drivers/s390/block/xpram.c - arm/linux-arm64-legacy - Git at Google

 /*
  * Xpram.c -- the S/390 expanded memory RAM-disk
  *
  * significant parts of this code are based on
  * the sbull device driver presented in
  * A. Rubini: Linux Device Drivers
  *
  * Author of XPRAM specific coding: Reinhard Buendgen
  *                                  buendgen@de.ibm.com
  * Rewrite for 2.5: Martin Schwidefsky <schwidefsky@de.ibm.com>
  *
  * External interfaces:
  *   Interfaces to linux kernel
  *        xpram_setup: read kernel parameters
  *   Device specific file operations
  *        xpram_iotcl
  *        xpram_open
  *
  * "ad-hoc" partitioning:
  *    the expanded memory can be partitioned among several devices
  *    (with different minors). The partitioning set up can be
  *    set by kernel or module parameters (int devs & int sizes[])
  *
  * Potential future improvements:
  *   generic hard disk support to replace ad-hoc partitioning
  */

 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/ctype.h>  /* isdigit, isxdigit */
 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/blkdev.h>
 #include <linux/blkpg.h>
 #include <linux/hdreg.h>  /* HDIO_GETGEO */
 #include <linux/sysdev.h>
 #include <linux/bio.h>
 #include <asm/uaccess.h>

 #define XPRAM_NAME	"xpram"
 #define XPRAM_DEVS	1	/* one partition */
 #define XPRAM_MAX_DEVS	32	/* maximal number of devices (partitions) */

 #define PRINT_DEBUG(x...)	printk(KERN_DEBUG XPRAM_NAME " debug:" x)
 #define PRINT_INFO(x...)	printk(KERN_INFO XPRAM_NAME " info:" x)
 #define PRINT_WARN(x...)	printk(KERN_WARNING XPRAM_NAME " warning:" x)
 #define PRINT_ERR(x...)		printk(KERN_ERR XPRAM_NAME " error:" x)


 typedef struct {
 	unsigned int	size;		/* size of xpram segment in pages */
 	unsigned int	offset;		/* start page of xpram segment */
 } xpram_device_t;

 static xpram_device_t xpram_devices[XPRAM_MAX_DEVS];
 static unsigned int xpram_sizes[XPRAM_MAX_DEVS];
 static struct gendisk *xpram_disks[XPRAM_MAX_DEVS];
 static unsigned int xpram_pages;
 static int xpram_devs;

 /*
  * Parameter parsing functions.
  */
 static int __initdata devs = XPRAM_DEVS;
 static char __initdata *sizes[XPRAM_MAX_DEVS];

 module_param(devs, int, 0);
 module_param_array(sizes, charp, NULL, 0);

 MODULE_PARM_DESC(devs, "number of devices (\"partitions\"), " \
 		 "the default is " __MODULE_STRING(XPRAM_DEVS) "\n");
 MODULE_PARM_DESC(sizes, "list of device (partition) sizes " \
 		 "the defaults are 0s \n" \
 		 "All devices with size 0 equally partition the "
 		 "remaining space on the expanded strorage not "
 		 "claimed by explicit sizes\n");
 MODULE_LICENSE("GPL");

 /*
  * Copy expanded memory page (4kB) into main memory
  * Arguments
  *           page_addr:    address of target page
  *           xpage_index:  index of expandeded memory page
  * Return value
  *           0:            if operation succeeds
  *           -EIO:         if pgin failed
  *           -ENXIO:       if xpram has vanished
  */
 static int xpram_page_in (unsigned long page_addr, unsigned int xpage_index)
 {
 	int cc = 2;	/* return unused cc 2 if pgin traps */

 	asm volatile(
 		"	.insn	rre,0xb22e0000,%1,%2\n"  /* pgin %1,%2 */
 		"0:	ipm	%0\n"
 		"	srl	%0,28\n"
 		"1:\n"
 		EX_TABLE(0b,1b)
 		: "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
 	if (cc == 3)
 		return -ENXIO;
 	if (cc == 2) {
 		PRINT_ERR("expanded storage lost!\n");
 		return -ENXIO;
 	}
 	if (cc == 1) {
 		PRINT_ERR("page in failed for page index %u.\n",
 			  xpage_index);
 		return -EIO;
 	}
 	return 0;
 }

