scsi: 53c700: remove dma_is_consistent usage

This driver is the only user of dma_is_consistent().  We plan to remove this
API.

The driver uses the API in the following way:

BUG_ON(!dma_is_consistent(hostdata->dev, pScript) && L1_CACHE_BYTES < dma_get_cache_alignment());

The above code tries to see if L1_CACHE_BYTES is greater than
dma_get_cache_alignment() on sysmtes that can not allocate coherent memory
(some old systems can't).

James Bottomley exmplained that this is necesary because the driver packs the
set of mailboxes into a single coherent area and separates the different
usages by a L1 cache stride.  So it's fatal if the dma

He also pointed out that we can kill this checking because we don't hit this
BUG_ON on all architectures that actually use the driver.

(akpm: stolen from the scsi tree because
dma-mapping-remove-dma_is_consistent-api.patch needs it)

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/scsi/53c700.c b/drivers/scsi/53c700.c
index 80dc3ac..89fc1c8 100644 (file)
--- a/drivers/scsi/53c700.c
+++ b/drivers/scsi/53c700.c
@@ -309,9 +309,6 @@ NCR_700_detect(struct scsi_host_template *tpnt,
        hostdata->msgin = memory + MSGIN_OFFSET;
        hostdata->msgout = memory + MSGOUT_OFFSET;
        hostdata->status = memory + STATUS_OFFSET;
-       /* all of these offsets are L1_CACHE_BYTES separated.  It is fatal
-        * if this isn't sufficient separation to avoid dma flushing issues */
-       BUG_ON(!dma_is_consistent(hostdata->dev, pScript) && L1_CACHE_BYTES < dma_get_cache_alignment());
        hostdata->slots = (struct NCR_700_command_slot *)(memory + SLOTS_OFFSET);
        hostdata->dev = dev;