+ * Clear timeout for a dasd_block.
+ */
+void dasd_block_clear_timer(struct dasd_block *block)
+{
+ del_timer(&block->timer);
+}
+
+/*
+ * Process finished error recovery ccw.
+ */
+static void __dasd_process_erp(struct dasd_device *device,
+ struct dasd_ccw_req *cqr)
+{
+ dasd_erp_fn_t erp_fn;
+
+ if (cqr->status == DASD_CQR_DONE)
+ DBF_DEV_EVENT(DBF_NOTICE, device, "%s", "ERP successful");
+ else
+ dev_err(&device->cdev->dev, "ERP failed for the DASD\n");
+ erp_fn = device->discipline->erp_postaction(cqr);
+ erp_fn(cqr);
+}
+
+/*
+ * Fetch requests from the block device queue.
+ */
+static void __dasd_process_request_queue(struct dasd_block *block)
+{
+ struct request_queue *queue;
+ struct request *req;
+ struct dasd_ccw_req *cqr;
+ struct dasd_device *basedev;
+ unsigned long flags;
+ queue = block->request_queue;
+ basedev = block->base;
+ /* No queue ? Then there is nothing to do. */
+ if (queue == NULL)
+ return;
+
+ /*
+ * We requeue request from the block device queue to the ccw
+ * queue only in two states. In state DASD_STATE_READY the
+ * partition detection is done and we need to requeue requests
+ * for that. State DASD_STATE_ONLINE is normal block device
+ * operation.
+ */
+ if (basedev->state < DASD_STATE_READY) {
+ while ((req = blk_fetch_request(block->request_queue)))
+ __blk_end_request_all(req, -EIO);
+ return;
+ }
+ /* Now we try to fetch requests from the request queue */
+ while (!blk_queue_plugged(queue) && (req = blk_peek_request(queue))) {
+ if (basedev->features & DASD_FEATURE_READONLY &&
+ rq_data_dir(req) == WRITE) {
+ DBF_DEV_EVENT(DBF_ERR, basedev,
+ "Rejecting write request %p",
+ req);
+ blk_start_request(req);
+ __blk_end_request_all(req, -EIO);
+ continue;
+ }
+ cqr = basedev->discipline->build_cp(basedev, block, req);
+ if (IS_ERR(cqr)) {
+ if (PTR_ERR(cqr) == -EBUSY)
+ break; /* normal end condition */
+ if (PTR_ERR(cqr) == -ENOMEM)
+ break; /* terminate request queue loop */
+ if (PTR_ERR(cqr) == -EAGAIN) {
+ /*
+ * The current request cannot be build right
+ * now, we have to try later. If this request
+ * is the head-of-queue we stop the device
+ * for 1/2 second.
+ */
+ if (!list_empty(&block->ccw_queue))
+ break;
+ spin_lock_irqsave(
+ get_ccwdev_lock(basedev->cdev), flags);
+ dasd_device_set_stop_bits(basedev,
+ DASD_STOPPED_PENDING);
+ spin_unlock_irqrestore(
+ get_ccwdev_lock(basedev->cdev), flags);
+ dasd_block_set_timer(block, HZ/2);
+ break;
+ }
+ DBF_DEV_EVENT(DBF_ERR, basedev,
+ "CCW creation failed (rc=%ld) "
+ "on request %p",
+ PTR_ERR(cqr), req);
+ blk_start_request(req);
+ __blk_end_request_all(req, -EIO);
+ continue;
+ }
+ /*
+ * Note: callback is set to dasd_return_cqr_cb in
+ * __dasd_block_start_head to cover erp requests as well
+ */
+ cqr->callback_data = (void *) req;
+ cqr->status = DASD_CQR_FILLED;
+ blk_start_request(req);
+ list_add_tail(&cqr->blocklist, &block->ccw_queue);
+ dasd_profile_start(block, cqr, req);
+ }
+}
+
+static void __dasd_cleanup_cqr(struct dasd_ccw_req *cqr)
+{
+ struct request *req;
+ int status;
+ int error = 0;
+
+ req = (struct request *) cqr->callback_data;
+ dasd_profile_end(cqr->block, cqr, req);
+ status = cqr->block->base->discipline->free_cp(cqr, req);
+ if (status <= 0)
+ error = status ? status : -EIO;
+ __blk_end_request_all(req, error);
+}
+
+/*
+ * Process ccw request queue.