 /*
  * Copy a 4kB page of main memory to an expanded memory page
  * Arguments
  *           page_addr:    address of source page
  *           xpage_index:  index of expandeded memory page
  * Return value
  *           0:            if operation succeeds
  *           -EIO:         if pgout failed
  *           -ENXIO:       if xpram has vanished
  */
 static long xpram_page_out (unsigned long page_addr, unsigned int xpage_index)
 {
 	int cc = 2;	/* return unused cc 2 if pgin traps */

 	asm volatile(
 		"	.insn	rre,0xb22f0000,%1,%2\n"  /* pgout %1,%2 */
 		"0:	ipm	%0\n"
 		"	srl	%0,28\n"
 		"1:\n"
 		EX_TABLE(0b,1b)
 		: "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
 	if (cc == 3)
 		return -ENXIO;
 	if (cc == 2) {
 		PRINT_ERR("expanded storage lost!\n");
 		return -ENXIO;
 	}
 	if (cc == 1) {
 		PRINT_ERR("page out failed for page index %u.\n",
 			  xpage_index);
 		return -EIO;
 	}
 	return 0;
 }

 /*
  * Check if xpram is available.
  */
 static int __init xpram_present(void)
 {
 	unsigned long mem_page;
 	int rc;

 	mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
 	if (!mem_page)
 		return -ENOMEM;
 	rc = xpram_page_in(mem_page, 0);
 	free_page(mem_page);
 	return rc ? -ENXIO : 0;
 }

 /*
  * Return index of the last available xpram page.
  */
 static unsigned long __init xpram_highest_page_index(void)
 {
 	unsigned int page_index, add_bit;
 	unsigned long mem_page;

 	mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
 	if (!mem_page)
 		return 0;

 	page_index = 0;
 	add_bit = 1ULL << (sizeof(unsigned int)*8 - 1);
 	while (add_bit > 0) {
 		if (xpram_page_in(mem_page, page_index | add_bit) == 0)
 			page_index |= add_bit;
 		add_bit >>= 1;
 	}

 	free_page (mem_page);

 	return page_index;
 }

 /*
  * Block device make request function.
  */
 static int xpram_make_request(struct request_queue *q, struct bio *bio)
 {
 	xpram_device_t *xdev = bio->bi_bdev->bd_disk->private_data;
 	struct bio_vec *bvec;
 	unsigned int index;
 	unsigned long page_addr;
 	unsigned long bytes;
 	int i;

 	if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
 		/* Request is not page-aligned. */
 		goto fail;
 	if ((bio->bi_size >> 12) > xdev->size)
 		/* Request size is no page-aligned. */
 		goto fail;
 	if ((bio->bi_sector >> 3) > 0xffffffffU - xdev->offset)
 		goto fail;
 	index = (bio->bi_sector >> 3) + xdev->offset;
 	bio_for_each_segment(bvec, bio, i) {
 		page_addr = (unsigned long)
 			kmap(bvec->bv_page) + bvec->bv_offset;
 		bytes = bvec->bv_len;
 		if ((page_addr & 4095) != 0 || (bytes & 4095) != 0)
 			/* More paranoia. */
 			goto fail;
 		while (bytes > 0) {
 			if (bio_data_dir(bio) == READ) {
 				if (xpram_page_in(page_addr, index) != 0)
 					goto fail;
 			} else {
 				if (xpram_page_out(page_addr, index) != 0)
 					goto fail;
 			}
 			page_addr += 4096;
 			bytes -= 4096;
 			index++;
 		}
 	}
 	set_bit(BIO_UPTODATE, &bio->bi_flags);
 	bio_endio(bio, 0);
 	return 0;
 fail:
 	bio_io_error(bio);
 	return 0;
 }

 static int xpram_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 {
 	unsigned long size;

