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sr.c

/*
 *  sr.c Copyright (C) 1992 David Giller
 *           Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
 *
 *  adapted from:
 *      sd.c Copyright (C) 1992 Drew Eckhardt
 *      Linux scsi disk driver by
 *              Drew Eckhardt <drew@colorado.edu>
 *
 *    Modified by Eric Youngdale ericy@andante.org to
 *    add scatter-gather, multiple outstanding request, and other
 *    enhancements.
 *
 *      Modified by Eric Youngdale eric@andante.org to support loadable
 *      low-level scsi drivers.
 *
 *      Modified by Thomas Quinot thomas@melchior.cuivre.fdn.fr to
 *      provide auto-eject.
 *
 *      Modified by Gerd Knorr <kraxel@cs.tu-berlin.de> to support the
 *      generic cdrom interface
 *
 *      Modified by Jens Axboe <axboe@suse.de> - Uniform sr_packet()
 *      interface, capabilities probe additions, ioctl cleanups, etc.
 *
 *    Modified by Richard Gooch <rgooch@atnf.csiro.au> to support devfs
 *
 *    Modified by Jens Axboe <axboe@suse.de> - support DVD-RAM
 *    transparently and lose the GHOST hack
 *
 *    Modified by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *    check resource allocation in sr_init and some cleanups
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/bio.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/cdrom.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/mutex.h>
#include <asm/uaccess.h>

#include <scsi/scsi.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_driver.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_ioctl.h>  /* For the door lock/unlock commands */

#include "scsi_logging.h"
#include "sr.h"


MODULE_DESCRIPTION("SCSI cdrom (sr) driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_CDROM_MAJOR);
MODULE_ALIAS_SCSI_DEVICE(TYPE_ROM);
MODULE_ALIAS_SCSI_DEVICE(TYPE_WORM);

#define SR_DISKS  256

#define MAX_RETRIES     3
#define SR_TIMEOUT      (30 * HZ)
#define SR_CAPABILITIES \
      (CDC_CLOSE_TRAY|CDC_OPEN_TRAY|CDC_LOCK|CDC_SELECT_SPEED| \
       CDC_SELECT_DISC|CDC_MULTI_SESSION|CDC_MCN|CDC_MEDIA_CHANGED| \
       CDC_PLAY_AUDIO|CDC_RESET|CDC_DRIVE_STATUS| \
       CDC_CD_R|CDC_CD_RW|CDC_DVD|CDC_DVD_R|CDC_DVD_RAM|CDC_GENERIC_PACKET| \
       CDC_MRW|CDC_MRW_W|CDC_RAM)

static int sr_probe(struct device *);
static int sr_remove(struct device *);
static int sr_done(struct scsi_cmnd *);

static struct scsi_driver sr_template = {
      .owner                  = THIS_MODULE,
      .gendrv = {
            .name       = "sr",
            .probe            = sr_probe,
            .remove           = sr_remove,
      },
      .done             = sr_done,
};

static unsigned long sr_index_bits[SR_DISKS / BITS_PER_LONG];
static DEFINE_SPINLOCK(sr_index_lock);

/* This semaphore is used to mediate the 0->1 reference get in the
 * face of object destruction (i.e. we can't allow a get on an
 * object after last put) */
static DEFINE_MUTEX(sr_ref_mutex);

static int sr_open(struct cdrom_device_info *, int);
static void sr_release(struct cdrom_device_info *);

static void get_sectorsize(struct scsi_cd *);
static void get_capabilities(struct scsi_cd *);

static int sr_media_change(struct cdrom_device_info *, int);
static int sr_packet(struct cdrom_device_info *, struct packet_command *);

static struct cdrom_device_ops sr_dops = {
      .open             = sr_open,
      .release          = sr_release,
      .drive_status           = sr_drive_status,
      .media_changed          = sr_media_change,
      .tray_move        = sr_tray_move,
      .lock_door        = sr_lock_door,
      .select_speed           = sr_select_speed,
      .get_last_session = sr_get_last_session,
      .get_mcn          = sr_get_mcn,
      .reset                  = sr_reset,
      .audio_ioctl            = sr_audio_ioctl,
      .capability       = SR_CAPABILITIES,
      .generic_packet         = sr_packet,
};

static void sr_kref_release(struct kref *kref);

static inline struct scsi_cd *scsi_cd(struct gendisk *disk)
{
      return container_of(disk->private_data, struct scsi_cd, driver);
}

