add generic 2.6.26 patches/files

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@11323 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 951 insertions, 0 deletions

diff --git a/target/linux/generic-2.6/patches-2.6.26/065-rootfs_split.patch b/target/linux/generic-2.6/patches-2.6.26/065-rootfs_split.patch
new file mode 100644
index 000000000..62a7e252e
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.26/065-rootfs_split.patch
@@ -0,0 +1,951 @@
+--- a/drivers/mtd/Kconfig
++++ b/drivers/mtd/Kconfig
+@@ -47,6 +47,16 @@
+ 	  devices. Partitioning on NFTL 'devices' is a different - that's the
+ 	  'normal' form of partitioning used on a block device.
+ 
++config MTD_ROOTFS_ROOT_DEV
++	bool "Automatically set 'rootfs' partition to be root filesystem"
++	depends on MTD_PARTITIONS
++	default y
++
++config MTD_ROOTFS_SPLIT
++	bool "Automatically split 'rootfs' partition for squashfs"
++	depends on MTD_PARTITIONS
++	default y
++
+ config MTD_REDBOOT_PARTS
+ 	tristate "RedBoot partition table parsing"
+ 	depends on MTD_PARTITIONS
+--- a/drivers/mtd/mtdpart.c
++++ b/drivers/mtd/mtdpart.c
+@@ -20,6 +20,8 @@
+ #include <linux/mtd/mtd.h>
+ #include <linux/mtd/partitions.h>
+ #include <linux/mtd/compatmac.h>
++#include <linux/squashfs_fs.h>
++#include <linux/root_dev.h>
+ 
+ /* Our partition linked list */
+ static LIST_HEAD(mtd_partitions);
+@@ -39,7 +41,7 @@
+  * the pointer to that structure with this macro.
+  */
+ #define PART(x)  ((struct mtd_part *)(x))
+-
++#define IS_PART(mtd) (mtd->read == part_read)
+ 
+ /*
+  * MTD methods which simply translate the effective address and pass through
+@@ -322,6 +324,316 @@
+ 	return 0;
+ }
+ 
++static u_int32_t cur_offset = 0;
++static int add_one_partition(struct mtd_info *master, const struct mtd_partition *part,
++		int i, struct mtd_part **slp)
++{
++	struct mtd_part *slave;
++
++	/* allocate the partition structure */
++	slave = kzalloc (sizeof(*slave), GFP_KERNEL);
++	if (!slave) {
++		printk ("memory allocation error while creating partitions for \"%s\"\n",
++			master->name);
++		del_mtd_partitions(master);
++		return -ENOMEM;
++	}
++	list_add(&slave->list, &mtd_partitions);
++
++	/* set up the MTD object for this partition */
++	slave->mtd.type = master->type;
++	slave->mtd.flags = master->flags & ~part->mask_flags;
++	slave->mtd.size = part->size;
++	slave->mtd.writesize = master->writesize;
++	slave->mtd.oobsize = master->oobsize;
++	slave->mtd.oobavail = master->oobavail;
++	slave->mtd.subpage_sft = master->subpage_sft;
++
++	slave->mtd.name = part->name;
++	slave->mtd.owner = master->owner;
++
++	slave->mtd.read = part_read;
++	slave->mtd.write = part_write;
++
++	if (master->panic_write)
++		slave->mtd.panic_write = part_panic_write;
++
++	slave->mtd.refresh_device = part->refresh_partition;
++
++	if(master->point && master->unpoint){
++		slave->mtd.point = part_point;
++		slave->mtd.unpoint = part_unpoint;
++	}
++
++	if (master->read_oob)
++		slave->mtd.read_oob = part_read_oob;
++	if (master->write_oob)
++		slave->mtd.write_oob = part_write_oob;
++	if(master->read_user_prot_reg)
++		slave->mtd.read_user_prot_reg = part_read_user_prot_reg;
++	if(master->read_fact_prot_reg)
++		slave->mtd.read_fact_prot_reg = part_read_fact_prot_reg;
++	if(master->write_user_prot_reg)
++		slave->mtd.write_user_prot_reg = part_write_user_prot_reg;
++	if(master->lock_user_prot_reg)
++		slave->mtd.lock_user_prot_reg = part_lock_user_prot_reg;
