ide-scsi.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,160 行 · 第 1/3 页

}

static inline struct bio *idescsi_kmalloc_bio (int count)
{
	struct bio *bh, *bhp, *first_bh;

	if ((first_bh = bhp = bh = bio_alloc(GFP_ATOMIC, 1)) == NULL)
		goto abort;
	bio_init(bh);
	bh->bi_vcnt = 1;
	while (--count) {
		if ((bh = bio_alloc(GFP_ATOMIC, 1)) == NULL)
			goto abort;
		bio_init(bh);
		bh->bi_vcnt = 1;
		bhp->bi_next = bh;
		bhp = bh;
		bh->bi_next = NULL;
	}
	return first_bh;
abort:
	idescsi_free_bio (first_bh);
	return NULL;
}

static inline int idescsi_set_direction (idescsi_pc_t *pc)
{
	switch (pc->c[0]) {
		case READ_6: case READ_10: case READ_12:
			clear_bit (PC_WRITING, &pc->flags);
			return 0;
		case WRITE_6: case WRITE_10: case WRITE_12:
			set_bit (PC_WRITING, &pc->flags);
			return 0;
		default:
			return 1;
	}
}

static inline struct bio *idescsi_dma_bio(ide_drive_t *drive, idescsi_pc_t *pc)
{
	struct bio *bh = NULL, *first_bh = NULL;
	int segments = pc->scsi_cmd->use_sg;
	struct scatterlist *sg = pc->scsi_cmd->request_buffer;

	if (!drive->using_dma || !pc->request_transfer || pc->request_transfer % 1024)
		return NULL;
	if (idescsi_set_direction(pc))
		return NULL;
	if (segments) {
		if ((first_bh = bh = idescsi_kmalloc_bio (segments)) == NULL)
			return NULL;
#if IDESCSI_DEBUG_LOG
		printk ("ide-scsi: %s: building DMA table, %d segments, %dkB total\n", drive->name, segments, pc->request_transfer >> 10);
#endif /* IDESCSI_DEBUG_LOG */
		while (segments--) {
			bh->bi_io_vec[0].bv_page = sg->page;
			bh->bi_io_vec[0].bv_len = sg->length;
			bh->bi_io_vec[0].bv_offset = sg->offset;
			bh->bi_size = sg->length;
			bh = bh->bi_next;
			sg++;
		}
	} else {
		if ((first_bh = bh = idescsi_kmalloc_bio (1)) == NULL)
			return NULL;
#if IDESCSI_DEBUG_LOG
		printk ("ide-scsi: %s: building DMA table for a single buffer (%dkB)\n", drive->name, pc->request_transfer >> 10);
#endif /* IDESCSI_DEBUG_LOG */
		bh->bi_io_vec[0].bv_page = virt_to_page(pc->scsi_cmd->request_buffer);
		bh->bi_io_vec[0].bv_offset = offset_in_page(pc->scsi_cmd->request_buffer);
		bh->bi_io_vec[0].bv_len = pc->request_transfer;
		bh->bi_size = pc->request_transfer;
	}
	return first_bh;
}

static inline int should_transform(ide_drive_t *drive, Scsi_Cmnd *cmd)
{
	idescsi_scsi_t *scsi = drive_to_idescsi(drive);

	/* this was a layering violation and we can't support it
	   anymore, sorry. */
#if 0
	struct gendisk *disk = cmd->request->rq_disk;

	if (disk) {
		struct Scsi_Device_Template **p = disk->private_data;
		if (strcmp((*p)->scsi_driverfs_driver.name, "sg") == 0)
			return test_bit(IDESCSI_SG_TRANSFORM, &scsi->transform);
	}
#endif
	return test_bit(IDESCSI_TRANSFORM, &scsi->transform);
}

static int idescsi_queue (Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *))
{
	struct Scsi_Host *host = cmd->device->host;
	idescsi_scsi_t *scsi = scsihost_to_idescsi(host);
	ide_drive_t *drive = scsi->drive;
	struct request *rq = NULL;
	idescsi_pc_t *pc = NULL;

	if (!drive) {
		printk (KERN_ERR "ide-scsi: drive id %d not present\n", cmd->device->id);
		goto abort;
	}
	scsi = drive_to_idescsi(drive);
	pc = kmalloc (sizeof (idescsi_pc_t), GFP_ATOMIC);
	rq = kmalloc (sizeof (struct request), GFP_ATOMIC);
	if (rq == NULL || pc == NULL) {
		printk (KERN_ERR "ide-scsi: %s: out of memory\n", drive->name);
		goto abort;
	}

