* [PATCH 1/3] mmc: wbsd: Replace mdelay with usleep_range in wbsd_init
@ 2018-04-11 2:46 Jia-Ju Bai
2018-04-11 15:04 ` Ulf Hansson
0 siblings, 1 reply; 3+ messages in thread
From: Jia-Ju Bai @ 2018-04-11 2:46 UTC (permalink / raw)
To: pierre, ulf.hansson; +Cc: linux-mmc, linux-kernel, Jia-Ju Bai
wbsd_init() is never called in atomic context.
The call chains ending up at wbsd_init() are:
[1] wbsd_init() <- wbsd_probe()
[2] wbsd_init() <- wbsd_pnp_probe()
wbsd_probe() is set as ".probe" in struct platform_driver.
wbsd_pnp_probe() is set as ".probe" in struct pnp_driver.
These functions are not called in atomic context.
Despite never getting called from atomic context, wbsd_init()
calls mdelay() to busily wait.
This is not necessary and can be replaced with usleep_range() 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/mmc/host/wbsd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/mmc/host/wbsd.c b/drivers/mmc/host/wbsd.c
index 546aaf8..6224d12 100644
--- a/drivers/mmc/host/wbsd.c
+++ b/drivers/mmc/host/wbsd.c
@@ -1709,7 +1709,7 @@ static int wbsd_init(struct device *dev, int base, int irq, int dma,
/*
* Allow device to initialise itself properly.
*/
- mdelay(5);
+ usleep_range(5000, 6000);
/*
* Reset the chip into a known state.
--
1.9.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 1/3] mmc: wbsd: Replace mdelay with usleep_range in wbsd_init
2018-04-11 2:46 [PATCH 1/3] mmc: wbsd: Replace mdelay with usleep_range in wbsd_init Jia-Ju Bai
@ 2018-04-11 15:04 ` Ulf Hansson
2018-04-12 1:34 ` Jia-Ju Bai
0 siblings, 1 reply; 3+ messages in thread
From: Ulf Hansson @ 2018-04-11 15:04 UTC (permalink / raw)
To: Jia-Ju Bai; +Cc: Pierre Ossman, linux-mmc, Linux Kernel Mailing List
On 11 April 2018 at 04:46, Jia-Ju Bai <baijiaju1990@gmail.com> wrote:
> wbsd_init() is never called in atomic context.
>
> The call chains ending up at wbsd_init() are:
> [1] wbsd_init() <- wbsd_probe()
> [2] wbsd_init() <- wbsd_pnp_probe()
>
> wbsd_probe() is set as ".probe" in struct platform_driver.
> wbsd_pnp_probe() is set as ".probe" in struct pnp_driver.
> These functions are not called in atomic context.
>
> Despite never getting called from atomic context, wbsd_init()
> calls mdelay() to busily wait.
> This is not necessary and can be replaced with usleep_range() 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>
The patch is good, however I think you should squash all three in this
series into one. For obvious reasons.
Kind regards
Uffe
> ---
> drivers/mmc/host/wbsd.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/wbsd.c b/drivers/mmc/host/wbsd.c
> index 546aaf8..6224d12 100644
> --- a/drivers/mmc/host/wbsd.c
> +++ b/drivers/mmc/host/wbsd.c
> @@ -1709,7 +1709,7 @@ static int wbsd_init(struct device *dev, int base, int irq, int dma,
> /*
> * Allow device to initialise itself properly.
> */
> - mdelay(5);
> + usleep_range(5000, 6000);
>
> /*
> * Reset the chip into a known state.
> --
> 1.9.1
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 1/3] mmc: wbsd: Replace mdelay with usleep_range in wbsd_init
2018-04-11 15:04 ` Ulf Hansson
@ 2018-04-12 1:34 ` Jia-Ju Bai
0 siblings, 0 replies; 3+ messages in thread
From: Jia-Ju Bai @ 2018-04-12 1:34 UTC (permalink / raw)
To: Ulf Hansson; +Cc: Pierre Ossman, linux-mmc, Linux Kernel Mailing List
On 2018/4/11 23:04, Ulf Hansson wrote:
> On 11 April 2018 at 04:46, Jia-Ju Bai <baijiaju1990@gmail.com> wrote:
>> wbsd_init() is never called in atomic context.
>>
>> The call chains ending up at wbsd_init() are:
>> [1] wbsd_init() <- wbsd_probe()
>> [2] wbsd_init() <- wbsd_pnp_probe()
>>
>> wbsd_probe() is set as ".probe" in struct platform_driver.
>> wbsd_pnp_probe() is set as ".probe" in struct pnp_driver.
>> These functions are not called in atomic context.
>>
>> Despite never getting called from atomic context, wbsd_init()
>> calls mdelay() to busily wait.
>> This is not necessary and can be replaced with usleep_range() 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>
> The patch is good, however I think you should squash all three in this
> series into one. For obvious reasons.
Hello, Ulf.
Thanks for your reply and advice :)
I will follow it in my future patches.
Best wishes,
Jia-Ju Bai
^ permalink raw reply [flat|nested] 3+ messages in thread
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2018-04-11 2:46 [PATCH 1/3] mmc: wbsd: Replace mdelay with usleep_range in wbsd_init Jia-Ju Bai
2018-04-11 15:04 ` Ulf Hansson
2018-04-12 1:34 ` Jia-Ju Bai
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