++	if(master->get_user_prot_info)
++		slave->mtd.get_user_prot_info = part_get_user_prot_info;
++	if(master->get_fact_prot_info)
++		slave->mtd.get_fact_prot_info = part_get_fact_prot_info;
++	if (master->sync)
++		slave->mtd.sync = part_sync;
++	if (!i && master->suspend && master->resume) {
++			slave->mtd.suspend = part_suspend;
++			slave->mtd.resume = part_resume;
++	}
++	if (master->writev)
++		slave->mtd.writev = part_writev;
++	if (master->lock)
++		slave->mtd.lock = part_lock;
++	if (master->unlock)
++		slave->mtd.unlock = part_unlock;
++	if (master->block_isbad)
++		slave->mtd.block_isbad = part_block_isbad;
++	if (master->block_markbad)
++		slave->mtd.block_markbad = part_block_markbad;
++	slave->mtd.erase = part_erase;
++	slave->master = master;
++	slave->offset = part->offset;
++	slave->index = i;
++
++	if (slave->offset == MTDPART_OFS_APPEND)
++		slave->offset = cur_offset;
++	if (slave->offset == MTDPART_OFS_NXTBLK) {
++		slave->offset = cur_offset;
++		if ((cur_offset % master->erasesize) != 0) {
++			/* Round up to next erasesize */
++			slave->offset = ((cur_offset / master->erasesize) + 1) * master->erasesize;
++			printk(KERN_NOTICE "Moving partition %d: "
++			       "0x%08x -> 0x%08x\n", i,
++			       cur_offset, slave->offset);
++		}
++	}
++	if (slave->mtd.size == MTDPART_SIZ_FULL)
++		slave->mtd.size = master->size - slave->offset;
++	cur_offset = slave->offset + slave->mtd.size;
++
++	printk (KERN_NOTICE "0x%08x-0x%08x : \"%s\"\n", slave->offset,
++		slave->offset + slave->mtd.size, slave->mtd.name);
++
++	/* let's do some sanity checks */
++	if (slave->offset >= master->size) {
++			/* let's register it anyway to preserve ordering */
++		slave->offset = 0;
++		slave->mtd.size = 0;
++		printk ("mtd: partition \"%s\" is out of reach -- disabled\n",
++			part->name);
++	}
++	if (slave->offset + slave->mtd.size > master->size) {
++		slave->mtd.size = master->size - slave->offset;
++		printk ("mtd: partition \"%s\" extends beyond the end of device \"%s\" -- size truncated to %#x\n",
++			part->name, master->name, slave->mtd.size);
++	}
++	if (master->numeraseregions>1) {
++		/* Deal with variable erase size stuff */
++		int i;
++		struct mtd_erase_region_info *regions = master->eraseregions;
++
++		/* Find the first erase regions which is part of this partition. */
++		for (i=0; i < master->numeraseregions && slave->offset >= regions[i].offset; i++)
++			;
++
++		for (i--; i < master->numeraseregions && slave->offset + slave->mtd.size > regions[i].offset; i++) {
++			if (slave->mtd.erasesize < regions[i].erasesize) {
++				slave->mtd.erasesize = regions[i].erasesize;
++			}
++		}
++	} else {
++		/* Single erase size */
++		slave->mtd.erasesize = master->erasesize;
++	}
++
++	if ((slave->mtd.flags & MTD_WRITEABLE) &&
++	    (slave->offset % slave->mtd.erasesize)) {
++		/* Doesn't start on a boundary of major erase size */
++		/* FIXME: Let it be writable if it is on a boundary of _minor_ erase size though */
++		slave->mtd.flags &= ~MTD_WRITEABLE;
++		printk ("mtd: partition \"%s\" doesn't start on an erase block boundary -- force read-only\n",
++			part->name);
++	}
++	if ((slave->mtd.flags & MTD_WRITEABLE) &&
++	    (slave->mtd.size % slave->mtd.erasesize)) {
++		slave->mtd.flags &= ~MTD_WRITEABLE;
++		printk ("mtd: partition \"%s\" doesn't end on an erase block -- force read-only\n",
++			part->name);
++	}
++
