Merge branch 'for-2.6.25' of git://git.kernel.dk/linux-2.6-block
* 'for-2.6.25' of git://git.kernel.dk/linux-2.6-block:
block: implement drain buffers
__bio_clone: don't calculate hw/phys segment counts
block: allow queue dma_alignment of zero
blktrace: Add blktrace ioctls to SCSI generic devices