* [PATCH] Input: atmel_mxt_ts - Remove unnecessary byte_offset check
@ 2017-10-08 18:44 Christos Gkekas
2017-10-08 19:41 ` Nick Dyer
0 siblings, 1 reply; 4+ messages in thread
From: Christos Gkekas @ 2017-10-08 18:44 UTC (permalink / raw)
To: Nick Dyer, Dmitry Torokhov, linux-input, linux-kernel; +Cc: Christos Gkekas
Variable byte_offset is unsigned so checking whether it is greater or
equal to zero is redundant.
Signed-off-by: Christos Gkekas <chris.gekas@gmail.com>
---
drivers/input/touchscreen/atmel_mxt_ts.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 7659bc4..baafaed 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -1356,7 +1356,7 @@ static int mxt_prepare_cfg_mem(struct mxt_data *data,
byte_offset = reg + i - cfg_start_ofs;
- if (byte_offset >= 0 && byte_offset < config_mem_size) {
+ if (byte_offset < config_mem_size) {
*(config_mem + byte_offset) = val;
} else {
dev_err(dev, "Bad object: reg:%d, T%d, ofs=%d\n",
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] Input: atmel_mxt_ts - Remove unnecessary byte_offset check
2017-10-08 18:44 [PATCH] Input: atmel_mxt_ts - Remove unnecessary byte_offset check Christos Gkekas
@ 2017-10-08 19:41 ` Nick Dyer
2017-10-09 17:38 ` Dmitry Torokhov
0 siblings, 1 reply; 4+ messages in thread
From: Nick Dyer @ 2017-10-08 19:41 UTC (permalink / raw)
To: Christos Gkekas; +Cc: Dmitry Torokhov, linux-input, linux-kernel
On Sun, Oct 08, 2017 at 07:44:18PM +0100, Christos Gkekas wrote:
> Variable byte_offset is unsigned so checking whether it is greater or
> equal to zero is redundant.
>
> Signed-off-by: Christos Gkekas <chris.gekas@gmail.com>
Yep - looks sensible to me.
Signed-off-by: Nick Dyer <nick@shmanahar.org>
> ---
> drivers/input/touchscreen/atmel_mxt_ts.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
> index 7659bc4..baafaed 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -1356,7 +1356,7 @@ static int mxt_prepare_cfg_mem(struct mxt_data *data,
>
> byte_offset = reg + i - cfg_start_ofs;
>
> - if (byte_offset >= 0 && byte_offset < config_mem_size) {
> + if (byte_offset < config_mem_size) {
> *(config_mem + byte_offset) = val;
> } else {
> dev_err(dev, "Bad object: reg:%d, T%d, ofs=%d\n",
> --
> 2.7.4
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Input: atmel_mxt_ts - Remove unnecessary byte_offset check
2017-10-08 19:41 ` Nick Dyer
@ 2017-10-09 17:38 ` Dmitry Torokhov
2017-10-09 21:06 ` Christos Gkekas
0 siblings, 1 reply; 4+ messages in thread
From: Dmitry Torokhov @ 2017-10-09 17:38 UTC (permalink / raw)
To: Nick Dyer; +Cc: Christos Gkekas, linux-input, linux-kernel
On Sun, Oct 08, 2017 at 08:41:16PM +0100, Nick Dyer wrote:
> On Sun, Oct 08, 2017 at 07:44:18PM +0100, Christos Gkekas wrote:
> > Variable byte_offset is unsigned so checking whether it is greater or
> > equal to zero is redundant.
> >
> > Signed-off-by: Christos Gkekas <chris.gekas@gmail.com>
>
> Yep - looks sensible to me.
>
> Signed-off-by: Nick Dyer <nick@shmanahar.org>
I believe this has been discussed before and Linus told us to keep the
such checks as is: they neatly document the ranges of values, safe in
case we ever change the type of the variables, and do not cost us
anything at execution time.
>
> > ---
> > drivers/input/touchscreen/atmel_mxt_ts.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
> > index 7659bc4..baafaed 100644
> > --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> > +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> > @@ -1356,7 +1356,7 @@ static int mxt_prepare_cfg_mem(struct mxt_data *data,
> >
> > byte_offset = reg + i - cfg_start_ofs;
> >
> > - if (byte_offset >= 0 && byte_offset < config_mem_size) {
> > + if (byte_offset < config_mem_size) {
> > *(config_mem + byte_offset) = val;
> > } else {
> > dev_err(dev, "Bad object: reg:%d, T%d, ofs=%d\n",
> > --
> > 2.7.4
> >
Thanks.
--
Dmitry
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Input: atmel_mxt_ts - Remove unnecessary byte_offset check
2017-10-09 17:38 ` Dmitry Torokhov
@ 2017-10-09 21:06 ` Christos Gkekas
0 siblings, 0 replies; 4+ messages in thread
From: Christos Gkekas @ 2017-10-09 21:06 UTC (permalink / raw)
To: Dmitry Torokhov; +Cc: Nick Dyer, linux-input, linux-kernel
On 09/10/17 10:38:55 -0700, Dmitry Torokhov wrote:
> On Sun, Oct 08, 2017 at 08:41:16PM +0100, Nick Dyer wrote:
> > On Sun, Oct 08, 2017 at 07:44:18PM +0100, Christos Gkekas wrote:
> > > Variable byte_offset is unsigned so checking whether it is greater or
> > > equal to zero is redundant.
> > >
> > > Signed-off-by: Christos Gkekas <chris.gekas@gmail.com>
> >
> > Yep - looks sensible to me.
> >
> > Signed-off-by: Nick Dyer <nick@shmanahar.org>
>
> I believe this has been discussed before and Linus told us to keep the
> such checks as is: they neatly document the ranges of values, safe in
> case we ever change the type of the variables, and do not cost us
> anything at execution time.
>
Fair enough, thanks for your feedback.
I believe you are referring to this:
https://lkml.org/lkml/2006/11/28/206
Regards,
Christos
>
> >
> > > ---
> > > drivers/input/touchscreen/atmel_mxt_ts.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
> > > index 7659bc4..baafaed 100644
> > > --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> > > +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> > > @@ -1356,7 +1356,7 @@ static int mxt_prepare_cfg_mem(struct mxt_data *data,
> > >
> > > byte_offset = reg + i - cfg_start_ofs;
> > >
> > > - if (byte_offset >= 0 && byte_offset < config_mem_size) {
> > > + if (byte_offset < config_mem_size) {
> > > *(config_mem + byte_offset) = val;
> > > } else {
> > > dev_err(dev, "Bad object: reg:%d, T%d, ofs=%d\n",
> > > --
> > > 2.7.4
> > >
>
> Thanks.
>
> --
> Dmitry
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-10-09 21:06 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-10-08 18:44 [PATCH] Input: atmel_mxt_ts - Remove unnecessary byte_offset check Christos Gkekas
2017-10-08 19:41 ` Nick Dyer
2017-10-09 17:38 ` Dmitry Torokhov
2017-10-09 21:06 ` Christos Gkekas
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).