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authorToshi Kani <toshi.kani@hpe.com>2016-06-23 02:54:53 +0300
committerMike Snitzer <snitzer@redhat.com>2016-07-21 06:49:49 +0300
commit545ed20e6df68a4d2584a29a2a28ee8b2f7e9547 (patch)
tree2d826caf0e6cfdf27d6a21401dea468cfb03e0d1 /include/linux/device-mapper.h
parente9ccb945c4d937189668f9e3cf00949da4727762 (diff)
downloadlinux-545ed20e6df68a4d2584a29a2a28ee8b2f7e9547.tar.xz
dm: add infrastructure for DAX support
Change mapped device to implement direct_access function, dm_blk_direct_access(), which calls a target direct_access function. 'struct target_type' is extended to have target direct_access interface. This function limits direct accessible size to the dm_target's limit with max_io_len(). Add dm_table_supports_dax() to iterate all targets and associated block devices to check for DAX support. To add DAX support to a DM target the target must only implement the direct_access function. Add a new dm type, DM_TYPE_DAX_BIO_BASED, which indicates that mapped device supports DAX and is bio based. This new type is used to assure that all target devices have DAX support and remain that way after QUEUE_FLAG_DAX is set in mapped device. At initial table load, QUEUE_FLAG_DAX is set to mapped device when setting DM_TYPE_DAX_BIO_BASED to the type. Any subsequent table load to the mapped device must have the same type, or else it fails per the check in table_load(). Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'include/linux/device-mapper.h')
-rw-r--r--include/linux/device-mapper.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 2ce339212b6e..b0db857f334b 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -26,6 +26,7 @@ struct bio_vec;
#define DM_TYPE_BIO_BASED 1
#define DM_TYPE_REQUEST_BASED 2
#define DM_TYPE_MQ_REQUEST_BASED 3
+#define DM_TYPE_DAX_BIO_BASED 4
typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
@@ -124,6 +125,14 @@ typedef void (*dm_io_hints_fn) (struct dm_target *ti,
*/
typedef int (*dm_busy_fn) (struct dm_target *ti);
+/*
+ * Returns:
+ * < 0 : error
+ * >= 0 : the number of bytes accessible at the address
+ */
+typedef long (*dm_direct_access_fn) (struct dm_target *ti, sector_t sector,
+ void __pmem **kaddr, pfn_t *pfn, long size);
+
void dm_error(const char *message);
struct dm_dev {
@@ -170,6 +179,7 @@ struct target_type {
dm_busy_fn busy;
dm_iterate_devices_fn iterate_devices;
dm_io_hints_fn io_hints;
+ dm_direct_access_fn direct_access;
/* For internal device-mapper use. */
struct list_head list;