+ */
+static void __dasd_process_block_ccw_queue(struct dasd_block *block,
+ struct list_head *final_queue)
+{
+ struct list_head *l, *n;
+ struct dasd_ccw_req *cqr;
+ dasd_erp_fn_t erp_fn;
+ unsigned long flags;
+ struct dasd_device *base = block->base;
+
+restart:
+ /* Process request with final status. */
+ list_for_each_safe(l, n, &block->ccw_queue) {
+ cqr = list_entry(l, struct dasd_ccw_req, blocklist);
+ if (cqr->status != DASD_CQR_DONE &&
+ cqr->status != DASD_CQR_FAILED &&
+ cqr->status != DASD_CQR_NEED_ERP &&
+ cqr->status != DASD_CQR_TERMINATED)
+ continue;
+
+ if (cqr->status == DASD_CQR_TERMINATED) {
+ base->discipline->handle_terminated_request(cqr);
+ goto restart;
+ }
+
+ /* Process requests that may be recovered */
+ if (cqr->status == DASD_CQR_NEED_ERP) {
+ erp_fn = base->discipline->erp_action(cqr);
+ if (IS_ERR(erp_fn(cqr)))
+ continue;
+ goto restart;
+ }
+
+ /* log sense for fatal error */
+ if (cqr->status == DASD_CQR_FAILED) {
+ dasd_log_sense(cqr, &cqr->irb);
+ }
+
+ /* First of all call extended error reporting. */
+ if (dasd_eer_enabled(base) &&
+ cqr->status == DASD_CQR_FAILED) {
+ dasd_eer_write(base, cqr, DASD_EER_FATALERROR);
+
+ /* restart request */
+ cqr->status = DASD_CQR_FILLED;
+ cqr->retries = 255;
+ spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags);
+ dasd_device_set_stop_bits(base, DASD_STOPPED_QUIESCE);
+ spin_unlock_irqrestore(get_ccwdev_lock(base->cdev),
+ flags);
+ goto restart;
+ }
+
+ /* Process finished ERP request. */
+ if (cqr->refers) {
+ __dasd_process_erp(base, cqr);
+ goto restart;
+ }
+
+ /* Rechain finished requests to final queue */
+ cqr->endclk = get_clock();
+ list_move_tail(&cqr->blocklist, final_queue);
+ }
+}
+
+static void dasd_return_cqr_cb(struct dasd_ccw_req *cqr, void *data)
+{
+ dasd_schedule_block_bh(cqr->block);
+}
+
+static void __dasd_block_start_head(struct dasd_block *block)
+{
+ struct dasd_ccw_req *cqr;
+
+ if (list_empty(&block->ccw_queue))
+ return;
+ /* We allways begin with the first requests on the queue, as some
+ * of previously started requests have to be enqueued on a
+ * dasd_device again for error recovery.
+ */
+ list_for_each_entry(cqr, &block->ccw_queue, blocklist) {
+ if (cqr->status != DASD_CQR_FILLED)
+ continue;
+ /* Non-temporary stop condition will trigger fail fast */
+ if (block->base->stopped & ~DASD_STOPPED_PENDING &&
+ test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
+ (!dasd_eer_enabled(block->base))) {
+ cqr->status = DASD_CQR_FAILED;
+ dasd_schedule_block_bh(block);
+ continue;
+ }
+ /* Don't try to start requests if device is stopped */
+ if (block->base->stopped)
+ return;
+
+ /* just a fail safe check, should not happen */
+ if (!cqr->startdev)
+ cqr->startdev = block->base;
+
+ /* make sure that the requests we submit find their way back */
+ cqr->callback = dasd_return_cqr_cb;
+
+ dasd_add_request_tail(cqr);
+ }
+}
+
+/*
+ * Central dasd_block layer routine. Takes requests from the generic
+ * block layer request queue, creates ccw requests, enqueues them on
+ * a dasd_device and processes ccw requests that have been returned.