	memset (pc->c, 0, 12);
	pc->flags = 0;
	pc->rq = rq;
	memcpy (pc->c, cmd->cmnd, cmd->cmd_len);
	if (cmd->use_sg) {
		pc->buffer = NULL;
		pc->sg = cmd->request_buffer;
	} else {
		pc->buffer = cmd->request_buffer;
		pc->sg = NULL;
	}
	pc->b_count = 0;
	pc->request_transfer = pc->buffer_size = cmd->request_bufflen;
	pc->scsi_cmd = cmd;
	pc->done = done;
	pc->timeout = jiffies + cmd->timeout_per_command;

	if (should_transform(drive, cmd))
		set_bit(PC_TRANSFORM, &pc->flags);
	idescsi_transform_pc1 (drive, pc);

	if (test_bit(IDESCSI_LOG_CMD, &scsi->log)) {
		printk ("ide-scsi: %s: que %lu, cmd = ", drive->name, cmd->serial_number);
		hexdump(cmd->cmnd, cmd->cmd_len);
		if (memcmp(pc->c, cmd->cmnd, cmd->cmd_len)) {
			printk ("ide-scsi: %s: que %lu, tsl = ", drive->name, cmd->serial_number);
			hexdump(pc->c, 12);
		}
	}

	ide_init_drive_cmd (rq);
	rq->special = (char *) pc;
	rq->bio = idescsi_dma_bio (drive, pc);
	rq->flags = REQ_SPECIAL;
	spin_unlock_irq(host->host_lock);
	(void) ide_do_drive_cmd (drive, rq, ide_end);
	spin_lock_irq(host->host_lock);
	return 0;
abort:
	if (pc) kfree (pc);
	if (rq) kfree (rq);
	cmd->result = DID_ERROR << 16;
	done(cmd);
	return 1;
}

static int idescsi_eh_abort (Scsi_Cmnd *cmd)
{
	idescsi_scsi_t *scsi  = scsihost_to_idescsi(cmd->device->host);
	ide_drive_t    *drive = scsi->drive;
	int		busy;
	int             ret   = FAILED;

	/* In idescsi_eh_abort we try to gently pry our command from the ide subsystem */

	if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
		printk (KERN_WARNING "ide-scsi: abort called for %lu\n", cmd->serial_number);

	if (!drive) {
		printk (KERN_WARNING "ide-scsi: Drive not set in idescsi_eh_abort\n");
		WARN_ON(1);
		goto no_drive;
	}

	/* First give it some more time, how much is "right" is hard to say :-( */

	busy = ide_wait_not_busy(HWIF(drive), 100);	/* FIXME - uses mdelay which causes latency? */
	if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
		printk (KERN_WARNING "ide-scsi: drive did%s become ready\n", busy?" not":"");

	spin_lock_irq(&ide_lock);

	/* If there is no pc running we're done (our interrupt took care of it) */
	if (!scsi->pc) {
		ret = SUCCESS;
		goto ide_unlock;
	}

	/* It's somewhere in flight. Does ide subsystem agree? */
	if (scsi->pc->scsi_cmd->serial_number == cmd->serial_number && !busy &&
	    elv_queue_empty(drive->queue) && HWGROUP(drive)->rq != scsi->pc->rq) {
		/*
		 * FIXME - not sure this condition can ever occur
		 */
		printk (KERN_ERR "ide-scsi: cmd aborted!\n");

		idescsi_free_bio(scsi->pc->rq->bio);
		if (scsi->pc->rq->flags & REQ_SENSE)
			kfree(scsi->pc->buffer);
		kfree(scsi->pc->rq);
		kfree(scsi->pc);
		scsi->pc = NULL;

		ret = SUCCESS;
	}

ide_unlock:
	spin_unlock_irq(&ide_lock);
no_drive:
	if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
		printk (KERN_WARNING "ide-scsi: abort returns %s\n", ret == SUCCESS?"success":"failed");

	return ret;
}

static int idescsi_eh_reset (Scsi_Cmnd *cmd)
{
	struct request *req;
	idescsi_scsi_t *scsi  = scsihost_to_idescsi(cmd->device->host);
	ide_drive_t    *drive = scsi->drive;
	int             ready = 0;
	int             ret   = SUCCESS;

	/* In idescsi_eh_reset we forcefully remove the command from the ide subsystem and reset the device. */

	if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
		printk (KERN_WARNING "ide-scsi: reset called for %lu\n", cmd->serial_number);

	if (!drive) {
		printk (KERN_WARNING "ide-scsi: Drive not set in idescsi_eh_reset\n");
		WARN_ON(1);
		return FAILED;
	}

	spin_lock_irq(&ide_lock);

	if (!scsi->pc || (req = scsi->pc->rq) != HWGROUP(drive)->rq || !HWGROUP(drive)->handler) {
		printk (KERN_WARNING "ide-scsi: No active request in idescsi_eh_reset\n");
		spin_unlock(&ide_lock);
		return FAILED;
	}

