return -EINVAL;	}	instr->fail_addr = 0xffffffff;	/* make a local copy of instr to avoid modifying the caller's struct */	erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);	if (!erase)		return -ENOMEM;	*erase = *instr;	length = instr->len;	/*	 * find the subdevice where the to-be-erased area begins, adjust	 * starting offset to be relative to the subdevice start	 */	for (i = 0; i < concat->num_subdev; i++) {		subdev = concat->subdev[i];		if (subdev->size <= erase->addr) {			erase->addr -= subdev->size;			offset += subdev->size;		} else {			break;		}	}	/* must never happen since size limit has been verified above */	if (i >= concat->num_subdev)		BUG();	/* now do the erase: */	err = 0;	for (; length > 0; i++) {		/* loop for all subdevices affected by this request */		subdev = concat->subdev[i];	/* get current subdevice */		/* limit length to subdevice's size: */		if (erase->addr + length > subdev->size)			erase->len = subdev->size - erase->addr;		else			erase->len = length;		if (!(subdev->flags & MTD_WRITEABLE)) {			err = -EROFS;			break;		}		length -= erase->len;		if ((err = concat_dev_erase(subdev, erase))) {			/* sanity check: should never happen since			 * block alignment has been checked above */			if (err == -EINVAL)				BUG();			if (erase->fail_addr != 0xffffffff)				instr->fail_addr = erase->fail_addr + offset;			break;		}		/*		 * erase->addr specifies the offset of the area to be		 * erased *within the current subdevice*. It can be		 * non-zero only the first time through this loop, i.e.		 * for the first subdevice where blocks need to be erased.		 * All the following erases must begin at the start of the		 * current subdevice, i.e. at offset zero.		 */		erase->addr = 0;		offset += subdev->size;	}	instr->state = erase->state;	kfree(erase);	if (err)		return err;	if (instr->callback)		instr->callback(instr);	return 0;}static int concat_lock(struct mtd_info *mtd, loff_t ofs, size_t len){	struct mtd_concat *concat = CONCAT(mtd);	int i, err = -EINVAL;	if ((len + ofs) > mtd->size)		return -EINVAL;	for (i = 0; i < concat->num_subdev; i++) {		struct mtd_info *subdev = concat->subdev[i];		size_t size;		if (ofs >= subdev->size) {			size = 0;			ofs -= subdev->size;			continue;		}		if (ofs + len > subdev->size)			size = subdev->size - ofs;		else			size = len;		err = subdev->lock(subdev, ofs, size);		if (err)			break;		len -= size;		if (len == 0)			break;		err = -EINVAL;		ofs = 0;	}	return err;}static int concat_unlock(struct mtd_info *mtd, loff_t ofs, size_t len){	struct mtd_concat *concat = CONCAT(mtd);	int i, err = 0;	if ((len + ofs) > mtd->size)		return -EINVAL;	for (i = 0; i < concat->num_subdev; i++) {		struct mtd_info *subdev = concat->subdev[i];		size_t size;		if (ofs >= subdev->size) {			size = 0;			ofs -= subdev->size;			continue;		}		if (ofs + len > subdev->size)			size = subdev->size - ofs;		else			size = len;		err = subdev->unlock(subdev, ofs, size);		if (err)			break;		len -= size;		if (len == 0)			break;		err = -EINVAL;		ofs = 0;	}	return err;}static void concat_sync(struct mtd_info *mtd){	struct mtd_concat *concat = CONCAT(mtd);	int i;	for (i = 0; i < concat->num_subdev; i++) {		struct mtd_info *subdev = concat->subdev[i];		subdev->sync(subdev);	}}static int concat_suspend(struct mtd_info *mtd){	struct mtd_concat *concat = CONCAT(mtd);	int i, rc = 0;	for (i = 0; i < concat->num_subdev; i++) {		struct mtd_info *subdev = concat->subdev[i];		if ((rc = subdev->suspend(subdev)) < 0)			return rc;	}	return rc;}static void concat_resume(struct mtd_info *mtd){	struct mtd_concat *concat = CONCAT(mtd);	int i;	for (i = 0; i < concat->num_subdev; i++) {		struct mtd_info *subdev = concat->subdev[i];		subdev->resume(subdev);	}}/* * This function constructs a