/*
 * The get and put routines for the struct scsi_cd.  Note this entity
 * has a scsi_device pointer and owns a reference to this.
 */
static inline struct scsi_cd *scsi_cd_get(struct gendisk *disk)
{
      struct scsi_cd *cd = NULL;

      mutex_lock(&sr_ref_mutex);
      if (disk->private_data == NULL)
            goto out;
      cd = scsi_cd(disk);
      kref_get(&cd->kref);
      if (scsi_device_get(cd->device))
            goto out_put;
      goto out;

 out_put:
      kref_put(&cd->kref, sr_kref_release);
      cd = NULL;
 out:
      mutex_unlock(&sr_ref_mutex);
      return cd;
}

static void scsi_cd_put(struct scsi_cd *cd)
{
      struct scsi_device *sdev = cd->device;

      mutex_lock(&sr_ref_mutex);
      kref_put(&cd->kref, sr_kref_release);
      scsi_device_put(sdev);
      mutex_unlock(&sr_ref_mutex);
}

/*
 * This function checks to see if the media has been changed in the
 * CDROM drive.  It is possible that we have already sensed a change,
 * or the drive may have sensed one and not yet reported it.  We must
 * be ready for either case. This function always reports the current
 * value of the changed bit.  If flag is 0, then the changed bit is reset.
 * This function could be done as an ioctl, but we would need to have
 * an inode for that to work, and we do not always have one.
 */

static int sr_media_change(struct cdrom_device_info *cdi, int slot)
{
      struct scsi_cd *cd = cdi->handle;
      int retval;

      if (CDSL_CURRENT != slot) {
            /* no changer support */
            return -EINVAL;
      }

      retval = scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES);
      if (retval) {
            /* Unable to test, unit probably not ready.  This usually
             * means there is no disc in the drive.  Mark as changed,
             * and we will figure it out later once the drive is
             * available again.  */
            cd->device->changed = 1;
            return 1;   /* This will force a flush, if called from
                         * check_disk_change */
      };

      retval = cd->device->changed;
      cd->device->changed = 0;
      /* If the disk changed, the capacity will now be different,
       * so we force a re-read of this information */
      if (retval) {
            /* check multisession offset etc */
            sr_cd_check(cdi);

            get_sectorsize(cd);
      }
      return retval;
}
 
/*
 * sr_done is the interrupt routine for the device driver.
 *
 * It will be notified on the end of a SCSI read / write, and will take one
 * of several actions based on success or failure.
 */
static int sr_done(struct scsi_cmnd *SCpnt)
{
      int result = SCpnt->result;
      int this_count = SCpnt->request_bufflen;
      int good_bytes = (result == 0 ? this_count : 0);
      int block_sectors = 0;
      long error_sector;
      struct scsi_cd *cd = scsi_cd(SCpnt->request->rq_disk);

#ifdef DEBUG
      printk("sr.c done: %x\n", result);
#endif

      /*
       * Handle MEDIUM ERRORs or VOLUME OVERFLOWs that indicate partial
       * success.  Since this is a relatively rare error condition, no
       * care is taken to avoid unnecessary additional work such as
       * memcpy's that could be avoided.
       */
      if (driver_byte(result) != 0 &&           /* An error occurred */
          (SCpnt->sense_buffer[0] & 0x7f) == 0x70) { /* Sense current */
            switch (SCpnt->sense_buffer[2]) {
            case MEDIUM_ERROR:
            case VOLUME_OVERFLOW:
            case ILLEGAL_REQUEST:
                  if (!(SCpnt->sense_buffer[0] & 0x90))
                        break;
                  error_sector = (SCpnt->sense_buffer[3] << 24) |
                        (SCpnt->sense_buffer[4] << 16) |
                        (SCpnt->sense_buffer[5] << 8) |
                        SCpnt->sense_buffer[6];
                  if (SCpnt->request->bio != NULL)
                        block_sectors =
                              bio_sectors(SCpnt->request->bio);
                  if (block_sectors < 4)
                        block_sectors = 4;
                  if (cd->device->sector_size == 2048)
                        error_sector <<= 2;
                  error_sector &= ~(block_sectors - 1);
                  good_bytes = (error_sector - SCpnt->request->sector) << 9;
                  if (good_bytes < 0 || good_bytes >= this_count)
                        good_bytes = 0;
                  /*
                   * The SCSI specification allows for the value
                   * returned by READ CAPACITY to be up to 75 2K
                   * sectors past the last readable block.
                   * Therefore, if we hit a medium error within the
                   * last 75 2K sectors, we decrease the saved size
                   * value.
                   */
                  if (error_sector < get_capacity(cd->disk) &&
                      cd->capacity - error_sector < 4 * 75)
                        set_capacity(cd->disk, error_sector);
                  break;