	/* kill current request */
	blkdev_dequeue_request(req);
	end_that_request_last(req);
	idescsi_free_bio(req->bio);
	if (req->flags & REQ_SENSE)
		kfree(scsi->pc->buffer);
	kfree(scsi->pc);
	scsi->pc = NULL;
	kfree(req);

	/* now nuke the drive queue */
	while ((req = elv_next_request(drive->queue))) {
		blkdev_dequeue_request(req);
		end_that_request_last(req);
	}

	HWGROUP(drive)->rq = NULL;
	HWGROUP(drive)->handler = NULL;
	HWGROUP(drive)->busy = 1;		/* will set this to zero when ide reset finished */
	spin_unlock_irq(&ide_lock);

	ide_do_reset(drive);

	/* ide_do_reset starts a polling handler which restarts itself every 50ms until the reset finishes */

	do {
		set_current_state(TASK_UNINTERRUPTIBLE);
		spin_unlock_irq(cmd->device->host->host_lock);
		schedule_timeout(HZ/20);
		spin_lock_irq(cmd->device->host->host_lock);
	} while ( HWGROUP(drive)->handler );

	ready = drive_is_ready(drive);
	HWGROUP(drive)->busy--;
	if (!ready) {
		printk (KERN_ERR "ide-scsi: reset failed!\n");
		ret = FAILED;
	}

	return ret;
}

static int idescsi_bios(struct scsi_device *sdev, struct block_device *bdev,
		sector_t capacity, int *parm)
{
	idescsi_scsi_t *idescsi = scsihost_to_idescsi(sdev->host);
	ide_drive_t *drive = idescsi->drive;

	if (drive->bios_cyl && drive->bios_head && drive->bios_sect) {
		parm[0] = drive->bios_head;
		parm[1] = drive->bios_sect;
		parm[2] = drive->bios_cyl;
	}
	return 0;
}

static Scsi_Host_Template idescsi_template = {
	.module			= THIS_MODULE,
	.name			= "idescsi",
	.info			= idescsi_info,
	.slave_configure        = idescsi_slave_configure,
	.ioctl			= idescsi_ioctl,
	.queuecommand		= idescsi_queue,
	.eh_abort_handler	= idescsi_eh_abort,
	.eh_host_reset_handler  = idescsi_eh_reset,
	.bios_param		= idescsi_bios,
	.can_queue		= 40,
	.this_id		= -1,
	.sg_tablesize		= 256,
	.cmd_per_lun		= 5,
	.max_sectors		= 128,
	.use_clustering		= DISABLE_CLUSTERING,
	.emulated		= 1,
	.proc_name		= "ide-scsi",
};

static int idescsi_attach(ide_drive_t *drive)
{
	idescsi_scsi_t *idescsi;
	struct Scsi_Host *host;
	static int warned;
	int err;

	if (!warned && drive->media == ide_cdrom) {
		printk(KERN_WARNING "ide-scsi is deprecated for cd burning! Use ide-cd and give dev=/dev/hdX as device\n");
		warned = 1;
	}

	if (!strstr("ide-scsi", drive->driver_req) ||
	    !drive->present ||
	    drive->media == ide_disk ||
	    !(host = scsi_host_alloc(&idescsi_template,sizeof(idescsi_scsi_t))))
		return 1;

	host->max_id = 1;

#if IDESCSI_DEBUG_LOG
	if (drive->id->last_lun)
		printk(KERN_NOTICE "%s: id->last_lun=%u\n", drive->name, drive->id->last_lun);
#endif
	if ((drive->id->last_lun & 0x7) != 7)
		host->max_lun = (drive->id->last_lun & 0x7) + 1;
	else
		host->max_lun = 1;

	drive->driver_data = host;
	idescsi = scsihost_to_idescsi(host);
	idescsi->drive = drive;
	err = ide_register_subdriver(drive, &idescsi_driver);
	if (!err) {
		idescsi_setup (drive, idescsi);
		drive->disk->fops = &idescsi_ops;
		err = scsi_add_host(host, &drive->gendev);
		if (!err) {
			scsi_scan_host(host);
			return 0;
		}
		/* fall through on error */
		ide_unregister_subdriver(drive);
	}

	scsi_host_put(host);
	return err;
}

static int __init init_idescsi_module(void)
{
	return ide_register_driver(&idescsi_driver);
}

static void __exit exit_idescsi_module(void)
{
	ide_unregister_driver(&idescsi_driver);
}

module_init(init_idescsi_module);
module_exit(exit_idescsi_module);
MODULE_LICENSE("GPL");