net/mlx4_core: add sanity check when creating bitmap structure

If a user tries to allocate bitmap structure with invalid values, this may
cause a kernel panic.

Signed-off-by: Dotan Barak <[email protected]>
Reviewed-by: Yishai Hadas <[email protected]>
(Ported from Mellanox OFED 2.4)

Signed-off-by: Mukesh Kacker <[email protected]>

Orabug: 27510503

(cherry picked from commit a6f7793)
cherry-pick-repo=linux-uek.git

Signed-off-by: Qing Huang <[email protected]>
Signed-off-by: Aron Silverton <[email protected]>
Signed-off-by: Somasundaram Krishnasamy <[email protected]>

Author: Dotan Barak

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

@@ -173,6 +173,10 @@ void mlx4_bitmap_free_range(struct mlx4_bitmap *bitmap, u32 obj, int cnt,
 int mlx4_bitmap_init(struct mlx4_bitmap *bitmap, u32 num, u32 mask,
 		     u32 reserved_bot, u32 reserved_top)
 {
+	/* sanity check */
+	if (num <= (u64)reserved_top + reserved_bot)
+		return -EINVAL;
+
 	/* num must be a power of 2 */
 	if (num != roundup_pow_of_two(num))
 		return -EINVAL;