sg.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 2,278 行 · 第 1/5 页

		if (result)
			return result;
		else {
			sg_req_info_t rinfo[SG_MAX_QUEUE];
			Sg_request *srp;
			read_lock_irqsave(&sfp->rq_list_lock, iflags);
			for (srp = sfp->headrp, val = 0; val < SG_MAX_QUEUE;
			     ++val, srp = srp ? srp->nextrp : srp) {
				memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
				if (srp) {
					rinfo[val].req_state = srp->done + 1;
					rinfo[val].problem =
					    srp->header.masked_status & 
					    srp->header.host_status & 
					    srp->header.driver_status;
					rinfo[val].duration =
					    srp->done ? srp->header.duration :
					    jiffies_to_msecs(
						jiffies - srp->header.duration);
					rinfo[val].orphan = srp->orphan;
					rinfo[val].sg_io_owned = srp->sg_io_owned;
					rinfo[val].pack_id = srp->header.pack_id;
					rinfo[val].usr_ptr = srp->header.usr_ptr;
				}
			}
			read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
			return (__copy_to_user(p, rinfo,
			        SZ_SG_REQ_INFO * SG_MAX_QUEUE) ? -EFAULT : 0);
		}
	case SG_EMULATED_HOST:
		if (sdp->detached)
			return -ENODEV;
		return put_user(sdp->device->host->hostt->emulated, ip);
	case SG_SCSI_RESET:
		if (sdp->detached)
			return -ENODEV;
		if (filp->f_flags & O_NONBLOCK) {
			if (test_bit(SHOST_RECOVERY,
				     &sdp->device->host->shost_state))
				return -EBUSY;
		} else if (!scsi_block_when_processing_errors(sdp->device))
			return -EBUSY;
		result = get_user(val, ip);
		if (result)
			return result;
		if (SG_SCSI_RESET_NOTHING == val)
			return 0;
		switch (val) {
		case SG_SCSI_RESET_DEVICE:
			val = SCSI_TRY_RESET_DEVICE;
			break;
		case SG_SCSI_RESET_BUS:
			val = SCSI_TRY_RESET_BUS;
			break;
		case SG_SCSI_RESET_HOST:
			val = SCSI_TRY_RESET_HOST;
			break;
		default:
			return -EINVAL;
		}
		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
			return -EACCES;
		return (scsi_reset_provider(sdp->device, val) ==
			SUCCESS) ? 0 : -EIO;
	case SCSI_IOCTL_SEND_COMMAND:
		if (sdp->detached)
			return -ENODEV;
		if (read_only) {
			unsigned char opcode = WRITE_6;
			Scsi_Ioctl_Command __user *siocp = p;

			if (copy_from_user(&opcode, siocp->data, 1))
				return -EFAULT;
			if (!sg_allow_access(opcode, sdp->device->type))
				return -EPERM;
		}
		return scsi_ioctl_send_command(sdp->device, p);
	case SG_SET_DEBUG:
		result = get_user(val, ip);
		if (result)
			return result;
		sdp->sgdebug = (char) val;
		return 0;
	case SCSI_IOCTL_GET_IDLUN:
	case SCSI_IOCTL_GET_BUS_NUMBER:
	case SCSI_IOCTL_PROBE_HOST:
	case SG_GET_TRANSFORM:
		if (sdp->detached)
			return -ENODEV;
		return scsi_ioctl(sdp->device, cmd_in, p);
	default:
		if (read_only)
			return -EPERM;	/* don't know so take safe approach */
		return scsi_ioctl(sdp->device, cmd_in, p);
	}
}

static unsigned int
sg_poll(struct file *filp, poll_table * wait)
{
	unsigned int res = 0;
	Sg_device *sdp;
	Sg_fd *sfp;
	Sg_request *srp;
	int count = 0;
	unsigned long iflags;

	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp))
	    || sfp->closed)
		return POLLERR;
	poll_wait(filp, &sfp->read_wait, wait);
	read_lock_irqsave(&sfp->rq_list_lock, iflags);
	for (srp = sfp->headrp; srp; srp = srp->nextrp) {
		/* if any read waiting, flag it */
		if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
			res = POLLIN | POLLRDNORM;
		++count;
	}
	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);

	if (sdp->detached)
		res |= POLLHUP;
	else if (!sfp->cmd_q) {
		if (0 == count)
			res |= POLLOUT | POLLWRNORM;
	} else if (count < SG_MAX_QUEUE)
		res |= POLLOUT | POLLWRNORM;
	SCSI_LOG_TIMEOUT(3, printk("sg_poll: %s, res=0x%x\n",
				   sdp->disk->disk_name, (int) res));
	return res;
}

static int
sg_fasync(int fd, struct file *filp, int mode)
{
	int retval;
	Sg_device *sdp;
	Sg_fd *sfp;

