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Message-Id: <20100115.011730.263631545.davem@davemloft.net>
Date: Fri, 15 Jan 2010 01:17:30 -0800 (PST)
From: David Miller <davem@...emloft.net>
To: hartleys@...ionengravers.com
Cc: linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
kuznet@....inr.ac.ru, pekkas@...core.fi, jmorris@...ei.org,
yoshfuji@...ux-ipv6.org, kaber@...sh.net
Subject: Re: [PATCH] net/ipv4/fib_semantics.c: quiet sparse "shadows" noise
From: H Hartley Sweeten <hartleys@...ionengravers.com>
Date: Thu, 14 Jan 2010 16:52:41 -0700
> net/ipv4/fib_semantics.c: quiet sparse "shadows" noise
>
> If CONFIG_IP_ROUTE_MULTIPATH is defined the symbol 'nh' is
> declared twice in the function fib_sync_down_dev. First as the
> loop variable used to iterate the hlist. Then again due to the
> change_nexthops macro. This produces a sparse warning and
> makes the code harder to understand.
>
> Fix the issue by renaming the first symbol.
>
> Signed-off-by: H Hartley Sweeten <hsweeten@...ionengravers.com>
I think it's easier to fix this by using a less simple name
in change_nexthops(), so I'll deal with this using the following
patch.
Thanks for reporting this:
ipv4: Use less conflicting local var name in change_nexthops() loop macro.
As noticed by H Hartley Sweeten, since change_nexthops() uses 'nh'
as it's iterator variable, it can conflict with other existing
local vars.
Use "nexthop_nh" to avoid the conflict and make it easier to figure
out where this magic variable comes from.
Signed-off-by: David S. Miller <davem@...emloft.net>
---
net/ipv4/fib_semantics.c | 76 ++++++++++++++++++++++++----------------------
1 files changed, 40 insertions(+), 36 deletions(-)
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index ed19aa6..96b2101 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -62,8 +62,8 @@ static DEFINE_SPINLOCK(fib_multipath_lock);
#define for_nexthops(fi) { int nhsel; const struct fib_nh * nh; \
for (nhsel=0, nh = (fi)->fib_nh; nhsel < (fi)->fib_nhs; nh++, nhsel++)
-#define change_nexthops(fi) { int nhsel; struct fib_nh * nh; \
-for (nhsel=0, nh = (struct fib_nh *)((fi)->fib_nh); nhsel < (fi)->fib_nhs; nh++, nhsel++)
+#define change_nexthops(fi) { int nhsel; struct fib_nh *nexthop_nh; \
+for (nhsel=0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); nhsel < (fi)->fib_nhs; nexthop_nh++, nhsel++)
#else /* CONFIG_IP_ROUTE_MULTIPATH */
@@ -72,7 +72,7 @@ for (nhsel=0, nh = (struct fib_nh *)((fi)->fib_nh); nhsel < (fi)->fib_nhs; nh++,
#define for_nexthops(fi) { int nhsel = 0; const struct fib_nh * nh = (fi)->fib_nh; \
for (nhsel=0; nhsel < 1; nhsel++)
-#define change_nexthops(fi) { int nhsel = 0; struct fib_nh * nh = (struct fib_nh *)((fi)->fib_nh); \
+#define change_nexthops(fi) { int nhsel = 0; struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
for (nhsel=0; nhsel < 1; nhsel++)
#endif /* CONFIG_IP_ROUTE_MULTIPATH */
@@ -145,9 +145,9 @@ void free_fib_info(struct fib_info *fi)
return;
}
change_nexthops(fi) {
- if (nh->nh_dev)
- dev_put(nh->nh_dev);
- nh->nh_dev = NULL;
+ if (nexthop_nh->nh_dev)
+ dev_put(nexthop_nh->nh_dev);
+ nexthop_nh->nh_dev = NULL;
} endfor_nexthops(fi);
fib_info_cnt--;
release_net(fi->fib_net);
@@ -162,9 +162,9 @@ void fib_release_info(struct fib_info *fi)
if (fi->fib_prefsrc)
hlist_del(&fi->fib_lhash);
change_nexthops(fi) {
- if (!nh->nh_dev)
+ if (!nexthop_nh->nh_dev)
continue;
- hlist_del(&nh->nh_hash);
+ hlist_del(&nexthop_nh->nh_hash);
} endfor_nexthops(fi)
fi->fib_dead = 1;
fib_info_put(fi);
@@ -395,19 +395,20 @@ static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
if (!rtnh_ok(rtnh, remaining))
return -EINVAL;
- nh->nh_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
- nh->nh_oif = rtnh->rtnh_ifindex;
- nh->nh_weight = rtnh->rtnh_hops + 1;
+ nexthop_nh->nh_flags =
+ (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
+ nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
+ nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
attrlen = rtnh_attrlen(rtnh);
if (attrlen > 0) {
struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
nla = nla_find(attrs, attrlen, RTA_GATEWAY);
- nh->nh_gw = nla ? nla_get_be32(nla) : 0;
+ nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0;
#ifdef CONFIG_NET_CLS_ROUTE
nla = nla_find(attrs, attrlen, RTA_FLOW);
- nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
+ nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
#endif
}
@@ -738,7 +739,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
fi->fib_nhs = nhs;
change_nexthops(fi) {
- nh->nh_parent = fi;
+ nexthop_nh->nh_parent = fi;
} endfor_nexthops(fi)
if (cfg->fc_mx) {
@@ -808,7 +809,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
goto failure;
} else {
change_nexthops(fi) {
- if ((err = fib_check_nh(cfg, fi, nh)) != 0)
+ if ((err = fib_check_nh(cfg, fi, nexthop_nh)) != 0)
goto failure;
} endfor_nexthops(fi)
}
@@ -843,11 +844,11 @@ link_it:
struct hlist_head *head;
unsigned int hash;
- if (!nh->nh_dev)
+ if (!nexthop_nh->nh_dev)
continue;
- hash = fib_devindex_hashfn(nh->nh_dev->ifindex);
+ hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
head = &fib_info_devhash[hash];
- hlist_add_head(&nh->nh_hash, head);
+ hlist_add_head(&nexthop_nh->nh_hash, head);
} endfor_nexthops(fi)
spin_unlock_bh(&fib_info_lock);
return fi;
@@ -1080,21 +1081,21 @@ int fib_sync_down_dev(struct net_device *dev, int force)
prev_fi = fi;
dead = 0;
change_nexthops(fi) {
- if (nh->nh_flags&RTNH_F_DEAD)
+ if (nexthop_nh->nh_flags&RTNH_F_DEAD)
dead++;
- else if (nh->nh_dev == dev &&
- nh->nh_scope != scope) {
- nh->nh_flags |= RTNH_F_DEAD;
+ else if (nexthop_nh->nh_dev == dev &&
+ nexthop_nh->nh_scope != scope) {
+ nexthop_nh->nh_flags |= RTNH_F_DEAD;
#ifdef CONFIG_IP_ROUTE_MULTIPATH
spin_lock_bh(&fib_multipath_lock);
- fi->fib_power -= nh->nh_power;
- nh->nh_power = 0;
+ fi->fib_power -= nexthop_nh->nh_power;
+ nexthop_nh->nh_power = 0;
spin_unlock_bh(&fib_multipath_lock);
#endif
dead++;
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
- if (force > 1 && nh->nh_dev == dev) {
+ if (force > 1 && nexthop_nh->nh_dev == dev) {
dead = fi->fib_nhs;
break;
}
@@ -1144,18 +1145,20 @@ int fib_sync_up(struct net_device *dev)
prev_fi = fi;
alive = 0;
change_nexthops(fi) {
- if (!(nh->nh_flags&RTNH_F_DEAD)) {
+ if (!(nexthop_nh->nh_flags&RTNH_F_DEAD)) {
alive++;
continue;
}
- if (nh->nh_dev == NULL || !(nh->nh_dev->flags&IFF_UP))
+ if (nexthop_nh->nh_dev == NULL ||
+ !(nexthop_nh->nh_dev->flags&IFF_UP))
continue;
- if (nh->nh_dev != dev || !__in_dev_get_rtnl(dev))
+ if (nexthop_nh->nh_dev != dev ||
+ !__in_dev_get_rtnl(dev))
continue;
alive++;
spin_lock_bh(&fib_multipath_lock);
- nh->nh_power = 0;
- nh->nh_flags &= ~RTNH_F_DEAD;
+ nexthop_nh->nh_power = 0;
+ nexthop_nh->nh_flags &= ~RTNH_F_DEAD;
spin_unlock_bh(&fib_multipath_lock);
} endfor_nexthops(fi)
@@ -1182,9 +1185,9 @@ void fib_select_multipath(const struct flowi *flp, struct fib_result *res)
if (fi->fib_power <= 0) {
int power = 0;
change_nexthops(fi) {
- if (!(nh->nh_flags&RTNH_F_DEAD)) {
- power += nh->nh_weight;
- nh->nh_power = nh->nh_weight;
+ if (!(nexthop_nh->nh_flags&RTNH_F_DEAD)) {
+ power += nexthop_nh->nh_weight;
+ nexthop_nh->nh_power = nexthop_nh->nh_weight;
}
} endfor_nexthops(fi);
fi->fib_power = power;
@@ -1204,9 +1207,10 @@ void fib_select_multipath(const struct flowi *flp, struct fib_result *res)
w = jiffies % fi->fib_power;
change_nexthops(fi) {
- if (!(nh->nh_flags&RTNH_F_DEAD) && nh->nh_power) {
- if ((w -= nh->nh_power) <= 0) {
- nh->nh_power--;
+ if (!(nexthop_nh->nh_flags&RTNH_F_DEAD) &&
+ nexthop_nh->nh_power) {
+ if ((w -= nexthop_nh->nh_power) <= 0) {
+ nexthop_nh->nh_power--;
fi->fib_power--;
res->nh_sel = nhsel;
spin_unlock_bh(&fib_multipath_lock);
--
1.6.5
--
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