Commit bfe17231 authored May 31, 2010 by FUJITA Tomonori Committed by Jens Axboe Aug 07, 2010

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>

parent b375a612

include/linux/blkdev.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -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

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