On 1/19/21 5:51 PM, David Hildenbrand wrote:
> On 18.01.21 14:12, Anshuman Khandual wrote:
>> This introduces memhp_range_allowed() which can be called in various memory
>> hotplug paths to prevalidate the address range which is being added, with
>> the platform. Then memhp_range_allowed() calls memhp_get_pluggable_range()
>> which provides applicable address range depending on whether linear mapping
>> is required or not. For ranges that require linear mapping, it calls a new
>> arch callback arch_get_mappable_range() which the platform can override. So
>> the new callback, in turn provides the platform an opportunity to configure
>> acceptable memory hotplug address ranges in case there are constraints.
>>
>> This mechanism will help prevent platform specific errors deep down during
>> hotplug calls. This drops now redundant check_hotplug_memory_addressable()
>> check in __add_pages() but instead adds a VM_BUG_ON() check which would
>
> In this patch, you keep the __add_pages() checks. But as discussed, we
> could perform it in mm/memremap.c:pagemap_range() insted and convert it
> to a VM_BUG_ON().
Just to be sure, will the following change achieve what you are
suggesting here. pagemap_range() after this change, will again
be the same like the V1 series.
---
mm/memory_hotplug.c | 3 +--
mm/memremap.c | 12 +++++-------
2 files changed, 6 insertions(+), 9 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 46faa914aa25..10d4ec8f349c 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -304,8 +304,7 @@ int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
if (WARN_ON_ONCE(!params->pgprot.pgprot))
return -EINVAL;
- if(!memhp_range_allowed(PFN_PHYS(pfn), nr_pages * PAGE_SIZE, false))
- return -E2BIG;
+ VM_BUG_ON(!memhp_range_allowed(PFN_PHYS(pfn), nr_pages * PAGE_SIZE, false));
if (altmap) {
/*
diff --git a/mm/memremap.c b/mm/memremap.c
index e15b13736f6a..26c1825756cc 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -185,6 +185,7 @@ static void dev_pagemap_percpu_release(struct percpu_ref *ref)
static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params,
int range_id, int nid)
{
+ const bool is_private = pgmap->type == MEMORY_DEVICE_PRIVATE;
struct range *range = &pgmap->ranges[range_id];
struct dev_pagemap *conflict_pgmap;
int error, is_ram;
@@ -230,6 +231,9 @@ static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params,
if (error)
goto err_pfn_remap;
+ if (!memhp_range_allowed(range->start, range_len(range), !is_private))
+ goto err_pfn_remap;
+
mem_hotplug_begin();
/*
@@ -243,7 +247,7 @@ static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params,
* the CPU, we do want the linear mapping and thus use
* arch_add_memory().
*/
- if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
+ if (is_private) {
error = add_pages(nid, PHYS_PFN(range->start),
PHYS_PFN(range_len(range)), params);
} else {
@@ -253,12 +257,6 @@ static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params,
goto err_kasan;
}
- if (!memhp_range_allowed(range->start, range_len(range), true)) {
- error = -ERANGE;
- mem_hotplug_done();
- goto err_add_memory;
- }
-
error = arch_add_memory(nid, range->start, range_len(range),
params);
}
--
2.20.1