 	/*
 	 * get geometry: we have to fake one...  trim the size to a
 	 * multiple of 64 (32k): tell we have 16 sectors, 4 heads,
 	 * whatever cylinders. Tell also that data starts at sector. 4.
 	 */
 	size = (xpram_pages * 8) & ~0x3f;
 	geo->cylinders = size >> 6;
 	geo->heads = 4;
 	geo->sectors = 16;
 	geo->start = 4;
 	return 0;
 }

 static struct block_device_operations xpram_devops =
 {
 	.owner	= THIS_MODULE,
 	.getgeo	= xpram_getgeo,
 };

 /*
  * Setup xpram_sizes array.
  */
 static int __init xpram_setup_sizes(unsigned long pages)
 {
 	unsigned long mem_needed;
 	unsigned long mem_auto;
 	unsigned long long size;
 	int mem_auto_no;
 	int i;

 	/* Check number of devices. */
 	if (devs <= 0 || devs > XPRAM_MAX_DEVS) {
 		PRINT_ERR("invalid number %d of devices\n",devs);
 		return -EINVAL;
 	}
 	xpram_devs = devs;

 	/*
 	 * Copy sizes array to xpram_sizes and align partition
 	 * sizes to page boundary.
 	 */
 	mem_needed = 0;
 	mem_auto_no = 0;
 	for (i = 0; i < xpram_devs; i++) {
 		if (sizes[i]) {
 			size = simple_strtoull(sizes[i], &sizes[i], 0);
 			switch (sizes[i][0]) {
 			case 'g':
 			case 'G':
 				size <<= 20;
 				break;
 			case 'm':
 			case 'M':
 				size <<= 10;
 			}
 			xpram_sizes[i] = (size + 3) & -4UL;
 		}
 		if (xpram_sizes[i])
 			mem_needed += xpram_sizes[i];
 		else
 			mem_auto_no++;
 	}

 	PRINT_INFO("  number of devices (partitions): %d \n", xpram_devs);
 	for (i = 0; i < xpram_devs; i++) {
 		if (xpram_sizes[i])
 			PRINT_INFO("  size of partition %d: %u kB\n",
 				   i, xpram_sizes[i]);
 		else
 			PRINT_INFO("  size of partition %d to be set "
 				   "automatically\n",i);
 	}
 	PRINT_DEBUG("  memory needed (for sized partitions): %lu kB\n",
 		    mem_needed);
 	PRINT_DEBUG("  partitions to be sized automatically: %d\n",
 		    mem_auto_no);

 	if (mem_needed > pages * 4) {
 		PRINT_ERR("Not enough expanded memory available\n");
 		return -EINVAL;
 	}

 	/*
 	 * partitioning:
 	 * xpram_sizes[i] != 0; partition i has size xpram_sizes[i] kB
 	 * else:             ; all partitions with zero xpram_sizes[i]
 	 *                     partition equally the remaining space
 	 */
 	if (mem_auto_no) {
 		mem_auto = ((pages - mem_needed / 4) / mem_auto_no) * 4;
 		PRINT_INFO("  automatically determined "
 			   "partition size: %lu kB\n", mem_auto);
 		for (i = 0; i < xpram_devs; i++)
 			if (xpram_sizes[i] == 0)
 				xpram_sizes[i] = mem_auto;
 	}
 	return 0;
 }

 static struct request_queue *xpram_queue;

 static int __init xpram_setup_blkdev(void)
 {
 	unsigned long offset;
 	int i, rc = -ENOMEM;

 	for (i = 0; i < xpram_devs; i++) {
 		struct gendisk *disk = alloc_disk(1);
 		if (!disk)
 			goto out;
 		xpram_disks[i] = disk;
 	}

 	/*
 	 * Register xpram major.
 	 */
 	rc = register_blkdev(XPRAM_MAJOR, XPRAM_NAME);
 	if (rc < 0)
 		goto out;

