[NET]: Fix heavy stack usage in seq_file output routines.

Plan C: we can follow the Al Viro's proposal about %n like in this patch.
The same applies to udp, fib (the /proc/net/route file), rt_cache and 
sctp debug. This is minus ~150-200 bytes for each.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 5 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 780e9484c825..ce25a13f3430 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -367,10 +367,10 @@ static int rt_cache_seq_show(struct seq_file *seq, void *v)
                            "HHUptod\tSpecDst");
         else {
                 struct rtable *r = v;
-                char temp[256];
+                int len;
 
-                sprintf(temp, "%s\t%08lX\t%08lX\t%8X\t%d\t%u\t%d\t"
-                              "%08lX\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X",
+                seq_printf(seq, "%s\t%08lX\t%08lX\t%8X\t%d\t%u\t%d\t"
+                              "%08lX\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X%n",
                         r->u.dst.dev ? r->u.dst.dev->name : "*",
                         (unsigned long)r->rt_dst, (unsigned long)r->rt_gateway,
                         r->rt_flags, atomic_read(&r->u.dst.__refcnt),
@@ -384,8 +384,9 @@ static int rt_cache_seq_show(struct seq_file *seq, void *v)
                         r->u.dst.hh ? atomic_read(&r->u.dst.hh->hh_refcnt) : -1,
                         r->u.dst.hh ? (r->u.dst.hh->hh_output ==
                                        dev_queue_xmit) : 0,
-                        r->rt_spec_dst);
-                seq_printf(seq, "%-127s\n", temp);
+                        r->rt_spec_dst, &len);
+
+                seq_printf(seq, "%*s\n", 127 - len, "");
         }
         return 0;
 }