| Message ID | 1523411485-2030-1-git-send-email-baijiaju1990@gmail.com |
|---|---|
| State | Rejected, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | net: dsa: b53: Replace mdelay with msleep in b53_switch_reset_gpio | expand |
On 11/04/2018 09:51, Jia-Ju Bai wrote: > b53_switch_reset_gpio() is never called in atomic context. > > The call chain ending up at b53_switch_reset_gpio() is: > [1] b53_switch_reset_gpio() <- b53_switch_reset() <- > b53_reset_switch() <- b53_setup() > > b53_switch_reset_gpio() is set as ".setup" in struct dsa_switch_ops. > This function is not called in atomic context. > > Despite never getting called from atomic context, b53_switch_reset_gpio() > calls mdelay() to busily wait. > This is not necessary and can be replaced with msleep() to > avoid busy waiting. > > This is found by a static analysis tool named DCNS written by myself. > And I also manually check it. > > Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> > --- > drivers/net/dsa/b53/b53_common.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c > index 274f367..e070ff6 100644 > --- a/drivers/net/dsa/b53/b53_common.c > +++ b/drivers/net/dsa/b53/b53_common.c > @@ -597,10 +597,10 @@ static void b53_switch_reset_gpio(struct b53_device *dev) > /* Reset sequence: RESET low(50ms)->high(20ms) > */ > gpio_set_value(gpio, 0); > - mdelay(50); > + msleep(50); > > gpio_set_value(gpio, 1); > - mdelay(20); > + msleep(20); > > dev->current_page = 0xff; > } > Would that also imply gpio_set_value could be gpio_set_value_cansleep?
On 2018/4/11 13:30, Phil Reid wrote: > On 11/04/2018 09:51, Jia-Ju Bai wrote: >> b53_switch_reset_gpio() is never called in atomic context. >> >> The call chain ending up at b53_switch_reset_gpio() is: >> [1] b53_switch_reset_gpio() <- b53_switch_reset() <- >> b53_reset_switch() <- b53_setup() >> >> b53_switch_reset_gpio() is set as ".setup" in struct dsa_switch_ops. >> This function is not called in atomic context. >> >> Despite never getting called from atomic context, >> b53_switch_reset_gpio() >> calls mdelay() to busily wait. >> This is not necessary and can be replaced with msleep() to >> avoid busy waiting. >> >> This is found by a static analysis tool named DCNS written by myself. >> And I also manually check it. >> >> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> >> --- >> drivers/net/dsa/b53/b53_common.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/net/dsa/b53/b53_common.c >> b/drivers/net/dsa/b53/b53_common.c >> index 274f367..e070ff6 100644 >> --- a/drivers/net/dsa/b53/b53_common.c >> +++ b/drivers/net/dsa/b53/b53_common.c >> @@ -597,10 +597,10 @@ static void b53_switch_reset_gpio(struct >> b53_device *dev) >> /* Reset sequence: RESET low(50ms)->high(20ms) >> */ >> gpio_set_value(gpio, 0); >> - mdelay(50); >> + msleep(50); >> gpio_set_value(gpio, 1); >> - mdelay(20); >> + msleep(20); >> dev->current_page = 0xff; >> } >> > Would that also imply gpio_set_value could be gpio_set_value_cansleep? > Yes, I think gpio_set_value_cansleep() is okay here? Do I need to send a V2 patch to replace gpio_set_value()? Best wishes, Jia-Ju Bai
On 04/11/2018 12:14 AM, Jia-Ju Bai wrote: > > > On 2018/4/11 13:30, Phil Reid wrote: >> On 11/04/2018 09:51, Jia-Ju Bai wrote: >>> b53_switch_reset_gpio() is never called in atomic context. >>> >>> The call chain ending up at b53_switch_reset_gpio() is: >>> [1] b53_switch_reset_gpio() <- b53_switch_reset() <- >>> b53_reset_switch() <- b53_setup() >>> >>> b53_switch_reset_gpio() is set as ".setup" in struct dsa_switch_ops. >>> This function is not called in atomic context. >>> >>> Despite never getting called from atomic context, >>> b53_switch_reset_gpio() >>> calls mdelay() to busily wait. >>> This is not necessary and can be replaced with msleep() to >>> avoid busy waiting. >>> >>> This is found by a static analysis tool named DCNS written by myself. >>> And I also manually check it. >>> >>> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> >>> --- >>> drivers/net/dsa/b53/b53_common.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/net/dsa/b53/b53_common.c >>> b/drivers/net/dsa/b53/b53_common.c >>> index 274f367..e070ff6 100644 >>> --- a/drivers/net/dsa/b53/b53_common.c >>> +++ b/drivers/net/dsa/b53/b53_common.c >>> @@ -597,10 +597,10 @@ static void b53_switch_reset_gpio(struct >>> b53_device *dev) >>> /* Reset sequence: RESET low(50ms)->high(20ms) >>> */ >>> gpio_set_value(gpio, 0); >>> - mdelay(50); >>> + msleep(50); >>> gpio_set_value(gpio, 1); >>> - mdelay(20); >>> + msleep(20); >>> dev->current_page = 0xff; >>> } >>> >> Would that also imply gpio_set_value could be gpio_set_value_cansleep? >> > > Yes, I think gpio_set_value_cansleep() is okay here? > Do I need to send a V2 patch to replace gpio_set_value()? Yes, I would lump these two changes in the same patch since this is effectively about solving sleeping vs. non sleeping operations. Thanks!
