diff options
Diffstat (limited to 'drivers/dax')
| -rw-r--r-- | drivers/dax/Kconfig | 7 | ||||
| -rw-r--r-- | drivers/dax/super.c | 81 |
2 files changed, 74 insertions, 14 deletions
diff --git a/drivers/dax/Kconfig b/drivers/dax/Kconfig index b7053eafd88e..b79aa8f7a497 100644 --- a/drivers/dax/Kconfig +++ b/drivers/dax/Kconfig @@ -19,7 +19,7 @@ config DEV_DAX config DEV_DAX_PMEM tristate "PMEM DAX: direct access to persistent memory" - depends on LIBNVDIMM && NVDIMM_DAX + depends on LIBNVDIMM && NVDIMM_DAX && DEV_DAX default DEV_DAX help Support raw access to persistent memory. Note that this @@ -28,9 +28,4 @@ config DEV_DAX_PMEM Say Y if unsure -config NR_DEV_DAX - int "Maximum number of Device-DAX instances" - default 32768 - range 256 2147483647 - endif diff --git a/drivers/dax/super.c b/drivers/dax/super.c index 465dcd7317d5..ebf43f531ada 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -14,16 +14,13 @@ #include <linux/module.h> #include <linux/mount.h> #include <linux/magic.h> +#include <linux/genhd.h> #include <linux/cdev.h> #include <linux/hash.h> #include <linux/slab.h> #include <linux/dax.h> #include <linux/fs.h> -static int nr_dax = CONFIG_NR_DEV_DAX; -module_param(nr_dax, int, S_IRUGO); -MODULE_PARM_DESC(nr_dax, "max number of dax device instances"); - static dev_t dax_devt; DEFINE_STATIC_SRCU(dax_srcu); static struct vfsmount *dax_mnt; @@ -47,6 +44,75 @@ void dax_read_unlock(int id) } EXPORT_SYMBOL_GPL(dax_read_unlock); +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 + * @blocksize: The block size of the device + * + * This is a library function for filesystems to check if the block device + * can be mounted with dax option. + * + * Return: negative errno if unsupported, 0 if supported. + */ +int __bdev_dax_supported(struct super_block *sb, int blocksize) +{ + struct block_device *bdev = sb->s_bdev; + struct dax_device *dax_dev; + pgoff_t pgoff; + int err, id; + void *kaddr; + pfn_t pfn; + long len; + + if (blocksize != PAGE_SIZE) { + pr_err("VFS (%s): error: unsupported blocksize for dax\n", + sb->s_id); + return -EINVAL; + } + + err = bdev_dax_pgoff(bdev, 0, PAGE_SIZE, &pgoff); + if (err) { + pr_err("VFS (%s): error: unaligned partition for dax\n", + sb->s_id); + return err; + } + + dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); + if (!dax_dev) { + pr_err("VFS (%s): error: device does not support dax\n", + sb->s_id); + return -EOPNOTSUPP; + } + + id = dax_read_lock(); + len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn); + dax_read_unlock(id); + + put_dax(dax_dev); + + if (len < 1) { + pr_err("VFS (%s): error: dax access failed (%ld)", + sb->s_id, len); + return len < 0 ? len : -EIO; + } + + return 0; +} +EXPORT_SYMBOL_GPL(__bdev_dax_supported); + /** * struct dax_device - anchor object for dax services * @inode: core vfs @@ -261,7 +327,7 @@ struct dax_device *alloc_dax(void *private, const char *__host, if (__host && !host) return NULL; - minor = ida_simple_get(&dax_minor_ida, 0, nr_dax, GFP_KERNEL); + minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); if (minor < 0) goto err_minor; @@ -405,8 +471,7 @@ static int __init dax_fs_init(void) if (rc) return rc; - nr_dax = max(nr_dax, 256); - rc = alloc_chrdev_region(&dax_devt, 0, nr_dax, "dax"); + rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); if (rc) __dax_fs_exit(); return rc; @@ -414,7 +479,7 @@ static int __init dax_fs_init(void) static void __exit dax_fs_exit(void) { - unregister_chrdev_region(dax_devt, nr_dax); + unregister_chrdev_region(dax_devt, MINORMASK+1); ida_destroy(&dax_minor_ida); __dax_fs_exit(); } |