[bug report] devlink: implement shared buffer occupancy monitoring interface

[Dan Carpenter <dan.carpenter@xxxxxxxxxx>]

Hello Jiri Pirko,

The patch df38dafd2559: "devlink: implement shared buffer occupancy
monitoring interface" from Apr 14, 2016 (linux-next), leads to the
following Smatch static checker warning:

	net/devlink/sb.c:699 devlink_nl_sb_tc_pool_bind_fill()
	warn: missing unwind goto?

net/devlink/sb.c
    651 static int
    652 devlink_nl_sb_tc_pool_bind_fill(struct sk_buff *msg, struct devlink *devlink,
    653                                 struct devlink_port *devlink_port,
    654                                 struct devlink_sb *devlink_sb, u16 tc_index,
    655                                 enum devlink_sb_pool_type pool_type,
    656                                 enum devlink_command cmd,
    657                                 u32 portid, u32 seq, int flags)
    658 {
    659         const struct devlink_ops *ops = devlink->ops;
    660         u16 pool_index;
    661         u32 threshold;
    662         void *hdr;
    663         int err;
    664 
    665         err = ops->sb_tc_pool_bind_get(devlink_port, devlink_sb->index,
    666                                        tc_index, pool_type,
    667                                        &pool_index, &threshold);
    668         if (err)
    669                 return err;
    670 
    671         hdr = genlmsg_put(msg, portid, seq, &devlink_nl_family, flags, cmd);
    672         if (!hdr)
    673                 return -EMSGSIZE;
    674 
    675         if (devlink_nl_put_handle(msg, devlink))
    676                 goto nla_put_failure;
    677         if (nla_put_u32(msg, DEVLINK_ATTR_PORT_INDEX, devlink_port->index))
    678                 goto nla_put_failure;
    679         if (nla_put_u32(msg, DEVLINK_ATTR_SB_INDEX, devlink_sb->index))
    680                 goto nla_put_failure;
    681         if (nla_put_u16(msg, DEVLINK_ATTR_SB_TC_INDEX, tc_index))
    682                 goto nla_put_failure;
    683         if (nla_put_u8(msg, DEVLINK_ATTR_SB_POOL_TYPE, pool_type))
    684                 goto nla_put_failure;
    685         if (nla_put_u16(msg, DEVLINK_ATTR_SB_POOL_INDEX, pool_index))
    686                 goto nla_put_failure;
    687         if (nla_put_u32(msg, DEVLINK_ATTR_SB_THRESHOLD, threshold))
    688                 goto nla_put_failure;
    689 
    690         if (ops->sb_occ_tc_port_bind_get) {
    691                 u32 cur;
    692                 u32 max;
    693 
    694                 err = ops->sb_occ_tc_port_bind_get(devlink_port,
    695                                                    devlink_sb->index,
    696                                                    tc_index, pool_type,
    697                                                    &cur, &max);
    698                 if (err && err != -EOPNOTSUPP)
--> 699                         return err;

Moving code around means re-visiting all the static checker warnings.
:)  Should this return genlmsg_cancel(msg, hdr) before returning?

    700                 if (!err) {
    701                         if (nla_put_u32(msg, DEVLINK_ATTR_SB_OCC_CUR, cur))
    702                                 goto nla_put_failure;
    703                         if (nla_put_u32(msg, DEVLINK_ATTR_SB_OCC_MAX, max))
    704                                 goto nla_put_failure;
    705                 }
    706         }
    707 
    708         genlmsg_end(msg, hdr);
    709         return 0;
    710 
    711 nla_put_failure:
    712         genlmsg_cancel(msg, hdr);
    713         return -EMSGSIZE;
    714 }

regards,
dan carpenter