 	/*
 	 * Assign the other needed values: make request function, sizes and
 	 * hardsect size. All the minor devices feature the same value.
 	 */
 	xpram_queue = blk_alloc_queue(GFP_KERNEL);
 	if (!xpram_queue) {
 		rc = -ENOMEM;
 		goto out_unreg;
 	}
 	blk_queue_make_request(xpram_queue, xpram_make_request);
 	blk_queue_hardsect_size(xpram_queue, 4096);

 	/*
 	 * Setup device structures.
 	 */
 	offset = 0;
 	for (i = 0; i < xpram_devs; i++) {
 		struct gendisk *disk = xpram_disks[i];

 		xpram_devices[i].size = xpram_sizes[i] / 4;
 		xpram_devices[i].offset = offset;
 		offset += xpram_devices[i].size;
 		disk->major = XPRAM_MAJOR;
 		disk->first_minor = i;
 		disk->fops = &xpram_devops;
 		disk->private_data = &xpram_devices[i];
 		disk->queue = xpram_queue;
 		sprintf(disk->disk_name, "slram%d", i);
 		set_capacity(disk, xpram_sizes[i] << 1);
 		add_disk(disk);
 	}

 	return 0;
 out_unreg:
 	unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
 out:
 	while (i--)
 		put_disk(xpram_disks[i]);
 	return rc;
 }

 /*
  * Finally, the init/exit functions.
  */
 static void __exit xpram_exit(void)
 {
 	int i;
 	for (i = 0; i < xpram_devs; i++) {
 		del_gendisk(xpram_disks[i]);
 		put_disk(xpram_disks[i]);
 	}
 	unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
 	blk_cleanup_queue(xpram_queue);
 }

 static int __init xpram_init(void)
 {
 	int rc;

 	/* Find out size of expanded memory. */
 	if (xpram_present() != 0) {
 		PRINT_WARN("No expanded memory available\n");
 		return -ENODEV;
 	}
 	xpram_pages = xpram_highest_page_index() + 1;
 	PRINT_INFO("  %u pages expanded memory found (%lu KB).\n",
 		   xpram_pages, (unsigned long) xpram_pages*4);
 	rc = xpram_setup_sizes(xpram_pages);
 	if (rc)
 		return rc;
 	return xpram_setup_blkdev();
 }

 module_init(xpram_init);
 module_exit(xpram_exit);
	/*
	* Xpram.c -- the S/390 expanded memory RAM-disk
	*
	* significant parts of this code are based on
	* the sbull device driver presented in
	* A. Rubini: Linux Device Drivers
	*
	* Author of XPRAM specific coding: Reinhard Buendgen
	* buendgen@de.ibm.com
	* Rewrite for 2.5: Martin Schwidefsky <schwidefsky@de.ibm.com>
	*
	* External interfaces:
	* Interfaces to linux kernel
	* xpram_setup: read kernel parameters
	* Device specific file operations
	* xpram_iotcl
	* xpram_open
	*
	* "ad-hoc" partitioning:
	* the expanded memory can be partitioned among several devices
	* (with different minors). The partitioning set up can be
	* set by kernel or module parameters (int devs & int sizes[])
	*
	* Potential future improvements:
	* generic hard disk support to replace ad-hoc partitioning
	*/

	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/ctype.h> /* isdigit, isxdigit */
	#include <linux/errno.h>
	#include <linux/init.h>
	#include <linux/slab.h>
	#include <linux/blkdev.h>
	#include <linux/blkpg.h>
	#include <linux/hdreg.h> /* HDIO_GETGEO */
	#include <linux/sysdev.h>
	#include <linux/bio.h>
	#include <asm/uaccess.h>

	#define XPRAM_NAME "xpram"
	#define XPRAM_DEVS 1 /* one partition */
	#define XPRAM_MAX_DEVS 32 /* maximal number of devices (partitions) */

