1 files changed, 492 insertions, 0 deletions
diff --git a/drivers/s390/char/tape_block.c b/drivers/s390/char/tape_block.c
new file mode 100644
index 000000000000..1efc9f21229e
--- /dev/null
+++ b/drivers/s390/char/tape_block.c
@@ -0,0 +1,492 @@
+/*
+ *  drivers/s390/char/tape_block.c
+ *    block device frontend for tape device driver
+ *
+ *  S390 and zSeries version
+ *    Copyright (C) 2001,2003 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ *    Author(s): Carsten Otte <cotte@de.ibm.com>
+ *		 Tuan Ngo-Anh <ngoanh@de.ibm.com>
+ *		 Martin Schwidefsky <schwidefsky@de.ibm.com>
+ *		 Stefan Bader <shbader@de.ibm.com>
+ */
+
+#include <linux/fs.h>
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/blkdev.h>
+#include <linux/interrupt.h>
+#include <linux/buffer_head.h>
+
+#include <asm/debug.h>
+
+#define TAPE_DBF_AREA	tape_core_dbf
+
+#include "tape.h"
+
+#define PRINTK_HEADER "TAPE_BLOCK: "
+
+#define TAPEBLOCK_MAX_SEC	100
+#define TAPEBLOCK_MIN_REQUEUE	3
+
+/*
+ * 2003/11/25  Stefan Bader <shbader@de.ibm.com>
+ *
+ * In 2.5/2.6 the block device request function is very likely to be called
+ * with disabled interrupts (e.g. generic_unplug_device). So the driver can't
+ * just call any function that tries to allocate CCW requests from that con-
+ * text since it might sleep. There are two choices to work around this:
+ *	a) do not allocate with kmalloc but use its own memory pool
+ *      b) take requests from the queue outside that context, knowing that
+ *         allocation might sleep
+ */
+
+/*
+ * file operation structure for tape block frontend
+ */
+static int tapeblock_open(struct inode *, struct file *);
+static int tapeblock_release(struct inode *, struct file *);
+static int tapeblock_ioctl(struct inode *, struct file *, unsigned int,
+				unsigned long);
+static int tapeblock_medium_changed(struct gendisk *);
+static int tapeblock_revalidate_disk(struct gendisk *);
+
+static struct block_device_operations tapeblock_fops = {
+	.owner		 = THIS_MODULE,
+	.open		 = tapeblock_open,
+	.release	 = tapeblock_release,
+	.ioctl           = tapeblock_ioctl,
+	.media_changed   = tapeblock_medium_changed,
+	.revalidate_disk = tapeblock_revalidate_disk,
+};
+
+static int tapeblock_major = 0;
+
+static void
+tapeblock_trigger_requeue(struct tape_device *device)
+{
+	/* Protect against rescheduling. */
+	if (atomic_compare_and_swap(0, 1, &device->blk_data.requeue_scheduled))
+		return;
+	schedule_work(&device->blk_data.requeue_task);
+}
+
+/*
+ * Post finished request.
+ */
+static inline void
+tapeblock_end_request(struct request *req, int uptodate)
+{
+	if (end_that_request_first(req, uptodate, req->hard_nr_sectors))
+		BUG();
+	end_that_request_last(req);
+}
+
+static void
+__tapeblock_end_request(struct tape_request *ccw_req, void *data)
+{
+	struct tape_device *device;
+	struct request *req;
+
+	DBF_LH(6, "__tapeblock_end_request()\n");
+
+	device = ccw_req->device;
+	req = (struct request *) data;
+	tapeblock_end_request(req, ccw_req->rc == 0);
+	if (ccw_req->rc == 0)
+		/* Update position. */
+		device->blk_data.block_position =
+			(req->sector + req->nr_sectors) >> TAPEBLOCK_HSEC_S2B;
+	else
+		/* We lost the position information due to an error. */
+		device->blk_data.block_position = -1;
+	device->discipline->free_bread(ccw_req);
+	if (!list_empty(&device->req_queue) ||
+	    elv_next_request(device->blk_data.request_queue))
+		tapeblock_trigger_requeue(device);
+}
+
+/*
+ * Feed the tape device CCW queue with requests supplied in a list.
