mm/memory_hotplug: Remove MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers

MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE memory notifiers were introduced
to prepare the transition of memory to and from a physically accessible
state. This enhancement was crucial for implementing the "memmap on memory"
feature for s390.

With introduction of dynamic (de)configuration of hotpluggable memory,
memory can be brought to accessible state before add_memory(). Memory
can be brought to inaccessible state before remove_memory(). Hence,
there is no need of MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE memory
notifiers anymore.

This basically reverts commit
c5f1e2d18909 ("mm/memory_hotplug: introduce MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers")
Additionally, apply minor adjustments to the function parameters of
move_pfn_range_to_zone() and mhp_supports_memmap_on_memory() to ensure
compatibility with the latest branch.

Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

1 files changed, 1 insertions, 22 deletions

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 6d84a02cfa5d..fc43f2703ae0 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -226,7 +226,6 @@ static int memory_block_online(struct memory_block *mem)
 	unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
 	unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
 	unsigned long nr_vmemmap_pages = 0;
-	struct memory_notify arg;
 	struct zone *zone;
 	int ret;
 
@@ -246,19 +245,9 @@ static int memory_block_online(struct memory_block *mem)
 	if (mem->altmap)
 		nr_vmemmap_pages = mem->altmap->free;
 
-	arg.altmap_start_pfn = start_pfn;
-	arg.altmap_nr_pages = nr_vmemmap_pages;
-	arg.start_pfn = start_pfn + nr_vmemmap_pages;
-	arg.nr_pages = nr_pages - nr_vmemmap_pages;
 	mem_hotplug_begin();
-	ret = memory_notify(MEM_PREPARE_ONLINE, &arg);
-	ret = notifier_to_errno(ret);
-	if (ret)
-		goto out_notifier;
-
 	if (nr_vmemmap_pages) {
-		ret = mhp_init_memmap_on_memory(start_pfn, nr_vmemmap_pages,
-						zone, mem->altmap->inaccessible);
+		ret = mhp_init_memmap_on_memory(start_pfn, nr_vmemmap_pages, zone);
 		if (ret)
 			goto out;
 	}
@@ -280,11 +269,7 @@ static int memory_block_online(struct memory_block *mem)
 					  nr_vmemmap_pages);
 
 	mem->zone = zone;
-	mem_hotplug_done();
-	return ret;
 out:
-	memory_notify(MEM_FINISH_OFFLINE, &arg);
-out_notifier:
 	mem_hotplug_done();
 	return ret;
 }
@@ -297,7 +282,6 @@ static int memory_block_offline(struct memory_block *mem)
 	unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
 	unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
 	unsigned long nr_vmemmap_pages = 0;
-	struct memory_notify arg;
 	int ret;
 
 	if (!mem->zone)
@@ -329,11 +313,6 @@ static int memory_block_offline(struct memory_block *mem)
 		mhp_deinit_memmap_on_memory(start_pfn, nr_vmemmap_pages);
 
 	mem->zone = NULL;
-	arg.altmap_start_pfn = start_pfn;
-	arg.altmap_nr_pages = nr_vmemmap_pages;
-	arg.start_pfn = start_pfn + nr_vmemmap_pages;
-	arg.nr_pages = nr_pages - nr_vmemmap_pages;
-	memory_notify(MEM_FINISH_OFFLINE, &arg);
 out:
 	mem_hotplug_done();
 	return ret;