diff mbox series

[v8,4/5] block: add a helper function to merge the segments

Message ID 1563859608-19456-5-git-send-email-yoshihiro.shimoda.uh@renesas.com (mailing list archive)
State New, archived
Headers show
Series treewide: improve R-Car SDHI performance | expand

Commit Message

Yoshihiro Shimoda July 23, 2019, 5:26 a.m. UTC 
This patch adds a helper function whether a queue can merge
the segments by the DMA MAP layer (e.g. via IOMMU).

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-settings.c   | 22 ++++++++++++++++++++++
 include/linux/blkdev.h |  2 ++
 2 files changed, 24 insertions(+)

Comments

Simon Horman July 25, 2019, 6:33 a.m. UTC | #1 
On Tue, Jul 23, 2019 at 02:26:47PM +0900, Yoshihiro Shimoda wrote:
> This patch adds a helper function whether a queue can merge
> the segments by the DMA MAP layer (e.g. via IOMMU).
> 
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
diff mbox series

Patch

diff --git a/block/blk-settings.c b/block/blk-settings.c
index 45f2c52..6a78ea0 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -4,6 +4,7 @@ 
  */
 #include <linux/bio.h>
 #include <linux/blkdev.h>
+#include <linux/dma-mapping.h>
 #include <linux/gcd.h>
 #include <linux/gfp.h>
 #include <linux/init.h>
@@ -831,6 +832,27 @@  void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
 }
 EXPORT_SYMBOL_GPL(blk_queue_write_cache);
 
+/**
+ * blk_queue_can_use_dma_map_merging - configure queue for merging segments.
+ * @q:		the request queue for the device
+ * @dev:	the device pointer for dma
+ *
+ * Tell the block layer about merging the segments by dma map of @q.
+ */
+bool blk_queue_can_use_dma_map_merging(struct request_queue *q,
+				       struct device *dev)
+{
+	unsigned long boundary = dma_get_merge_boundary(dev);
+
+	if (!boundary)
+		return false;
+
+	/* No need to update max_segment_size. see blk_queue_virt_boundary() */
+	blk_queue_virt_boundary(q, boundary);
+
+	return true;
+}
+
 static int __init blk_settings_init(void)
 {
 	blk_max_low_pfn = max_low_pfn - 1;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1ef375d..f6d55e2 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1085,6 +1085,8 @@  extern void blk_queue_dma_alignment(struct request_queue *, int);
 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
 extern void blk_queue_write_cache(struct request_queue *q, bool enabled, bool fua);
+extern bool blk_queue_can_use_dma_map_merging(struct request_queue *q,
+					      struct device *dev);
 
 /*
  * Number of physical segments as sent to the device.