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