dasd_eer.c

来自「LINUX 2.6.17.4的源码」· C语言 代码 · 共 683 行 · 第 1/2 页

		data_size = SNSS_DATA_SIZE;

	header.total_size = sizeof(header) + data_size + 4; /* "EOR" */
	header.trigger = DASD_EER_STATECHANGE;
	do_gettimeofday(&tv);
	header.tv_sec = tv.tv_sec;
	header.tv_usec = tv.tv_usec;
	strncpy(header.busid, device->cdev->dev.bus_id, DASD_EER_BUSID_SIZE);

	spin_lock_irqsave(&bufferlock, flags);
	list_for_each_entry(eerb, &bufferlist, list) {
		dasd_eer_start_record(eerb, header.total_size);
		dasd_eer_write_buffer(eerb, (char *) &header , sizeof(header));
		if (!snss_rc)
			dasd_eer_write_buffer(eerb, cqr->data, SNSS_DATA_SIZE);
		dasd_eer_write_buffer(eerb, "EOR", 4);
	}
	spin_unlock_irqrestore(&bufferlock, flags);
	wake_up_interruptible(&dasd_eer_read_wait_queue);
}

/*
 * This function is called for all triggers. It calls the appropriate
 * function that writes the actual trigger records.
 */
void dasd_eer_write(struct dasd_device *device, struct dasd_ccw_req *cqr,
		    unsigned int id)
{
	if (!device->eer_cqr)
		return;
	switch (id) {
	case DASD_EER_FATALERROR:
	case DASD_EER_PPRCSUSPEND:
		dasd_eer_write_standard_trigger(device, cqr, id);
		break;
	case DASD_EER_NOPATH:
		dasd_eer_write_standard_trigger(device, NULL, id);
		break;
	case DASD_EER_STATECHANGE:
		dasd_eer_write_snss_trigger(device, cqr, id);
		break;
	default: /* unknown trigger, so we write it without any sense data */
		dasd_eer_write_standard_trigger(device, NULL, id);
		break;
	}
}
EXPORT_SYMBOL(dasd_eer_write);

/*
 * Start a sense subsystem status request.
 * Needs to be called with the device held.
 */
void dasd_eer_snss(struct dasd_device *device)
{
	struct dasd_ccw_req *cqr;

	cqr = device->eer_cqr;
	if (!cqr)	/* Device not eer enabled. */
		return;
	if (test_and_set_bit(DASD_FLAG_EER_IN_USE, &device->flags)) {
		/* Sense subsystem status request in use. */
		set_bit(DASD_FLAG_EER_SNSS, &device->flags);
		return;
	}
	clear_bit(DASD_FLAG_EER_SNSS, &device->flags);
	cqr->status = DASD_CQR_QUEUED;
	list_add(&cqr->list, &device->ccw_queue);
	dasd_schedule_bh(device);
}

/*
 * Callback function for use with sense subsystem status request.
 */
static void dasd_eer_snss_cb(struct dasd_ccw_req *cqr, void *data)
{
        struct dasd_device *device = cqr->device;
	unsigned long flags;

	dasd_eer_write(device, cqr, DASD_EER_STATECHANGE);
	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
	if (device->eer_cqr == cqr) {
		clear_bit(DASD_FLAG_EER_IN_USE, &device->flags);
		if (test_bit(DASD_FLAG_EER_SNSS, &device->flags))
			/* Another SNSS has been requested in the meantime. */
			dasd_eer_snss(device);
		cqr = NULL;
	}
	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
	if (cqr)
		/*
		 * Extended error recovery has been switched off while
		 * the SNSS request was running. It could even have
		 * been switched off and on again in which case there
		 * is a new ccw in device->eer_cqr. Free the "old"
		 * snss request now.
		 */
		dasd_kfree_request(cqr, device);
}