            case RECOVERED_ERROR:

                  /*
                   * An error occured, but it recovered.  Inform the
                   * user, but make sure that it's not treated as a
                   * hard error.
                   */
                  scsi_print_sense("sr", SCpnt);
                  SCpnt->result = 0;
                  SCpnt->sense_buffer[0] = 0x0;
                  good_bytes = this_count;
                  break;

            default:
                  break;
            }
      }

      return good_bytes;
}

static int sr_prep_fn(struct request_queue *q, struct request *rq)
{
      int block=0, this_count, s_size, timeout = SR_TIMEOUT;
      struct scsi_cd *cd;
      struct scsi_cmnd *SCpnt;
      struct scsi_device *sdp = q->queuedata;
      int ret;

      if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
            ret = scsi_setup_blk_pc_cmnd(sdp, rq);
            goto out;
      } else if (rq->cmd_type != REQ_TYPE_FS) {
            ret = BLKPREP_KILL;
            goto out;
      }
      ret = scsi_setup_fs_cmnd(sdp, rq);
      if (ret != BLKPREP_OK)
            goto out;
      SCpnt = rq->special;
      cd = scsi_cd(rq->rq_disk);

      /* from here on until we're complete, any goto out
       * is used for a killable error condition */
      ret = BLKPREP_KILL;

      SCSI_LOG_HLQUEUE(1, printk("Doing sr request, dev = %s, block = %d\n",
                        cd->disk->disk_name, block));

      if (!cd->device || !scsi_device_online(cd->device)) {
            SCSI_LOG_HLQUEUE(2, printk("Finishing %ld sectors\n",
                              rq->nr_sectors));
            SCSI_LOG_HLQUEUE(2, printk("Retry with 0x%p\n", SCpnt));
            goto out;
      }

      if (cd->device->changed) {
            /*
             * quietly refuse to do anything to a changed disc until the
             * changed bit has been reset
             */
            goto out;
      }

      /*
       * we do lazy blocksize switching (when reading XA sectors,
       * see CDROMREADMODE2 ioctl) 
       */
      s_size = cd->device->sector_size;
      if (s_size > 2048) {
            if (!in_interrupt())
                  sr_set_blocklength(cd, 2048);
            else
                  printk("sr: can't switch blocksize: in interrupt\n");
      }

      if (s_size != 512 && s_size != 1024 && s_size != 2048) {
            scmd_printk(KERN_ERR, SCpnt, "bad sector size %d\n", s_size);
            goto out;
      }

      if (rq_data_dir(rq) == WRITE) {
            if (!cd->device->writeable)
                  goto out;
            SCpnt->cmnd[0] = WRITE_10;
            SCpnt->sc_data_direction = DMA_TO_DEVICE;
            cd->cdi.media_written = 1;
      } else if (rq_data_dir(rq) == READ) {
            SCpnt->cmnd[0] = READ_10;
            SCpnt->sc_data_direction = DMA_FROM_DEVICE;
      } else {
            blk_dump_rq_flags(rq, "Unknown sr command");
            goto out;
      }

      {
            struct scatterlist *sg = SCpnt->request_buffer;
            int i, size = 0;
            for (i = 0; i < SCpnt->use_sg; i++)
                  size += sg[i].length;

            if (size != SCpnt->request_bufflen && SCpnt->use_sg) {
                  scmd_printk(KERN_ERR, SCpnt,
                        "mismatch count %d, bytes %d\n",
                        size, SCpnt->request_bufflen);
                  if (SCpnt->request_bufflen > size)
                        SCpnt->request_bufflen = size;
            }
      }

