Quanquan Cao ec745eeff4 cxl/region:Fix overflow issue in alloc_hpa()
commit d76779dd3681c01a4c6c3cae4d0627c9083e0ee6 upstream.

Creating a region with 16 memory devices caused a problem. The div_u64_rem
function, used for dividing an unsigned 64-bit number by a 32-bit one,
faced an issue when SZ_256M * p->interleave_ways. The result surpassed
the maximum limit of the 32-bit divisor (4G), leading to an overflow
and a remainder of 0.
note: At this point, p->interleave_ways is 16, meaning 16 * 256M = 4G

To fix this issue, I replaced the div_u64_rem function with div64_u64_rem
and adjusted the type of the remainder.

Signed-off-by: Quanquan Cao <caoqq@fujitsu.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Fixes: 23a22cd1c98b ("cxl/region: Allocate HPA capacity to regions")
Cc: <stable@vger.kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-01-31 16:17:12 -08:00
..
2022-04-22 16:09:42 -07:00
2023-03-10 09:34:20 +01:00
2022-07-19 15:38:05 -07:00