dm: do not override error code returned from dm_get_device()

Some of the device mapper targets override the error code returned by
dm_get_device() and return either -EINVAL or -ENXIO.  There is nothing
gained by this override.  It is better to propagate the returned error
code unchanged to caller.

This work was motivated by hitting an issue where the underlying device
was busy but -EINVAL was being returned.  After this change we get
-EBUSY instead and it is easier to figure out the problem.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 53e848c..62c26e4 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -30,6 +30,7 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	struct linear_c *lc;
 	unsigned long long tmp;
 	char dummy;
+	int ret;
 
 	if (argc != 2) {
 		ti->error = "Invalid argument count";
@@ -42,13 +43,15 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		return -ENOMEM;
 	}
 
+	ret = -EINVAL;
 	if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1) {
 		ti->error = "dm-linear: Invalid device sector";
 		goto bad;
 	}
 	lc->start = tmp;
 
-	if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev)) {
+	ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev);
+	if (ret) {
 		ti->error = "dm-linear: Device lookup failed";
 		goto bad;
 	}
@@ -61,7 +64,7 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
       bad:
 	kfree(lc);
-	return -EINVAL;
+	return ret;
 }
 
 static void linear_dtr(struct dm_target *ti)