Below is v2 of this patch with v2 it works properly:
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Date: Wed, 12 Sep 2018 19:22:22 -0700
Subject: [PATCH] mm, devm_memremap_pages: Add MEMORY_DEVICE_PRIVATE support v2
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In preparation for consolidating all ZONE_DEVICE enabling via
devm_memremap_pages(), teach it how to handle the constraints of
MEMORY_DEVICE_PRIVATE ranges.
Changed since v1:
- move_pfn_range_to_zone() for private device memory too
Cc: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Jérôme Glisse <jglisse@xxxxxxxxxx>
Reported-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Reviewed-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
kernel/memremap.c | 53 ++++++++++++++++++++++++++++++++++++-----------
1 file changed, 41 insertions(+), 12 deletions(-)
diff --git a/kernel/memremap.c b/kernel/memremap.c
index 5b3b6f23fd35..adba623a25f4 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -132,9 +132,15 @@ static void devm_memremap_pages_release(void *data)
- align_start;
mem_hotplug_begin();
- arch_remove_memory(align_start, align_size, pgmap->altmap_valid ?
- &pgmap->altmap : NULL);
- kasan_remove_zero_shadow(__va(align_start), align_size);
+ if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
+ pfn = align_start >> PAGE_SHIFT;
+ __remove_pages(page_zone(pfn_to_page(pfn)), pfn,
+ align_size >> PAGE_SHIFT, NULL);
+ } else {
+ arch_remove_memory(align_start, align_size,
+ pgmap->altmap_valid ? &pgmap->altmap : NULL);
+ kasan_remove_zero_shadow(__va(align_start), align_size);
+ }
mem_hotplug_done();
untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
@@ -234,17 +240,40 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap,
goto err_pfn_remap;
mem_hotplug_begin();
- error = kasan_add_zero_shadow(__va(align_start), align_size);
- if (error) {
- mem_hotplug_done();
- goto err_kasan;
+
+ /*
+ * For device private memory we call add_pages() as we only need to
+ * allocate and initialize struct page for the device memory. More-
+ * over the device memory is un-accessible thus we do not want to
+ * create a linear mapping for the memory like arch_add_memory()
+ * would do.
+ *
+ * For all other device memory types, which are accessible by
+ * the CPU, we do want the linear mapping and thus use
+ * arch_add_memory().
+ */
+ if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
+ error = add_pages(nid, align_start >> PAGE_SHIFT,
+ align_size >> PAGE_SHIFT, NULL, false);
+ } else {
+ error = kasan_add_zero_shadow(__va(align_start), align_size);
+ if (error) {
+ mem_hotplug_done();
+ goto err_kasan;
+ }
+
+ error = arch_add_memory(nid, align_start, align_size, altmap,
+ false);
+ }
+
+ if (!error) {
+ struct zone *zone;
+
+ zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
+ move_pfn_range_to_zone(zone, align_start >> PAGE_SHIFT,
+ align_size >> PAGE_SHIFT, altmap);
}
- error = arch_add_memory(nid, align_start, align_size, altmap, false);
- if (!error)
- move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
- align_start >> PAGE_SHIFT,
- align_size >> PAGE_SHIFT, altmap);
mem_hotplug_done();
if (error)
goto err_add_memory;
--
2.17.1
