On Tue, Dec 08, 2020 at 09:46:18AM +0530, Anshuman Khandual wrote:
> This overrides arch_get_mappabble_range() on s390 platform which will be
> used with recently added generic framework. It drops a redundant similar
> check in vmem_add_mapping() while compensating __segment_load() with a new
> address range check to preserve the existing functionality. It also adds a
> VM_BUG_ON() check that would ensure that memhp_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
> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> ---
> arch/s390/mm/extmem.c | 5 +++++
> arch/s390/mm/init.c | 10 ++++++++++
> arch/s390/mm/vmem.c | 4 ----
> 3 files changed, 15 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/init.c b/arch/s390/mm/init.c
> index 77767850d0d0..64937baabf93 100644
> --- a/arch/s390/mm/init.c
> +++ b/arch/s390/mm/init.c
> @@ -278,6 +278,15 @@ device_initcall(s390_cma_mem_init);
>
> #endif /* CONFIG_CMA */
>
> +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 arch_add_memory(int nid, u64 start, u64 size,
> struct mhp_params *params)
> {
> @@ -291,6 +300,7 @@ 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(!memhp_range_allowed(start, size, 1));
> 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 b239f2ba93b0..749eab43aa93 100644
> --- a/arch/s390/mm/vmem.c
> +++ b/arch/s390/mm/vmem.c
> @@ -536,10 +536,6 @@ int vmem_add_mapping(unsigned long start, unsigned long size)
> {
> int ret;
>
> - if (start + size > VMEM_MAX_PHYS ||
> - start + size < start)
> - return -ERANGE;
> -
Is there a reason why you added the memhp_range_allowed() check call
to arch_add_memory() instead of vmem_add_mapping()? If you would do
that, then the extra code in __segment_load() wouldn't be
required.
Even though the error message from memhp_range_allowed() might be
highly confusing.