+ */
+static void dasd_block_tasklet(struct dasd_block *block)
+{
+ struct list_head final_queue;
+ struct list_head *l, *n;
+ struct dasd_ccw_req *cqr;
+
+ atomic_set(&block->tasklet_scheduled, 0);
+ INIT_LIST_HEAD(&final_queue);
+ spin_lock(&block->queue_lock);
+ /* Finish off requests on ccw queue */
+ __dasd_process_block_ccw_queue(block, &final_queue);
+ spin_unlock(&block->queue_lock);
+ /* Now call the callback function of requests with final status */
+ spin_lock_irq(&block->request_queue_lock);
+ list_for_each_safe(l, n, &final_queue) {
+ cqr = list_entry(l, struct dasd_ccw_req, blocklist);
+ list_del_init(&cqr->blocklist);
+ __dasd_cleanup_cqr(cqr);
+ }
+ spin_lock(&block->queue_lock);
+ /* Get new request from the block device request queue */
+ __dasd_process_request_queue(block);
+ /* Now check if the head of the ccw queue needs to be started. */
+ __dasd_block_start_head(block);
+ spin_unlock(&block->queue_lock);
+ spin_unlock_irq(&block->request_queue_lock);
+ dasd_put_device(block->base);
+}
+
+static void _dasd_wake_block_flush_cb(struct dasd_ccw_req *cqr, void *data)
+{
+ wake_up(&dasd_flush_wq);
+}
+
+/*
+ * Go through all request on the dasd_block request queue, cancel them
+ * on the respective dasd_device, and return them to the generic
+ * block layer.
+ */
+static int dasd_flush_block_queue(struct dasd_block *block)
+{
+ struct dasd_ccw_req *cqr, *n;
+ int rc, i;
+ struct list_head flush_queue;
+
+ INIT_LIST_HEAD(&flush_queue);
+ spin_lock_bh(&block->queue_lock);
+ rc = 0;
+restart:
+ list_for_each_entry_safe(cqr, n, &block->ccw_queue, blocklist) {
+ /* if this request currently owned by a dasd_device cancel it */
+ if (cqr->status >= DASD_CQR_QUEUED)
+ rc = dasd_cancel_req(cqr);
+ if (rc < 0)
+ break;
+ /* Rechain request (including erp chain) so it won't be
+ * touched by the dasd_block_tasklet anymore.
+ * Replace the callback so we notice when the request
+ * is returned from the dasd_device layer.
+ */
+ cqr->callback = _dasd_wake_block_flush_cb;
+ for (i = 0; cqr != NULL; cqr = cqr->refers, i++)
+ list_move_tail(&cqr->blocklist, &flush_queue);
+ if (i > 1)
+ /* moved more than one request - need to restart */
+ goto restart;
+ }
+ spin_unlock_bh(&block->queue_lock);
+ /* Now call the callback function of flushed requests */
+restart_cb:
+ list_for_each_entry_safe(cqr, n, &flush_queue, blocklist) {
+ wait_event(dasd_flush_wq, (cqr->status < DASD_CQR_QUEUED));
+ /* Process finished ERP request. */
+ if (cqr->refers) {
+ spin_lock_bh(&block->queue_lock);
+ __dasd_process_erp(block->base, cqr);
+ spin_unlock_bh(&block->queue_lock);
+ /* restart list_for_xx loop since dasd_process_erp
+ * might remove multiple elements */
+ goto restart_cb;
+ }
+ /* call the callback function */
+ spin_lock_irq(&block->request_queue_lock);
+ cqr->endclk = get_clock();
+ list_del_init(&cqr->blocklist);
+ __dasd_cleanup_cqr(cqr);
+ spin_unlock_irq(&block->request_queue_lock);
+ }
+ return rc;
+}
+
+/*
+ * Schedules a call to dasd_tasklet over the device tasklet.
+ */
+void dasd_schedule_block_bh(struct dasd_block *block)
+{
+ /* Protect against rescheduling. */
+ if (atomic_cmpxchg(&block->tasklet_scheduled, 0, 1) != 0)
+ return;
+ /* life cycle of block is bound to it's base device */
+ dasd_get_device(block->base);
+ tasklet_hi_schedule(&block->tasklet);
+}
+
+
+/*
+ * SECTION: external block device operations
+ * (request queue handling, open, release, etc.)