From 1647b9b959c7b1b3c20e8efa2c40529e7dce756a Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 25 Jan 2017 16:54:45 -0800 Subject: [PATCH] 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: Dan Williams --- drivers/block/Kconfig | 1 + drivers/block/brd.c | 65 +++++++++++++++++++++++++++++++++++-------- 2 files changed, 55 insertions(+), 11 deletions(-) diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig index f744de7a0f9b..e66956fc2c88 100644 --- a/drivers/block/Kconfig +++ b/drivers/block/Kconfig @@ -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 diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 3adc32a3153b..60f3193c9ce2 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -21,6 +21,7 @@ #include #ifdef CONFIG_BLK_DEV_RAM_DAX #include +#include #endif #include @@ -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); } -- GitLab