block: implement an unprep function corresponding directly to prep

Reviewed-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 3c3789492c10..5ab3ac22930c 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -608,6 +608,7 @@ blk_init_allocated_queue_node(struct request_queue *q, request_fn_proc *rfn,
 
         q->request_fn           = rfn;
         q->prep_rq_fn           = NULL;
+        q->unprep_rq_fn         = NULL;
         q->unplug_fn            = generic_unplug_device;
         q->queue_flags          = QUEUE_FLAG_DEFAULT;
         q->queue_lock           = lock;
@@ -2133,6 +2134,26 @@ static bool blk_update_bidi_request(struct request *rq, int error,
         return false;
 }
 
+/**
+ * blk_unprep_request - unprepare a request
+ * @req:        the request
+ *
+ * This function makes a request ready for complete resubmission (or
+ * completion).  It happens only after all error handling is complete,
+ * so represents the appropriate moment to deallocate any resources
+ * that were allocated to the request in the prep_rq_fn.  The queue
+ * lock is held when calling this.
+ */
+void blk_unprep_request(struct request *req)
+{
+        struct request_queue *q = req->q;
+
+        req->cmd_flags &= ~REQ_DONTPREP;
+        if (q->unprep_rq_fn)
+                q->unprep_rq_fn(q, req);
+}
+EXPORT_SYMBOL_GPL(blk_unprep_request);
+
 /*
  * queue lock must be held
  */
@@ -2148,6 +2169,10 @@ static void blk_finish_request(struct request *req, int error)
 
         blk_delete_timer(req);
 
+        if (req->cmd_flags & REQ_DONTPREP)
+                blk_unprep_request(req);
+
+
         blk_account_io_done(req);
 
         if (req->end_io)