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authorDan Williams <dan.j.williams@intel.com>2016-01-15 16:56:14 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-15 17:56:32 -0800
commit34c0fd540e79fb49ef9ce864dae1058cca265780 (patch)
tree7f404f3a644322d0eca02b54daa228261ed24f39 /drivers/block
parentba049e93aef7e8c571567088b1b73f4f5b99272a (diff)
downloadlinux-34c0fd540e79fb49ef9ce864dae1058cca265780.tar.bz2
mm, dax, pmem: introduce pfn_t
For the purpose of communicating the optional presence of a 'struct page' for the pfn returned from ->direct_access(), introduce a type that encapsulates a page-frame-number plus flags. These flags contain the historical "page_link" encoding for a scatterlist entry, but can also denote "device memory". Where "device memory" is a set of pfns that are not part of the kernel's linear mapping by default, but are accessed via the same memory controller as ram. The motivation for this new type is large capacity persistent memory that needs struct page entries in the 'memmap' to support 3rd party DMA (i.e. O_DIRECT I/O with a persistent memory source/target). However, we also need it in support of maintaining a list of mapped inodes which need to be unmapped at driver teardown or freeze_bdev() time. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Hansen <dave@sr71.net> 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>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/brd.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index a5880f4ab40e..cb27190e9f39 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -19,6 +19,9 @@
#include <linux/radix-tree.h>
#include <linux/fs.h>
#include <linux/slab.h>
+#ifdef CONFIG_BLK_DEV_RAM_DAX
+#include <linux/pfn_t.h>
+#endif
#include <asm/uaccess.h>
@@ -378,7 +381,7 @@ static int brd_rw_page(struct block_device *bdev, sector_t sector,
#ifdef CONFIG_BLK_DEV_RAM_DAX
static long brd_direct_access(struct block_device *bdev, sector_t sector,
- void __pmem **kaddr, unsigned long *pfn)
+ void __pmem **kaddr, pfn_t *pfn)
{
struct brd_device *brd = bdev->bd_disk->private_data;
struct page *page;
@@ -389,7 +392,7 @@ static long brd_direct_access(struct block_device *bdev, sector_t sector,
if (!page)
return -ENOSPC;
*kaddr = (void __pmem *)page_address(page);
- *pfn = page_to_pfn(page);
+ *pfn = page_to_pfn_t(page);
return PAGE_SIZE;
}