rbd: have __rbd_add_snap_dev() return a pointer

It's not obvious whether the snapshot pointer whose address is
provided to __rbd_add_snap_dev() will be assigned by that function.
Change it to return the snapshot, or a pointer-coded errno in the
event of a failure.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 30eb01e..aba0d71 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2029,15 +2029,21 @@ static int rbd_register_snap_dev(struct rbd_snap *snap,
        return ret;
 }
 
-static int __rbd_add_snap_dev(struct rbd_device *rbd_dev,
-                             int i, const char *name,
-                             struct rbd_snap **snapp)
+static struct rbd_snap *__rbd_add_snap_dev(struct rbd_device *rbd_dev,
+                                             int i, const char *name)
 {
+       struct rbd_snap *snap;
        int ret;
-       struct rbd_snap *snap = kzalloc(sizeof(*snap), GFP_KERNEL);
+
+       snap = kzalloc(sizeof (*snap), GFP_KERNEL);
        if (!snap)
-               return -ENOMEM;
+               return ERR_PTR(-ENOMEM);
+
+       ret = -ENOMEM;
        snap->name = kstrdup(name, GFP_KERNEL);
+       if (!snap->name)
+               goto err;
+
        snap->size = rbd_dev->header.snap_sizes[i];
        snap->id = rbd_dev->header.snapc->snaps[i];
        if (device_is_registered(&rbd_dev->dev)) {
@@ -2045,12 +2051,14 @@ static int __rbd_add_snap_dev(struct rbd_device *rbd_dev,
                if (ret < 0)
                        goto err;
        }
-       *snapp = snap;
-       return 0;
+
+       return snap;
+
 err:
        kfree(snap->name);
        kfree(snap);
-       return ret;
+
+       return ERR_PTR(ret);
 }
 
 /*
@@ -2083,7 +2091,6 @@ static int __rbd_init_snaps_header(struct rbd_device *rbd_dev)
        const char *name, *first_name;
        int i = rbd_dev->header.total_snaps;
        struct rbd_snap *snap, *old_snap = NULL;
-       int ret;
        struct list_head *p, *n;
 
        first_name = rbd_dev->header.snap_names;
@@ -2126,9 +2133,9 @@ static int __rbd_init_snaps_header(struct rbd_device *rbd_dev)
                        if (cur_id >= old_snap->id)
                                break;
                        /* a new snapshot */
-                       ret = __rbd_add_snap_dev(rbd_dev, i - 1, name, &snap);
-                       if (ret < 0)
-                               return ret;
+                       snap = __rbd_add_snap_dev(rbd_dev, i - 1, name);
+                       if (IS_ERR(snap))
+                               return PTR_ERR(snap);
 
                        /* note that we add it backward so using n and not p */
                        list_add(&snap->node, n);
@@ -2142,9 +2149,9 @@ static int __rbd_init_snaps_header(struct rbd_device *rbd_dev)
                        WARN_ON(1);
                        return -EINVAL;
                }
-               ret = __rbd_add_snap_dev(rbd_dev, i - 1, name, &snap);
-               if (ret < 0)
-                       return ret;
+               snap = __rbd_add_snap_dev(rbd_dev, i - 1, name);
+               if (IS_ERR(snap))
+                       return PTR_ERR(snap);
                list_add(&snap->node, &rbd_dev->snaps);
        }