+ */
+static inline int
+tapeblock_start_request(struct tape_device *device, struct request *req)
+{
+	struct tape_request *	ccw_req;
+	int			rc;
+
+	DBF_LH(6, "tapeblock_start_request(%p, %p)\n", device, req);
+
+	ccw_req = device->discipline->bread(device, req);
+	if (IS_ERR(ccw_req)) {
+		DBF_EVENT(1, "TBLOCK: bread failed\n");
+		tapeblock_end_request(req, 0);
+		return PTR_ERR(ccw_req);
+	}
+	ccw_req->callback = __tapeblock_end_request;
+	ccw_req->callback_data = (void *) req;
+	ccw_req->retries = TAPEBLOCK_RETRIES;
+
+	rc = tape_do_io_async(device, ccw_req);
+	if (rc) {
+		/*
+		 * Start/enqueueing failed. No retries in
+		 * this case.
+		 */
+		tapeblock_end_request(req, 0);
+		device->discipline->free_bread(ccw_req);
+	}
+
+	return rc;
+}
+
+/*
+ * Move requests from the block device request queue to the tape device ccw
+ * queue.
+ */
+static void
+tapeblock_requeue(void *data) {
+	struct tape_device *	device;
+	request_queue_t *	queue;
+	int			nr_queued;
+	struct request *	req;
+	struct list_head *	l;
+	int			rc;
+
+	device = (struct tape_device *) data;
+	if (!device)
+		return;
+
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	queue  = device->blk_data.request_queue;
+
+	/* Count number of requests on ccw queue. */
+	nr_queued = 0;
+	list_for_each(l, &device->req_queue)
+		nr_queued++;
+	spin_unlock(get_ccwdev_lock(device->cdev));
+
+	spin_lock(&device->blk_data.request_queue_lock);
+	while (
+		!blk_queue_plugged(queue) &&
+		elv_next_request(queue)   &&
+		nr_queued < TAPEBLOCK_MIN_REQUEUE
+	) {
+		req = elv_next_request(queue);
+		if (rq_data_dir(req) == WRITE) {
+			DBF_EVENT(1, "TBLOCK: Rejecting write request\n");
+			blkdev_dequeue_request(req);
+			tapeblock_end_request(req, 0);
+			continue;
+		}
+		spin_unlock_irq(&device->blk_data.request_queue_lock);
+		rc = tapeblock_start_request(device, req);
+		spin_lock_irq(&device->blk_data.request_queue_lock);
+		blkdev_dequeue_request(req);
+		nr_queued++;
+	}
+	spin_unlock_irq(&device->blk_data.request_queue_lock);
+	atomic_set(&device->blk_data.requeue_scheduled, 0);
+}
+
+/*
+ * Tape request queue function. Called from ll_rw_blk.c
+ */
+static void
+tapeblock_request_fn(request_queue_t *queue)
+{
+	struct tape_device *device;
+
+	device = (struct tape_device *) queue->queuedata;
+	DBF_LH(6, "tapeblock_request_fn(device=%p)\n", device);
+	if (device == NULL)
+		BUG();
+
+	tapeblock_trigger_requeue(device);
+}
+
+/*
+ * This function is called for every new tapedevice
+ */
+int
+tapeblock_setup_device(struct tape_device * device)
+{
+	struct tape_blk_data *	blkdat;
+	struct gendisk *	disk;
+	int			rc;
+
+	blkdat = &device->blk_data;
+	spin_lock_init(&blkdat->request_queue_lock);
+	atomic_set(&blkdat->requeue_scheduled, 0);
+
+	blkdat->request_queue = blk_init_queue(
+		tapeblock_request_fn,
+		&blkdat->request_queue_lock
+	);
+	if (!blkdat->request_queue)
+		return -ENOMEM;
+
+	elevator_exit(blkdat->request_queue->elevator);
+	rc = elevator_init(blkdat->request_queue, "noop");
+	if (rc)
+		goto cleanup_queue;
+
+	blk_queue_hardsect_size(blkdat->request_queue, TAPEBLOCK_HSEC_SIZE);
+	blk_queue_max_sectors(blkdat->request_queue, TAPEBLOCK_MAX_SEC);
