[PATCH] staging: qlge: replace msleep with usleep_range

[PATCH] staging: qlge: replace msleep with usleep_range

[Arun Vijayshankar]

qlge_close uses msleep for 1ms, in which case (1 - 20ms) it is preferable
to use usleep_range in non-atomic contexts, as documented in
Documentation/timers/timers-howto.rst. A range of 1 - 1.05ms is
specified here, in case the device takes slightly longer than 1ms to recover from
reset.

Signed-off-by: Arun Vijayshankar <arunvijayshankar@gmail.com>
---
 drivers/staging/qlge/qlge_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/qlge/qlge_main.c b/drivers/staging/qlge/qlge_main.c
index 689a87d58f27..3cc4f1902c80 100644
--- a/drivers/staging/qlge/qlge_main.c
+++ b/drivers/staging/qlge/qlge_main.c
@@ -3886,7 +3886,7 @@ static int qlge_close(struct net_device *ndev)
 	 * (Rarely happens, but possible.)
 	 */
 	while (!test_bit(QL_ADAPTER_UP, &qdev->flags))
-		msleep(1);
+		usleep_range(1000, 1050);
 
 	/* Make sure refill_work doesn't re-enable napi */
 	for (i = 0; i < qdev->rss_ring_count; i++)
-- 
2.34.1

Re: [PATCH] staging: qlge: replace msleep with usleep_range

[Greg KH]

On Sun, Jun 26, 2022 at 09:53:33PM -0700, Arun Vijayshankar wrote:
> qlge_close uses msleep for 1ms, in which case (1 - 20ms) it is preferable
> to use usleep_range in non-atomic contexts, as documented in
> Documentation/timers/timers-howto.rst. A range of 1 - 1.05ms is
> specified here, in case the device takes slightly longer than 1ms to recover from
> reset.
> 
> Signed-off-by: Arun Vijayshankar <arunvijayshankar@gmail.com>
> ---
>  drivers/staging/qlge/qlge_main.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/qlge/qlge_main.c b/drivers/staging/qlge/qlge_main.c
> index 689a87d58f27..3cc4f1902c80 100644
> --- a/drivers/staging/qlge/qlge_main.c
> +++ b/drivers/staging/qlge/qlge_main.c
> @@ -3886,7 +3886,7 @@ static int qlge_close(struct net_device *ndev)
>  	 * (Rarely happens, but possible.)
>  	 */
>  	while (!test_bit(QL_ADAPTER_UP, &qdev->flags))
> -		msleep(1);
> +		usleep_range(1000, 1050);

Have you tested this with a device?  Doing these types of changes
without access to the hardware isn't a good idea.

Also, a loop that has the chance to never end should be fixed up, don't
you think?

thanks,

greg k-h

Re: [PATCH] staging: qlge: replace msleep with usleep_range

[Arun Vijayshankar]

On Mon, Jun 27, 2022 at 08:12:38AM +0200, Greg KH wrote:
>> On Sun, Jun 26, 2022 at 09:53:33PM -0700, Arun Vijayshankar wrote:
>>> qlge_close uses msleep for 1ms, in which case (1 - 20ms) it is preferable
>>> to use usleep_range in non-atomic contexts, as documented in
>>> Documentation/timers/timers-howto.rst. A range of 1 - 1.05ms is
>>> specified here, in case the device takes slightly longer than 1ms to recover from
>>> reset.
>>>
>>> Signed-off-by: Arun Vijayshankar <arunvijayshankar@gmail.com>
>>> ---
>>>  drivers/staging/qlge/qlge_main.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/staging/qlge/qlge_main.c b/drivers/staging/qlge/qlge_main.c
>>> index 689a87d58f27..3cc4f1902c80 100644
>>> --- a/drivers/staging/qlge/qlge_main.c
>>> +++ b/drivers/staging/qlge/qlge_main.c
>>> @@ -3886,7 +3886,7 @@ static int qlge_close(struct net_device *ndev)
>>>  	 * (Rarely happens, but possible.)
>>>  	 */
>>>  	while (!test_bit(QL_ADAPTER_UP, &qdev->flags))
>>> -		msleep(1);
>>> +		usleep_range(1000, 1050);
>> Have you tested this with a device?  Doing these types of changes
>> without access to the hardware isn't a good idea.
>>
>> Also, a loop that has the chance to never end should be fixed up, don't
>> you think?
>>
>> thanks,
>>
>> greg k-h
> I have not tested the change with the hardware. I have checked that the module loads on my PC, but I do not have the actual adapter
> to test it out. Would you mind sharing any pointers on testing changes on the actual device if I don't have the specific device?
> I tried to find an emulator or virtual device for the QL adapter, but there doesn't seem to be any. Sorry if this is a very basic 
> question. This is my first patch ever. If there isn't a good way to test the changes with hardware, would you recommend withdrawing it?
>
> Thanks for pointing out the potential runaway loop. I'm a little embarrased on having missed it. I can add a timeout if the device doesn't 
> recover within a given time, but I was wondering if there is a better way of doing it?
>
> Best regards
> Arun Vijayshankar