virtual MTD device by concatenating * num_devs MTD devices. A pointer to the new device object is * stored to *new_dev upon success. This function does _not_ * register any devices: this is the caller's responsibility. */struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],	/* subdevices to concatenate */				   int num_devs,	/* number of subdevices      */				   char *name){				/* name for the new device   */	int i;	size_t size;	struct mtd_concat *concat;	u_int32_t max_erasesize, curr_erasesize;	int num_erase_region;	printk(KERN_NOTICE "Concatenating MTD devices:\n");	for (i = 0; i < num_devs; i++)		printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);	printk(KERN_NOTICE "into device \"%s\"\n", name);	/* allocate the device structure */	size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);	concat = kmalloc(size, GFP_KERNEL);	if (!concat) {		printk		    ("memory allocation error while creating concatenated device \"%s\"\n",		     name);		return NULL;	}	memset(concat, 0, size);	concat->subdev = (struct mtd_info **) (concat + 1);	/*	 * Set up the new "super" device's MTD object structure, check for	 * incompatibilites between the subdevices.	 */	concat->mtd.type = subdev[0]->type;	concat->mtd.flags = subdev[0]->flags;	concat->mtd.size = subdev[0]->size;	concat->mtd.erasesize = subdev[0]->erasesize;	concat->mtd.oobblock = subdev[0]->oobblock;	concat->mtd.oobsize = subdev[0]->oobsize;	concat->mtd.ecctype = subdev[0]->ecctype;	concat->mtd.eccsize = subdev[0]->eccsize;	if (subdev[0]->read_ecc)		concat->mtd.read_ecc = concat_read_ecc;	if (subdev[0]->write_ecc)		concat->mtd.write_ecc = concat_write_ecc;	if (subdev[0]->read_oob)		concat->mtd.read_oob = concat_read_oob;	if (subdev[0]->write_oob)		concat->mtd.write_oob = concat_write_oob;	concat->subdev[0] = subdev[0];	for (i = 1; i < num_devs; i++) {		if (concat->mtd.type != subdev[i]->type) {			kfree(concat);			printk("Incompatible device type on \"%s\"\n",			       subdev[i]->name);			return NULL;		}		if (concat->mtd.flags != subdev[i]->flags) {			/*			 * Expect all flags except MTD_WRITEABLE to be			 * equal on all subdevices.			 */			if ((concat->mtd.flags ^ subdev[i]->			     flags) & ~MTD_WRITEABLE) {				kfree(concat);				printk("Incompatible device flags on \"%s\"\n",				       subdev[i]->name);				return NULL;			} else				/* if writeable attribute differs,				   make super device writeable */				concat->mtd.flags |=				    subdev[i]->flags & MTD_WRITEABLE;		}		concat->mtd.size += subdev[i]->size;		if (concat->mtd.oobblock   !=  subdev[i]->oobblock ||		    concat->mtd.oobsize    !=  subdev[i]->oobsize ||		    concat->mtd.ecctype    !=  subdev[i]->ecctype ||		    concat->mtd.eccsize    !=  subdev[i]->eccsize ||		    !concat->mtd.read_ecc  != !subdev[i]->read_ecc ||		    !concat->mtd.write_ecc != !subdev[i]->write_ecc ||		    !concat->mtd.read_oob  != !subdev[i]->read_oob ||		    !concat->mtd.write_oob != !subdev[i]->write_oob) {			kfree(concat);			printk("Incompatible OOB or ECC data on \"%s\"\n",			       subdev[i]->name);			return NULL;		}		concat->subdev[i] = subdev[i];	}	concat->num_subdev = num_devs;	concat->mtd.name = name;	/*	 * NOTE: for now, we do not provide any readv()/writev() methods	 *       because they are messy to implement and they are not	 *       used to a great extent anyway.	 */	concat->mtd.erase = concat_erase;	concat->mtd.read = concat_read;	concat->mtd.write = concat_write;	concat->mtd.sync = concat_sync;	concat->mtd.lock = concat_lock;	concat->mtd.unlock = concat_unlock;	concat->mtd.suspend = concat_suspend;	concat->mtd.resume = concat_resume;	/*	 * Combine the erase block size info of the subdevices:	 *	 * first, walk the map of the new device and see how	 * many changes in erase size we have	 */	max_erasesize = curr_erasesize = subdev[0]->erasesize;	num_erase_region = 1;	for (i = 0; i < num_devs; i++) {		if (subdev[i]->numeraseregions == 0) {			/* current subdevice has uniform erase size */			if (subdev[i]->erasesize != curr_erasesize) {				/* if it differs from the last subdevice's erase size, count it */				++num_erase_region;				curr_erasesize = subdev[i]->erasesize;				if (curr_erasesize > max_erasesize)					max_erasesize = curr_erasesize;			}		} else {			/* current subdevice has variable erase size */			int j;			for (j = 0; j < subdev[i]->numeraseregions; j++) {				/* walk the list of erase regions, count any changes */				if (subdev[i]->eraseregions[j].erasesize !=				    curr_erasesize) {					++num_erase_region;					curr_erasesize =					    subdev[i]->eraseregions[j].					    erasesize;					if (curr_erasesize > max_erasesize)						max_erasesize = curr_erasesize;				}			}		}	}	if (num_erase_region == 1) {		/*		 * All subdevices have the same uniform erase size.		 * This is easy:		 */		concat->mtd.erasesize = curr_erasesize;		concat->mtd.numeraseregions = 0;	} else {		/*		 * erase block size varies across the subdevices: allocate		 * space to store the data describing the variable erase regions		 */		struct mtd_erase_region_info *erase_region_p;		u_int32_t begin, position;		concat->mtd.erasesize = max_erasesize;		concat->mtd.numeraseregions = num_erase_region;		concat->mtd.eraseregions = erase_region_p =		    kmalloc(num_erase_region *			    sizeof (struct mtd_erase_region_info), GFP_KERNEL);		if (!erase_region_p) {			kfree(concat);			printk			    ("memory allocation error while creating erase region list"			     " for device \"%s\"\n", name);			return NULL;		}		/*		 * walk the map of the new device once more and fill in		 * in erase region info:		 */		curr_erasesize = subdev[0]->erasesize;		begin = position = 0;		for (i = 0; i < num_devs; i++) {			if (subdev[i]->numeraseregions == 0) {				/* current subdevice has uniform erase size */				if (subdev[i]->erasesize != curr_erasesize) {					/*					 *  fill in an mtd_erase_region_info structure for the area					 *  we have walked so far:					 */					erase_region_p->offset = begin;					erase_region_p->erasesize =					    curr_erasesize;					erase_region_p->numblocks =					    (position - begin) / curr_erasesize;					begin = position;					curr_erasesize = subdev[i]->erasesize;					++erase_region_p;				}				position += subdev[i]->size;			} else {				/* current subdevice has variable erase size */				int j;				for (j = 0; j < subdev[i]->numeraseregions; j++) {					/* walk the list of erase regions, count any changes */					if (subdev[i]->eraseregions[j].					    erasesize != curr_erasesize) {						erase_region_p->offset = begin;						erase_region_p->erasesize =						    curr_erasesize;						erase_region_p->numblocks =						    (position -						     begin) / curr_erasesize;						begin = position;						curr_erasesize =						    subdev[i]->eraseregions[j].						    erasesize;						++erase_region_p;					}					position +=					    subdev[i]->eraseregions[j].					    numblocks * curr_erasesize;				}			}		}		/* Now write the final entry */		erase_region_p->offset = begin;		erase_region_p->erasesize = curr_erasesize;		erase_region_p->numblocks = (position - begin) / curr_erasesize;	}	return &concat->mtd;}/*  * This function destroys an MTD object obtained from concat_mtd_devs() */void mtd_concat_destroy(struct mtd_info *mtd){	struct mtd_concat *concat = CONCAT(mtd);	if (concat->mtd.numeraseregions)		kfree(concat->mtd.eraseregions);	kfree(concat);}EXPORT_SYMBOL(mtd_concat_create);EXPORT_SYMBOL(mtd_concat_destroy);MODULE_LICENSE("GPL");MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");