/*
 * Enable error reporting on a given device.
 */
int dasd_eer_enable(struct dasd_device *device)
{
	struct dasd_ccw_req *cqr;
	unsigned long flags;

	if (device->eer_cqr)
		return 0;

	if (!device->discipline || strcmp(device->discipline->name, "ECKD"))
		return -EPERM;	/* FIXME: -EMEDIUMTYPE ? */

	cqr = dasd_kmalloc_request("ECKD", 1 /* SNSS */,
				   SNSS_DATA_SIZE, device);
	if (!cqr)
		return -ENOMEM;

	cqr->device = device;
	cqr->retries = 255;
	cqr->expires = 10 * HZ;

	cqr->cpaddr->cmd_code = DASD_ECKD_CCW_SNSS;
	cqr->cpaddr->count = SNSS_DATA_SIZE;
	cqr->cpaddr->flags = 0;
	cqr->cpaddr->cda = (__u32)(addr_t) cqr->data;

	cqr->buildclk = get_clock();
	cqr->status = DASD_CQR_FILLED;
	cqr->callback = dasd_eer_snss_cb;

	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
	if (!device->eer_cqr) {
		device->eer_cqr = cqr;
		cqr = NULL;
	}
	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
	if (cqr)
		dasd_kfree_request(cqr, device);
	return 0;
}

/*
 * Disable error reporting on a given device.
 */
void dasd_eer_disable(struct dasd_device *device)
{
	struct dasd_ccw_req *cqr;
	unsigned long flags;
	int in_use;

	if (!device->eer_cqr)
		return;
	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
	cqr = device->eer_cqr;
	device->eer_cqr = NULL;
	clear_bit(DASD_FLAG_EER_SNSS, &device->flags);
	in_use = test_and_clear_bit(DASD_FLAG_EER_IN_USE, &device->flags);
	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
	if (cqr && !in_use)
		dasd_kfree_request(cqr, device);
}

/*
 * SECTION: the device operations
 */

/*
 * On the one side we need a lock to access our internal buffer, on the
 * other side a copy_to_user can sleep. So we need to copy the data we have
 * to transfer in a readbuffer, which is protected by the readbuffer_mutex.
 */
static char readbuffer[PAGE_SIZE];
static DECLARE_MUTEX(readbuffer_mutex);

static int dasd_eer_open(struct inode *inp, struct file *filp)
{
	struct eerbuffer *eerb;
	unsigned long flags;

	eerb = kzalloc(sizeof(struct eerbuffer), GFP_KERNEL);
	eerb->buffer_page_count = eer_pages;
	if (eerb->buffer_page_count < 1 ||
	    eerb->buffer_page_count > INT_MAX / PAGE_SIZE) {
		kfree(eerb);
		MESSAGE(KERN_WARNING, "can't open device since module "
			"parameter eer_pages is smaller then 1 or"
			" bigger then %d", (int)(INT_MAX / PAGE_SIZE));
		return -EINVAL;
	}
	eerb->buffersize = eerb->buffer_page_count * PAGE_SIZE;
	eerb->buffer = kmalloc(eerb->buffer_page_count * sizeof(char *),
			       GFP_KERNEL);
        if (!eerb->buffer) {
		kfree(eerb);
                return -ENOMEM;
	}
	if (dasd_eer_allocate_buffer_pages(eerb->buffer,
					   eerb->buffer_page_count)) {
		kfree(eerb->buffer);
		kfree(eerb);
		return -ENOMEM;
	}
	filp->private_data = eerb;
	spin_lock_irqsave(&bufferlock, flags);
	list_add(&eerb->list, &bufferlist);
	spin_unlock_irqrestore(&bufferlock, flags);

	return nonseekable_open(inp,filp);
}

static int dasd_eer_close(struct inode *inp, struct file *filp)
{
	struct eerbuffer *eerb;
	unsigned long flags;

