On Thu, Jan 16, 2025 at 05:30:55PM -0800, SeongJae Park wrote:
> Split out the madvise behavior-dependent mmap_lock operations from
> do_madvise(), for easier reuse of the logic in an upcoming change.
>
> Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Looks good to me, a decent cleanup regardless of application.
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
> ---
> mm/madvise.c | 45 ++++++++++++++++++++++++++++++++-------------
> 1 file changed, 32 insertions(+), 13 deletions(-)
>
> diff --git a/mm/madvise.c b/mm/madvise.c
> index 49f3a75046f6..ae0964bc4d88 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -1565,6 +1565,33 @@ int madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
> madvise_vma_anon_name);
> }
> #endif /* CONFIG_ANON_VMA_NAME */
> +
> +static int madvise_lock(struct mm_struct *mm, int behavior)
> +{
> +
> +#ifdef CONFIG_MEMORY_FAILURE
> + if (behavior == MADV_HWPOISON || behavior == MADV_SOFT_OFFLINE)
> + return 0;
> +#endif
> +
> + if (madvise_need_mmap_write(behavior)) {
> + if (mmap_write_lock_killable(mm))
> + return -EINTR;
> + } else {
> + mmap_read_lock(mm);
> + }
> + return 0;
> +
> +}
> +
> +static void madvise_unlock(struct mm_struct *mm, int behavior)
> +{
> + if (madvise_need_mmap_write(behavior))
> + mmap_write_unlock(mm);
> + else
> + mmap_read_unlock(mm);
> +}
> +
> /*
> * The madvise(2) system call.
> *
> @@ -1641,7 +1668,6 @@ int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int beh
> {
> unsigned long end;
> int error;
> - int write;
> size_t len;
> struct blk_plug plug;
>
> @@ -1663,19 +1689,15 @@ int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int beh
> if (end == start)
> return 0;
>
> + error = madvise_lock(mm, behavior);
> + if (error)
> + return error;
> +
> #ifdef CONFIG_MEMORY_FAILURE
> if (behavior == MADV_HWPOISON || behavior == MADV_SOFT_OFFLINE)
> return madvise_inject_error(behavior, start, start + len_in);
> #endif
>
> - write = madvise_need_mmap_write(behavior);
> - if (write) {
> - if (mmap_write_lock_killable(mm))
> - return -EINTR;
> - } else {
> - mmap_read_lock(mm);
> - }
> -
> start = untagged_addr_remote(mm, start);
> end = start + len;
>
> @@ -1692,10 +1714,7 @@ int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int beh
> }
> blk_finish_plug(&plug);
>
> - if (write)
> - mmap_write_unlock(mm);
> - else
> - mmap_read_unlock(mm);
> + madvise_unlock(mm, behavior);
>
> return error;
> }
> --
> 2.39.5
