x86: Work around compiler code generation bug with -Os

Some versions of gcc generate incorrect code for the inet_check_attr()
function, apparently due to a totally bogus index -> pointer comparison
transformation.

At least "gcc version 4.0.1 20050727 (Red Hat 4.0.1-5)" from FC4 is
affected, possibly others too.

This changes the function subtly so that the buggy gcc transformation
doesn't trigger.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 5b25fc0d980c..4e3d3811dea2 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -289,13 +289,13 @@ static int inet_check_attr(struct rtmsg *r, struct rtattr **rta)
 {
         int i;
 
-        for (i=1; i<=RTA_MAX; i++) {
-                struct rtattr *attr = rta[i-1];
+        for (i=1; i<=RTA_MAX; i++, rta++) {
+                struct rtattr *attr = *rta;
                 if (attr) {
                         if (RTA_PAYLOAD(attr) < 4)
                                 return -EINVAL;
                         if (i != RTA_MULTIPATH && i != RTA_METRICS)
-                                rta[i-1] = (struct rtattr*)RTA_DATA(attr);
+                                *rta = (struct rtattr*)RTA_DATA(attr);
                 }
         }
         return 0;