[PATCH v6 06/18] dm: Add support for block PR read keys/reservation

[Mike Christie <michael.christie@oracle.com>]

This adds support in dm for the block PR read keys and read reservation
callouts.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
---
 drivers/md/dm.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index dfde0088147a..b4103cb6eb9a 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -3119,6 +3119,8 @@ struct dm_pr {
 	bool	fail_early;
 	int	ret;
 	enum pr_type type;
+	struct pr_keys *read_keys;
+	struct pr_held_reservation *rsv;
 };
 
 static int dm_call_pr(struct block_device *bdev, iterate_devices_callout_fn fn,
@@ -3351,12 +3353,79 @@ static int dm_pr_clear(struct block_device *bdev, u64 key)
 	return r;
 }
 
+static int __dm_pr_read_keys(struct dm_target *ti, struct dm_dev *dev,
+			     sector_t start, sector_t len, void *data)
+{
+	struct dm_pr *pr = data;
+	const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
+
+	if (!ops || !ops->pr_read_keys) {
+		pr->ret = -EOPNOTSUPP;
+		return -1;
+	}
+
+	pr->ret = ops->pr_read_keys(dev->bdev, pr->read_keys);
+	if (!pr->ret)
+		return -1;
+
+	return 0;
+}
+
+static int dm_pr_read_keys(struct block_device *bdev, struct pr_keys *keys)
+{
+	struct dm_pr pr = {
+		.read_keys = keys,
+	};
+	int ret;
+
+	ret = dm_call_pr(bdev, __dm_pr_read_keys, &pr);
+	if (ret)
+		return ret;
+
+	return pr.ret;
+}
+
+static int __dm_pr_read_reservation(struct dm_target *ti, struct dm_dev *dev,
+				    sector_t start, sector_t len, void *data)
+{
+	struct dm_pr *pr = data;
+	const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
+
+	if (!ops || !ops->pr_read_reservation) {
+		pr->ret = -EOPNOTSUPP;
+		return -1;
+	}
+
+	pr->ret = ops->pr_read_reservation(dev->bdev, pr->rsv);
+	if (!pr->ret)
+		return -1;
+
+	return 0;
+}
+
+static int dm_pr_read_reservation(struct block_device *bdev,
+				  struct pr_held_reservation *rsv)
+{
+	struct dm_pr pr = {
+		.rsv = rsv,
+	};
+	int ret;
+
+	ret = dm_call_pr(bdev, __dm_pr_read_reservation, &pr);
+	if (ret)
+		return ret;
+
+	return pr.ret;
+}
+
 static const struct pr_ops dm_pr_ops = {
 	.pr_register	= dm_pr_register,
 	.pr_reserve	= dm_pr_reserve,
 	.pr_release	= dm_pr_release,
 	.pr_preempt	= dm_pr_preempt,
 	.pr_clear	= dm_pr_clear,
+	.pr_read_keys	= dm_pr_read_keys,
+	.pr_read_reservation = dm_pr_read_reservation,
 };
 
 static const struct block_device_operations dm_blk_dops = {
-- 
2.25.1