+ scsi-53c700-remove-dma_is_consistent-usage.patch added to -mm tree

[akpm@linux-foundation.org]

The patch titled
     scsi: 53c700: remove dma_is_consistent usage
has been added to the -mm tree.  Its filename is
     scsi-53c700-remove-dma_is_consistent-usage.patch

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------------------------------------------------------
Subject: scsi: 53c700: remove dma_is_consistent usage
From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

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>
---

 drivers/scsi/53c700.c |    3 ---
 1 file changed, 3 deletions(-)

diff -puN drivers/scsi/53c700.c~scsi-53c700-remove-dma_is_consistent-usage drivers/scsi/53c700.c
--- a/drivers/scsi/53c700.c~scsi-53c700-remove-dma_is_consistent-usage
+++ a/drivers/scsi/53c700.c
@@ -309,9 +309,6 @@ NCR_700_detect(struct scsi_host_template
 	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;
 
_

Patches currently in -mm which might be from fujita.tomonori@lab.ntt.co.jp are

origin.patch
dma-mapping-rename-arch_kmalloc_minalign-to-arch_dma_minalign.patch
dma-mapping-unify-dma_get_cache_alignment-implementations.patch
dma-mapping-parisc-set-arch_dma_minalign.patch
scsi-53c700-remove-dma_is_consistent-usage.patch
dma-mapping-remove-dma_is_consistent-api.patch
documentation-dma-api-howtotxt-add-multiple-types-of-iommus-support.patch
pci-add-pci-dma-unamp-state-api-to-feature-removal-scheduletxt.patch
dma-mapping-add-dma_xxbit_mask-to-feature-removal-scheduletxt.patch