dm io: new interface
Add a new API to dm-io.c that uses a private mempool and bio_set for each
client.
The new functions to use are dm_io_client_create(), dm_io_client_destroy(),
dm_io_client_resize() and dm_io().
Signed-off-by: Heinz Mauelshagen <[email protected]>
Signed-off-by: Alasdair G Kergon <[email protected]>
Cc: Milan Broz <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/drivers/md/dm-io.h b/drivers/md/dm-io.h
index f9035bf..05b1338 100644
--- a/drivers/md/dm-io.h
+++ b/drivers/md/dm-io.h
@@ -20,13 +20,47 @@
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 */
+};
+
+/*
+ * IO request structure
+ */
+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 */
+};
/*
* Before anyone uses the IO interface they should call
@@ -39,6 +73,16 @@
void dm_io_put(unsigned int num_pages);
/*
+ * 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.
+ *
+ * Create/destroy may block.
+ */
+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);
+
+/*
* Synchronous IO.
*
* Please ensure that the rw flag in the next two functions is
@@ -71,4 +115,10 @@
int dm_io_async_vm(unsigned int num_regions, struct io_region *where, int rw,
void *data, io_notify_fn fn, void *context);
+/*
+ * IO interface using private per-client pools.
+ */
+int dm_io(struct dm_io_request *io_req, unsigned num_regions,
+ struct io_region *region, unsigned long *sync_error_bits);
+
#endif
