Re: [PATCH] usbnet: ignore get interface retval of -EINPROGRESS

Oliver,

Thanks for the quick feedback.  True usbnet_start_xmit() could be
running at anytime, but the usb_autopm_get_interface_async() will only
return -EINPROGRESS when rpm_resume detects that
dev->power.runtime_status == RPM_RESUMING.  My understanding is that
for an asynchronous request, the promise that the device is resuming
would be equivalent to cases where usb_autopm_get_interface_async()
returns success.

In all other cases, when we are not attempting to resume an already
resuming interface, this change should have no impact.

Are you recommending that I add an additional check for DEV_ASLEEP,
possibly to decide whether to drop the or continue on?  Or am I
missing your point?  I had not done anything similar because my
understanding was that knowing that the device is in fact resuming
would be sufficient.

Jim

On Sat, Sep 3, 2011 at 11:37 AM, Oliver Neukum [off-list ref] wrote:

Am Samstag, 3. September 2011, 16:21:00 schrieb Jim Wylder:

quoted

When calling pm_runtime_get, usb_autopm_get_interface_async
treats a return value of -EINPROGRESS as a success and
increments the usage count.  Since the interface is resuming,
it is safe for usbnet_start_xmit to submit the urb.

usbnet_start_xmit() is exported, so simply stating that it is
called when the interface is resumingisn't enough. It seems to
me that the later check for DEV_ASLEEP will save as, but have
you checked for that?

       Regards
               Oliver