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Commit 1647b9b9 authored by Dan Williams's avatar Dan Williams
Browse files

brd: add dax_operations support 


    
Setup a dax_inode to have the same lifetime as the brd block device and
add a ->direct_access() method that is equivalent to
brd_direct_access(). Once fs/dax.c has been converted to use
dax_operations the old brd_direct_access() will be removed.

Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 60fcd55c

drivers/block/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -339,6 +339,7 @@ config BLK_DEV_SX8 


config BLK_DEV_RAM

	tristate "RAM block device support"

	select DAX if BLK_DEV_RAM_DAX

	---help---

	  Saying Y here will allow you to use a portion of your RAM memory as

	  a block device, so that you can make file systems on it, read and

drivers/block/brd.c

+54 −11
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/slab.h>

#ifdef CONFIG_BLK_DEV_RAM_DAX

#include <linux/pfn_t.h>

#include <linux/dax.h>

#endif



#include <linux/uaccess.h>
@@ -41,6 +42,9 @@ struct brd_device { 


	struct request_queue	*brd_queue;

	struct gendisk		*brd_disk;

#ifdef CONFIG_BLK_DEV_RAM_DAX

	struct dax_device	*dax_dev;

#endif

	struct list_head	brd_list;



	/*
@@ -375,30 +379,53 @@ 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 **kaddr, pfn_t *pfn, long size)

static long __brd_direct_access(struct brd_device *brd, pgoff_t pgoff,

		long nr_pages, void **kaddr, pfn_t *pfn)

{

	struct brd_device *brd = bdev->bd_disk->private_data;

	struct page *page;



	if (!brd)

		return -ENODEV;

	page = brd_insert_page(brd, sector);

	page = brd_insert_page(brd, PFN_PHYS(pgoff) / 512);

	if (!page)

		return -ENOSPC;

	*kaddr = page_address(page);

	*pfn = page_to_pfn_t(page);



	return PAGE_SIZE;

	return 1;

}



static long brd_blk_direct_access(struct block_device *bdev, sector_t sector,

			void **kaddr, pfn_t *pfn, long size)

{

	struct brd_device *brd = bdev->bd_disk->private_data;

	long nr_pages = __brd_direct_access(brd, PHYS_PFN(sector * 512),

			PHYS_PFN(size), kaddr, pfn);



	if (nr_pages < 0)

		return nr_pages;

	return nr_pages * PAGE_SIZE;

}



static long brd_dax_direct_access(struct dax_device *dax_dev,

		pgoff_t pgoff, long nr_pages, void **kaddr, pfn_t *pfn)

{

	struct brd_device *brd = dax_get_private(dax_dev);



	return __brd_direct_access(brd, pgoff, nr_pages, kaddr, pfn);

}



static const struct dax_operations brd_dax_ops = {

	.direct_access = brd_dax_direct_access,

};

#else

#define brd_direct_access NULL

#define brd_blk_direct_access NULL

#endif



static const struct block_device_operations brd_fops = {

	.owner =		THIS_MODULE,

	.rw_page =		brd_rw_page,

	.direct_access =	brd_direct_access,

	.direct_access =	brd_blk_direct_access,

};



/*
@@ -441,7 +468,9 @@ static struct brd_device *brd_alloc(int i) 
{

	struct brd_device *brd;

	struct gendisk *disk;



#ifdef CONFIG_BLK_DEV_RAM_DAX

	struct dax_device *dax_dev;

#endif

	brd = kzalloc(sizeof(*brd), GFP_KERNEL);

	if (!brd)

		goto out;
@@ -469,9 +498,6 @@ static struct brd_device *brd_alloc(int i) 
	blk_queue_max_discard_sectors(brd->brd_queue, UINT_MAX);

	brd->brd_queue->limits.discard_zeroes_data = 1;

	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, brd->brd_queue);

#ifdef CONFIG_BLK_DEV_RAM_DAX

	queue_flag_set_unlocked(QUEUE_FLAG_DAX, brd->brd_queue);

#endif

	disk = brd->brd_disk = alloc_disk(max_part);

	if (!disk)

		goto out_free_queue;
@@ -484,8 +510,21 @@ static struct brd_device *brd_alloc(int i) 
	sprintf(disk->disk_name, "ram%d", i);

	set_capacity(disk, rd_size * 2);



#ifdef CONFIG_BLK_DEV_RAM_DAX

	queue_flag_set_unlocked(QUEUE_FLAG_DAX, brd->brd_queue);

	dax_dev = alloc_dax(brd, disk->disk_name, &brd_dax_ops);

	if (!dax_dev)

		goto out_free_inode;

#endif





	return brd;



#ifdef CONFIG_BLK_DEV_RAM_DAX

out_free_inode:

	kill_dax(dax_dev);

	put_dax(dax_dev);

#endif

out_free_queue:

	blk_cleanup_queue(brd->brd_queue);

out_free_dev:
@@ -525,6 +564,10 @@ static struct brd_device *brd_init_one(int i, bool *new) 
static void brd_del_one(struct brd_device *brd)

{

	list_del(&brd->brd_list);

#ifdef CONFIG_BLK_DEV_RAM_DAX

	kill_dax(brd->dax_dev);

	put_dax(brd->dax_dev);

#endif

	del_gendisk(brd->brd_disk);

	brd_free(brd);

}