	eerb = (struct eerbuffer *) filp->private_data;
	spin_lock_irqsave(&bufferlock, flags);
	list_del(&eerb->list);
	spin_unlock_irqrestore(&bufferlock, flags);
	dasd_eer_free_buffer_pages(eerb->buffer, eerb->buffer_page_count);
	kfree(eerb->buffer);
	kfree(eerb);

	return 0;
}

static ssize_t dasd_eer_read(struct file *filp, char __user *buf,
			     size_t count, loff_t *ppos)
{
	int tc,rc;
	int tailcount,effective_count;
        unsigned long flags;
	struct eerbuffer *eerb;

	eerb = (struct eerbuffer *) filp->private_data;
	if (down_interruptible(&readbuffer_mutex))
		return -ERESTARTSYS;

	spin_lock_irqsave(&bufferlock, flags);

	if (eerb->residual < 0) { /* the remainder of this record */
		                  /* has been deleted             */
		eerb->residual = 0;
		spin_unlock_irqrestore(&bufferlock, flags);
		up(&readbuffer_mutex);
		return -EIO;
	} else if (eerb->residual > 0) {
		/* OK we still have a second half of a record to deliver */
		effective_count = min(eerb->residual, (int) count);
		eerb->residual -= effective_count;
	} else {
		tc = 0;
		while (!tc) {
			tc = dasd_eer_read_buffer(eerb, (char *) &tailcount,
						  sizeof(tailcount));
			if (!tc) {
				/* no data available */
				spin_unlock_irqrestore(&bufferlock, flags);
				up(&readbuffer_mutex);
				if (filp->f_flags & O_NONBLOCK)
					return -EAGAIN;
				rc = wait_event_interruptible(
					dasd_eer_read_wait_queue,
					eerb->head != eerb->tail);
				if (rc)
					return rc;
				if (down_interruptible(&readbuffer_mutex))
					return -ERESTARTSYS;
				spin_lock_irqsave(&bufferlock, flags);
			}
		}
		WARN_ON(tc != sizeof(tailcount));
		effective_count = min(tailcount,(int)count);
		eerb->residual = tailcount - effective_count;
	}

	tc = dasd_eer_read_buffer(eerb, readbuffer, effective_count);
	WARN_ON(tc != effective_count);

	spin_unlock_irqrestore(&bufferlock, flags);

	if (copy_to_user(buf, readbuffer, effective_count)) {
		up(&readbuffer_mutex);
		return -EFAULT;
	}

	up(&readbuffer_mutex);
	return effective_count;
}

static unsigned int dasd_eer_poll(struct file *filp, poll_table *ptable)
{
	unsigned int mask;
	unsigned long flags;
	struct eerbuffer *eerb;

	eerb = (struct eerbuffer *) filp->private_data;
	poll_wait(filp, &dasd_eer_read_wait_queue, ptable);
	spin_lock_irqsave(&bufferlock, flags);
	if (eerb->head != eerb->tail)
		mask = POLLIN | POLLRDNORM ;
	else
		mask = 0;
	spin_unlock_irqrestore(&bufferlock, flags);
	return mask;
}

static struct file_operations dasd_eer_fops = {
	.open		= &dasd_eer_open,
	.release	= &dasd_eer_close,
	.read		= &dasd_eer_read,
	.poll		= &dasd_eer_poll,
	.owner		= THIS_MODULE,
};

static struct miscdevice dasd_eer_dev = {
	.minor	    = MISC_DYNAMIC_MINOR,
	.name	    = "dasd_eer",
	.fops	    = &dasd_eer_fops,
};

int __init dasd_eer_init(void)
{
	int rc;

	rc = misc_register(&dasd_eer_dev);
	if (rc) {
		MESSAGE(KERN_ERR, "%s", "dasd_eer_init could not "
		       "register misc device");
		return rc;
	}

	return 0;
}

void __exit dasd_eer_exit(void)
{
	WARN_ON(misc_deregister(&dasd_eer_dev) != 0);
}