2 files changed, 24 insertions, 14 deletions

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 8536fabbf984..52ad1bfce85a 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -577,6 +577,11 @@ struct drbd_request {
         struct bio *master_bio;       /* master bio pointer */
         unsigned long rq_state; /* see comments above _req_mod() */
         unsigned long start_time;
+
+        /* once it hits 0, we may complete the master_bio */
+        atomic_t completion_ref;
+        /* once it hits 0, we may destroy this drbd_request object */
+        struct kref kref;
 };
 
 struct drbd_epoch {
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 6bac415358d7..ae894af428c1 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -85,17 +85,15 @@ static struct drbd_request *drbd_req_new(struct drbd_conf *mdev,
         INIT_LIST_HEAD(&req->tl_requests);
         INIT_LIST_HEAD(&req->w.list);
 
+        atomic_set(&req->completion_ref, 1);
+        kref_init(&req->kref);
         return req;
 }
 
-static void drbd_req_free(struct drbd_request *req)
-{
-        mempool_free(req, drbd_request_mempool);
-}
-
-/* rw is bio_data_dir(), only READ or WRITE */
-static void _req_is_done(struct drbd_conf *mdev, struct drbd_request *req, const int rw)
+static void drbd_req_destroy(struct kref *kref)
 {
+        struct drbd_request *req = container_of(kref, struct drbd_request, kref);
+        struct drbd_conf *mdev = req->w.mdev;
         const unsigned long s = req->rq_state;
 
         /* remove it from the transfer log.
@@ -109,7 +107,7 @@ static void _req_is_done(struct drbd_conf *mdev, struct drbd_request *req, const
         /* if it was a write, we may have to set the corresponding
          * bit(s) out-of-sync first. If it had a local part, we need to
          * release the reference to the activity log. */
-        if (rw == WRITE) {
+        if (s & RQ_WRITE) {
                 /* Set out-of-sync unless both OK flags are set
                  * (local only or remote failed).
                  * Other places where we set out-of-sync:
@@ -146,7 +144,7 @@ static void _req_is_done(struct drbd_conf *mdev, struct drbd_request *req, const
         if (s & RQ_POSTPONED)
                 drbd_restart_request(req);
         else
-                drbd_req_free(req);
+                mempool_free(req, drbd_request_mempool);
 }
 
 static void wake_all_senders(struct drbd_tconn *tconn) {
@@ -196,12 +194,10 @@ static
 void req_may_be_done(struct drbd_request *req)
 {
         const unsigned long s = req->rq_state;
-        struct drbd_conf *mdev = req->w.mdev;
-        int rw = req->rq_state & RQ_WRITE ? WRITE : READ;
 
         /* req->master_bio still present means: Not yet completed.
          *
-         * Unless this is RQ_POSTPONED, which will cause _req_is_done() to
+         * Unless this is RQ_POSTPONED, which will cause drbd_req_destroy() to
          * queue it on the retry workqueue instead of destroying it.
          */
         if (req->master_bio && !(s & RQ_POSTPONED))
@@ -216,7 +212,7 @@ void req_may_be_done(struct drbd_request *req)
                 /* this is disconnected (local only) operation,
                  * or protocol A, B, or C P_BARRIER_ACK,
                  * or killed from the transfer log due to connection loss. */
-                _req_is_done(mdev, req, rw);
+                kref_put(&req->kref, drbd_req_destroy);
         }
         /* else: network part and not DONE yet. that is
          * protocol A, B, or C, barrier ack still pending... */
@@ -250,6 +246,15 @@ void req_may_be_completed(struct drbd_request *req, struct bio_and_error *m)
         if (s & RQ_NET_PENDING)
                 return;
 
+        /* FIXME
+         * instead of all the RQ_FLAGS, actually use the completion_ref
+         * to decide if this is ready to be completed. */
+        if (req->master_bio) {
+                int complete = atomic_dec_and_test(&req->completion_ref);
+                D_ASSERT(complete != 0);
+        } else
+                D_ASSERT(atomic_read(&req->completion_ref) == 0);
+
         if (req->master_bio) {
                 int rw = bio_rw(req->master_bio);
 
@@ -1113,7 +1118,7 @@ struct drbd_request *find_oldest_request(struct drbd_tconn *tconn)
          * and find the oldest not yet completed request */
         struct drbd_request *r;
         list_for_each_entry(r, &tconn->transfer_log, tl_requests) {
-                if (r->rq_state & (RQ_NET_PENDING|RQ_LOCAL_PENDING))
+                if (atomic_read(&r->completion_ref))
                         return r;
         }
         return NULL;