      /*
       * request doesn't start on hw block boundary, add scatter pads
       */
      if (((unsigned int)rq->sector % (s_size >> 9)) ||
          (SCpnt->request_bufflen % s_size)) {
            scmd_printk(KERN_NOTICE, SCpnt, "unaligned transfer\n");
            goto out;
      }

      this_count = (SCpnt->request_bufflen >> 9) / (s_size >> 9);


      SCSI_LOG_HLQUEUE(2, printk("%s : %s %d/%ld 512 byte blocks.\n",
                        cd->cdi.name,
                        (rq_data_dir(rq) == WRITE) ?
                              "writing" : "reading",
                        this_count, rq->nr_sectors));

      SCpnt->cmnd[1] = 0;
      block = (unsigned int)rq->sector / (s_size >> 9);

      if (this_count > 0xffff) {
            this_count = 0xffff;
            SCpnt->request_bufflen = this_count * s_size;
      }

      SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
      SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
      SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
      SCpnt->cmnd[5] = (unsigned char) block & 0xff;
      SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
      SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
      SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;

      /*
       * We shouldn't disconnect in the middle of a sector, so with a dumb
       * host adapter, it's safe to assume that we can at least transfer
       * this many bytes between each connect / disconnect.
       */
      SCpnt->transfersize = cd->device->sector_size;
      SCpnt->underflow = this_count << 9;
      SCpnt->allowed = MAX_RETRIES;
      SCpnt->timeout_per_command = timeout;

      /*
       * This indicates that the command is ready from our end to be
       * queued.
       */
      ret = BLKPREP_OK;
 out:
      return scsi_prep_return(q, rq, ret);
}

static int sr_block_open(struct inode *inode, struct file *file)
{
      struct gendisk *disk = inode->i_bdev->bd_disk;
      struct scsi_cd *cd;
      int ret = 0;

      if(!(cd = scsi_cd_get(disk)))
            return -ENXIO;

      if((ret = cdrom_open(&cd->cdi, inode, file)) != 0)
            scsi_cd_put(cd);

      return ret;
}

static int sr_block_release(struct inode *inode, struct file *file)
{
      int ret;
      struct scsi_cd *cd = scsi_cd(inode->i_bdev->bd_disk);
      ret = cdrom_release(&cd->cdi, file);
      if(ret)
            return ret;
      
      scsi_cd_put(cd);

      return 0;
}

static int sr_block_ioctl(struct inode *inode, struct file *file, unsigned cmd,
                    unsigned long arg)
{
      struct scsi_cd *cd = scsi_cd(inode->i_bdev->bd_disk);
      struct scsi_device *sdev = cd->device;
      void __user *argp = (void __user *)arg;
      int ret;

      /*
       * Send SCSI addressing ioctls directly to mid level, send other
       * ioctls to cdrom/block level.
       */
      switch (cmd) {
      case SCSI_IOCTL_GET_IDLUN:
      case SCSI_IOCTL_GET_BUS_NUMBER:
            return scsi_ioctl(sdev, cmd, argp);
      }

      ret = cdrom_ioctl(file, &cd->cdi, inode, cmd, arg);
      if (ret != -ENOSYS)
            return ret;

      /*
       * ENODEV means that we didn't recognise the ioctl, or that we
       * cannot execute it in the current device state.  In either
       * case fall through to scsi_ioctl, which will return ENDOEV again
       * if it doesn't recognise the ioctl
       */
      ret = scsi_nonblockable_ioctl(sdev, cmd, argp, NULL);
      if (ret != -ENODEV)
            return ret;
      return scsi_ioctl(sdev, cmd, argp);
}

static int sr_block_media_changed(struct gendisk *disk)
{
      struct scsi_cd *cd = scsi_cd(disk);
      return cdrom_media_changed(&cd->cdi);
}

static struct block_device_operations sr_bdops =
{
      .owner            = THIS_MODULE,
      .open       = sr_block_open,
      .release    = sr_block_release,
      .ioctl            = sr_block_ioctl,
      .media_changed    = sr_block_media_changed,
      /* 
       * No compat_ioctl for now because sr_block_ioctl never
       * seems to pass arbitary ioctls down to host drivers.
       */
};

static int sr_open(struct cdrom_device_info *cdi, int purpose)
{
      struct scsi_cd *cd = cdi->handle;
      struct scsi_device *sdev = cd->device;
      int retval;

