1 files changed, 44 insertions, 39 deletions

diff --git a/drivers/md/dm-io.h b/drivers/md/dm-io.h
index f9035bfd1a9f..f647e2cceaa6 100644
--- a/drivers/md/dm-io.h
+++ b/drivers/md/dm-io.h
@@ -12,7 +12,7 @@
 struct io_region {
 	struct block_device *bdev;
 	sector_t sector;
-	sector_t count;
+	sector_t count;		/* If this is zero the region is ignored. */
 };
 
 struct page_list {
@@ -20,55 +20,60 @@ struct page_list {
 	struct page *page;
 };
 
-
-/*
- * 'error' is a bitset, with each bit indicating whether an error
- * occurred doing io to the corresponding region.
- */
 typedef void (*io_notify_fn)(unsigned long error, void *context);
 
+enum dm_io_mem_type {
+	DM_IO_PAGE_LIST,/* Page list */
+	DM_IO_BVEC,	/* Bio vector */
+	DM_IO_VMA,	/* Virtual memory area */
+	DM_IO_KMEM,	/* Kernel memory */
+};
+
+struct dm_io_memory {
+	enum dm_io_mem_type type;
+
+	union {
+		struct page_list *pl;
+		struct bio_vec *bvec;
+		void *vma;
+		void *addr;
+	} ptr;
+
+	unsigned offset;
+};
+
+struct dm_io_notify {
+	io_notify_fn fn;	/* Callback for asynchronous requests */
+	void *context;		/* Passed to callback */
+};
 
 /*
- * Before anyone uses the IO interface they should call
- * dm_io_get(), specifying roughly how many pages they are
- * expecting to perform io on concurrently.
- *
- * This function may block.
+ * IO request structure
  */
-int dm_io_get(unsigned int num_pages);
-void dm_io_put(unsigned int num_pages);
+struct dm_io_client;
+struct dm_io_request {
+	int bi_rw;			/* READ|WRITE - not READA */
+	struct dm_io_memory mem;	/* Memory to use for io */
+	struct dm_io_notify notify;	/* Synchronous if notify.fn is NULL */
+	struct dm_io_client *client;	/* Client memory handler */
+};
 
 /*
- * Synchronous IO.
+ * For async io calls, users can alternatively use the dm_io() function below
+ * and dm_io_client_create() to create private mempools for the client.
  *
- * Please ensure that the rw flag in the next two functions is
- * either READ or WRITE, ie. we don't take READA.  Any
- * regions with a zero count field will be ignored.
+ * Create/destroy may block.
  */
-int dm_io_sync(unsigned int num_regions, struct io_region *where, int rw,
-	       struct page_list *pl, unsigned int offset,
-	       unsigned long *error_bits);
-
-int dm_io_sync_bvec(unsigned int num_regions, struct io_region *where, int rw,
-		    struct bio_vec *bvec, unsigned long *error_bits);
-
-int dm_io_sync_vm(unsigned int num_regions, struct io_region *where, int rw,
-		  void *data, unsigned long *error_bits);
+struct dm_io_client *dm_io_client_create(unsigned num_pages);
+int dm_io_client_resize(unsigned num_pages, struct dm_io_client *client);
+void dm_io_client_destroy(struct dm_io_client *client);
 
 /*
- * Aynchronous IO.
- *
- * The 'where' array may be safely allocated on the stack since
- * the function takes a copy.
+ * IO interface using private per-client pools.
+ * Each bit in the optional 'sync_error_bits' bitset indicates whether an
+ * error occurred doing io to the corresponding region.
  */
-int dm_io_async(unsigned int num_regions, struct io_region *where, int rw,
-		struct page_list *pl, unsigned int offset,
-		io_notify_fn fn, void *context);
-
-int dm_io_async_bvec(unsigned int num_regions, struct io_region *where, int rw,
-		     struct bio_vec *bvec, io_notify_fn fn, void *context);
-
-int dm_io_async_vm(unsigned int num_regions, struct io_region *where, int rw,
-		   void *data, io_notify_fn fn, void *context);
+int dm_io(struct dm_io_request *io_req, unsigned num_regions,
+	  struct io_region *region, unsigned long *sync_error_bits);
 
 #endif