1 files changed, 26 insertions, 0 deletions

diff --git a/include/linux/dax.h b/include/linux/dax.h
index 0dd316a74a29..becaea5f4488 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -19,6 +19,12 @@ struct dax_operations {
          */
         long (*direct_access)(struct dax_device *, pgoff_t, long,
                         void **, pfn_t *);
+        /*
+         * Validate whether this device is usable as an fsdax backing
+         * device.
+         */
+        bool (*dax_supported)(struct dax_device *, struct block_device *, int,
+                        sector_t, sector_t);
         /* copy_from_iter: required operation for fs-dax direct-i/o */
         size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
                         struct iov_iter *);
@@ -75,6 +81,17 @@ static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
         return __bdev_dax_supported(bdev, blocksize);
 }
 
+bool __generic_fsdax_supported(struct dax_device *dax_dev,
+                struct block_device *bdev, int blocksize, sector_t start,
+                sector_t sectors);
+static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
+                struct block_device *bdev, int blocksize, sector_t start,
+                sector_t sectors)
+{
+        return __generic_fsdax_supported(dax_dev, bdev, blocksize, start,
+                        sectors);
+}
+
 static inline struct dax_device *fs_dax_get_by_host(const char *host)
 {
         return dax_get_by_host(host);
@@ -99,6 +116,13 @@ static inline bool bdev_dax_supported(struct block_device *bdev,
         return false;
 }
 
+static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
+                struct block_device *bdev, int blocksize, sector_t start,
+                sector_t sectors)
+{
+        return false;
+}
+
 static inline struct dax_device *fs_dax_get_by_host(const char *host)
 {
         return NULL;
@@ -142,6 +166,8 @@ bool dax_alive(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);
+bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
+                int blocksize, sector_t start, sector_t len);
 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
                 size_t bytes, struct iov_iter *i);
 size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,