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

On Mon, Jun 27, 2022 at 08:12:38AM +0200, Greg KH wrote:

quoted

On Sun, Jun 26, 2022 at 09:53:33PM -0700, Arun Vijayshankar wrote:

quoted

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 <redacted>
---
 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