On 2018/4/12 0:19, Florian Fainelli wrote: > On 04/11/2018 12:14 AM, Jia-Ju Bai wrote: >> >> On 2018/4/11 13:30, Phil Reid wrote: >>> On 11/04/2018 09:51, Jia-Ju Bai wrote: >>>> b53_switch_reset_gpio() is never called in atomic context. >>>> >>>> The call chain ending up at b53_switch_reset_gpio() is: >>>> [1] b53_switch_reset_gpio() <- b53_switch_reset() <- >>>> b53_reset_switch() <- b53_setup() >>>> >>>> b53_switch_reset_gpio() is set as ".setup" in struct dsa_switch_ops. >>>> This function is not called in atomic context. >>>> >>>> Despite never getting called from atomic context, >>>> b53_switch_reset_gpio() >>>> calls mdelay() to busily wait. >>>> This is not necessary and can be replaced with msleep() to >>>> avoid busy waiting. >>>> >>>> This is found by a static analysis tool named DCNS written by myself. >>>> And I also manually check it. >>>> >>>> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> >>>> --- >>>> drivers/net/dsa/b53/b53_common.c | 4 ++-- >>>> 1 file changed, 2 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/net/dsa/b53/b53_common.c >>>> b/drivers/net/dsa/b53/b53_common.c >>>> index 274f367..e070ff6 100644 >>>> --- a/drivers/net/dsa/b53/b53_common.c >>>> +++ b/drivers/net/dsa/b53/b53_common.c >>>> @@ -597,10 +597,10 @@ static void b53_switch_reset_gpio(struct >>>> b53_device *dev) >>>> /* Reset sequence: RESET low(50ms)->high(20ms) >>>> */ >>>> gpio_set_value(gpio, 0); >>>> - mdelay(50); >>>> + msleep(50); >>>> gpio_set_value(gpio, 1); >>>> - mdelay(20); >>>> + msleep(20); >>>> dev->current_page = 0xff; >>>> } >>>> >>> Would that also imply gpio_set_value could be gpio_set_value_cansleep? >>> >> Yes, I think gpio_set_value_cansleep() is okay here? >> Do I need to send a V2 patch to replace gpio_set_value()? > Yes, I would lump these two changes in the same patch since this is > effectively about solving sleeping vs. non sleeping operations. Okay, I have sent a V2 patch, and you can have a look :) Best wishes, Jia-Ju Bai
diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c index 274f367..e070ff6 100644 --- a/drivers/net/dsa/b53/b53_common.c +++ b/drivers/net/dsa/b53/b53_common.c @@ -597,10 +597,10 @@ static void b53_switch_reset_gpio(struct b53_device *dev) /* Reset sequence: RESET low(50ms)->high(20ms) */ gpio_set_value(gpio, 0); - mdelay(50); + msleep(50); gpio_set_value(gpio, 1); - mdelay(20); + msleep(20); dev->current_page = 0xff; }
b53_switch_reset_gpio() is never called in atomic context. The call chain ending up at b53_switch_reset_gpio() is: [1] b53_switch_reset_gpio() <- b53_switch_reset() <- b53_reset_switch() <- b53_setup() b53_switch_reset_gpio() is set as ".setup" in struct dsa_switch_ops. This function is not called in atomic context. Despite never getting called from atomic context, b53_switch_reset_gpio() calls mdelay() to busily wait. This is not necessary and can be replaced with msleep() to avoid busy waiting. This is found by a static analysis tool named DCNS written by myself. And I also manually check it. Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> --- drivers/net/dsa/b53/b53_common.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)