rbd: encapsulate argument parsing for rbd_add()

Move the code that parses the arguments provided to rbd_add() (which
are supplied via /sys/bus/rbd/add) into a separate function.

Also rename the "mon_dev_name" variable in rbd_add() to be
"mon_addrs".   The variable represents a list of one or more
comma-separated monitor IP addresses, each with an optional port
number.  I think "mon_addrs" captures that notion a little better.

Signed-off-by: Alex Elder <elder@dreamhost.com>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 8ac26ab..caafe1d 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2220,12 +2220,43 @@ static void rbd_id_put(struct rbd_device *rbd_dev)
        atomic64_cmpxchg(&rbd_id_max, rbd_id, max_id);
 }
 
+/*
+ * This fills in the pool_name, obj, obj_len, snap_name, obj_len,
+ * rbd_dev, rbd_md_name, and name fields of the given rbd_dev, based
+ * on the list of monitor addresses and other options provided via
+ * /sys/bus/rbd/add.
+ */
+static int rbd_add_parse_args(struct rbd_device *rbd_dev,
+                             const char *buf,
+                             char *mon_addrs,
+                             char *options)
+{
+       if (sscanf(buf, "%" __stringify(RBD_MAX_OPT_LEN) "s "
+                  "%" __stringify(RBD_MAX_OPT_LEN) "s "
+                  "%" __stringify(RBD_MAX_POOL_NAME_LEN) "s "
+                  "%" __stringify(RBD_MAX_OBJ_NAME_LEN) "s"
+                  "%" __stringify(RBD_MAX_SNAP_NAME_LEN) "s",
+                  mon_addrs, options, rbd_dev->pool_name,
+                  rbd_dev->obj, rbd_dev->snap_name) < 4)
+               return -EINVAL;
+
+       if (rbd_dev->snap_name[0] == 0)
+               memcpy(rbd_dev->snap_name, RBD_SNAP_HEAD_NAME,
+                       sizeof (RBD_SNAP_HEAD_NAME));
+
+       rbd_dev->obj_len = strlen(rbd_dev->obj);
+       snprintf(rbd_dev->obj_md_name, sizeof(rbd_dev->obj_md_name), "%s%s",
+                rbd_dev->obj, RBD_SUFFIX);
+
+       return 0;
+}
+
 static ssize_t rbd_add(struct bus_type *bus,
                       const char *buf,
                       size_t count)
 {
        struct rbd_device *rbd_dev;
-       char *mon_dev_name = NULL;
+       char *mon_addrs = NULL;
        char *options = NULL;
        struct ceph_osd_client *osdc;
        int rc = -ENOMEM;
@@ -2236,8 +2267,8 @@ static ssize_t rbd_add(struct bus_type *bus,
        rbd_dev = kzalloc(sizeof(*rbd_dev), GFP_KERNEL);
        if (!rbd_dev)
                goto err_nomem;
-       mon_dev_name = kmalloc(count, GFP_KERNEL);
-       if (!mon_dev_name)
+       mon_addrs = kmalloc(count, GFP_KERNEL);
+       if (!mon_addrs)
                goto err_nomem;
        options = kmalloc(count, GFP_KERNEL);
        if (!options)
@@ -2253,30 +2284,15 @@ static ssize_t rbd_add(struct bus_type *bus,
        /* generate unique id: find highest unique id, add one */
        rbd_id_get(rbd_dev);
 
+       /* Fill in the device name, now that we have its id. */
+       snprintf(rbd_dev->name, DEV_NAME_LEN, RBD_DRV_NAME "%d", rbd_dev->id);
+
        /* parse add command */
-       if (sscanf(buf, "%" __stringify(RBD_MAX_OPT_LEN) "s "
-                  "%" __stringify(RBD_MAX_OPT_LEN) "s "
-                  "%" __stringify(RBD_MAX_POOL_NAME_LEN) "s "
-                  "%" __stringify(RBD_MAX_OBJ_NAME_LEN) "s"
-                  "%" __stringify(RBD_MAX_SNAP_NAME_LEN) "s",
-                  mon_dev_name, options, rbd_dev->pool_name,
-                  rbd_dev->obj, rbd_dev->snap_name) < 4) {
-               rc = -EINVAL;
+       rc = rbd_add_parse_args(rbd_dev, buf, mon_addrs, options);
+       if (rc)
                goto err_put_id;
-       }
-
-       if (rbd_dev->snap_name[0] == 0)
-               memcpy(rbd_dev->snap_name, RBD_SNAP_HEAD_NAME,
-                       sizeof (RBD_SNAP_HEAD_NAME));
-
-       rbd_dev->obj_len = strlen(rbd_dev->obj);
-       snprintf(rbd_dev->obj_md_name, sizeof(rbd_dev->obj_md_name), "%s%s",
-                rbd_dev->obj, RBD_SUFFIX);
-
-       /* initialize rest of new object */
-       snprintf(rbd_dev->name, DEV_NAME_LEN, RBD_DRV_NAME "%d", rbd_dev->id);
 
-       rbd_dev->rbd_client = rbd_get_client(mon_dev_name, options);
+       rbd_dev->rbd_client = rbd_get_client(mon_addrs, options);
        if (IS_ERR(rbd_dev->rbd_client)) {
                rc = PTR_ERR(rbd_dev->rbd_client);
                goto err_put_id;
@@ -2317,7 +2333,7 @@ err_out_bus:
 
        rbd_bus_del_dev(rbd_dev);
        kfree(options);
-       kfree(mon_dev_name);
+       kfree(mon_addrs);
        return rc;
 
 err_out_blkdev:
@@ -2328,7 +2344,7 @@ err_put_id:
        rbd_id_put(rbd_dev);
 err_nomem:
        kfree(options);
-       kfree(mon_dev_name);
+       kfree(mon_addrs);
        kfree(rbd_dev);
 
        dout("Error adding device %s\n", buf);