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brd: add dax_operations support

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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: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2017-01-25 16:54:45 -08:00
parent 60fcd55cc2
commit 1647b9b959
2 changed files with 55 additions and 11 deletions
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1
drivers/block/Kconfig
View File

@ -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

65
drivers/block/brd.c
View File

@ -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 @@ out:
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);
}