Re: do_exit() and lock_kernel() semantics

Manfred Spraul (
Mon, 25 Mar 2002 21:13:15 +0100

> Thus, for each receive we have to convert the virt address of the
> user-land receive buffer to a physical address (in the kernel region)
> before doing the memcpy (copy_to_user doesn't work from interrupt
> context).

Why do you want to do that at interrupt time?
I'd call map_user_kiobuf() when the user-land buffer is set up, and then
write directly (i.e. with kmap_atomic()) into the pages stored in
iobuf->maplist[]. It avoids the page table scan at interrupt time.

Which platform do you use? map_user_kiobuf() doesn't enforce cache
coherency internally, outside of i386 you might need additional
flush_cache_whatever (see Documentation/cachetlb.txt)


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