net: ethernet: mlx4: Fix memory allocation in mlx4_buddy_init()

On machines with much memory (> 2 TByte) and log_mtts_per_seg == 0, a
max_order of 31 will be passed to mlx_buddy_init(), which results in
s = BITS_TO_LONGS(1 << 31) becoming a negative value, leading to
kvmalloc_array() failure when it is converted to size_t.

  mlx4_core 0000:b1:00.0: Failed to initialize memory region table, aborting
  mlx4_core: probe of 0000:b1:00.0 failed with error -12

Fix this issue by changing the left shifting operand from a signed literal to
an unsigned one.

Fixes: 225c7b1 ("IB/mlx4: Add a driver Mellanox ConnectX InfiniBand adapters")
Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/mr.c

@@ -114,7 +114,7 @@ static int mlx4_buddy_init(struct mlx4_buddy *buddy, int max_order)
 		goto err_out;
 
 	for (i = 0; i <= buddy->max_order; ++i) {
-		s = BITS_TO_LONGS(1 << (buddy->max_order - i));
+		s = BITS_TO_LONGS(1UL << (buddy->max_order - i));
 		buddy->bits[i] = kvmalloc_array(s, sizeof(long), GFP_KERNEL | __GFP_ZERO);
 		if (!buddy->bits[i])
 			goto err_out_free;