	#define PRINT_DEBUG(x...) printk(KERN_DEBUG XPRAM_NAME " debug:" x)
	#define PRINT_INFO(x...) printk(KERN_INFO XPRAM_NAME " info:" x)
	#define PRINT_WARN(x...) printk(KERN_WARNING XPRAM_NAME " warning:" x)
	#define PRINT_ERR(x...) printk(KERN_ERR XPRAM_NAME " error:" x)


	typedef struct {
	unsigned int size; /* size of xpram segment in pages */
	unsigned int offset; /* start page of xpram segment */
	} xpram_device_t;

	static xpram_device_t xpram_devices[XPRAM_MAX_DEVS];
	static unsigned int xpram_sizes[XPRAM_MAX_DEVS];
	static struct gendisk *xpram_disks[XPRAM_MAX_DEVS];
	static unsigned int xpram_pages;
	static int xpram_devs;

	/*
	* Parameter parsing functions.
	*/
	static int __initdata devs = XPRAM_DEVS;
	static char __initdata *sizes[XPRAM_MAX_DEVS];

	module_param(devs, int, 0);
	module_param_array(sizes, charp, NULL, 0);

	MODULE_PARM_DESC(devs, "number of devices (\"partitions\"), " \
	"the default is " __MODULE_STRING(XPRAM_DEVS) "\n");
	MODULE_PARM_DESC(sizes, "list of device (partition) sizes " \
	"the defaults are 0s \n" \
	"All devices with size 0 equally partition the "
	"remaining space on the expanded strorage not "
	"claimed by explicit sizes\n");
	MODULE_LICENSE("GPL");

	/*
	* Copy expanded memory page (4kB) into main memory
	* Arguments
	* page_addr: address of target page
	* xpage_index: index of expandeded memory page
	* Return value
	* 0: if operation succeeds
	* -EIO: if pgin failed
	* -ENXIO: if xpram has vanished
	*/
	static int xpram_page_in (unsigned long page_addr, unsigned int xpage_index)
	{
	int cc = 2; /* return unused cc 2 if pgin traps */

	asm volatile(
	" .insn rre,0xb22e0000,%1,%2\n" /* pgin %1,%2 */
	"0: ipm %0\n"
	" srl %0,28\n"
	"1:\n"
	EX_TABLE(0b,1b)
	: "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
	if (cc == 3)
	return -ENXIO;
	if (cc == 2) {
	PRINT_ERR("expanded storage lost!\n");
	return -ENXIO;
	}
	if (cc == 1) {
	PRINT_ERR("page in failed for page index %u.\n",
	xpage_index);
	return -EIO;
	}
	return 0;
	}

	/*
	* Copy a 4kB page of main memory to an expanded memory page
	* Arguments
	* page_addr: address of source page
	* xpage_index: index of expandeded memory page
	* Return value
	* 0: if operation succeeds
	* -EIO: if pgout failed
	* -ENXIO: if xpram has vanished
	*/
	static long xpram_page_out (unsigned long page_addr, unsigned int xpage_index)
	{
	int cc = 2; /* return unused cc 2 if pgin traps */

	asm volatile(
	" .insn rre,0xb22f0000,%1,%2\n" /* pgout %1,%2 */
	"0: ipm %0\n"
	" srl %0,28\n"
	"1:\n"
	EX_TABLE(0b,1b)
	: "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
	if (cc == 3)
	return -ENXIO;
	if (cc == 2) {
	PRINT_ERR("expanded storage lost!\n");
	return -ENXIO;
	}
	if (cc == 1) {
	PRINT_ERR("page out failed for page index %u.\n",
	xpage_index);
	return -EIO;
	}
	return 0;
	}

	/*
	* Check if xpram is available.
	*/
	static int __init xpram_present(void)
	{
	unsigned long mem_page;
	int rc;

	mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
	if (!mem_page)
	return -ENOMEM;
	rc = xpram_page_in(mem_page, 0);
	free_page(mem_page);
	return rc ? -ENXIO : 0;
	}