+	blk_queue_max_phys_segments(blkdat->request_queue, -1L);
+	blk_queue_max_hw_segments(blkdat->request_queue, -1L);
+	blk_queue_max_segment_size(blkdat->request_queue, -1L);
+	blk_queue_segment_boundary(blkdat->request_queue, -1L);
+
+	disk = alloc_disk(1);
+	if (!disk) {
+		rc = -ENOMEM;
+		goto cleanup_queue;
+	}
+
+	disk->major = tapeblock_major;
+	disk->first_minor = device->first_minor;
+	disk->fops = &tapeblock_fops;
+	disk->private_data = tape_get_device_reference(device);
+	disk->queue = blkdat->request_queue;
+	set_capacity(disk, 0);
+	sprintf(disk->disk_name, "btibm%d",
+		device->first_minor / TAPE_MINORS_PER_DEV);
+
+	blkdat->disk = disk;
+	blkdat->medium_changed = 1;
+	blkdat->request_queue->queuedata = tape_get_device_reference(device);
+
+	add_disk(disk);
+
+	INIT_WORK(&blkdat->requeue_task, tapeblock_requeue,
+		tape_get_device_reference(device));
+
+	return 0;
+
+cleanup_queue:
+	blk_cleanup_queue(blkdat->request_queue);
+	blkdat->request_queue = NULL;
+
+	return rc;
+}
+
+void
+tapeblock_cleanup_device(struct tape_device *device)
+{
+	flush_scheduled_work();
+	device->blk_data.requeue_task.data = tape_put_device(device);
+
+	if (!device->blk_data.disk) {
+		PRINT_ERR("(%s): No gendisk to clean up!\n",
+			device->cdev->dev.bus_id);
+		goto cleanup_queue;
+	}
+
+	del_gendisk(device->blk_data.disk);
+	device->blk_data.disk->private_data =
+		tape_put_device(device->blk_data.disk->private_data);
+	put_disk(device->blk_data.disk);
+
+	device->blk_data.disk = NULL;
+cleanup_queue:
+	device->blk_data.request_queue->queuedata = tape_put_device(device);
+
+	blk_cleanup_queue(device->blk_data.request_queue);
+	device->blk_data.request_queue = NULL;
+}
+
+/*
+ * Detect number of blocks of the tape.
+ * FIXME: can we extent this to detect the blocks size as well ?
+ */
+static int
+tapeblock_revalidate_disk(struct gendisk *disk)
+{
+	struct tape_device *	device;
+	unsigned int		nr_of_blks;
+	int			rc;
+
+	device = (struct tape_device *) disk->private_data;
+	if (!device)
+		BUG();
+
+	if (!device->blk_data.medium_changed)
+		return 0;
+
+	PRINT_INFO("Detecting media size...\n");
+	rc = tape_mtop(device, MTFSFM, 1);
+	if (rc)
+		return rc;
+
+	rc = tape_mtop(device, MTTELL, 1);
+	if (rc < 0)
+		return rc;
+
+	DBF_LH(3, "Image file ends at %d\n", rc);
+	nr_of_blks = rc;
+
+	/* This will fail for the first file. Catch the error by checking the
+	 * position. */
+	tape_mtop(device, MTBSF, 1);
+
+	rc = tape_mtop(device, MTTELL, 1);
+	if (rc < 0)
+		return rc;
+
+	if (rc > nr_of_blks)
+		return -EINVAL;
+
+	DBF_LH(3, "Image file starts at %d\n", rc);
+	device->bof = rc;
+	nr_of_blks -= rc;
+
+	PRINT_INFO("Found %i blocks on media\n", nr_of_blks);
+	set_capacity(device->blk_data.disk,
+		nr_of_blks*(TAPEBLOCK_HSEC_SIZE/512));
+
+	device->blk_data.block_position = 0;
+	device->blk_data.medium_changed = 0;
+	return 0;
+}
+
+static int
+tapeblock_medium_changed(struct gendisk *disk)
+{
+	struct tape_device *device;
+
+	device = (struct tape_device *) disk->private_data;
+	DBF_LH(6, "tapeblock_medium_changed(%p) = %d\n",
+		device, device->blk_data.medium_changed);
+
+	return device->blk_data.medium_changed;
+}
+
+/*
+ * Block frontend tape device open function.
