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| author | Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> | 2019-08-28 21:35:42 +0900 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2019-09-03 08:32:50 +0200 |
| commit | 45147fb522bb459e79bdcb7504ee7ec8cfd4c12c (patch) | |
| tree | 5b02f6cc1daaaf79add184033aa31d399e8909ca | |
| parent | db91427b6502e8e46db4b616e4eaa9b9cf4e6363 (diff) | |
| download | linux-45147fb522bb459e79bdcb7504ee7ec8cfd4c12c.tar.bz2 | |
block: add a helper function to merge the segments
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
Signed-off-by: Christoph Hellwig <hch@lst.de>
| -rw-r--r-- | block/blk-settings.c | 23 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 2 |
2 files changed, 25 insertions, 0 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c index 2c1831207a8f..c3632fc6d540 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -12,6 +12,7 @@ #include <linux/lcm.h> #include <linux/jiffies.h> #include <linux/gfp.h> +#include <linux/dma-mapping.h> #include "blk.h" #include "blk-wbt.h" @@ -832,6 +833,28 @@ 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; +} +EXPORT_SYMBOL_GPL(blk_queue_can_use_dma_map_merging); + 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 1ef375dafb1c..f6d55e2490dc 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. |