	/*
	* Return index of the last available xpram page.
	*/
	static unsigned long __init xpram_highest_page_index(void)
	{
	unsigned int page_index, add_bit;
	unsigned long mem_page;

	mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
	if (!mem_page)
	return 0;

	page_index = 0;
	add_bit = 1ULL << (sizeof(unsigned int)*8 - 1);
	while (add_bit > 0) {
	if (xpram_page_in(mem_page, page_index \| add_bit) == 0)
	page_index \|= add_bit;
	add_bit >>= 1;
	}

	free_page (mem_page);

	return page_index;
	}

	/*
	* Block device make request function.
	*/
	static int xpram_make_request(struct request_queue q, struct bio bio)
	{
	xpram_device_t *xdev = bio->bi_bdev->bd_disk->private_data;
	struct bio_vec *bvec;
	unsigned int index;
	unsigned long page_addr;
	unsigned long bytes;
	int i;

	if ((bio->bi_sector & 7) != 0 \|\| (bio->bi_size & 4095) != 0)
	/* Request is not page-aligned. */
	goto fail;
	if ((bio->bi_size >> 12) > xdev->size)
	/* Request size is no page-aligned. */
	goto fail;
	if ((bio->bi_sector >> 3) > 0xffffffffU - xdev->offset)
	goto fail;
	index = (bio->bi_sector >> 3) + xdev->offset;
	bio_for_each_segment(bvec, bio, i) {
	page_addr = (unsigned long)
	kmap(bvec->bv_page) + bvec->bv_offset;
	bytes = bvec->bv_len;
	if ((page_addr & 4095) != 0 \|\| (bytes & 4095) != 0)
	/* More paranoia. */
	goto fail;
	while (bytes > 0) {
	if (bio_data_dir(bio) == READ) {
	if (xpram_page_in(page_addr, index) != 0)
	goto fail;
	} else {
	if (xpram_page_out(page_addr, index) != 0)
	goto fail;
	}
	page_addr += 4096;
	bytes -= 4096;
	index++;
	}
	}
	set_bit(BIO_UPTODATE, &bio->bi_flags);
	bio_endio(bio, 0);
	return 0;
	fail:
	bio_io_error(bio);
	return 0;
	}

	static int xpram_getgeo(struct block_device bdev, struct hd_geometry geo)
	{
	unsigned long size;

	/*
	* get geometry: we have to fake one... trim the size to a
	* multiple of 64 (32k): tell we have 16 sectors, 4 heads,
	* whatever cylinders. Tell also that data starts at sector. 4.
	*/
	size = (xpram_pages * 8) & ~0x3f;
	geo->cylinders = size >> 6;
	geo->heads = 4;
	geo->sectors = 16;
	geo->start = 4;
	return 0;
	}

	static struct block_device_operations xpram_devops =
	{
	.owner = THIS_MODULE,
	.getgeo = xpram_getgeo,
	};

	/*
	* Setup xpram_sizes array.
	*/
	static int __init xpram_setup_sizes(unsigned long pages)
	{
	unsigned long mem_needed;
	unsigned long mem_auto;
	unsigned long long size;
	int mem_auto_no;
	int i;

	/* Check number of devices. */
	if (devs <= 0 \|\| devs > XPRAM_MAX_DEVS) {
	PRINT_ERR("invalid number %d of devices\n",devs);
	return -EINVAL;
	}
	xpram_devs = devs;

	/*
	* Copy sizes array to xpram_sizes and align partition
	* sizes to page boundary.
	*/
	mem_needed = 0;
	mem_auto_no = 0;
	for (i = 0; i < xpram_devs; i++) {
	if (sizes[i]) {
	size = simple_strtoull(sizes[i], &sizes[i], 0);
	switch (sizes[i][0]) {
	case 'g':
	case 'G':
	size <<= 20;
	break;
	case 'm':
	case 'M':
	size <<= 10;
	}
	xpram_sizes[i] = (size + 3) & -4UL;
	}
	if (xpram_sizes[i])
	mem_needed += xpram_sizes[i];
	else
	mem_auto_no++;
	}

