Commit dbb0020b authored by SeongJae Park's avatar SeongJae Park Committed by Andrew Morton
Browse files

mm/madvise: split out madvise input validity check 

Split out the madvise parameters validation logic from do_madvise(), for
easy reuse of the logic from a future change.

Link: https://lkml.kernel.org/r/20250206061517.2958-3-sj@kernel.org


Signed-off-by: default avatarSeongJae Park <sj@kernel.org>
Reviewed-by: default avatarShakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: default avatarLorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: default avatarDavidlohr Bueso <dave@stgolabs.net>
Reviewed-by: default avatarLiam R. Howlett <howlett@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 4cc39f91

mm/madvise.c

+22 −10
Original line number Diff line number Diff line
@@ -1618,6 +1618,27 @@ static void madvise_unlock(struct mm_struct *mm, int behavior) 
		mmap_read_unlock(mm);

}



static bool is_valid_madvise(unsigned long start, size_t len_in, int behavior)

{

	size_t len;



	if (!madvise_behavior_valid(behavior))

		return false;



	if (!PAGE_ALIGNED(start))

		return false;

	len = PAGE_ALIGN(len_in);



	/* Check to see whether len was rounded up from small -ve to zero */

	if (len_in && !len)

		return false;



	if (start + len < start)

		return false;



	return true;

}



/*

 * The madvise(2) system call.

 *
@@ -1697,20 +1718,11 @@ int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int beh 
	size_t len;

	struct blk_plug plug;



	if (!madvise_behavior_valid(behavior))

	if (!is_valid_madvise(start, len_in, behavior))

		return -EINVAL;



	if (!PAGE_ALIGNED(start))

		return -EINVAL;

	len = PAGE_ALIGN(len_in);



	/* Check to see whether len was rounded up from small -ve to zero */

	if (len_in && !len)

		return -EINVAL;



	end = start + len;

	if (end < start)

		return -EINVAL;



	if (end == start)

		return 0;