netns: remove BUG_ONs from net_generic()

This inline has ~500 callsites.

On 04/14/2015 08:37 PM, David Miller wrote:
> That BUG_ON() was added 7 years ago, and I don't remember it ever
> triggering or helping us diagnose something, so just remove it and
> keep the function inlined.

On x86 allyesconfig build:

    text     data      bss       dec     hex filename
82447071 22255384 20627456 125329911 77861f7 vmlinux4
82441375 22255384 20627456 125324215 7784bb7 vmlinux5prime
Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com>
CC: Eric W. Biederman <ebiederm@xmission.com>
CC: David S. Miller <davem@davemloft.net>
CC: Jan Engelhardt <jengelh@medozas.de>
CC: Jiri Pirko <jpirko@redhat.com>
CC: linux-kernel@vger.kernel.org
CC: netdev@vger.kernel.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/netns/generic.h

@@ -38,11 +38,9 @@ static inline void *net_generic(const struct net *net, int id)
 
 	rcu_read_lock();
 	ng = rcu_dereference(net->gen);
-	BUG_ON(id == 0 || id > ng->len);
 	ptr = ng->ptr[id - 1];
 	rcu_read_unlock();
 
-	BUG_ON(!ptr);
 	return ptr;
 }
 #endif