	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
		return -ENXIO;
	SCSI_LOG_TIMEOUT(3, printk("sg_fasync: %s, mode=%d\n",
				   sdp->disk->disk_name, mode));

	retval = fasync_helper(fd, filp, mode, &sfp->async_qp);
	return (retval < 0) ? retval : 0;
}

static inline unsigned char *
sg_scatg2virt(const struct scatterlist *sclp)
{
	return (sclp && sclp->page) ?
	    (unsigned char *) page_address(sclp->page) + sclp->offset : NULL;
}

/* When startFinish==1 increments page counts for pages other than the 
   first of scatter gather elements obtained from __get_free_pages().
   When startFinish==0 decrements ... */
static void
sg_rb_correct4mmap(Sg_scatter_hold * rsv_schp, int startFinish)
{
	void *page_ptr;
	struct page *page;
	int k, m;

	SCSI_LOG_TIMEOUT(3, printk("sg_rb_correct4mmap: startFinish=%d, scatg=%d\n", 
				   startFinish, rsv_schp->k_use_sg));
	/* N.B. correction _not_ applied to base page of each allocation */
	if (rsv_schp->k_use_sg) {	/* reserve buffer is a scatter gather list */
		struct scatterlist *sclp = rsv_schp->buffer;

		for (k = 0; k < rsv_schp->k_use_sg; ++k, ++sclp) {
			for (m = PAGE_SIZE; m < sclp->length; m += PAGE_SIZE) {
				page_ptr = sg_scatg2virt(sclp) + m;
				page = virt_to_page(page_ptr);
				if (startFinish)
					get_page(page);
				else {
					if (page_count(page) > 0)
						__put_page(page);
				}
			}
		}
	} else {		/* reserve buffer is just a single allocation */
		for (m = PAGE_SIZE; m < rsv_schp->bufflen; m += PAGE_SIZE) {
			page_ptr = (unsigned char *) rsv_schp->buffer + m;
			page = virt_to_page(page_ptr);
			if (startFinish)
				get_page(page);
			else {
				if (page_count(page) > 0)
					__put_page(page);
			}
		}
	}
}

static struct page *
sg_vma_nopage(struct vm_area_struct *vma, unsigned long addr, int *type)
{
	Sg_fd *sfp;
	struct page *page = NOPAGE_SIGBUS;
	void *page_ptr = NULL;
	unsigned long offset;
	Sg_scatter_hold *rsv_schp;

	if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
		return page;
	rsv_schp = &sfp->reserve;
	offset = addr - vma->vm_start;
	if (offset >= rsv_schp->bufflen)
		return page;
	SCSI_LOG_TIMEOUT(3, printk("sg_vma_nopage: offset=%lu, scatg=%d\n",
				   offset, rsv_schp->k_use_sg));
	if (rsv_schp->k_use_sg) {	/* reserve buffer is a scatter gather list */
		int k;
		unsigned long sa = vma->vm_start;
		unsigned long len;
		struct scatterlist *sclp = rsv_schp->buffer;

		for (k = 0; (k < rsv_schp->k_use_sg) && (sa < vma->vm_end);
		     ++k, ++sclp) {
			len = vma->vm_end - sa;
			len = (len < sclp->length) ? len : sclp->length;
			if (offset < len) {
				page_ptr = sg_scatg2virt(sclp) + offset;
				page = virt_to_page(page_ptr);
				get_page(page);	/* increment page count */
				break;
			}
			sa += len;
			offset -= len;
		}
	} else {		/* reserve buffer is just a single allocation */
		page_ptr = (unsigned char *) rsv_schp->buffer + offset;
		page = virt_to_page(page_ptr);
		get_page(page);	/* increment page count */
	}
	if (type)
		*type = VM_FAULT_MINOR;
	return page;
}

static struct vm_operations_struct sg_mmap_vm_ops = {
	.nopage = sg_vma_nopage,
};