      /*
       * If the device is in error recovery, wait until it is done.
       * If the device is offline, then disallow any access to it.
       */
      retval = -ENXIO;
      if (!scsi_block_when_processing_errors(sdev))
            goto error_out;

      return 0;

error_out:
      return retval;    
}

static void sr_release(struct cdrom_device_info *cdi)
{
      struct scsi_cd *cd = cdi->handle;

      if (cd->device->sector_size > 2048)
            sr_set_blocklength(cd, 2048);

}

static int sr_probe(struct device *dev)
{
      struct scsi_device *sdev = to_scsi_device(dev);
      struct gendisk *disk;
      struct scsi_cd *cd;
      int minor, error;

      error = -ENODEV;
      if (sdev->type != TYPE_ROM && sdev->type != TYPE_WORM)
            goto fail;

      error = -ENOMEM;
      cd = kzalloc(sizeof(*cd), GFP_KERNEL);
      if (!cd)
            goto fail;

      kref_init(&cd->kref);

      disk = alloc_disk(1);
      if (!disk)
            goto fail_free;

      spin_lock(&sr_index_lock);
      minor = find_first_zero_bit(sr_index_bits, SR_DISKS);
      if (minor == SR_DISKS) {
            spin_unlock(&sr_index_lock);
            error = -EBUSY;
            goto fail_put;
      }
      __set_bit(minor, sr_index_bits);
      spin_unlock(&sr_index_lock);

      disk->major = SCSI_CDROM_MAJOR;
      disk->first_minor = minor;
      sprintf(disk->disk_name, "sr%d", minor);
      disk->fops = &sr_bdops;
      disk->flags = GENHD_FL_CD;

      cd->device = sdev;
      cd->disk = disk;
      cd->driver = &sr_template;
      cd->disk = disk;
      cd->capacity = 0x1fffff;
      cd->device->changed = 1;      /* force recheck CD type */
      cd->use = 1;
      cd->readcd_known = 0;
      cd->readcd_cdda = 0;

      cd->cdi.ops = &sr_dops;
      cd->cdi.handle = cd;
      cd->cdi.mask = 0;
      cd->cdi.capacity = 1;
      sprintf(cd->cdi.name, "sr%d", minor);

      sdev->sector_size = 2048;     /* A guess, just in case */

      /* FIXME: need to handle a get_capabilities failure properly ?? */
      get_capabilities(cd);
      blk_queue_prep_rq(sdev->request_queue, sr_prep_fn);
      sr_vendor_init(cd);

      disk->driverfs_dev = &sdev->sdev_gendev;
      set_capacity(disk, cd->capacity);
      disk->private_data = &cd->driver;
      disk->queue = sdev->request_queue;
      cd->cdi.disk = disk;

      if (register_cdrom(&cd->cdi))
            goto fail_put;

      dev_set_drvdata(dev, cd);
      disk->flags |= GENHD_FL_REMOVABLE;
      add_disk(disk);

      sdev_printk(KERN_DEBUG, sdev,
                "Attached scsi CD-ROM %s\n", cd->cdi.name);
      return 0;

fail_put:
      put_disk(disk);
fail_free:
      kfree(cd);
fail:
      return error;
}


static void get_sectorsize(struct scsi_cd *cd)
{
      unsigned char cmd[10];
      unsigned char *buffer;
      int the_result, retries = 3;
      int sector_size;
      struct request_queue *queue;

      buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
      if (!buffer)
            goto Enomem;

      do {
            cmd[0] = READ_CAPACITY;
            memset((void *) &cmd[1], 0, 9);
            memset(buffer, 0, 8);

            /* Do the command and wait.. */
            the_result = scsi_execute_req(cd->device, cmd, DMA_FROM_DEVICE,
                                    buffer, 8, NULL, SR_TIMEOUT,
                                    MAX_RETRIES);

            retries--;

