & ~SHORT_ATOM_LEN_MASK) {
> header_len = 2;
> @@ -602,17 +599,27 @@ static void add_token_bytestring(int *err, struct opal_dev *cmd,
>
> if (!can_add(err, cmd, header_len + len)) {
> pr_debug("Error adding bytestring: end of buffer.\n");
> - return;
> + return NULL;
> }
>
> if (is_short_atom)
> add_short_atom_header(cmd, true, false, len);
> else
> add_medium_atom_header(cmd, true, false, len);
> + start = &cmd->cmd[cmd->pos];
> + return start;
> +}
>
> - memcpy(&cmd->cmd[cmd->pos], bytestring, len);
> - cmd->pos += len;
> +static void add_token_bytestring(int *err, struct opal_dev *cmd,
> + const u8 *bytestring, size_t len)
> +{
> + u8 *start;
>
> + start = add_bytestring_header(err, cmd, len);
> + if (!start)
> + return;
> + memcpy(start, bytestring, len);
> + cmd->pos += len;
> }
>
> static int build_locking_range(u8 *buffer, size_t length, u8 lr)[unhandled content-type:application/x-pkcs7-signature]
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