static int
sg_mmap(struct file *filp, struct vm_area_struct *vma)
{
	Sg_fd *sfp;
	unsigned long req_sz = vma->vm_end - vma->vm_start;
	Sg_scatter_hold *rsv_schp;

	if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
		return -ENXIO;
	SCSI_LOG_TIMEOUT(3, printk("sg_mmap starting, vm_start=%p, len=%d\n",
				   (void *) vma->vm_start, (int) req_sz));
	if (vma->vm_pgoff)
		return -EINVAL;	/* want no offset */
	rsv_schp = &sfp->reserve;
	if (req_sz > rsv_schp->bufflen)
		return -ENOMEM;	/* cannot map more than reserved buffer */

	if (rsv_schp->k_use_sg) { /* reserve buffer is a scatter gather list */
		int k;
		unsigned long sa = vma->vm_start;
		unsigned long len;
		struct scatterlist *sclp = rsv_schp->buffer;

		for (k = 0; (k < rsv_schp->k_use_sg) && (sa < vma->vm_end);
		     ++k, ++sclp) {
			if (0 != sclp->offset)
				return -EFAULT;	/* non page aligned memory ?? */
			len = vma->vm_end - sa;
			len = (len < sclp->length) ? len : sclp->length;
			sa += len;
		}
	} else {	/* reserve buffer is just a single allocation */
		if ((unsigned long) rsv_schp->buffer & (PAGE_SIZE - 1))
			return -EFAULT;	/* non page aligned memory ?? */
	}
	if (0 == sfp->mmap_called) {
		sg_rb_correct4mmap(rsv_schp, 1);	/* do only once per fd lifetime */
		sfp->mmap_called = 1;
	}
	vma->vm_flags |= (VM_RESERVED | VM_IO);
	vma->vm_private_data = sfp;
	vma->vm_ops = &sg_mmap_vm_ops;
	return 0;
}

/* This function is a "bottom half" handler that is called by the
 * mid level when a command is completed (or has failed). */
static void
sg_cmd_done(Scsi_Cmnd * SCpnt)
{
	Scsi_Request *SRpnt = NULL;
	Sg_device *sdp = NULL;
	Sg_fd *sfp;
	Sg_request *srp = NULL;

	if (SCpnt && (SRpnt = SCpnt->sc_request))
		srp = (Sg_request *) SRpnt->upper_private_data;
	if (NULL == srp) {
		printk(KERN_ERR "sg_cmd_done: NULL request\n");
		if (SRpnt)
			scsi_release_request(SRpnt);
		return;
	}
	sfp = srp->parentfp;
	if (sfp)
		sdp = sfp->parentdp;
	if ((NULL == sdp) || sdp->detached) {
		printk(KERN_INFO "sg_cmd_done: device detached\n");
		scsi_release_request(SRpnt);
		return;
	}

	/* First transfer ownership of data buffers to sg_device object. */
	srp->data.k_use_sg = SRpnt->sr_use_sg;
	srp->data.sglist_len = SRpnt->sr_sglist_len;
	srp->data.bufflen = SRpnt->sr_bufflen;
	srp->data.buffer = SRpnt->sr_buffer;
	/* now clear out request structure */
	SRpnt->sr_use_sg = 0;
	SRpnt->sr_sglist_len = 0;
	SRpnt->sr_bufflen = 0;
	SRpnt->sr_buffer = NULL;
	SRpnt->sr_underflow = 0;
	SRpnt->sr_request->rq_disk = NULL; /* "sg" _disowns_ request blk */

	srp->my_cmdp = NULL;

	SCSI_LOG_TIMEOUT(4, printk("sg_cmd_done: %s, pack_id=%d, res=0x%x\n",
		sdp->disk->disk_name, srp->header.pack_id, (int) SRpnt->sr_result));
	srp->header.resid = SCpnt->resid;
	/* N.B. unit of duration changes here from jiffies to millisecs */
	srp->header.duration =
	    jiffies_to_msecs(jiffies - srp->header.duration);
	if (0 != SRpnt->sr_result) {
		memcpy(srp->sense_b, SRpnt->sr_sense_buffer,
		       sizeof (srp->sense_b));
		srp->header.status = 0xff & SRpnt->sr_result;
		srp->header.masked_status = status_byte(SRpnt->sr_result);
		srp->header.msg_status = msg_byte(SRpnt->sr_result);
		srp->header.host_status = host_byte(SRpnt->sr_result);
		srp->header.driver_status = driver_byte(SRpnt->sr_result);
		if ((sdp->sgdebug > 0) &&
		    ((CHECK_CONDITION == srp->header.masked_status) ||
		     (COMMAND_TERMINATED == srp->header.masked_status)))
			print_req_sense("sg_cmd_done", SRpnt);

