[PATCH] remove kiobufs

[PATCH] remove kiobufs

This patch from Christoph Hellwig removes the kiobuf/kiovec
infrastructure.

This affects three subsystems:

video-buf.c:

   This patch includes an earlier diff from Gerd which converts
    video-buf.c to use get_user_pages() directly.

   Gerd has acked this patch.

LVM1:

   Is now even more broken.

drivers/mtd/devices/blkmtd.c:

   blkmtd is broken by this change.  I contacted Simon Evans, who
   said "I had done a rewrite of blkmtd anyway and just need to convert
   it to BIO.  Feel free to break it in the 2.5 tree, it will force me
   to finish my code."

Neither EVMS nor LVM2 use kiobufs.  The only remaining breakage
of which I am aware is a proprietary MPEG2 streaming module.  It
could use get_user_pages().