mm: introduce find_dev_pagemap()
There are several scenarios where we need to retrieve and update
metadata associated with a given devm_memremap_pages() mapping, and the
only lookup key available is a pfn in the range:
1/ We want to augment vmemmap_populate() (called via arch_add_memory())
to allocate memmap storage from pre-allocated pages reserved by the
device driver. At vmemmap_alloc_block_buf() time it grabs device pages
rather than page allocator pages. This is in support of
devm_memremap_pages() mappings where the memmap is too large to fit in
main memory (i.e. large persistent memory devices).
2/ Taking a reference against the mapping when inserting device pages
into the address_space radix of a given inode. This facilitates
unmap_mapping_range() and truncate_inode_pages() operations when the
driver is tearing down the mapping.
3/ get_user_pages() operations on ZONE_DEVICE memory require taking a
reference against the mapping so that the driver teardown path can
revoke and drain usage of device pages.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 5def7f4..904629b 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -21,9 +21,9 @@
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/module.h>
-#include <linux/memory_hotplug.h>
#include <linux/moduleparam.h>
#include <linux/badblocks.h>
+#include <linux/memremap.h>
#include <linux/vmalloc.h>
#include <linux/pfn_t.h>
#include <linux/slab.h>