sd.c

linux 内核源代码

		   SCpnt->device->use_10_for_rw) {
		if (this_count > 0xffff)
			this_count = 0xffff;

		SCpnt->cmnd[0] += READ_10 - READ_6;
		SCpnt->cmnd[1] |= blk_fua_rq(rq) ? 0x8 : 0;
		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;
	} else {
		if (unlikely(blk_fua_rq(rq))) {
			/*
			 * This happens only if this drive failed
			 * 10byte rw command with ILLEGAL_REQUEST
			 * during operation and thus turned off
			 * use_10_for_rw.
			 */
			scmd_printk(KERN_ERR, SCpnt,
				    "FUA write on READ/WRITE(6) drive\n");
			goto out;
		}

		SCpnt->cmnd[1] |= (unsigned char) ((block >> 16) & 0x1f);
		SCpnt->cmnd[2] = (unsigned char) ((block >> 8) & 0xff);
		SCpnt->cmnd[3] = (unsigned char) block & 0xff;
		SCpnt->cmnd[4] = (unsigned char) this_count;
		SCpnt->cmnd[5] = 0;
	}
	SCpnt->request_bufflen = this_count * sdp->sector_size;

	/*
	 * 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 = sdp->sector_size;
	SCpnt->underflow = this_count << 9;
	SCpnt->allowed = SD_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);
}

/**
 *	sd_open - open a scsi disk device
 *	@inode: only i_rdev member may be used
 *	@filp: only f_mode and f_flags may be used
 *
 *	Returns 0 if successful. Returns a negated errno value in case 
 *	of error.
 *
 *	Note: This can be called from a user context (e.g. fsck(1) )
 *	or from within the kernel (e.g. as a result of a mount(1) ).
 *	In the latter case @inode and @filp carry an abridged amount
 *	of information as noted above.
 **/
static int sd_open(struct inode *inode, struct file *filp)
{
	struct gendisk *disk = inode->i_bdev->bd_disk;
	struct scsi_disk *sdkp;
	struct scsi_device *sdev;
	int retval;

	if (!(sdkp = scsi_disk_get(disk)))
		return -ENXIO;


	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_open\n"));

	sdev = sdkp->device;

	/*
	 * 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;

	if (sdev->removable || sdkp->write_prot)
		check_disk_change(inode->i_bdev);

	/*
	 * If the drive is empty, just let the open fail.
	 */
	retval = -ENOMEDIUM;
	if (sdev->removable && !sdkp->media_present &&
	    !(filp->f_flags & O_NDELAY))
		goto error_out;

	/*
	 * If the device has the write protect tab set, have the open fail
	 * if the user expects to be able to write to the thing.
	 */
	retval = -EROFS;
	if (sdkp->write_prot && (filp->f_mode & FMODE_WRITE))
		goto error_out;

	/*
	 * It is possible that the disk changing stuff resulted in
	 * the device being taken offline.  If this is the case,
	 * report this to the user, and don't pretend that the
	 * open actually succeeded.
	 */
	retval = -ENXIO;
	if (!scsi_device_online(sdev))
		goto error_out;

	if (!sdkp->openers++ && sdev->removable) {
		if (scsi_block_when_processing_errors(sdev))
			scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
	}

	return 0;

error_out:
	scsi_disk_put(sdkp);
	return retval;	
}

/**
 *	sd_release - invoked when the (last) close(2) is called on this
 *	scsi disk.
 *	@inode: only i_rdev member may be used
 *	@filp: only f_mode and f_flags may be used
 *
 *	Returns 0. 
 *
 *	Note: may block (uninterruptible) if error recovery is underway
 *	on this disk.
 **/
static int sd_release(struct inode *inode, struct file *filp)
{
	struct gendisk *disk = inode->i_bdev->bd_disk;
	struct scsi_disk *sdkp = scsi_disk(disk);
	struct scsi_device *sdev = sdkp->device;

	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_release\n"));

	if (!--sdkp->openers && sdev->removable) {
		if (scsi_block_when_processing_errors(sdev))
			scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW);
	}

	/*
	 * XXX and what if there are packets in flight and this close()
	 * XXX is followed by a "rmmod sd_mod"?
	 */
	scsi_disk_put(sdkp);
	return 0;
}

static int sd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
	struct scsi_disk *sdkp = scsi_disk(bdev->bd_disk);
	struct scsi_device *sdp = sdkp->device;
	struct Scsi_Host *host = sdp->host;
	int diskinfo[4];

	/* default to most commonly used values */
        diskinfo[0] = 0x40;	/* 1 << 6 */
       	diskinfo[1] = 0x20;	/* 1 << 5 */
       	diskinfo[2] = sdkp->capacity >> 11;
	
