[dm-devel] [PATCH 2/7] dm-bufio: introduce dm_bufio_forget

[Mikulas Patocka]

Introduce a new function dm_bufio_forget. It frees the given buffer.

Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>

---
 drivers/md/dm-bufio.c |   22 ++++++++++++++++++++++
 drivers/md/dm-bufio.h |    7 +++++++
 2 files changed, 29 insertions(+)

Index: linux-3.13-rc7/drivers/md/dm-bufio.c
===================================================================
--- linux-3.13-rc7.orig/drivers/md/dm-bufio.c	2014-01-10 00:04:40.000000000 +0100
+++ linux-3.13-rc7/drivers/md/dm-bufio.c	2014-01-10 00:15:33.000000000 +0100
@@ -1354,6 +1354,28 @@ retry:
 }
 EXPORT_SYMBOL_GPL(dm_bufio_release_move);
 
+/*
+ * Free the given buffer.
+ *
+ * This is just a hint, if the buffer is in use or dirty, this function
+ * does nothing.
+ */
+void dm_bufio_forget(struct dm_bufio_client *c, sector_t block)
+{
+	struct dm_buffer *b;
+
+	dm_bufio_lock(c);
+
+	b = __find(c, block);
+	if (b && likely(!b->hold_count) && likely(!b->state)) {
+		__unlink_buffer(b);
+		__free_buffer_wake(b);
+	}
+
+	dm_bufio_unlock(c);
+}
+EXPORT_SYMBOL(dm_bufio_forget);
+
 unsigned dm_bufio_get_block_size(struct dm_bufio_client *c)
 {
 	return c->block_size;
Index: linux-3.13-rc7/drivers/md/dm-bufio.h
===================================================================
--- linux-3.13-rc7.orig/drivers/md/dm-bufio.h	2014-01-10 00:11:58.000000000 +0100
+++ linux-3.13-rc7/drivers/md/dm-bufio.h	2014-01-10 00:13:27.000000000 +0100
@@ -108,6 +108,13 @@ int dm_bufio_issue_flush(struct dm_bufio
  */
 void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block);
 
+/*
+ * Free the given buffer.
+ * This is just a hint, if the buffer is in use or dirty, this function
+ * does nothing.
+ */
+void dm_bufio_forget(struct dm_bufio_client *c, sector_t block);
+
 unsigned dm_bufio_get_block_size(struct dm_bufio_client *c);
 sector_t dm_bufio_get_device_size(struct dm_bufio_client *c);
 sector_t dm_bufio_get_block_number(struct dm_buffer *b);