tree 07a8caec8d3ab5e68f42026f9bea8cad31a968ce
parent 820bf5c419e4b85298e5c3001bd1b5be46d60765
author Mikulas Patocka <mpatocka@redhat.com> 1505308677 -0400
committer Jens Axboe <axboe@kernel.dk> 1506351365 -0600

brd: fix overflow in __brd_direct_access

The code in __brd_direct_access multiplies the pgoff variable by page size
and divides it by 512. It can cause overflow on 32-bit architectures. The
overflow happens if we create ramdisk larger than 4G and use it as a
sparse device.

This patch replaces multiplication and division with multiplication by the
number of sectors per page.

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 1647b9b959c7 ("brd: add dax_operations support")
Cc: stable@vger.kernel.org	# 4.12+
Signed-off-by: Jens Axboe <axboe@kernel.dk>