Re: [PATCH] usb/core/devio.c: Don't use GFP_KERNEL while we cannotreset a storage device

[Ming Lei]

On Mon, Mar 11, 2013 at 11:32 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
>
> Of course you have to lock the device before changing its driver.  What
> would happen if two different threads tried to change a device's driver
> at the same time?

Yes, claim/release interface need device lock, but the patch doesn't
touch claim/release command handling.

>
> usbdev_do_ioctl() needs to acquire the device lock in order to prevent
> races with driver_disconnect() and usbdev_remove().

Looks the patch basically converts the allocation inside URB submit path,
and actually I mean why we need to hold device lock in submitting
URB path?  Device lock isn't required before submitting URBs
in kernel driver.


Thanks,
-- 
Ming Lei
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/