Re: Problem with map_user_kiobuf() not mapping to physical memory

[Bjorn Wesen]

On Wed, 2 May 2001, Terry Barnaby wrote:
> However, I note that if the user just mallocs memory and does not access
> it
> (No physical memory pages created) and then passes this virtual address
> space
> to the driver which performs a map_user_kiobuf() on it, the resulting
> kiobuf
> structure has all of the pagelist[] physical address entries set to the
> same value
> and the maplist[] entries set to 0. The devices access to this memory
> now
> causes system problems.
> Is map_user_kiobuf() working correctly ?
> Should I call some function to map the virtual address space into
> physical memory
> or at least pages before I call map_user_kiobuf() ?

No.. but you might just have done something wrong.

See the example in arch/cris/drivers/examples/kiobuftest.c

(that example does not deallocate the vectors properly IIRC, but the
actual kiobuf mapping sequence should work)

/BW