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From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
To: ulf.hansson@linaro.org, hch@lst.de, m.szyprowski@samsung.com,
	robin.murphy@arm.com, joro@8bytes.org, axboe@kernel.dk
Cc: wsa+renesas@sang-engineering.com, linux-mmc@vger.kernel.org,
	iommu@lists.linux-foundation.org, linux-block@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Subject: [PATCH v8 4/5] block: add a helper function to merge the segments
Date: Tue, 23 Jul 2019 14:26:47 +0900	[thread overview]
Message-ID: <1563859608-19456-5-git-send-email-yoshihiro.shimoda.uh@renesas.com> (raw)
In-Reply-To: <1563859608-19456-1-git-send-email-yoshihiro.shimoda.uh@renesas.com>

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(+)

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.
-- 
2.7.4


  parent reply	other threads:[~2019-07-23  5:27 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-23  5:26 [PATCH v8 0/5] treewide: improve R-Car SDHI performance Yoshihiro Shimoda
2019-07-23  5:26 ` [PATCH v8 1/5] dma: Introduce dma_get_merge_boundary() Yoshihiro Shimoda
2019-07-25  6:32   ` Simon Horman
2019-07-23  5:26 ` [PATCH v8 2/5] iommu/dma: Add a new dma_map_ops of get_merge_boundary() Yoshihiro Shimoda
2019-07-23  8:17   ` Sergei Shtylyov
2019-07-25  6:33     ` Simon Horman
2019-07-26  7:50     ` Yoshihiro Shimoda
2019-07-23  5:26 ` [PATCH v8 3/5] block: sort headers on blk-setting.c Yoshihiro Shimoda
2019-07-25  6:33   ` Simon Horman
2019-07-23  5:26 ` Yoshihiro Shimoda [this message]
2019-07-25  6:33   ` [PATCH v8 4/5] block: add a helper function to merge the segments Simon Horman
2019-07-23  5:26 ` [PATCH v8 5/5] mmc: queue: Use bigger segments if DMA MAP layer can " Yoshihiro Shimoda
2019-07-25  6:34   ` Simon Horman

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