Re: [PATCH 1/3] mmc: wbsd: Replace mdelay with usleep_range in wbsd_init

2018-04-11 Thread Jia-Ju Bai



On 2018/4/11 23:04, Ulf Hansson wrote:

On 11 April 2018 at 04:46, Jia-Ju Bai  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 

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


Re: [PATCH 1/3] mmc: wbsd: Replace mdelay with usleep_range in wbsd_init

2018-04-11 Thread Ulf Hansson
On 11 April 2018 at 04:46, Jia-Ju Bai  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 

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
>