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block: kill ISA_DMA_THRESHOLD usage

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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>
This commit is contained in:
FUJITA Tomonori 2010-05-31 15:59:03 +09:00 committed by Jens Axboe
parent b375a612ad
commit bfe172310e
1 changed files with 1 additions and 1 deletions
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2
include/linux/blkdev.h
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@ -712,7 +712,7 @@ extern unsigned long blk_max_low_pfn, blk_max_pfn;
#define BLK_BOUNCE_HIGH -1ULL
#endif
#define BLK_BOUNCE_ANY (-1ULL)
#define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
#define BLK_BOUNCE_ISA (DMA_BIT_MASK(24))
/*
* default timeout for SG_IO if none specified