+++ /dev/null
-/*
- * 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>
- */
-
-#define KMSG_COMPONENT "tape"
-#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
-
-#include <linux/fs.h>
-#include <linux/module.h>
-#include <linux/blkdev.h>
-#include <linux/mutex.h>
-#include <linux/interrupt.h>
-#include <linux/buffer_head.h>
-#include <linux/kernel.h>
-
-#include <asm/debug.h>
-
-#define TAPE_DBF_AREA tape_core_dbf
-
-#include "tape.h"
-
-#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 DEFINE_MUTEX(tape_block_mutex);
-static int tapeblock_open(struct block_device *, fmode_t);
-static int tapeblock_release(struct gendisk *, fmode_t);
-static unsigned int tapeblock_check_events(struct gendisk *, unsigned int);
-static int tapeblock_revalidate_disk(struct gendisk *);
-
-static const struct block_device_operations tapeblock_fops = {
- .owner = THIS_MODULE,
- .open = tapeblock_open,
- .release = tapeblock_release,
- .check_events = tapeblock_check_events,
- .revalidate_disk = tapeblock_revalidate_disk,
-};
-
-static int tapeblock_major = 0;
-
-static void
-tapeblock_trigger_requeue(struct tape_device *device)
-{
- /* Protect against rescheduling. */
- if (atomic_cmpxchg(&device->blk_data.requeue_scheduled, 0, 1) != 0)
- return;
- schedule_work(&device->blk_data.requeue_task);
-}
-
-/*
- * Post finished request.
- */
-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;
- blk_end_request_all(req, (ccw_req->rc == 0) ? 0 : -EIO);
- if (ccw_req->rc == 0)
- /* Update position. */
- device->blk_data.block_position =
- (blk_rq_pos(req) + blk_rq_sectors(req)) >> 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) ||
- blk_peek_request(device->blk_data.request_queue))
- tapeblock_trigger_requeue(device);
-}
-
-/*
- * Feed the tape device CCW queue with requests supplied in a list.
- */
-static 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");
- blk_end_request_all(req, -EIO);
- 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.
- */
- blk_end_request_all(req, -EIO);
- 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(struct work_struct *work) {
- struct tape_blk_data * blkdat;
- struct tape_device * device;
- struct request_queue * queue;
- int nr_queued;
- struct request * req;
- struct list_head * l;
- int rc;
-
- blkdat = container_of(work, struct tape_blk_data, requeue_task);
- device = blkdat->device;
- 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_irq(&device->blk_data.request_queue_lock);
- while (
- blk_peek_request(queue) &&
- nr_queued < TAPEBLOCK_MIN_REQUEUE
- ) {
- req = blk_fetch_request(queue);
- if (rq_data_dir(req) == WRITE) {
- DBF_EVENT(1, "TBLOCK: Rejecting write request\n");
- spin_unlock_irq(&device->blk_data.request_queue_lock);
- blk_end_request_all(req, -EIO);
- spin_lock_irq(&device->blk_data.request_queue_lock);
- continue;
- }
- nr_queued++;
- spin_unlock_irq(&device->blk_data.request_queue_lock);
- rc = tapeblock_start_request(device, req);
- spin_lock_irq(&device->blk_data.request_queue_lock);
- }
- 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(struct request_queue *queue)
-{
- struct tape_device *device;
-
- device = (struct tape_device *) queue->queuedata;
- DBF_LH(6, "tapeblock_request_fn(device=%p)\n", device);
- BUG_ON(device == NULL);
- 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;
- blkdat->device = device;
- 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;
-
- rc = elevator_change(blkdat->request_queue, "noop");
- if (rc)
- goto cleanup_queue;
-
- blk_queue_logical_block_size(blkdat->request_queue, TAPEBLOCK_HSEC_SIZE);
- blk_queue_max_hw_sectors(blkdat->request_queue, TAPEBLOCK_MAX_SEC);
- blk_queue_max_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(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(device);
-
- add_disk(disk);
-
- tape_get_device(device);
- INIT_WORK(&blkdat->requeue_task, tapeblock_requeue);
-
- 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_work_sync(&device->blk_data.requeue_task);
- tape_put_device(device);
-
- if (!device->blk_data.disk) {
- goto cleanup_queue;
- }
-
- del_gendisk(device->blk_data.disk);
- device->blk_data.disk->private_data = NULL;
- tape_put_device(device);
- put_disk(device->blk_data.disk);
-
- device->blk_data.disk = NULL;
-cleanup_queue:
- device->blk_data.request_queue->queuedata = NULL;
- 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;
- BUG_ON(!device);
-
- if (!device->blk_data.medium_changed)
- return 0;
-
- rc = tape_mtop(device, MTFSFM, 1);
- if (rc)
- return rc;
-
- rc = tape_mtop(device, MTTELL, 1);
- if (rc < 0)
- return rc;
-
- pr_info("%s: Determining the size of the recorded area...\n",
- dev_name(&device->cdev->dev));
- 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;
-
- pr_info("%s: The size of the recorded area is %i blocks\n",
- dev_name(&device->cdev->dev), 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 unsigned int
-tapeblock_check_events(struct gendisk *disk, unsigned int clearing)
-{
- 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 ? DISK_EVENT_MEDIA_CHANGE : 0;
-}
-
-/*
- * Block frontend tape device open function.
- */
-static int
-tapeblock_open(struct block_device *bdev, fmode_t mode)
-{
- struct gendisk * disk = bdev->bd_disk;
- struct tape_device * device;
- int rc;
-
- mutex_lock(&tape_block_mutex);
- device = tape_get_device(disk->private_data);
-
- if (device->required_tapemarks) {
- DBF_EVENT(2, "TBLOCK: missing tapemarks\n");
- pr_warning("%s: Opening the tape failed because of missing "
- "end-of-file marks\n", dev_name(&device->cdev->dev));
- 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);
- mutex_unlock(&tape_block_mutex);
- return 0;
-
-release:
- tape_release(device);
- put_device:
- tape_put_device(device);
- mutex_unlock(&tape_block_mutex);
- 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 gendisk *disk, fmode_t mode)
-{
- struct tape_device *device = disk->private_data;
-
- mutex_lock(&tape_block_mutex);
- tape_state_set(device, TS_IN_USE);
- tape_release(device);
- tape_put_device(device);
- mutex_unlock(&tape_block_mutex);
-
- return 0;
-}
-
-/*
- * 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;
- return 0;
-}
-
-/*
- * Deregister major for block device frontend
- */
-void
-tapeblock_exit(void)
-{
- unregister_blkdev(tapeblock_major, "tBLK");
-}
projects / users / willy / linux.git / commitdiff