+ */
+static int
+tapeblock_open(struct inode *inode, struct file *filp)
+{
+	struct gendisk *	disk;
+	struct tape_device *	device;
+	int			rc;
+
+	disk   = inode->i_bdev->bd_disk;
+	device = tape_get_device_reference(disk->private_data);
+
+	if (device->required_tapemarks) {
+		DBF_EVENT(2, "TBLOCK: missing tapemarks\n");
+		PRINT_ERR("TBLOCK: Refusing to open tape with missing"
+			" end of file marks.\n");
+		rc = -EPERM;
+		goto put_device;
+	}
+
+	rc = tape_open(device);
+	if (rc)
+		goto put_device;
+
+	rc = tapeblock_revalidate_disk(disk);
+	if (rc)
+		goto release;
+
+	/*
+	 * Note: The reference to <device> is hold until the release function
+	 *       is called.
+	 */
+	tape_state_set(device, TS_BLKUSE);
+	return 0;
+
+release:
+	tape_release(device);
+ put_device:
+	tape_put_device(device);
+	return rc;
+}
+
+/*
+ * Block frontend tape device release function.
+ *
+ * Note: One reference to the tape device was made by the open function. So
+ *       we just get the pointer here and release the reference.
+ */
+static int
+tapeblock_release(struct inode *inode, struct file *filp)
+{
+	struct gendisk *disk = inode->i_bdev->bd_disk;
+	struct tape_device *device = disk->private_data;
+
+	tape_state_set(device, TS_IN_USE);
+	tape_release(device);
+	tape_put_device(device);
+
+	return 0;
+}
+
+/*
+ * Support of some generic block device IOCTLs.
+ */
+static int
+tapeblock_ioctl(
+	struct inode *		inode,
+	struct file *		file,
+	unsigned int		command,
+	unsigned long		arg
+) {
+	int rc;
+	int minor;
+	struct gendisk *disk = inode->i_bdev->bd_disk;
+	struct tape_device *device = disk->private_data;
+
+	rc     = 0;
+	disk   = inode->i_bdev->bd_disk;
+	if (!disk)
+		BUG();
+	device = disk->private_data;
+	if (!device)
+		BUG();
+	minor  = iminor(inode);
+
+	DBF_LH(6, "tapeblock_ioctl(0x%0x)\n", command);
+	DBF_LH(6, "device = %d:%d\n", tapeblock_major, minor);
+
+	switch (command) {
+		/* Refuse some IOCTL calls without complaining (mount). */
+		case 0x5310:		/* CDROMMULTISESSION */
+			rc = -EINVAL;
+			break;
+		default:
+			PRINT_WARN("invalid ioctl 0x%x\n", command);
+			rc = -EINVAL;
+	}
+
+	return rc;
+}
+
+/*
+ * Initialize block device frontend.
+ */
+int
+tapeblock_init(void)
+{
+	int rc;
+
+	/* Register the tape major number to the kernel */
+	rc = register_blkdev(tapeblock_major, "tBLK");
+	if (rc < 0)
+		return rc;
+
+	if (tapeblock_major == 0)
+		tapeblock_major = rc;
+	PRINT_INFO("tape gets major %d for block device\n", tapeblock_major);
+	return 0;
+}
+
+/*
+ * Deregister major for block device frontend
+ */
+void
+tapeblock_exit(void)
+{
+	unregister_blkdev(tapeblock_major, "tBLK");
+}