      } while (the_result && retries);


      if (the_result) {
            cd->capacity = 0x1fffff;
            sector_size = 2048;     /* A guess, just in case */
      } else {
#if 0
            if (cdrom_get_last_written(&cd->cdi,
                                 &cd->capacity))
#endif
                  cd->capacity = 1 + ((buffer[0] << 24) |
                                        (buffer[1] << 16) |
                                        (buffer[2] << 8) |
                                        buffer[3]);
            sector_size = (buffer[4] << 24) |
                (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
            switch (sector_size) {
                  /*
                   * HP 4020i CD-Recorder reports 2340 byte sectors
                   * Philips CD-Writers report 2352 byte sectors
                   *
                   * Use 2k sectors for them..
                   */
            case 0:
            case 2340:
            case 2352:
                  sector_size = 2048;
                  /* fall through */
            case 2048:
                  cd->capacity *= 4;
                  /* fall through */
            case 512:
                  break;
            default:
                  printk("%s: unsupported sector size %d.\n",
                         cd->cdi.name, sector_size);
                  cd->capacity = 0;
            }

            cd->device->sector_size = sector_size;

            /*
             * Add this so that we have the ability to correctly gauge
             * what the device is capable of.
             */
            set_capacity(cd->disk, cd->capacity);
      }

      queue = cd->device->request_queue;
      blk_queue_hardsect_size(queue, sector_size);
out:
      kfree(buffer);
      return;

Enomem:
      cd->capacity = 0x1fffff;
      cd->device->sector_size = 2048;     /* A guess, just in case */
      goto out;
}

static void get_capabilities(struct scsi_cd *cd)
{
      unsigned char *buffer;
      struct scsi_mode_data data;
      unsigned char cmd[MAX_COMMAND_SIZE];
      struct scsi_sense_hdr sshdr;
      unsigned int the_result;
      int retries, rc, n;

      static const char *loadmech[] =
      {
            "caddy",
            "tray",
            "pop-up",
            "",
            "changer",
            "cartridge changer",
            "",
            ""
      };


      /* allocate transfer buffer */
      buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
      if (!buffer) {
            printk(KERN_ERR "sr: out of memory.\n");
            return;
      }

      /* issue TEST_UNIT_READY until the initial startup UNIT_ATTENTION
       * conditions are gone, or a timeout happens
       */
      retries = 0;
      do {
            memset((void *)cmd, 0, MAX_COMMAND_SIZE);
            cmd[0] = TEST_UNIT_READY;

            the_result = scsi_execute_req (cd->device, cmd, DMA_NONE, NULL,
                                     0, &sshdr, SR_TIMEOUT,
                                     MAX_RETRIES);

            retries++;
      } while (retries < 5 && 
             (!scsi_status_is_good(the_result) ||
              (scsi_sense_valid(&sshdr) &&
               sshdr.sense_key == UNIT_ATTENTION)));

      /* ask for mode page 0x2a */
      rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, 128,
                       SR_TIMEOUT, 3, &data, NULL);

      if (!scsi_status_is_good(rc)) {
            /* failed, drive doesn't have capabilities mode page */
            cd->cdi.speed = 1;
            cd->cdi.mask |= (CDC_CD_R | CDC_CD_RW | CDC_DVD_R |
                         CDC_DVD | CDC_DVD_RAM |
                         CDC_SELECT_DISC | CDC_SELECT_SPEED |
                         CDC_MRW | CDC_MRW_W | CDC_RAM);
            kfree(buffer);
            printk("%s: scsi-1 drive\n", cd->cdi.name);
            return;
      }

