iommu sg merging: add accessors for segment_boundary_mask in device_dma_parameters()
This adds new accessors for segment_boundary_mask in device_dma_parameters
structure in the same way I did for max_segment_size. So we can easily change
where to place struct device_dma_parameters in the future.
dma_get_segment boundary returns 0xffffffff if dma_parms in struct device
isn't set up properly. 0xffffffff is the default value used in the block
layer and the scsi mid layer.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index df3a361..3320307 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -75,6 +75,21 @@
return -EIO;
}
+static inline unsigned long dma_get_seg_boundary(struct device *dev)
+{
+ return dev->dma_parms ?
+ dev->dma_parms->segment_boundary_mask : 0xffffffff;
+}
+
+static inline int dma_set_seg_boundary(struct device *dev, unsigned long mask)
+{
+ if (dev->dma_parms) {
+ dev->dma_parms->segment_boundary_mask = mask;
+ return 0;
+ } else
+ return -EIO;
+}
+
/* flags for the coherent memory api */
#define DMA_MEMORY_MAP 0x01
#define DMA_MEMORY_IO 0x02