Whether this is set or not is important for whether good performance is
possible, when using the block device as a backstore for the kernel
target. Exposing this will let kernel target configuration tools provide
this information to the user when configuring LIO targets.
Reviewed-by: Chris Leech <cleech@xxxxxxxxxx>
Signed-off-by: Andy Grover <agrover@xxxxxxxxxx>
---
block/genhd.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/block/genhd.c b/block/genhd.c
index 791f419..258fadc 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -958,6 +958,14 @@ static ssize_t disk_capability_show(struct device *dev,
return sprintf(buf, "%x\n", disk->flags);
}
+static ssize_t req_flush_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+
+ return sprintf(buf, "%x\n", !!(disk->queue->flush_flags & REQ_FLUSH));
+}
+
static ssize_t disk_alignment_offset_show(struct device *dev,
struct device_attribute *attr,
char *buf)
@@ -985,6 +993,7 @@ static DEVICE_ATTR(alignment_offset, S_IRUGO, disk_alignment_offset_show, NULL);
static DEVICE_ATTR(discard_alignment, S_IRUGO, disk_discard_alignment_show,
NULL);
static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL);
+static DEVICE_ATTR(req_flush, S_IRUGO, req_flush_show, NULL);
static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
#ifdef CONFIG_FAIL_MAKE_REQUEST
@@ -1006,6 +1015,7 @@ static struct attribute *disk_attrs[] = {
&dev_attr_alignment_offset.attr,
&dev_attr_discard_alignment.attr,
&dev_attr_capability.attr,
+ &dev_attr_req_flush.attr,
&dev_attr_stat.attr,
&dev_attr_inflight.attr,
#ifdef CONFIG_FAIL_MAKE_REQUEST
--
1.9.0
--
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