* [PATCH] staging: sm750fb: skip unnecessary comparisons
@ 2017-07-03 1:26 Lynn Lei
2017-07-03 6:19 ` Greg KH
0 siblings, 1 reply; 2+ messages in thread
From: Lynn Lei @ 2017-07-03 1:26 UTC (permalink / raw)
To: sudipm.mukherjee; +Cc: teddy.wang, linux-fbdev, linux-kernel, devel
introduced early checks to skip unnecessary comparisons when flags set.
Signed-off-by: Lynn Lei <lynnl.wit@gmail.com>
---
drivers/staging/sm750fb/sm750.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/sm750fb/sm750.c b/drivers/staging/sm750fb/sm750.c
index 386d4adcd91d..9e57a2d32465 100644
--- a/drivers/staging/sm750fb/sm750.c
+++ b/drivers/staging/sm750fb/sm750.c
@@ -1171,11 +1171,16 @@ static int __init lynxfb_setup(char *options)
*/
while ((opt = strsep(&options, ":")) != NULL) {
/* options that mean for any lynx chips are configured here */
- if (!strncmp(opt, "noaccel", strlen("noaccel"))) {
+
+ /*
+ * NOTE: the length of options is hard-coded
+ * if any of those options changed please update its length
+ */
+ if (!g_noaccel && !strncmp(opt, "noaccel", 7)) {
g_noaccel = 1;
- } else if (!strncmp(opt, "nomtrr", strlen("nomtrr"))) {
+ } else if (!g_nomtrr && !strncmp(opt, "nomtrr", 6)) {
g_nomtrr = 1;
- } else if (!strncmp(opt, "dual", strlen("dual"))) {
+ } else if (!g_dualview && !strncmp(opt, "dual", 4)) {
g_dualview = 1;
} else {
strcat(tmp, opt);
--
2.13.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] staging: sm750fb: skip unnecessary comparisons
2017-07-03 1:26 [PATCH] staging: sm750fb: skip unnecessary comparisons Lynn Lei
@ 2017-07-03 6:19 ` Greg KH
0 siblings, 0 replies; 2+ messages in thread
From: Greg KH @ 2017-07-03 6:19 UTC (permalink / raw)
To: Lynn Lei; +Cc: sudipm.mukherjee, devel, linux-fbdev, teddy.wang, linux-kernel
On Mon, Jul 03, 2017 at 09:26:47AM +0800, Lynn Lei wrote:
> introduced early checks to skip unnecessary comparisons when flags set.
Why?
>
> Signed-off-by: Lynn Lei <lynnl.wit@gmail.com>
> ---
> drivers/staging/sm750fb/sm750.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/staging/sm750fb/sm750.c b/drivers/staging/sm750fb/sm750.c
> index 386d4adcd91d..9e57a2d32465 100644
> --- a/drivers/staging/sm750fb/sm750.c
> +++ b/drivers/staging/sm750fb/sm750.c
> @@ -1171,11 +1171,16 @@ static int __init lynxfb_setup(char *options)
> */
> while ((opt = strsep(&options, ":")) != NULL) {
> /* options that mean for any lynx chips are configured here */
> - if (!strncmp(opt, "noaccel", strlen("noaccel"))) {
> +
> + /*
> + * NOTE: the length of options is hard-coded
> + * if any of those options changed please update its length
> + */
That's not good, why require this? What is wrong with the original code
here? It doesn't have that type of restriction, right?
> + if (!g_noaccel && !strncmp(opt, "noaccel", 7)) {
> g_noaccel = 1;
> - } else if (!strncmp(opt, "nomtrr", strlen("nomtrr"))) {
> + } else if (!g_nomtrr && !strncmp(opt, "nomtrr", 6)) {
I don't see the benefit of this change at all, what am I missing?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 2+ messages in thread
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