block: kill ISA_DMA_THRESHOLD usage
authorFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Mon, 31 May 2010 06:59:03 +0000 (15:59 +0900)
committerJens Axboe <jaxboe@fusionio.com>
Sat, 7 Aug 2010 16:15:49 +0000 (18:15 +0200)
commitbfe172310e58225f0d07f9354b683abacbd6a0d8
tree6f50393419bd29dabb27316e6875bc5715816789
parentb375a612ad931264b71cf162d692b4420f2578a9
block: kill ISA_DMA_THRESHOLD usage

block uses ISA_DMA_THRESHOLD for BLK_BOUNCE_ISA. Only SCSI uses
ISA_DMA_THRESHOLD for ancient drivers with non-zero
unchecked_isa_dma. Nowadays drivers (and subsystems) use dma_mask
properly instead of ISA_DMA_THRESHOLD.

Documentation/scsi/scsi_mid_low_api.txt says:

unchecked_isa_dma - 1=>only use bottom 16 MB of ram (ISA DMA addressing
                   restriction), 0=>can use full 32 bit (or better) DMA
                   address space

So block simply uses DMA_BIT_MASK(24) for BLK_BOUNCE_ISA for SCSI.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
include/linux/blkdev.h