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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: linux-renesas-soc@vger.kernel.org, linux-mmc@vger.kernel.org,
	linux-block@vger.kernel.org, wsa+renesas@sang-engineering.com,
	iommu@lists.linux-foundation.org
Subject: [PATCH v9 4/5] block: add a helper function to merge the segments
Date: Fri, 26 Jul 2019 17:31:15 +0900
Message-ID: <1564129876-28261-5-git-send-email-yoshihiro.shimoda.uh@renesas.com> (raw)
In-Reply-To: <1564129876-28261-1-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>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
---
 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

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  parent reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-26  8:31 [PATCH v9 0/5] treewide: improve R-Car SDHI performance Yoshihiro Shimoda
2019-07-26  8:31 ` [PATCH v9 1/5] dma: Introduce dma_get_merge_boundary() Yoshihiro Shimoda
2019-07-26  8:31 ` [PATCH v9 2/5] iommu/dma: Add a new dma_map_ops of get_merge_boundary() Yoshihiro Shimoda
2019-08-16 19:48   ` Wolfram Sang
2019-08-19 12:45   ` Joerg Roedel
2019-08-19 12:54   ` Robin Murphy
2019-08-20  1:42     ` Yoshihiro Shimoda
2019-07-26  8:31 ` [PATCH v9 3/5] block: sort headers on blk-setting.c Yoshihiro Shimoda
2019-08-16 19:50   ` Wolfram Sang
2019-08-19 14:53     ` Jens Axboe
2019-08-20  1:50       ` Yoshihiro Shimoda
2019-08-22  9:35       ` Wolfram Sang
2019-07-26  8:31 ` Yoshihiro Shimoda [this message]
2019-07-26  8:31 ` [PATCH v9 5/5] mmc: queue: Use bigger segments if DMA MAP layer can merge the segments Yoshihiro Shimoda
2019-08-15  7:30 ` [PATCH v9 0/5] treewide: improve R-Car SDHI performance Christoph Hellwig

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