Number of nexthops and number of alive nexthops are tracked using an unsigned int. A route should never have more than 255 nexthops so convert both to u8. Update all references and intermediate variables to consistently use u8 as well.
Shrinks the size of mpls_route from 32 bytes to 24 bytes with a 2-byte hole before the nexthops. Also, the ACCESS_ONCE is changed to READ_ONCE per checkpatch message. Signed-off-by: David Ahern <d...@cumulusnetworks.com> --- net/mpls/af_mpls.c | 29 ++++++++++++++++++----------- net/mpls/internal.h | 4 ++-- 2 files changed, 20 insertions(+), 13 deletions(-) diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c index cd8be8d5e4ad..d3dc6c43a1d1 100644 --- a/net/mpls/af_mpls.c +++ b/net/mpls/af_mpls.c @@ -192,7 +192,7 @@ static u32 mpls_multipath_hash(struct mpls_route *rt, struct sk_buff *skb) static struct mpls_nh *mpls_select_multipath(struct mpls_route *rt, struct sk_buff *skb) { - int alive = ACCESS_ONCE(rt->rt_nhn_alive); + u8 alive = READ_ONCE(rt->rt_nhn_alive); u32 hash = 0; int nh_index = 0; int n = 0; @@ -458,7 +458,7 @@ struct mpls_route_config { int rc_mp_len; }; -static struct mpls_route *mpls_rt_alloc(int num_nh, u8 max_alen) +static struct mpls_route *mpls_rt_alloc(u8 num_nh, u8 max_alen) { u8 max_alen_aligned = ALIGN(max_alen, VIA_ALEN_ALIGN); struct mpls_route *rt; @@ -736,11 +736,11 @@ static int mpls_nh_build(struct net *net, struct mpls_route *rt, return err; } -static int mpls_count_nexthops(struct rtnexthop *rtnh, int len, - u8 cfg_via_alen, u8 *max_via_alen) +static u8 mpls_count_nexthops(struct rtnexthop *rtnh, int len, + u8 cfg_via_alen, u8 *max_via_alen) { - int nhs = 0; int remaining = len; + u8 nhs = 0; if (!rtnh) { *max_via_alen = cfg_via_alen; @@ -765,7 +765,14 @@ static int mpls_count_nexthops(struct rtnexthop *rtnh, int len, via_alen); } + /* number of nexthops is tracked by a u8. + * Check for overflow. + */ + if (nhs == 255) + return 0; + nhs++; + rtnh = rtnh_next(rtnh, &remaining); } @@ -779,8 +786,8 @@ static int mpls_nh_build_multi(struct mpls_route_config *cfg, struct rtnexthop *rtnh = cfg->rc_mp; struct nlattr *nla_via, *nla_newdst; int remaining = cfg->rc_mp_len; - int nhs = 0; int err = 0; + u8 nhs = 0; change_nexthops(rt) { int attrlen; @@ -834,7 +841,7 @@ static int mpls_route_add(struct mpls_route_config *cfg) int err = -EINVAL; u8 max_via_alen; unsigned index; - int nhs; + u8 nhs; index = cfg->rc_label; @@ -1299,8 +1306,8 @@ static void mpls_ifdown(struct net_device *dev, int event) struct mpls_route __rcu **platform_label; struct net *net = dev_net(dev); unsigned int nh_flags = RTNH_F_DEAD | RTNH_F_LINKDOWN; - unsigned int alive; unsigned index; + u8 alive; platform_label = rtnl_dereference(net->mpls.platform_label); for (index = 0; index < net->mpls.platform_labels; index++) { @@ -1339,7 +1346,7 @@ static void mpls_ifup(struct net_device *dev, unsigned int nh_flags) struct mpls_route __rcu **platform_label; struct net *net = dev_net(dev); unsigned index; - int alive; + u8 alive; platform_label = rtnl_dereference(net->mpls.platform_label); for (index = 0; index < net->mpls.platform_labels; index++) { @@ -1761,8 +1768,8 @@ static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event, } else { struct rtnexthop *rtnh; struct nlattr *mp; - int dead = 0; - int linkdown = 0; + u8 linkdown = 0; + u8 dead = 0; mp = nla_nest_start(skb, RTA_MULTIPATH); if (!mp) diff --git a/net/mpls/internal.h b/net/mpls/internal.h index 62928d8fabd1..66f388ba2d49 100644 --- a/net/mpls/internal.h +++ b/net/mpls/internal.h @@ -123,8 +123,8 @@ struct mpls_route { /* next hop label forwarding entry */ u8 rt_payload_type; u8 rt_max_alen; u8 rt_ttl_propagate; - unsigned int rt_nhn; - unsigned int rt_nhn_alive; + u8 rt_nhn; + u8 rt_nhn_alive; struct mpls_nh rt_nh[0]; }; -- 2.1.4