diff options
| -rw-r--r-- | drivers/block/Kconfig | 13 | ||||
| -rw-r--r-- | drivers/block/brd.c | 14 |
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 }; /* |