++	slave->mtd.ecclayout = master->ecclayout;
++	if (master->block_isbad) {
++		uint32_t offs = 0;
++
++		while(offs < slave->mtd.size) {
++			if (master->block_isbad(master,
++						offs + slave->offset))
++				slave->mtd.ecc_stats.badblocks++;
++			offs += slave->mtd.erasesize;
++		}
++	}
++
++	if(part->mtdp)
++	{	/* store the object pointer (caller may or may not register it */
++		*part->mtdp = &slave->mtd;
++		slave->registered = 0;
++	}
++	else
++	{
++		/* register our partition */
++		add_mtd_device(&slave->mtd);
++		slave->registered = 1;
++	}
++
++	if (slp)
++		*slp = slave;
++
++	return 0;
++}
++
++#ifdef CONFIG_MTD_ROOTFS_SPLIT
++#define ROOTFS_SPLIT_NAME "rootfs_data"
++#define ROOTFS_REMOVED_NAME "<removed>"
++static int split_squashfs(struct mtd_info *master, int offset, int *split_offset)
++{
++	char buf[512];
++	struct squashfs_super_block *sb = (struct squashfs_super_block *) buf;
++	int len, ret;
++
++	ret = master->read(master, offset, sizeof(*sb), &len, buf);
++	if (ret || (len != sizeof(*sb))) {
++		printk(KERN_ALERT "split_squashfs: error occured while reading "
++			"from \"%s\"\n", master->name);
++		return -EINVAL;
++	}
++
++	if (*((u32 *) buf) != SQUASHFS_MAGIC) {
++		printk(KERN_ALERT "split_squashfs: no squashfs found in \"%s\"\n",
++			master->name);
++		*split_offset = 0;
++		return 0;
++	}
++
++	if (sb->bytes_used <= 0) {
++		printk(KERN_ALERT "split_squashfs: squashfs is empty in \"%s\"\n",
++			master->name);
++		*split_offset = 0;
++		return 0;
++	}
++
++	len = (u32) sb->bytes_used;
++	len += (offset & 0x000fffff);
++	len +=  (master->erasesize - 1);
++	len &= ~(master->erasesize - 1);
++	len -= (offset & 0x000fffff);
++	*split_offset = offset + len;
++
++	return 0;
++}
++
++static int split_rootfs_data(struct mtd_info *master, struct mtd_info *rpart, struct mtd_partition *part,
++		int index)
++{
++	struct mtd_partition *dpart;
++	struct mtd_part *slave = NULL;
++	int split_offset = 0;
++	int ret;
++
++	ret = split_squashfs(master, part->offset, &split_offset);
++	if (ret)
++		return ret;
++
++	if (split_offset <= 0)
++		return 0;
++
++	dpart = kmalloc(sizeof(*part)+sizeof(ROOTFS_SPLIT_NAME)+1, GFP_KERNEL);
++	if (dpart == NULL) {
++		printk(KERN_INFO "split_squashfs: no memory for partition \"%s\"\n",
++			ROOTFS_SPLIT_NAME);
++		return -ENOMEM;
++	}
++
++	memcpy(dpart, part, sizeof(*part));
++	dpart->name = (unsigned char *)&dpart[1];
++	strcpy(dpart->name, ROOTFS_SPLIT_NAME);
++
++	dpart->size -= split_offset - dpart->offset;
++	dpart->offset = split_offset;
++
++	if (dpart == NULL)
++		return 1;
++
++	printk(KERN_INFO "mtd: partition \"%s\" created automatically, ofs=%X, len=%X \n",
++		ROOTFS_SPLIT_NAME, dpart->offset, dpart->size);
++
++	ret = add_one_partition(master, dpart, index, &slave);
++	if (ret)
++		kfree(dpart);
++	else if (slave)
++		rpart->split = &slave->mtd;
++
++	return ret;
++}
++
++static int refresh_rootfs_split(struct mtd_info *mtd)
++{
++	struct mtd_partition tpart;
++	struct mtd_part *part;
++	int index = 0;
++	int offset, size;
++	int ret;
++
++	part = PART(mtd);
++
++	/* check for the new squashfs offset first */
++	ret = split_squashfs(part->master, part->offset, &offset);
++	if (ret)
++		return ret;
++
++	if ((offset > 0) && !mtd->split) {
++		printk(KERN_INFO "%s: creating new split partition for \"%s\"\n", __func__, mtd->name);
++		/* if we don't have a rootfs split partition, create a new one */
++		tpart.name = mtd->name;
