rbd: make rbd_create_rw_ops() return a pointer

Either rbd_create_rw_ops() will succeed, or it will fail because a
memory allocation failed.  Have it just return a valid pointer or
null rather than stuffing a pointer into a provided address and
returning an errno.

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 aba0d71a0345e783e5c48bd80778fdc525e765b4..28670c0c68d52dec42501211357694affca4d501 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -788,22 +788,24 @@ err_out:
 /*
  * helpers for osd request op vectors.
  */
-static int rbd_create_rw_ops(struct ceph_osd_req_op **ops,
-                           int num_ops,
-                           int opcode,
-                           u32 payload_len)
-{
-       *ops = kzalloc(sizeof(struct ceph_osd_req_op) * (num_ops + 1),
-                      GFP_NOIO);
-       if (!*ops)
-               return -ENOMEM;
-       (*ops)[0].op = opcode;
+static struct ceph_osd_req_op *rbd_create_rw_ops(int num_ops,
+                                       int opcode, u32 payload_len)
+{
+       struct ceph_osd_req_op *ops;
+
+       ops = kzalloc(sizeof (*ops) * (num_ops + 1), GFP_NOIO);
+       if (!ops)
+               return NULL;
+
+       ops[0].op = opcode;
+
        /*
         * op extent offset and length will be set later on
         * in calc_raw_layout()
         */
-       (*ops)[0].payload_len = payload_len;
-       return 0;
+       ops[0].payload_len = payload_len;
+
+       return ops;
 }
 
 static void rbd_destroy_ops(struct ceph_osd_req_op *ops)
@@ -1040,8 +1042,9 @@ static int rbd_req_sync_op(struct rbd_device *rbd_dev,
 
        if (!orig_ops) {
                payload_len = (flags & CEPH_OSD_FLAG_WRITE ? len : 0);
-               ret = rbd_create_rw_ops(&ops, 1, opcode, payload_len);
-               if (ret < 0)
+               ret = -ENOMEM;
+               ops = rbd_create_rw_ops(1, opcode, payload_len);
+               if (!ops)
                        goto done;
 
                if ((flags & CEPH_OSD_FLAG_WRITE) && buf) {
@@ -1104,8 +1107,9 @@ static int rbd_do_op(struct request *rq,
 
        payload_len = (flags & CEPH_OSD_FLAG_WRITE ? seg_len : 0);
 
-       ret = rbd_create_rw_ops(&ops, 1, opcode, payload_len);
-       if (ret < 0)
+       ret = -ENOMEM;
+       ops = rbd_create_rw_ops(1, opcode, payload_len);
+       if (!ops)
                goto done;
 
        /* we've taken care of segment sizes earlier when we
@@ -1191,9 +1195,9 @@ static int rbd_req_sync_notify_ack(struct rbd_device *rbd_dev,
        struct ceph_osd_req_op *ops;
        int ret;
 
-       ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_NOTIFY_ACK, 0);
-       if (ret < 0)
-               return ret;
+       ops = rbd_create_rw_ops(1, CEPH_OSD_OP_NOTIFY_ACK, 0);
+       if (!ops)
+               return -ENOMEM;
 
        ops[0].watch.ver = cpu_to_le64(ver);
        ops[0].watch.cookie = notify_id;
@@ -1241,10 +1245,11 @@ static int rbd_req_sync_watch(struct rbd_device *rbd_dev)
 {
        struct ceph_osd_req_op *ops;
        struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
+       int ret;
 
-       int ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_WATCH, 0);
-       if (ret < 0)
-               return ret;
+       ops = rbd_create_rw_ops(1, CEPH_OSD_OP_WATCH, 0);
+       if (!ops)
+               return -ENOMEM;
 
        ret = ceph_osdc_create_event(osdc, rbd_watch_cb, 0,
                                     (void *)rbd_dev, &rbd_dev->watch_event);
@@ -1284,10 +1289,11 @@ fail:
 static int rbd_req_sync_unwatch(struct rbd_device *rbd_dev)
 {
        struct ceph_osd_req_op *ops;
+       int ret;
 
-       int ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_WATCH, 0);
-       if (ret < 0)
-               return ret;
+       ops = rbd_create_rw_ops(1, CEPH_OSD_OP_WATCH, 0);
+       if (!ops)
+               return -ENOMEM;
 
        ops[0].watch.ver = 0;
        ops[0].watch.cookie = cpu_to_le64(rbd_dev->watch_event->cookie);
@@ -1335,9 +1341,9 @@ static int rbd_req_sync_notify(struct rbd_device *rbd_dev)
        int payload_len = sizeof(u32) + sizeof(u32);
        int ret;
 
-       ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_NOTIFY, payload_len);
-       if (ret < 0)
-               return ret;
+       ops = rbd_create_rw_ops(1, CEPH_OSD_OP_NOTIFY, payload_len);
+       if (!ops)
+               return -ENOMEM;
 
        info.rbd_dev = rbd_dev;
 
@@ -1388,10 +1394,12 @@ static int rbd_req_sync_exec(struct rbd_device *rbd_dev,
        struct ceph_osd_req_op *ops;
        int class_name_len = strlen(class_name);
        int method_name_len = strlen(method_name);
-       int ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_CALL,
+       int ret;
+
+       ops = rbd_create_rw_ops(1, CEPH_OSD_OP_CALL,
                                    class_name_len + method_name_len + len);
-       if (ret < 0)
-               return ret;
+       if (!ops)
+               return -ENOMEM;
 
        ops[0].cls.class_name = class_name;
        ops[0].cls.class_len = (__u8) class_name_len;