drbd: fix request leak introduced by locking/atomic, kref: Kill kref_sub()
When killing kref_sub(), the unconditional additional kref_get()
was not properly paired with the necessary kref_put(), causing
a leak of struct drbd_requests (~ 224 Bytes) per submitted bio,
and breaking DRBD in general, as the destructor of those "drbd_requests"
does more than just the mempoll_free().
Fixes: bdfafc4ffdd2 ("locking/atomic, kref: Kill kref_sub()")
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Cc: stable@vger.kernel.org # v4.11
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index b5730e1..6566243 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -315,24 +315,32 @@
}
/* still holds resource->req_lock */
-static int drbd_req_put_completion_ref(struct drbd_request *req, struct bio_and_error *m, int put)
+static void drbd_req_put_completion_ref(struct drbd_request *req, struct bio_and_error *m, int put)
{
struct drbd_device *device = req->device;
D_ASSERT(device, m || (req->rq_state & RQ_POSTPONED));
+ if (!put)
+ return;
+
if (!atomic_sub_and_test(put, &req->completion_ref))
- return 0;
+ return;
drbd_req_complete(req, m);
+ /* local completion may still come in later,
+ * we need to keep the req object around. */
+ if (req->rq_state & RQ_LOCAL_ABORTED)
+ return;
+
if (req->rq_state & RQ_POSTPONED) {
/* don't destroy the req object just yet,
* but queue it for retry */
drbd_restart_request(req);
- return 0;
+ return;
}
- return 1;
+ kref_put(&req->kref, drbd_req_destroy);
}
static void set_if_null_req_next(struct drbd_peer_device *peer_device, struct drbd_request *req)
@@ -519,12 +527,8 @@
if (req->i.waiting)
wake_up(&device->misc_wait);
- if (c_put) {
- if (drbd_req_put_completion_ref(req, m, c_put))
- kref_put(&req->kref, drbd_req_destroy);
- } else {
- kref_put(&req->kref, drbd_req_destroy);
- }
+ drbd_req_put_completion_ref(req, m, c_put);
+ kref_put(&req->kref, drbd_req_destroy);
}
static void drbd_report_io_error(struct drbd_device *device, struct drbd_request *req)
@@ -1366,8 +1370,7 @@
}
out:
- if (drbd_req_put_completion_ref(req, &m, 1))
- kref_put(&req->kref, drbd_req_destroy);
+ drbd_req_put_completion_ref(req, &m, 1);
spin_unlock_irq(&resource->req_lock);
/* Even though above is a kref_put(), this is safe.