diff options
Diffstat (limited to 'drivers/block/drbd/drbd_req.c')
| -rw-r--r-- | drivers/block/drbd/drbd_req.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c index 447c975f5481..5cf43f13e7eb 100644 --- a/drivers/block/drbd/drbd_req.c +++ b/drivers/block/drbd/drbd_req.c @@ -1279,6 +1279,56 @@ static bool may_do_writes(struct drbd_device *device) return s.disk == D_UP_TO_DATE || s.pdsk == D_UP_TO_DATE; } +struct drbd_plug_cb { + struct blk_plug_cb cb; + struct drbd_request *most_recent_req; + /* do we need more? */ +}; + +static void drbd_unplug(struct blk_plug_cb *cb, bool from_schedule) +{ + struct drbd_plug_cb *plug = container_of(cb, struct drbd_plug_cb, cb); + struct drbd_resource *resource = plug->cb.data; + struct drbd_request *req = plug->most_recent_req; + + if (!req) + return; + + spin_lock_irq(&resource->req_lock); + /* In case the sender did not process it yet, raise the flag to + * have it followed with P_UNPLUG_REMOTE just after. */ + req->rq_state |= RQ_UNPLUG; + /* but also queue a generic unplug */ + drbd_queue_unplug(req->device); + spin_unlock_irq(&resource->req_lock); + kref_put(&req->kref, drbd_req_destroy); +} + +static struct drbd_plug_cb* drbd_check_plugged(struct drbd_resource *resource) +{ + /* A lot of text to say + * return (struct drbd_plug_cb*)blk_check_plugged(); */ + struct drbd_plug_cb *plug; + struct blk_plug_cb *cb = blk_check_plugged(drbd_unplug, resource, sizeof(*plug)); + + if (cb) + plug = container_of(cb, struct drbd_plug_cb, cb); + else + plug = NULL; + return plug; +} + +static void drbd_update_plug(struct drbd_plug_cb *plug, struct drbd_request *req) +{ + struct drbd_request *tmp = plug->most_recent_req; + /* Will be sent to some peer. + * Remember to tag it with UNPLUG_REMOTE on unplug */ + kref_get(&req->kref); + plug->most_recent_req = req; + if (tmp) + kref_put(&tmp->kref, drbd_req_destroy); +} + static void drbd_send_and_submit(struct drbd_device *device, struct drbd_request *req) { struct drbd_resource *resource = device->resource; @@ -1287,6 +1337,8 @@ static void drbd_send_and_submit(struct drbd_device *device, struct drbd_request bool no_remote = false; bool submit_private_bio = false; + struct drbd_plug_cb *plug = drbd_check_plugged(resource); + spin_lock_irq(&resource->req_lock); if (rw == WRITE) { /* This may temporarily give up the req_lock, @@ -1351,6 +1403,9 @@ static void drbd_send_and_submit(struct drbd_device *device, struct drbd_request no_remote = true; } + if (plug != NULL && no_remote == false) + drbd_update_plug(plug, req); + /* If it took the fast path in drbd_request_prepare, add it here. * The slow path has added it already. */ if (list_empty(&req->req_pending_master_completion)) |