Merge branch 'akpm' (patches from Andrew)

Merge fifth set of updates from Andrew Morton:

 - A few things which were awaiting merges from linux-next:
     - rtc
     - ocfs2
     - misc others

 - Willy's "dax" feature: direct fs access to memory (mainly NV-DIMMs)
   which isn't backed by pageframes.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (37 commits)
  rtc: add driver for DS1685 family of real time clocks
  MAINTAINERS: add entry for Maxim PMICs on Samsung boards
  lib/Kconfig: use bool instead of boolean
  powerpc: drop _PAGE_FILE and pte_file()-related helpers
  ocfs2: set append dio as a ro compat feature
  ocfs2: wait for orphan recovery first once append O_DIRECT write crash
  ocfs2: complete the rest request through buffer io
  ocfs2: do not fallback to buffer I/O write if appending
  ocfs2: allocate blocks in ocfs2_direct_IO_get_blocks
  ocfs2: implement ocfs2_direct_IO_write
  ocfs2: add orphan recovery types in ocfs2_recover_orphans
  ocfs2: add functions to add and remove inode in orphan dir
  ocfs2: prepare some interfaces used in append direct io
  MAINTAINERS: fix spelling mistake & remove trailing WS
  dax: does not work correctly with virtual aliasing caches
  brd: rename XIP to DAX
  ext4: add DAX functionality
  dax: add dax_zero_page_range
  ext2: get rid of most mentions of XIP in ext2
  ext2: remove ext2_aops_xip
  ...

2 files changed, 14 insertions, 13 deletions

diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 014a1cfc41c5..1b8094d4d7af 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -393,14 +393,15 @@ config BLK_DEV_RAM_SIZE
 	  The default value is 4096 kilobytes. Only change this if you know
 	  what you are doing.
 
-config BLK_DEV_XIP
-	bool "Support XIP filesystems on RAM block device"
-	depends on BLK_DEV_RAM
+config BLK_DEV_RAM_DAX
+	bool "Support Direct Access (DAX) to RAM block devices"
+	depends on BLK_DEV_RAM && FS_DAX
 	default n
 	help
-	  Support XIP filesystems (such as ext2 with XIP support on) on
-	  top of block ram device. This will slightly enlarge the kernel, and
-	  will prevent RAM block device backing store memory from being
+	  Support filesystems using DAX to access RAM block devices.  This
+	  avoids double-buffering data in the page cache before copying it
+	  to the block device.  Answering Y will slightly enlarge the kernel,
+	  and will prevent RAM block device backing store memory from being
 	  allocated from highmem (only a problem for highmem systems).
 
 config CDROM_PKTCDVD
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index c01b921b1b4a..64ab4951e9d6 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -97,13 +97,13 @@ static struct page *brd_insert_page(struct brd_device *brd, sector_t sector)
 	 * Must use NOIO because we don't want to recurse back into the
 	 * block or filesystem layers from page reclaim.
 	 *
-	 * Cannot support XIP and highmem, because our ->direct_access
-	 * routine for XIP must return memory that is always addressable.
-	 * If XIP was reworked to use pfns and kmap throughout, this
+	 * Cannot support DAX and highmem, because our ->direct_access
+	 * routine for DAX must return memory that is always addressable.
+	 * If DAX was reworked to use pfns and kmap throughout, this
 	 * restriction might be able to be lifted.
 	 */
 	gfp_flags = GFP_NOIO | __GFP_ZERO;
-#ifndef CONFIG_BLK_DEV_XIP
+#ifndef CONFIG_BLK_DEV_RAM_DAX
 	gfp_flags |= __GFP_HIGHMEM;
 #endif
 	page = alloc_page(gfp_flags);
@@ -369,7 +369,7 @@ static int brd_rw_page(struct block_device *bdev, sector_t sector,
 	return err;
 }
 
-#ifdef CONFIG_BLK_DEV_XIP
+#ifdef CONFIG_BLK_DEV_RAM_DAX
 static long brd_direct_access(struct block_device *bdev, sector_t sector,
 			void **kaddr, unsigned long *pfn, long size)
 {
@@ -390,6 +390,8 @@ static long brd_direct_access(struct block_device *bdev, sector_t sector,
 	 */
 	return PAGE_SIZE;
 }
+#else
+#define brd_direct_access NULL
 #endif
 
 static int brd_ioctl(struct block_device *bdev, fmode_t mode,
@@ -430,9 +432,7 @@ static const struct block_device_operations brd_fops = {
 	.owner =		THIS_MODULE,
 	.rw_page =		brd_rw_page,
 	.ioctl =		brd_ioctl,
-#ifdef CONFIG_BLK_DEV_XIP
 	.direct_access =	brd_direct_access,
-#endif
 };
 
 /*