rationalise return value for ->hot_add_disk method.

For all array types but linear, ->hot_add_disk returns 1 on
success, 0 on failure.
For linear, it returns 0 on success and -errno on failure.

This doesn't cause a functional problem because the ->hot_add_disk
function of linear is used quite differently to the others.
However it is confusing.

So convert all to return 0 for success or -errno on failure
and fix call sites to match.

Signed-off-by: Neil Brown <neilb@suse.de>

5 files changed, 21 insertions, 20 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 5d6fac1fd39..45e255d4916 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1977,10 +1977,8 @@ slot_store(mdk_rdev_t *rdev, const char *buf, size_t len)
                         rdev->saved_raid_disk = -1;
                 err = rdev->mddev->pers->
                         hot_add_disk(rdev->mddev, rdev);
-                if (err != 1) {
+                if (err) {
                         rdev->raid_disk = -1;
-                        if (err == 0)
-                                return -EEXIST;
                         return err;
                 }
                 sprintf(nm, "rd%d", rdev->raid_disk);
@@ -5920,7 +5918,8 @@ static int remove_and_add_spares(mddev_t *mddev)
                         if (rdev->raid_disk < 0
                             && !test_bit(Faulty, &rdev->flags)) {
                                 rdev->recovery_offset = 0;
-                                if (mddev->pers->hot_add_disk(mddev,rdev)) {
+                                if (mddev->pers->
+                                    hot_add_disk(mddev, rdev) == 0) {
                                         char nm[20];
                                         sprintf(nm, "rd%d", rdev->raid_disk);
                                         if (sysfs_create_link(&mddev->kobj,
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index 4a1d714c048..541cbe3414b 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -281,7 +281,7 @@ static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 {
         multipath_conf_t *conf = mddev->private;
         struct request_queue *q;
-        int found = 0;
+        int err = -EEXIST;
         int path;
         struct multipath_info *p;
         int first = 0;
@@ -312,11 +312,13 @@ static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                         rdev->raid_disk = path;
                         set_bit(In_sync, &rdev->flags);
                         rcu_assign_pointer(p->rdev, rdev);
-                        found = 1;
+                        err = 0;
+                        break;
                 }
 
         print_multipath_conf(conf);
-        return found;
+
+        return err;
 }
 
 static int multipath_remove_disk(mddev_t *mddev, int number)
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index d32fc559ff0..f05d5983efb 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1100,7 +1100,7 @@ static int raid1_spare_active(mddev_t *mddev)
 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 {
         conf_t *conf = mddev->private;
-        int found = 0;
+        int err = -EEXIST;
         int mirror = 0;
         mirror_info_t *p;
         int first = 0;
@@ -1124,7 +1124,7 @@ static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 
                         p->head_position = 0;
                         rdev->raid_disk = mirror;
-                        found = 1;
+                        err = 0;
                         /* As all devices are equivalent, we don't need a full recovery
                          * if this was recently any drive of the array
                          */
@@ -1135,7 +1135,7 @@ static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                 }
 
         print_conf(conf);
-        return found;
+        return err;
 }
 
 static int raid1_remove_disk(mddev_t *mddev, int number)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 50ad8d2ae0e..df08a9fa3a1 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1113,7 +1113,7 @@ static int raid10_spare_active(mddev_t *mddev)
 static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 {
         conf_t *conf = mddev->private;
-        int found = 0;
+        int err = -EEXIST;
         int mirror;
         mirror_info_t *p;
         int first = 0;
@@ -1123,9 +1123,9 @@ static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                 /* only hot-add to in-sync arrays, as recovery is
                  * very different from resync
                  */
-                return 0;
+                return -EBUSY;
         if (!enough(conf))
-                return 0;
+                return -EINVAL;
 
         if (rdev->raid_disk)
                 first = last = rdev->raid_disk;
@@ -1151,7 +1151,7 @@ static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 
                         p->head_position = 0;
                         rdev->raid_disk = mirror;
-                        found = 1;
+                        err = 0;
                         if (rdev->saved_raid_disk != mirror)
                                 conf->fullsync = 1;
                         rcu_assign_pointer(p->rdev, rdev);
@@ -1159,7 +1159,7 @@ static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                 }
 
         print_conf(conf);
-        return found;
+        return err;
 }
 
 static int raid10_remove_disk(mddev_t *mddev, int number)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 002f33b1ae0..8c4e6149dae 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4604,7 +4604,7 @@ abort:
 static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 {
         raid5_conf_t *conf = mddev->private;
-        int found = 0;
+        int err = -EEXIST;
         int disk;
         struct disk_info *p;
         int first = 0;
@@ -4612,7 +4612,7 @@ static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 
         if (mddev->degraded > conf->max_degraded)
                 /* no point adding a device */
-                return 0;
+                return -EINVAL;
 
         if (rdev->raid_disk >= 0)
                 first = last = rdev->raid_disk;
@@ -4631,14 +4631,14 @@ static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                 if ((p=conf->disks + disk)->rdev == NULL) {
                         clear_bit(In_sync, &rdev->flags);
                         rdev->raid_disk = disk;
-                        found = 1;
+                        err = 0;
                         if (rdev->saved_raid_disk != disk)
                                 conf->fullsync = 1;
                         rcu_assign_pointer(p->rdev, rdev);
                         break;
                 }
         print_raid5_conf(conf);
-        return found;
+        return err;
 }
 
 static int raid5_resize(mddev_t *mddev, sector_t sectors)
@@ -4739,7 +4739,7 @@ static int raid5_start_reshape(mddev_t *mddev)
         rdev_for_each(rdev, rtmp, mddev)
                 if (rdev->raid_disk < 0 &&
                     !test_bit(Faulty, &rdev->flags)) {
-                        if (raid5_add_disk(mddev, rdev)) {
+                        if (raid5_add_disk(mddev, rdev) == 0) {
                                 char nm[20];
                                 set_bit(In_sync, &rdev->flags);
                                 added_devices++;