	/* override with calculated, extended default, or driver values */
	if (host->hostt->bios_param)
		host->hostt->bios_param(sdp, bdev, sdkp->capacity, diskinfo);
	else
		scsicam_bios_param(bdev, sdkp->capacity, diskinfo);

	geo->heads = diskinfo[0];
	geo->sectors = diskinfo[1];
	geo->cylinders = diskinfo[2];
	return 0;
}

/**
 *	sd_ioctl - process an ioctl
 *	@inode: only i_rdev/i_bdev members may be used
 *	@filp: only f_mode and f_flags may be used
 *	@cmd: ioctl command number
 *	@arg: this is third argument given to ioctl(2) system call.
 *	Often contains a pointer.
 *
 *	Returns 0 if successful (some ioctls return postive numbers on
 *	success as well). Returns a negated errno value in case of error.
 *
 *	Note: most ioctls are forward onto the block subsystem or further
 *	down in the scsi subsystem.
 **/
static int sd_ioctl(struct inode * inode, struct file * filp, 
		    unsigned int cmd, unsigned long arg)
{
	struct block_device *bdev = inode->i_bdev;
	struct gendisk *disk = bdev->bd_disk;
	struct scsi_device *sdp = scsi_disk(disk)->device;
	void __user *p = (void __user *)arg;
	int error;
    
	SCSI_LOG_IOCTL(1, printk("sd_ioctl: disk=%s, cmd=0x%x\n",
						disk->disk_name, cmd));

	/*
	 * If we are in the middle of error recovery, don't let anyone
	 * else try and use this device.  Also, if error recovery fails, it
	 * may try and take the device offline, in which case all further
	 * access to the device is prohibited.
	 */
	error = scsi_nonblockable_ioctl(sdp, cmd, p, filp);
	if (!scsi_block_when_processing_errors(sdp) || !error)
		return error;

	/*
	 * Send SCSI addressing ioctls directly to mid level, send other
	 * ioctls to block level and then onto mid level if they can't be
	 * resolved.
	 */
	switch (cmd) {
		case SCSI_IOCTL_GET_IDLUN:
		case SCSI_IOCTL_GET_BUS_NUMBER:
			return scsi_ioctl(sdp, cmd, p);
		default:
			error = scsi_cmd_ioctl(filp, disk->queue, disk, cmd, p);
			if (error != -ENOTTY)
				return error;
	}
	return scsi_ioctl(sdp, cmd, p);
}

static void set_media_not_present(struct scsi_disk *sdkp)
{
	sdkp->media_present = 0;
	sdkp->capacity = 0;
	sdkp->device->changed = 1;
}

/**
 *	sd_media_changed - check if our medium changed
 *	@disk: kernel device descriptor 
 *
 *	Returns 0 if not applicable or no change; 1 if change
 *
 *	Note: this function is invoked from the block subsystem.
 **/
static int sd_media_changed(struct gendisk *disk)
{
	struct scsi_disk *sdkp = scsi_disk(disk);
	struct scsi_device *sdp = sdkp->device;
	int retval;

	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_media_changed\n"));

	if (!sdp->removable)
		return 0;

	/*
	 * If the device is offline, don't send any commands - just pretend as
	 * if the command failed.  If the device ever comes back online, we
	 * can deal with it then.  It is only because of unrecoverable errors
	 * that we would ever take a device offline in the first place.
	 */
	if (!scsi_device_online(sdp))
		goto not_present;

	/*
	 * Using TEST_UNIT_READY enables differentiation between drive with
	 * no cartridge loaded - NOT READY, drive with changed cartridge -
	 * UNIT ATTENTION, or with same cartridge - GOOD STATUS.
	 *
	 * Drives that auto spin down. eg iomega jaz 1G, will be started
	 * by sd_spinup_disk() from sd_revalidate_disk(), which happens whenever
	 * sd_revalidate() is called.
	 */
	retval = -ENODEV;
	if (scsi_block_when_processing_errors(sdp))
		retval = scsi_test_unit_ready(sdp, SD_TIMEOUT, SD_MAX_RETRIES);

	/*
	 * 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.
	 */
	if (retval)
		 goto not_present;

	/*
	 * For removable scsi disk we have to recognise the presence
	 * of a disk in the drive. This is kept in the struct scsi_disk
	 * struct and tested at open !  Daniel Roche ([e-mail])
	 */
	sdkp->media_present = 1;

	retval = sdp->changed;
	sdp->changed = 0;

	return retval;

not_present:
	set_media_not_present(sdkp);
	return 1;
}

static int sd_sync_cache(struct scsi_disk *sdkp)
{
	int retries, res;
	struct scsi_device *sdp = sdkp->device;
	struct scsi_sense_hdr sshdr;

	if (!scsi_device_online(sdp))
		return -ENODEV;


	for (retries = 3; retries > 0; --retries) {
		unsigned char cmd[10] = { 0 };

