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>
diff --git a/block/blk-core.c b/block/blk-core.c
index 3c37894..5ab3ac2 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -608,6 +608,7 @@
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 @@
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 @@
blk_delete_timer(req);
+ if (req->cmd_flags & REQ_DONTPREP)
+ blk_unprep_request(req);
+
+
blk_account_io_done(req);
if (req->end_io)
diff --git a/block/blk-settings.c b/block/blk-settings.c
index f5ed5a1..a234f4b 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -37,6 +37,23 @@
EXPORT_SYMBOL(blk_queue_prep_rq);
/**
+ * blk_queue_unprep_rq - set an unprepare_request function for queue
+ * @q: queue
+ * @ufn: unprepare_request function
+ *
+ * It's possible for a queue to register an unprepare_request callback
+ * which is invoked before the request is finally completed. The goal
+ * of the function is to deallocate any data that was allocated in the
+ * prepare_request callback.
+ *
+ */
+void blk_queue_unprep_rq(struct request_queue *q, unprep_rq_fn *ufn)
+{
+ q->unprep_rq_fn = ufn;
+}
+EXPORT_SYMBOL(blk_queue_unprep_rq);
+
+/**
* blk_queue_merge_bvec - set a merge_bvec function for queue
* @q: queue
* @mbfn: merge_bvec_fn