On Mon, Nov 30, 2020 at 08:59:52AM +0530, Anshuman Khandual wrote:
> This overrides arch_get_mappabble_range() on s390 platform and drops now
> redundant similar check in vmem_add_mapping(). This compensates by adding
> a new check __segment_load() to preserve the existing functionality.
>
> Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
> Cc: David Hildenbrand <david@xxxxxxxxxx>
> Cc: linux-s390@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> ---
> arch/s390/mm/extmem.c | 5 +++++
> arch/s390/mm/vmem.c | 13 +++++++++----
> 2 files changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/arch/s390/mm/extmem.c b/arch/s390/mm/extmem.c
> index 5060956b8e7d..cc055a78f7b6 100644
> --- a/arch/s390/mm/extmem.c
> +++ b/arch/s390/mm/extmem.c
> @@ -337,6 +337,11 @@ __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long
> goto out_free_resource;
> }
>
> + if (seg->end + 1 > VMEM_MAX_PHYS || seg->end + 1 < seg->start_addr) {
> + rc = -ERANGE;
> + goto out_resource;
> + }
> +
> rc = vmem_add_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
> if (rc)
> goto out_resource;
> diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
> index b239f2ba93b0..06dddcc0ce06 100644
> --- a/arch/s390/mm/vmem.c
> +++ b/arch/s390/mm/vmem.c
> @@ -532,14 +532,19 @@ void vmem_remove_mapping(unsigned long start, unsigned long size)
> mutex_unlock(&vmem_mutex);
> }
>
> +struct range arch_get_mappable_range(void)
> +{
> + struct range memhp_range;
> +
> + memhp_range.start = 0;
> + memhp_range.end = VMEM_MAX_PHYS;
> + return memhp_range;
> +}
> +
> int vmem_add_mapping(unsigned long start, unsigned long size)
> {
> int ret;
>
> - if (start + size > VMEM_MAX_PHYS ||
> - start + size < start)
> - return -ERANGE;
> -
I really fail to see how this could be considered an improvement for
s390. Especially I do not like that the (central) range check is now
moved to the caller (__segment_load). Which would mean potential
additional future callers would have to duplicate that code as well.
