On Fri, Aug 20, 2021 at 12:21:54PM +0900, Damien Le Moal wrote:
> Remove unnecessary gotos in scsi_get_vpd_page() to improve the code
> readability and use memchr() instead of an open coded search loop.
> Also update the outdated kernel doc comment for this function.
>
> Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx>
> ---
> Changes from v1:
> * Fix memchr() use to avoid accesses beyond the buffer and result size.
>
> drivers/scsi/scsi.c | 31 ++++++++++++++-----------------
> 1 file changed, 14 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
> index b241f9e3885c..6be68b3427a0 100644
> --- a/drivers/scsi/scsi.c
> +++ b/drivers/scsi/scsi.c
> @@ -339,47 +339,44 @@ static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
> *
> * SCSI devices may optionally supply Vital Product Data. Each 'page'
> * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
> - * If the device supports this VPD page, this routine returns a pointer
> - * to a buffer containing the data from that page. The caller is
> - * responsible for calling kfree() on this pointer when it is no longer
> - * needed. If we cannot retrieve the VPD page this routine returns %NULL.
> + * If the device supports this VPD page, this routine fills @buf
> + * with the data from that page and return 0. If the VPD page is not
> + * supported or its content cannot be retrieved, -EINVAL is returned.
> */
> int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
> int buf_len)
> {
> - int i, result;
> + int result, len;
>
> if (sdev->skip_vpd_pages)
> - goto fail;
> + return -EINVAL;
>
> /* Ask for all the pages supported by this device */
> result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
> if (result < 4)
> - goto fail;
> + return -EINVAL;
>
> /* If the user actually wanted this page, we can skip the rest */
> if (page == 0)
> return 0;
>
> - for (i = 4; i < min(result, buf_len); i++)
> - if (buf[i] == page)
> - goto found;
> + len = min(result, buf_len);
> + if (len > 4 && memchr(&buf[4], page, len - 4))
> + goto found;
>
> - if (i < result && i >= buf_len)
> - /* ran off the end of the buffer, give us benefit of doubt */
> + /* If we ran off the end of the buffer, give us benefit of doubt */
> + if (result > buf_len)
> goto found;
> +
> /* The device claims it doesn't support the requested page */
> - goto fail;
> + return -EINVAL;
>
> found:
> result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
> if (result < 0)
> - goto fail;
> + return -EINVAL;
>
> return 0;
> -
> - fail:
> - return -EINVAL;
> }
> EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
>
(Nit: I think you forgot to bump the version. Subject for this is v2, which
is the same as the previous "scsi: simplify scsi_get_vpd_page()" patch.)
Reviewed-by: Niklas Cassel <niklas.cassel@xxxxxxx>
