On Thu, Jan 16, 2025 at 05:30:56PM -0800, SeongJae Park wrote:
> Split out the madvise parameters validation logic from do_madvise(), for
> easy reuse of the logic from a future change.
>
> Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Another decent cleanup, regardless of appllication, so:
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
> ---
> mm/madvise.c | 32 ++++++++++++++++++++++----------
> 1 file changed, 22 insertions(+), 10 deletions(-)
>
> diff --git a/mm/madvise.c b/mm/madvise.c
> index ae0964bc4d88..9cc31efe875a 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -1592,6 +1592,27 @@ 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);
Kind of a pity to duplicate this, but not exactly a big deal.
> +
> + /* 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.
> *
> @@ -1671,20 +1692,11 @@ 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;
> --
> 2.39.5
