* [PATCH] net: dsa: b53: Replace mdelay with msleep in b53_switch_reset_gpio
@ 2018-04-11 1:51 Jia-Ju Bai
2018-04-11 5:30 ` Phil Reid
0 siblings, 1 reply; 5+ messages in thread
From: Jia-Ju Bai @ 2018-04-11 1:51 UTC (permalink / raw)
To: f.fainelli, andrew, vivien.didelot; +Cc: netdev, linux-kernel, Jia-Ju Bai
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;
}
--
1.9.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] net: dsa: b53: Replace mdelay with msleep in b53_switch_reset_gpio
2018-04-11 1:51 [PATCH] net: dsa: b53: Replace mdelay with msleep in b53_switch_reset_gpio Jia-Ju Bai
@ 2018-04-11 5:30 ` Phil Reid
2018-04-11 7:14 ` Jia-Ju Bai
0 siblings, 1 reply; 5+ messages in thread
From: Phil Reid @ 2018-04-11 5:30 UTC (permalink / raw)
To: Jia-Ju Bai, f.fainelli, andrew, vivien.didelot; +Cc: netdev, linux-kernel
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?
--
Regards
Phil Reid
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] net: dsa: b53: Replace mdelay with msleep in b53_switch_reset_gpio
2018-04-11 5:30 ` Phil Reid
@ 2018-04-11 7:14 ` Jia-Ju Bai
2018-04-11 16:19 ` Florian Fainelli
0 siblings, 1 reply; 5+ messages in thread
From: Jia-Ju Bai @ 2018-04-11 7:14 UTC (permalink / raw)
To: Phil Reid, f.fainelli, andrew, vivien.didelot; +Cc: netdev, linux-kernel
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
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] net: dsa: b53: Replace mdelay with msleep in b53_switch_reset_gpio
2018-04-11 7:14 ` Jia-Ju Bai
@ 2018-04-11 16:19 ` Florian Fainelli
2018-04-12 1:49 ` Jia-Ju Bai
0 siblings, 1 reply; 5+ messages in thread
From: Florian Fainelli @ 2018-04-11 16:19 UTC (permalink / raw)
To: Jia-Ju Bai, Phil Reid, andrew, vivien.didelot; +Cc: netdev, linux-kernel
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!
--
Florian
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] net: dsa: b53: Replace mdelay with msleep in b53_switch_reset_gpio
2018-04-11 16:19 ` Florian Fainelli
@ 2018-04-12 1:49 ` Jia-Ju Bai
0 siblings, 0 replies; 5+ messages in thread
From: Jia-Ju Bai @ 2018-04-12 1:49 UTC (permalink / raw)
To: Florian Fainelli, Phil Reid, andrew, vivien.didelot; +Cc: netdev, linux-kernel
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
^ permalink raw reply [flat|nested] 5+ messages in thread
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2018-04-11 1:51 [PATCH] net: dsa: b53: Replace mdelay with msleep in b53_switch_reset_gpio Jia-Ju Bai
2018-04-11 5:30 ` Phil Reid
2018-04-11 7:14 ` Jia-Ju Bai
2018-04-11 16:19 ` Florian Fainelli
2018-04-12 1:49 ` Jia-Ju Bai
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