From 5a023cdba50c5f5f2bc351783b3131699deb3937 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Mon, 30 Nov 2015 10:20:29 -0800 Subject: block: enable dax for raw block devices If an application wants exclusive access to all of the persistent memory provided by an NVDIMM namespace it can use this raw-block-dax facility to forgo establishing a filesystem. This capability is targeted primarily to hypervisors wanting to provision persistent memory for guests. It can be disabled / enabled dynamically via the new BLKDAXSET ioctl. Cc: Jeff Moyer Cc: Christoph Hellwig Cc: Dave Chinner Cc: Andrew Morton Cc: Ross Zwisler Reported-by: kbuild test robot Reviewed-by: Jan Kara Signed-off-by: Dan Williams --- include/linux/fs.h | 11 +++++++++++ include/uapi/linux/fs.h | 2 ++ 2 files changed, 13 insertions(+) (limited to 'include') diff --git a/include/linux/fs.h b/include/linux/fs.h index 3aa514254161..96fabc93b583 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -482,6 +482,9 @@ struct block_device { int bd_fsfreeze_count; /* Mutex for freeze */ struct mutex bd_fsfreeze_mutex; +#ifdef CONFIG_FS_DAX + int bd_map_count; +#endif }; /* @@ -2264,6 +2267,14 @@ extern struct super_block *freeze_bdev(struct block_device *); extern void emergency_thaw_all(void); extern int thaw_bdev(struct block_device *bdev, struct super_block *sb); extern int fsync_bdev(struct block_device *); +#ifdef CONFIG_FS_DAX +extern bool blkdev_dax_capable(struct block_device *bdev); +#else +static inline bool blkdev_dax_capable(struct block_device *bdev) +{ + return false; +} +#endif extern struct super_block *blockdev_superblock; diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index f15d980249b5..401c409e9239 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -152,6 +152,8 @@ struct inodes_stat_t { #define BLKSECDISCARD _IO(0x12,125) #define BLKROTATIONAL _IO(0x12,126) #define BLKZEROOUT _IO(0x12,127) +#define BLKDAXSET _IO(0x12,128) +#define BLKDAXGET _IO(0x12,129) #define BMAP_IOCTL 1 /* obsolete - kept for compatibility */ #define FIBMAP _IO(0x00,1) /* bmap access */ -- cgit v1.2.3