From: Keith Busch <kbusch@kernel.org>

User space may want to know how to align their buffers to avoid
bouncing. Export the queue attribute.

Signed-off-by: Keith Busch <kbusch@kernel.org>
---
  block/blk-sysfs.c | 7 +++++++
  1 file changed, 7 insertions(+)

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 88bd41d4cb59..14607565d781 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c

@@ -274,6 +274,11 @@ static ssize_t queue_virt_boundary_mask_show(struct request_queue *q, char *page
  	return queue_var_show(q->limits.virt_boundary_mask, page);
  }
  
+static ssize_t queue_dma_alignment_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(queue_dma_alignment(q), page);
+}
+
  #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)				\
  static ssize_t								\
  queue_##name##_show(struct request_queue *q, char *page)		\

@@ -606,6 +611,7 @@ QUEUE_RO_ENTRY(queue_dax, "dax");
  QUEUE_RW_ENTRY(queue_io_timeout, "io_timeout");
  QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");
  QUEUE_RO_ENTRY(queue_virt_boundary_mask, "virt_boundary_mask");
+QUEUE_RO_ENTRY(queue_dma_alignment, "dma_alignment");
  
  #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
  QUEUE_RW_ENTRY(blk_throtl_sample_time, "throttle_sample_time");

@@ -667,6 +673,7 @@ static struct attribute *queue_attrs[] = {
  	&blk_throtl_sample_time_entry.attr,
  #endif
  	&queue_virt_boundary_mask_entry.attr,
+	&queue_dma_alignment_entry.attr,
  	NULL,
  };