Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

[cascardo/linux.git] / net / ipv4 / route.c

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index b52496f..654a9af 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -476,12 +476,18 @@ u32 ip_idents_reserve(u32 hash, int segs)
        atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
        u32 old = ACCESS_ONCE(*p_tstamp);
        u32 now = (u32)jiffies;
-       u32 delta = 0;
+       u32 new, delta = 0;
 
        if (old != now && cmpxchg(p_tstamp, old, now) == old)
                delta = prandom_u32_max(now - old);
 
-       return atomic_add_return(segs + delta, p_id) - segs;
+       /* Do not use atomic_add_return() as it makes UBSAN unhappy */
+       do {
+               old = (u32)atomic_read(p_id);
+               new = old + delta + segs;
+       } while (atomic_cmpxchg(p_id, old, new) != old);
+
+       return new - segs;
 }
 EXPORT_SYMBOL(ip_idents_reserve);