Messages in this thread | | | Subject | Re: [PATCH] net: dsa: b53: Replace mdelay with msleep in b53_switch_reset_gpio | From | Jia-Ju Bai <> | Date | Thu, 12 Apr 2018 09:49:33 +0800 |
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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
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