dax: Introduce a ->copy_to_iter dax operation

Similar to the ->copy_from_iter() operation, a platform may want to
deploy an architecture or device specific routine for handling reads
from a dax_device like /dev/pmemX. On x86 this routine will point to a
machine check safe version of copy_to_iter(). For now, add the plumbing
to device-mapper and the dax core.

Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams
2018-05-02 06:46:33 -07:00
parent 522239b445
commit b3a9a0c36e
10 changed files with 111 additions and 3 deletions

View File

@@ -133,7 +133,7 @@ typedef int (*dm_busy_fn) (struct dm_target *ti);
*/
typedef long (*dm_dax_direct_access_fn) (struct dm_target *ti, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn);
typedef size_t (*dm_dax_copy_from_iter_fn)(struct dm_target *ti, pgoff_t pgoff,
typedef size_t (*dm_dax_copy_iter_fn)(struct dm_target *ti, pgoff_t pgoff,
void *addr, size_t bytes, struct iov_iter *i);
#define PAGE_SECTORS (PAGE_SIZE / 512)
@@ -184,7 +184,8 @@ struct target_type {
dm_iterate_devices_fn iterate_devices;
dm_io_hints_fn io_hints;
dm_dax_direct_access_fn direct_access;
dm_dax_copy_from_iter_fn dax_copy_from_iter;
dm_dax_copy_iter_fn dax_copy_from_iter;
dm_dax_copy_iter_fn dax_copy_to_iter;
/* For internal device-mapper use. */
struct list_head list;