devlink: Return right error code in case of errors for region read

devlink_nl_cmd_region_read_dumpit() misses to return right error code on
most error conditions.
Return the right error code on such errors.

Fixes: 4e54795a ("devlink: Add support for region snapshot read command")
Signed-off-by: NParav Pandit <parav@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/devlink.c

@@ -3646,26 +3646,34 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
 		goto out_free;
 
 	devlink = devlink_get_from_attrs(sock_net(cb->skb->sk), attrs);
-	if (IS_ERR(devlink))
+	if (IS_ERR(devlink)) {
+		err = PTR_ERR(devlink);
 		goto out_free;
+	}
 
 	mutex_lock(&devlink_mutex);
 	mutex_lock(&devlink->lock);
 
 	if (!attrs[DEVLINK_ATTR_REGION_NAME] ||
-	    !attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID])
+	    !attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]) {
+		err = -EINVAL;
 		goto out_unlock;
+	}
 
 	region_name = nla_data(attrs[DEVLINK_ATTR_REGION_NAME]);
 	region = devlink_region_get_by_name(devlink, region_name);
-	if (!region)
+	if (!region) {
+		err = -EINVAL;
 		goto out_unlock;
+	}
 
 	hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
 			  &devlink_nl_family, NLM_F_ACK | NLM_F_MULTI,
 			  DEVLINK_CMD_REGION_READ);
-	if (!hdr)
+	if (!hdr) {
+		err = -EMSGSIZE;
 		goto out_unlock;
+	}
 
 	err = devlink_nl_put_handle(skb, devlink);
 	if (err)
@@ -3676,8 +3684,10 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
 		goto nla_put_failure;
 
 	chunks_attr = nla_nest_start(skb, DEVLINK_ATTR_REGION_CHUNKS);
-	if (!chunks_attr)
+	if (!chunks_attr) {
+		err = -EMSGSIZE;
 		goto nla_put_failure;
+	}
 
 	if (attrs[DEVLINK_ATTR_REGION_CHUNK_ADDR] &&
 	    attrs[DEVLINK_ATTR_REGION_CHUNK_LEN]) {
@@ -3700,8 +3710,10 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
 		goto nla_put_failure;
 
 	/* Check if there was any progress done to prevent infinite loop */
-	if (ret_offset == start_offset)
+	if (ret_offset == start_offset) {
+		err = -EINVAL;
 		goto nla_put_failure;
+	}
 
 	*((u64 *)&cb->args[0]) = ret_offset;
 
@@ -3720,7 +3732,7 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
 	mutex_unlock(&devlink_mutex);
 out_free:
 	kfree(attrs);
-	return 0;
+	return err;
 }
 
 struct devlink_info_req {