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, 11 insertions, 5 deletions

diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c
index 57b6a19..b34f6e2 100644
--- a/drivers/md/dm-delay.c
+++ b/drivers/md/dm-delay.c
@@ -129,6 +129,7 @@ static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	struct delay_c *dc;
 	unsigned long long tmpll;
 	char dummy;
+	int ret;
 
 	if (argc != 3 && argc != 6) {
 		ti->error = "requires exactly 3 or 6 arguments";
@@ -143,6 +144,7 @@ static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
 	dc->reads = dc->writes = 0;
 
+	ret = -EINVAL;
 	if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1) {
 		ti->error = "Invalid device sector";
 		goto bad;
@@ -154,12 +156,14 @@ static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto bad;
 	}
 
-	if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
-			  &dc->dev_read)) {
+	ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
+			    &dc->dev_read);
+	if (ret) {
 		ti->error = "Device lookup failed";
 		goto bad;
 	}
 
+	ret = -EINVAL;
 	dc->dev_write = NULL;
 	if (argc == 3)
 		goto out;
@@ -175,13 +179,15 @@ static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto bad_dev_read;
 	}
 
-	if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table),
-			  &dc->dev_write)) {
+	ret = dm_get_device(ti, argv[3], dm_table_get_mode(ti->table),
+			    &dc->dev_write);
+	if (ret) {
 		ti->error = "Write device lookup failed";
 		goto bad_dev_read;
 	}
 
 out:
+	ret = -EINVAL;
 	dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
 	if (!dc->kdelayd_wq) {
 		DMERR("Couldn't start kdelayd");
@@ -208,7 +214,7 @@ bad_dev_read:
 	dm_put_device(ti, dc->dev_read);
 bad:
 	kfree(dc);
-	return -EINVAL;
+	return ret;
 }
 
 static void delay_dtr(struct dm_target *ti)