[NET]: Make sure l_linger is unsigned to avoid negative timeouts

[NET]: Make sure l_linger is unsigned to avoid negative timeouts

One of my x86_64 (linux 2.6.13) server log is filled with :

schedule_timeout: wrong timeout value ffffffffffffff06 from ffffffff802e63ca
schedule_timeout: wrong timeout value ffffffffffffff06 from ffffffff802e63ca
schedule_timeout: wrong timeout value ffffffffffffff06 from ffffffff802e63ca
schedule_timeout: wrong timeout value ffffffffffffff06 from ffffffff802e63ca
schedule_timeout: wrong timeout value ffffffffffffff06 from ffffffff802e63ca

This is because some application does a

struct linger li;
li.l_onoff = 1;
li.l_linger = -1;
setsockopt(sock, SOL_SOCKET, SO_LINGER, &li, sizeof(li));

And unfortunatly l_linger is defined as a 'signed int' in
include/linux/socket.h:

struct linger {
         int             l_onoff;        /* Linger active                */
         int             l_linger;       /* How long to linger for       */
};

I dont know if it's safe to change l_linger to 'unsigned int' in the
include file (It might be defined as int in ABI specs)

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>