		cmd[0] = SYNCHRONIZE_CACHE;
		/*
		 * Leave the rest of the command zero to indicate
		 * flush everything.
		 */
		res = scsi_execute_req(sdp, cmd, DMA_NONE, NULL, 0, &sshdr,
				       SD_TIMEOUT, SD_MAX_RETRIES);
		if (res == 0)
			break;
	}

	if (res) {
		sd_print_result(sdkp, res);
		if (driver_byte(res) & DRIVER_SENSE)
			sd_print_sense_hdr(sdkp, &sshdr);
	}

	if (res)
		return -EIO;
	return 0;
}

static void sd_prepare_flush(struct request_queue *q, struct request *rq)
{
	memset(rq->cmd, 0, sizeof(rq->cmd));
	rq->cmd_type = REQ_TYPE_BLOCK_PC;
	rq->timeout = SD_TIMEOUT;
	rq->cmd[0] = SYNCHRONIZE_CACHE;
	rq->cmd_len = 10;
}

static void sd_rescan(struct device *dev)
{
	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);

	if (sdkp) {
		sd_revalidate_disk(sdkp->disk);
		scsi_disk_put(sdkp);
	}
}


#ifdef CONFIG_COMPAT
/* 
 * This gets directly called from VFS. When the ioctl 
 * is not recognized we go back to the other translation paths. 
 */
static long sd_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	struct block_device *bdev = file->f_path.dentry->d_inode->i_bdev;
	struct gendisk *disk = bdev->bd_disk;
	struct scsi_device *sdev = scsi_disk(disk)->device;

	/*
	 * If we are in the middle of error recovery, don't let anyone
	 * else try and use this device.  Also, if error recovery fails, it
	 * may try and take the device offline, in which case all further
	 * access to the device is prohibited.
	 */
	if (!scsi_block_when_processing_errors(sdev))
		return -ENODEV;
	       
	if (sdev->host->hostt->compat_ioctl) {
		int ret;

		ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);

		return ret;
	}

	/* 
	 * Let the static ioctl translation table take care of it.
	 */
	return -ENOIOCTLCMD; 
}
#endif

static struct block_device_operations sd_fops = {
	.owner			= THIS_MODULE,
	.open			= sd_open,
	.release		= sd_release,
	.ioctl			= sd_ioctl,
	.getgeo			= sd_getgeo,
#ifdef CONFIG_COMPAT
	.compat_ioctl		= sd_compat_ioctl,
#endif
	.media_changed		= sd_media_changed,
	.revalidate_disk	= sd_revalidate_disk,
};

/**
 *	sd_done - bottom half handler: called when the lower level
 *	driver has completed (successfully or otherwise) a scsi command.
 *	@SCpnt: mid-level's per command structure.
 *
 *	Note: potentially run from within an ISR. Must not block.
 **/
static int sd_done(struct scsi_cmnd *SCpnt)
{
	int result = SCpnt->result;
 	unsigned int xfer_size = SCpnt->request_bufflen;
 	unsigned int good_bytes = result ? 0 : xfer_size;
 	u64 start_lba = SCpnt->request->sector;
 	u64 bad_lba;
	struct scsi_sense_hdr sshdr;
	int sense_valid = 0;
	int sense_deferred = 0;
	int info_valid;

	if (result) {
		sense_valid = scsi_command_normalize_sense(SCpnt, &sshdr);
		if (sense_valid)
			sense_deferred = scsi_sense_is_deferred(&sshdr);
	}
#ifdef CONFIG_SCSI_LOGGING
	SCSI_LOG_HLCOMPLETE(1, scsi_print_result(SCpnt));
	if (sense_valid) {
		SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, SCpnt,
						   "sd_done: sb[respc,sk,asc,"
						   "ascq]=%x,%x,%x,%x\n",
						   sshdr.response_code,
						   sshdr.sense_key, sshdr.asc,
						   sshdr.ascq));
	}
#endif
	if (driver_byte(result) != DRIVER_SENSE &&
	    (!sense_valid || sense_deferred))
		goto out;

	switch (sshdr.sense_key) {
	case HARDWARE_ERROR:
	case MEDIUM_ERROR:
		if (!blk_fs_request(SCpnt->request))
			goto out;
		info_valid = scsi_get_sense_info_fld(SCpnt->sense_buffer,
						     SCSI_SENSE_BUFFERSIZE,
						     &bad_lba);
		if (!info_valid)
			goto out;
		if (xfer_size <= SCpnt->device->sector_size)
			goto out;
		switch (SCpnt->device->sector_size) {
		case 256:
			start_lba <<= 1;
			break;
		case 512:
			break;
		case 1024:
			start_lba >>= 1;
			break;
		case 2048:
			start_lba >>= 2;
			break;
		case 4096: