> On Fri, Mar 08, 2002 at 06:59:57PM +0530, V Ganesh wrote:
> > hi,
> > I noticed that usb_submit_urb() is supposed to be used with a GFP
> > flag, which ought to be GFP_ATOMIC if called from an interrupt handler or
> > bottom half. however, a grep of GFP_ATOMIC in drivers/usb/serial/* in greg's
> > 2.5 tree draws a total blank. I would have thought a function like
> > visor_read_bulk_callback() should have used GFP_ATOMIC rather than GFP_KERNEL
> > to resubmit the bulk read urb. could someone please clarify this?
>
> Like Oliver said, you are right. Want to make a patch to fix all of
> drivers/usb/serial/* ?
>
> thanks,
>
> greg k-h
I'm halfway through. this is the approach I'm using, please comment:
1. all *_callback() functions must use GFP_ATOMIC.
2. anything inside a spinlock must use GFP_ATOMIC.
3. *_open(), *_startup(), *_set_termios() use GFP_KERNEL.
4. *_write(), *_unthrottle() can be called from user context as well as
bottom half context. so I define a macro in usb-serial.h
#define ALLOC_FLAGS (in_interrupt() ? GFP_ATOMIC : GFP_KERNEL)
and use it in these functions. the alternative is to always do a
GFP_ATOMIC.
thanks,
ganesh
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