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");
+}