diff options
| -rw-r--r-- | block/Kconfig | 1 | ||||
| -rw-r--r-- | drivers/dax/super.c | 39 | ||||
| -rw-r--r-- | fs/block_dev.c | 14 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 1 | ||||
| -rw-r--r-- | include/linux/dax.h | 2 |
5 files changed, 57 insertions, 0 deletions
diff --git a/block/Kconfig b/block/Kconfig index e9f780f815f5..93da7fc3f254 100644 --- a/block/Kconfig +++ b/block/Kconfig @@ -6,6 +6,7 @@ menuconfig BLOCK default y select SBITMAP select SRCU + select DAX help Provide block layer support for the kernel. diff --git a/drivers/dax/super.c b/drivers/dax/super.c index 1a58542ee8fd..465dcd7317d5 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -65,6 +65,45 @@ struct dax_device { const struct dax_operations *ops; }; +/** + * dax_direct_access() - translate a device pgoff to an absolute pfn + * @dax_dev: a dax_device instance representing the logical memory range + * @pgoff: offset in pages from the start of the device to translate + * @nr_pages: number of consecutive pages caller can handle relative to @pfn + * @kaddr: output parameter that returns a virtual address mapping of pfn + * @pfn: output parameter that returns an absolute pfn translation of @pgoff + * + * Return: negative errno if an error occurs, otherwise the number of + * pages accessible at the device relative @pgoff. + */ +long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, + void **kaddr, pfn_t *pfn) +{ + long avail; + + /* + * The device driver is allowed to sleep, in order to make the + * memory directly accessible. + */ + might_sleep(); + + if (!dax_dev) + return -EOPNOTSUPP; + + if (!dax_alive(dax_dev)) + return -ENXIO; + + if (nr_pages < 0) + return nr_pages; + + avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, + kaddr, pfn); + if (!avail) + return -ERANGE; + return min(avail, nr_pages); +} +EXPORT_SYMBOL_GPL(dax_direct_access); + bool dax_alive(struct dax_device *dax_dev) { lockdep_assert_held(&dax_srcu); diff --git a/fs/block_dev.c b/fs/block_dev.c index 7f40ea2f0875..2f7885712575 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -18,6 +18,7 @@ #include <linux/module.h> #include <linux/blkpg.h> #include <linux/magic.h> +#include <linux/dax.h> #include <linux/buffer_head.h> #include <linux/swap.h> #include <linux/pagevec.h> @@ -762,6 +763,19 @@ long bdev_direct_access(struct block_device *bdev, struct blk_dax_ctl *dax) } EXPORT_SYMBOL_GPL(bdev_direct_access); +int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, + pgoff_t *pgoff) +{ + phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512; + + if (pgoff) + *pgoff = PHYS_PFN(phys_off); + if (phys_off % PAGE_SIZE || size % PAGE_SIZE) + return -EINVAL; + return 0; +} +EXPORT_SYMBOL(bdev_dax_pgoff); + /** * bdev_dax_supported() - Check if the device supports dax for filesystem * @sb: The superblock of the device diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index f72708399b83..612c497d1461 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1958,6 +1958,7 @@ extern int bdev_write_page(struct block_device *, sector_t, struct page *, struct writeback_control *); extern long bdev_direct_access(struct block_device *, struct blk_dax_ctl *); extern int bdev_dax_supported(struct super_block *, int); +int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff); #else /* CONFIG_BLOCK */ struct block_device; diff --git a/include/linux/dax.h b/include/linux/dax.h index 39a0312c45c3..7e62e280c11f 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -27,6 +27,8 @@ void put_dax(struct dax_device *dax_dev); bool dax_alive(struct dax_device *dax_dev); void kill_dax(struct dax_device *dax_dev); void *dax_get_private(struct dax_device *dax_dev); +long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, + void **kaddr, pfn_t *pfn); /* * We use lowest available bit in exceptional entry for locking, one bit for |