Re: [PATCH linux-next] cdrom: Remove redundant variable and its assignment.

From: Phillip Potter
Date: Mon Oct 18 2021 - 19:30:10 EST


On Mon, Oct 18, 2021 at 09:08:34AM +0000, luo penghao wrote:
> From: penghao luo <luo.penghao@xxxxxxxxxx>
>
> Variable is not used in functions, and its assignment is redundant too.
> So it should be deleted.
>
> The clang_analyzer complains as follows:
>
> drivers/cdrom/cdrom.c:877: warning:
>
> Although the value stored to 'ret' is used in the enclosing expression,
> the value is never actually read from 'ret’.
>
> Reported-by: Zeal Robot <zealci@xxxxxxxxxx>
> Signed-off-by: penghao luo <luo.penghao@xxxxxxxxxx>
> ---

Dear Penghao,

Thank you for the patch, looks good, but please could I ask for a small
tweak:

> drivers/cdrom/cdrom.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
> index 89a6845..393acf4 100644
> --- a/drivers/cdrom/cdrom.c
> +++ b/drivers/cdrom/cdrom.c
> @@ -871,7 +871,7 @@ static void cdrom_mmc3_profile(struct cdrom_device_info *cdi)
> {
> struct packet_command cgc;
> char buffer[32];
> - int ret, mmc3_profile;
> + int mmc3_profile;
>
> init_cdrom_command(&cgc, buffer, sizeof(buffer), CGC_DATA_READ);
>
> @@ -881,7 +881,7 @@ static void cdrom_mmc3_profile(struct cdrom_device_info *cdi)
> cgc.cmd[8] = sizeof(buffer); /* Allocation Length */
> cgc.quiet = 1;
>
> - if ((ret = cdi->ops->generic_packet(cdi, &cgc)))
> + if ((cdi->ops->generic_packet(cdi, &cgc)))

We no longer need the inner-most set of parentheses now, as we are
checking the result of the expression:
cdi->ops->generic_packet(cdi, &cgc)

rather than the result of the assignment expression:
(ret = cdi->ops->generic_packet(cdi, &cgc))

Please resubmit with this change and I'd be happy to approve the patch.
Many thanks.

Regards,
Phil