Re: [PATCH V5 3/4] s390/mm: Define arch_get_mappable_range()

[David Hildenbrand]

On 01.02.21 04:25, Anshuman Khandual wrote:
> This overrides arch_get_mappabble_range() on s390 platform which will be
> used with recently added generic framework. It modifies the existing range
> check in vmem_add_mapping() using arch_get_mappable_range(). It also adds a
> VM_BUG_ON() check that would ensure that mhp_range_allowed() has already
> been called on the hotplug path.
>
> Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
> Cc: David Hildenbrand <david@xxxxxxxxxx>
> Cc: linux-s390@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Acked-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> ---
>   arch/s390/mm/init.c |  1 +
>   arch/s390/mm/vmem.c | 14 +++++++++++++-
>   2 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
> index 73a163065b95..0e76b2127dc6 100644
> --- a/arch/s390/mm/init.c
> +++ b/arch/s390/mm/init.c
> @@ -297,6 +297,7 @@ int arch_add_memory(int nid, u64 start, u64 size,
>   	if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot))
>   		return -EINVAL;
>   
> +	VM_BUG_ON(!mhp_range_allowed(start, size, true));
>   	rc = vmem_add_mapping(start, size);
>   	if (rc)
>   		return rc;
> diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
> index 01f3a5f58e64..82dbf9450105 100644
> --- a/arch/s390/mm/vmem.c
> +++ b/arch/s390/mm/vmem.c
> @@ -4,6 +4,7 @@
>    *    Author(s): Heiko Carstens <heiko.carstens@xxxxxxxxxx>
>    */
>   
> +#include <linux/memory_hotplug.h>
>   #include <linux/memblock.h>
>   #include <linux/pfn.h>
>   #include <linux/mm.h>
> @@ -532,11 +533,22 @@ void vmem_remove_mapping(unsigned long start, unsigned long size)
>   	mutex_unlock(&vmem_mutex);
>   }
>   
> +struct range arch_get_mappable_range(void)
> +{
> +	struct range mhp_range;
> +
> +	mhp_range.start = 0;
> +	mhp_range.end =  VMEM_MAX_PHYS - 1;
> +	return mhp_range;
> +}
> +
>   int vmem_add_mapping(unsigned long start, unsigned long size)
>   {
> +	struct range range = arch_get_mappable_range();
>   	int ret;
>   
> -	if (start + size > VMEM_MAX_PHYS ||
> +	if (start < range.start ||
> +	    start + size > range.end + 1 ||
>   	    start + size < start)
>   		return -ERANGE;
>   

Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>

--
Thanks,

David / dhildenb