		/* Following if statement is a patch supplied by Eric Youngdale */
		if (driver_byte(SRpnt->sr_result) != 0
		    && (SRpnt->sr_sense_buffer[0] & 0x7f) == 0x70
		    && (SRpnt->sr_sense_buffer[2] & 0xf) == UNIT_ATTENTION
		    && sdp->device->removable) {
			/* Detected disc change. Set the bit - this may be used if */
			/* there are filesystems using this device. */
			sdp->device->changed = 1;
		}
	}
	/* Rely on write phase to clean out srp status values, so no "else" */

	scsi_release_request(SRpnt);
	SRpnt = NULL;
	if (sfp->closed) {	/* whoops this fd already released, cleanup */
		SCSI_LOG_TIMEOUT(1, printk("sg_cmd_done: already closed, freeing ...\n"));
		sg_finish_rem_req(srp);
		srp = NULL;
		if (NULL == sfp->headrp) {
			SCSI_LOG_TIMEOUT(1, printk("sg...bh: already closed, final cleanup\n"));
			if (0 == sg_remove_sfp(sdp, sfp)) {	/* device still present */
				scsi_device_put(sdp->device);
			}
			sfp = NULL;
		}
	} else if (srp && srp->orphan) {
		if (sfp->keep_orphan)
			srp->sg_io_owned = 0;
		else {
			sg_finish_rem_req(srp);
			srp = NULL;
		}
	}
	if (sfp && srp) {
		/* Now wake up any sg_read() that is waiting for this packet. */
		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
		srp->done = 1;
		wake_up_interruptible(&sfp->read_wait);
	}
}

static struct file_operations sg_fops = {
	.owner = THIS_MODULE,
	.read = sg_read,
	.write = sg_write,
	.poll = sg_poll,
	.ioctl = sg_ioctl,
	.open = sg_open,
	.mmap = sg_mmap,
	.release = sg_release,
	.fasync = sg_fasync,
};

static struct class_simple * sg_sysfs_class;

static int sg_sysfs_valid = 0;

static int sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
{
	Sg_device *sdp;
	unsigned long iflags;
	void *old_sg_dev_arr = NULL;
	int k, error;

	sdp = kmalloc(sizeof(Sg_device), GFP_KERNEL);
	if (!sdp) {
		printk(KERN_WARNING "kmalloc Sg_device failure\n");
		return -ENOMEM;
	}

	write_lock_irqsave(&sg_dev_arr_lock, iflags);
	if (unlikely(sg_nr_dev >= sg_dev_max)) {	/* try to resize */
		Sg_device **tmp_da;
		int tmp_dev_max = sg_nr_dev + SG_DEV_ARR_LUMP;
		write_unlock_irqrestore(&sg_dev_arr_lock, iflags);

		tmp_da = kmalloc(tmp_dev_max * sizeof(Sg_device *), GFP_KERNEL);
		if (unlikely(!tmp_da))
			goto expand_failed;

		write_lock_irqsave(&sg_dev_arr_lock, iflags);
		memset(tmp_da, 0, tmp_dev_max * sizeof(Sg_device *));
		memcpy(tmp_da, sg_dev_arr, sg_dev_max * sizeof(Sg_device *));
		old_sg_dev_arr = sg_dev_arr;
		sg_dev_arr = tmp_da;
		sg_dev_max = tmp_dev_max;
	}

	for (k = 0; k < sg_dev_max; k++)
		if (!sg_dev_arr[k])
			break;
	if (unlikely(k >= SG_MAX_DEVS))
		goto overflow;

	memset(sdp, 0, sizeof(*sdp));
	SCSI_LOG_TIMEOUT(3, printk("sg_alloc: dev=%d \n", k));
	sprintf(disk->disk_name, "sg%d", k);
	disk->first_minor = k;
	sdp->disk = disk;
	sdp->device = scsidp;
	init_waitqueue_head(&sdp->o_excl_wait);
	sdp->sg_tablesize = scsidp->host ? scsidp->host->sg_tablesize : 0;