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net: remove DST_NOCACHE flag
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DST_NOCACHE flag check has been removed from dst_release() and
dst_hold_safe() in a previous patch because all the dst are now ref
counted properly and can be released based on refcnt only.
Looking at the rest of the DST_NOCACHE use, all of them can now be
removed or replaced with other checks.
So this patch gets rid of all the DST_NOCACHE usage and remove this flag
completely.

Signed-off-by: Wei Wang <weiwan@google.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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@tracywwnj @davem330
tracywwnj authored and davem330 committed Jun 18, 2017
1 parent b2a9c0e commit a4c2fd7
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Showing 8 changed files with 17 additions and 25 deletions.
2 changes: 1 addition & 1 deletion drivers/net/vrf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -563,7 +563,7 @@ static void vrf_rt6_release(struct net_device *dev, struct net_vrf *vrf)

static int vrf_rt6_create(struct net_device *dev)
{
int flags = DST_HOST | DST_NOPOLICY | DST_NOXFRM | DST_NOCACHE;
int flags = DST_HOST | DST_NOPOLICY | DST_NOXFRM;
struct net_vrf *vrf = netdev_priv(dev);
struct net *net = dev_net(dev);
struct fib6_table *rt6i_table;
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1 change: 0 additions & 1 deletion include/net/dst.h
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Original file line number Diff line number Diff line change
Expand Up @@ -51,7 +51,6 @@ struct dst_entry {
#define DST_HOST 0x0001
#define DST_NOXFRM 0x0002
#define DST_NOPOLICY 0x0004
#define DST_NOCACHE 0x0010
#define DST_NOCOUNT 0x0020
#define DST_FAKE_RTABLE 0x0040
#define DST_XFRM_TUNNEL 0x0080
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2 changes: 1 addition & 1 deletion include/net/ip6_fib.h
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Original file line number Diff line number Diff line change
Expand Up @@ -170,7 +170,7 @@ static inline void rt6_update_expires(struct rt6_info *rt0, int timeout)
static inline u32 rt6_get_cookie(const struct rt6_info *rt)
{
if (rt->rt6i_flags & RTF_PCPU ||
(unlikely(rt->dst.flags & DST_NOCACHE) && rt->dst.from))
(unlikely(!list_empty(&rt->rt6i_uncached)) && rt->dst.from))
rt = (struct rt6_info *)(rt->dst.from);

return rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
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2 changes: 1 addition & 1 deletion net/core/dst.c
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Original file line number Diff line number Diff line change
Expand Up @@ -270,7 +270,7 @@ static void __metadata_dst_init(struct metadata_dst *md_dst, u8 optslen)

dst = &md_dst->dst;
dst_init(dst, &md_dst_ops, NULL, 1, DST_OBSOLETE_NONE,
DST_METADATA | DST_NOCACHE | DST_NOCOUNT);
DST_METADATA | DST_NOCOUNT);

dst->input = dst_md_discard;
dst->output = dst_md_discard_out;
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23 changes: 11 additions & 12 deletions net/ipv4/route.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1299,7 +1299,7 @@ static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
}

static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
__be32 daddr)
__be32 daddr, const bool do_cache)
{
bool ret = false;

Expand Down Expand Up @@ -1328,7 +1328,7 @@ static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
if (!rt->rt_gateway)
rt->rt_gateway = daddr;

if (!(rt->dst.flags & DST_NOCACHE)) {
if (do_cache) {
dst_hold(&rt->dst);
rcu_assign_pointer(*porig, rt);
if (orig) {
Expand Down Expand Up @@ -1441,7 +1441,8 @@ static bool rt_cache_valid(const struct rtable *rt)
static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
const struct fib_result *res,
struct fib_nh_exception *fnhe,
struct fib_info *fi, u16 type, u32 itag)
struct fib_info *fi, u16 type, u32 itag,
const bool do_cache)
{
bool cached = false;

