[RFC/RFT PATCH 3/5] scsi: Use dma_max_pfn(dev) helper for bounce_limit calculations

[Santosh Shilimkar]

DMA bounce limit is the maximum direct DMA'able memory beyond which
bounce buffers has to be used to perform dma operations. SCSI driver
relies on dma_mask but its calculation is based on max_*pfn which
don't have uniform meaning across architectures. So make use of
dma_max_pfn() which is expected to return the DMAable maximum pfn
value across architectures.

Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: linux-scsi@xxxxxxxxxxxxxxx

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
---
 drivers/scsi/scsi_lib.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 86d5220..e8275fa 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1668,7 +1668,7 @@ u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
 
 	host_dev = scsi_get_device(shost);
 	if (host_dev && host_dev->dma_mask)
-		bounce_limit = *host_dev->dma_mask;
+		bounce_limit = dma_max_pfn(host_dev) << PAGE_SHIFT;
 
 	return bounce_limit;
 }
-- 
1.7.9.5

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