On Thu, 11 Nov 1999 12:08:25 +0100 (CET), Ingo Molnar
<mingo@chiara.csoma.elte.hu> said:
> On Thu, 11 Nov 1999, Keith Owens wrote:
>> Trying to port the SGI lcrash code to 2.3.26 ix86. It compiles, runs,
>> traps the oops, starts writing the dump to swap, dies with -EFAULT in
>> sd_raw_rw. My guess is because the buffer address is c2c00000, i.e. I
>> am trying to do I/O directly from kernel pages, not from user space.
>> sd_raw_rw() calls map_user_kiobuf() which is perfect for user space
>> callers, no good for kernel callers. How do I get around this?
> yes, map_user_kiobuf() works only on user addresses.
SGI's code added support for other address spaces in kiobufs. Either
way, the addresses you pass to IO functions should be kernel virtual
addresses anyway if you are passing kiobufs.
I'm actually working on the kiobuf code right now, mainly to separate
out the locking of pages from the mapping of virtual addresses, and
getting kernel VA mapping functions in place is one thing I'm merging.
--Stephen
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