Messages in this thread | | | Date | Mon, 11 Mar 2013 23:52:08 +0800 | Subject | Re: [PATCH] usb/core/devio.c: Don't use GFP_KERNEL while we cannot reset a storage device | From | Ming Lei <> |
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On Mon, Mar 11, 2013 at 11:32 PM, Alan Stern <stern@rowland.harvard.edu> 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
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