	PRINT_INFO(" number of devices (partitions): %d \n", xpram_devs);
	for (i = 0; i < xpram_devs; i++) {
	if (xpram_sizes[i])
	PRINT_INFO(" size of partition %d: %u kB\n",
	i, xpram_sizes[i]);
	else
	PRINT_INFO(" size of partition %d to be set "
	"automatically\n",i);
	}
	PRINT_DEBUG(" memory needed (for sized partitions): %lu kB\n",
	mem_needed);
	PRINT_DEBUG(" partitions to be sized automatically: %d\n",
	mem_auto_no);

	if (mem_needed > pages * 4) {
	PRINT_ERR("Not enough expanded memory available\n");
	return -EINVAL;
	}

	/*
	* partitioning:
	* xpram_sizes[i] != 0; partition i has size xpram_sizes[i] kB
	* else: ; all partitions with zero xpram_sizes[i]
	* partition equally the remaining space
	*/
	if (mem_auto_no) {
	mem_auto = ((pages - mem_needed / 4) / mem_auto_no) * 4;
	PRINT_INFO(" automatically determined "
	"partition size: %lu kB\n", mem_auto);
	for (i = 0; i < xpram_devs; i++)
	if (xpram_sizes[i] == 0)
	xpram_sizes[i] = mem_auto;
	}
	return 0;
	}

	static struct request_queue *xpram_queue;

	static int __init xpram_setup_blkdev(void)
	{
	unsigned long offset;
	int i, rc = -ENOMEM;

	for (i = 0; i < xpram_devs; i++) {
	struct gendisk *disk = alloc_disk(1);
	if (!disk)
	goto out;
	xpram_disks[i] = disk;
	}

	/*
	* Register xpram major.
	*/
	rc = register_blkdev(XPRAM_MAJOR, XPRAM_NAME);
	if (rc < 0)
	goto out;

	/*
	* Assign the other needed values: make request function, sizes and
	* hardsect size. All the minor devices feature the same value.
	*/
	xpram_queue = blk_alloc_queue(GFP_KERNEL);
	if (!xpram_queue) {
	rc = -ENOMEM;
	goto out_unreg;
	}
	blk_queue_make_request(xpram_queue, xpram_make_request);
	blk_queue_hardsect_size(xpram_queue, 4096);

	/*
	* Setup device structures.
	*/
	offset = 0;
	for (i = 0; i < xpram_devs; i++) {
	struct gendisk *disk = xpram_disks[i];

	xpram_devices[i].size = xpram_sizes[i] / 4;
	xpram_devices[i].offset = offset;
	offset += xpram_devices[i].size;
	disk->major = XPRAM_MAJOR;
	disk->first_minor = i;
	disk->fops = &xpram_devops;
	disk->private_data = &xpram_devices[i];
	disk->queue = xpram_queue;
	sprintf(disk->disk_name, "slram%d", i);
	set_capacity(disk, xpram_sizes[i] << 1);
	add_disk(disk);
	}

	return 0;
	out_unreg:
	unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
	out:
	while (i--)
	put_disk(xpram_disks[i]);
	return rc;
	}

	/*
	* Finally, the init/exit functions.
	*/
	static void __exit xpram_exit(void)
	{
	int i;
	for (i = 0; i < xpram_devs; i++) {
	del_gendisk(xpram_disks[i]);
	put_disk(xpram_disks[i]);
	}
	unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
	blk_cleanup_queue(xpram_queue);
	}

	static int __init xpram_init(void)
	{
	int rc;

	/* Find out size of expanded memory. */
	if (xpram_present() != 0) {
	PRINT_WARN("No expanded memory available\n");
	return -ENODEV;
	}
	xpram_pages = xpram_highest_page_index() + 1;
	PRINT_INFO(" %u pages expanded memory found (%lu KB).\n",
	xpram_pages, (unsigned long) xpram_pages*4);
	rc = xpram_setup_sizes(xpram_pages);
	if (rc)
	return rc;
	return xpram_setup_blkdev();
	}

	module_init(xpram_init);
	module_exit(xpram_exit);