      n = data.header_length + data.block_descriptor_length;
      cd->cdi.speed = ((buffer[n + 8] << 8) + buffer[n + 9]) / 176;
      cd->readcd_known = 1;
      cd->readcd_cdda = buffer[n + 5] & 0x01;
      /* print some capability bits */
      printk("%s: scsi3-mmc drive: %dx/%dx %s%s%s%s%s%s\n", cd->cdi.name,
             ((buffer[n + 14] << 8) + buffer[n + 15]) / 176,
             cd->cdi.speed,
             buffer[n + 3] & 0x01 ? "writer " : "", /* CD Writer */
             buffer[n + 3] & 0x20 ? "dvd-ram " : "",
             buffer[n + 2] & 0x02 ? "cd/rw " : "", /* can read rewriteable */
             buffer[n + 4] & 0x20 ? "xa/form2 " : "", /* can read xa/from2 */
             buffer[n + 5] & 0x01 ? "cdda " : "", /* can read audio data */
             loadmech[buffer[n + 6] >> 5]);
      if ((buffer[n + 6] >> 5) == 0)
            /* caddy drives can't close tray... */
            cd->cdi.mask |= CDC_CLOSE_TRAY;
      if ((buffer[n + 2] & 0x8) == 0)
            /* not a DVD drive */
            cd->cdi.mask |= CDC_DVD;
      if ((buffer[n + 3] & 0x20) == 0) 
            /* can't write DVD-RAM media */
            cd->cdi.mask |= CDC_DVD_RAM;
      if ((buffer[n + 3] & 0x10) == 0)
            /* can't write DVD-R media */
            cd->cdi.mask |= CDC_DVD_R;
      if ((buffer[n + 3] & 0x2) == 0)
            /* can't write CD-RW media */
            cd->cdi.mask |= CDC_CD_RW;
      if ((buffer[n + 3] & 0x1) == 0)
            /* can't write CD-R media */
            cd->cdi.mask |= CDC_CD_R;
      if ((buffer[n + 6] & 0x8) == 0)
            /* can't eject */
            cd->cdi.mask |= CDC_OPEN_TRAY;

      if ((buffer[n + 6] >> 5) == mechtype_individual_changer ||
          (buffer[n + 6] >> 5) == mechtype_cartridge_changer)
            cd->cdi.capacity =
                cdrom_number_of_slots(&cd->cdi);
      if (cd->cdi.capacity <= 1)
            /* not a changer */
            cd->cdi.mask |= CDC_SELECT_DISC;
      /*else    I don't think it can close its tray
            cd->cdi.mask |= CDC_CLOSE_TRAY; */

      /*
       * if DVD-RAM, MRW-W or CD-RW, we are randomly writable
       */
      if ((cd->cdi.mask & (CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) !=
                  (CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) {
            cd->device->writeable = 1;
      }

      kfree(buffer);
}

/*
 * sr_packet() is the entry point for the generic commands generated
 * by the Uniform CD-ROM layer. 
 */
static int sr_packet(struct cdrom_device_info *cdi,
            struct packet_command *cgc)
{
      if (cgc->timeout <= 0)
            cgc->timeout = IOCTL_TIMEOUT;

      sr_do_ioctl(cdi->handle, cgc);

      return cgc->stat;
}

/**
 *    sr_kref_release - Called to free the scsi_cd structure
 *    @kref: pointer to embedded kref
 *
 *    sr_ref_mutex must be held entering this routine.  Because it is
 *    called on last put, you should always use the scsi_cd_get()
 *    scsi_cd_put() helpers which manipulate the semaphore directly
 *    and never do a direct kref_put().
 **/
static void sr_kref_release(struct kref *kref)
{
      struct scsi_cd *cd = container_of(kref, struct scsi_cd, kref);
      struct gendisk *disk = cd->disk;

      spin_lock(&sr_index_lock);
      clear_bit(disk->first_minor, sr_index_bits);
      spin_unlock(&sr_index_lock);

      unregister_cdrom(&cd->cdi);

      disk->private_data = NULL;

      put_disk(disk);

      kfree(cd);
}

static int sr_remove(struct device *dev)
{
      struct scsi_cd *cd = dev_get_drvdata(dev);

      del_gendisk(cd->disk);

      mutex_lock(&sr_ref_mutex);
      kref_put(&cd->kref, sr_kref_release);
      mutex_unlock(&sr_ref_mutex);

      return 0;
}

static int __init init_sr(void)
{
      int rc;

      rc = register_blkdev(SCSI_CDROM_MAJOR, "sr");
      if (rc)
            return rc;
      rc = scsi_register_driver(&sr_template.gendrv);
      if (rc)
            unregister_blkdev(SCSI_CDROM_MAJOR, "sr");

      return rc;
}

static void __exit exit_sr(void)
{
      scsi_unregister_driver(&sr_template.gendrv);
      unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
}

module_init(init_sr);
module_exit(exit_sr);
MODULE_LICENSE("GPL");

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