Expand All @@ -1462,16 +1463,15 @@ static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
#endif
rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
if (unlikely(fnhe))
cached = rt_bind_exception(rt, fnhe, daddr);
else if (!(rt->dst.flags & DST_NOCACHE))
cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
else if (do_cache)
cached = rt_cache_route(nh, rt);
if (unlikely(!cached)) {
/* Routes we intend to cache in nexthop exception or
* FIB nexthop have the DST_NOCACHE bit clear.
* However, if we are unsuccessful at storing this
* route into the cache we really need to set it.
*/
rt->dst.flags |= DST_NOCACHE;
if (!rt->rt_gateway)
rt->rt_gateway = daddr;
rt_add_uncached_list(rt);
Expand All @@ -1494,7 +1494,7 @@ struct rtable *rt_dst_alloc(struct net_device *dev,
struct rtable *rt;

rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
(will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
(will_cache ? 0 : DST_HOST) |
(nopolicy ? DST_NOPOLICY : 0) |
(noxfrm ? DST_NOXFRM : 0));

Expand Down Expand Up @@ -1738,7 +1738,8 @@ static int __mkroute_input(struct sk_buff *skb,

rth->dst.input = ip_forward;

rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
do_cache);
set_lwt_redirect(rth);
skb_dst_set(skb, &rth->dst);
out:
Expand Down Expand Up @@ -2026,10 +2027,8 @@ out: return err;
rth->dst.input = lwtunnel_input;
}

if (unlikely(!rt_cache_route(nh, rth))) {
rth->dst.flags |= DST_NOCACHE;
if (unlikely(!rt_cache_route(nh, rth)))
rt_add_uncached_list(rth);
}
}
skb_dst_set(skb, &rth->dst);
err = 0;
Expand Down Expand Up @@ -2260,7 +2259,7 @@ static struct rtable *__mkroute_output(const struct fib_result *res,
#endif
}

rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
set_lwt_redirect(rth);

return rth;
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4 changes: 1 addition & 3 deletions net/ipv6/ip6_fib.c
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Original file line number Diff line number Diff line change
Expand Up @@ -975,8 +975,7 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt,
int replace_required = 0;
int sernum = fib6_new_sernum(info->nl_net);

if (WARN_ON_ONCE((rt->dst.flags & DST_NOCACHE) &&
!atomic_read(&rt->dst.__refcnt)))
if (WARN_ON_ONCE(!atomic_read(&rt->dst.__refcnt)))
return -EINVAL;

if (info->nlh) {
Expand Down Expand Up @@ -1073,7 +1072,6 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt,
fib6_start_gc(info->nl_net, rt);
if (!(rt->rt6i_flags & RTF_CACHE))
fib6_prune_clones(info->nl_net, pn);
rt->dst.flags &= ~DST_NOCACHE;
}

out:
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7 changes: 2 additions & 5 deletions net/ipv6/route.c
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Original file line number Diff line number Diff line change
Expand Up @@ -128,7 +128,6 @@ static void rt6_uncached_list_add(struct rt6_info *rt)
{
struct uncached_list *ul = raw_cpu_ptr(&rt6_uncached_list);

rt->dst.flags |= DST_NOCACHE;
rt->rt6i_uncached_list = ul;

spin_lock_bh(&ul->lock);
Expand Down Expand Up @@ -1326,7 +1325,7 @@ static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie)
rt6_dst_from_metrics_check(rt);

if (rt->rt6i_flags & RTF_PCPU ||
(unlikely(dst->flags & DST_NOCACHE) && rt->dst.from))
(unlikely(!list_empty(&rt->rt6i_uncached)) && rt->dst.from))
return rt6_dst_from_check(rt, cookie);
else
return rt6_check(rt, cookie);
Expand Down Expand Up @@ -2130,8 +2129,7 @@ static int __ip6_del_rt(struct rt6_info *rt, struct nl_info *info)
struct fib6_table *table;
struct net *net = dev_net(rt->dst.dev);

if (rt == net->ipv6.ip6_null_entry ||
rt->dst.flags & DST_NOCACHE) {
if (rt == net->ipv6.ip6_null_entry) {
err = -ENOENT;
goto out;
}
Expand Down Expand Up @@ -2722,7 +2720,6 @@ struct rt6_info *addrconf_dst_alloc(struct inet6_dev *idev,
rt->rt6i_dst.plen = 128;
tb_id = l3mdev_fib_table(idev->dev) ? : RT6_TABLE_LOCAL;
rt->rt6i_table = fib6_get_table(net, tb_id);
rt->dst.flags |= DST_NOCACHE;

return rt;
}
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1 change: 0 additions & 1 deletion net/xfrm/xfrm_policy.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2231,7 +2231,6 @@ struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
}

dst_hold(&xdst->u.dst);
xdst->u.dst.flags |= DST_NOCACHE;
route = xdst->route;
}
}
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