++		tpart.size = mtd->size;
++		tpart.offset = part->offset;
++
++		/* find the index of the last partition */
++		if (!list_empty(&mtd_partitions))
++			index = list_first_entry(&mtd_partitions, struct mtd_part, list)->index + 1;
++
++		return split_rootfs_data(part->master, &part->mtd, &tpart, index);
++	} else if ((offset > 0) && mtd->split) {
++		/* update the offsets of the existing partition */
++		size = mtd->size + part->offset - offset;
++
++		part = PART(mtd->split);
++		part->offset = offset;
++		part->mtd.size = size;
++		printk(KERN_INFO "%s: %s partition \"" ROOTFS_SPLIT_NAME "\", offset: 0x%06x (0x%06x)\n",
++			__func__, (!strcmp(part->mtd.name, ROOTFS_SPLIT_NAME) ? "updating" : "creating"),
++			part->offset, part->mtd.size);
++		strcpy(part->mtd.name, ROOTFS_SPLIT_NAME);
++	} else if ((offset <= 0) && mtd->split) {
++		printk(KERN_INFO "%s: removing partition \"%s\"\n", __func__, mtd->split->name);
++
++		/* mark existing partition as removed */
++		part = PART(mtd->split);
++		strcpy(part->mtd.name, ROOTFS_REMOVED_NAME);
++		part->offset = 0;
++		part->mtd.size = 0;
++	}
++
++	return 0;
++}
++#endif /* CONFIG_MTD_ROOTFS_SPLIT */
++
+ /*
+  * This function, given a master MTD object and a partition table, creates
+  * and registers slave MTD objects which are bound to the master according to
+@@ -334,171 +646,31 @@
+ 		       int nbparts)
+ {
+ 	struct mtd_part *slave;
+-	u_int32_t cur_offset = 0;
+-	int i;
++	struct mtd_partition *part;
++	int i, j, ret = 0;
+ 
+ 	printk (KERN_NOTICE "Creating %d MTD partitions on \"%s\":\n", nbparts, master->name);
+ 
+-	for (i = 0; i < nbparts; i++) {
+-
+-		/* allocate the partition structure */
+-		slave = kzalloc (sizeof(*slave), GFP_KERNEL);
+-		if (!slave) {
+-			printk ("memory allocation error while creating partitions for \"%s\"\n",
+-				master->name);
+-			del_mtd_partitions(master);
+-			return -ENOMEM;
+-		}
+-		list_add(&slave->list, &mtd_partitions);
+-
+-		/* set up the MTD object for this partition */
+-		slave->mtd.type = master->type;
+-		slave->mtd.flags = master->flags & ~parts[i].mask_flags;
+-		slave->mtd.size = parts[i].size;
+-		slave->mtd.writesize = master->writesize;
+-		slave->mtd.oobsize = master->oobsize;
+-		slave->mtd.oobavail = master->oobavail;
+-		slave->mtd.subpage_sft = master->subpage_sft;
+-
+-		slave->mtd.name = parts[i].name;
+-		slave->mtd.owner = master->owner;
+-
+-		slave->mtd.read = part_read;
+-		slave->mtd.write = part_write;
+-
+-		if (master->panic_write)
+-			slave->mtd.panic_write = part_panic_write;
+-
+-		if(master->point && master->unpoint){
+-			slave->mtd.point = part_point;
+-			slave->mtd.unpoint = part_unpoint;
+-		}
+-
+-		if (master->read_oob)
+-			slave->mtd.read_oob = part_read_oob;
+-		if (master->write_oob)
+-			slave->mtd.write_oob = part_write_oob;
+-		if(master->read_user_prot_reg)
+-			slave->mtd.read_user_prot_reg = part_read_user_prot_reg;
+-		if(master->read_fact_prot_reg)
+-			slave->mtd.read_fact_prot_reg = part_read_fact_prot_reg;
+-		if(master->write_user_prot_reg)
+-			slave->mtd.write_user_prot_reg = part_write_user_prot_reg;
+-		if(master->lock_user_prot_reg)
+-			slave->mtd.lock_user_prot_reg = part_lock_user_prot_reg;
+-		if(master->get_user_prot_info)
+-			slave->mtd.get_user_prot_info = part_get_user_prot_info;
+-		if(master->get_fact_prot_info)
+-			slave->mtd.get_fact_prot_info = part_get_fact_prot_info;
+-		if (master->sync)
+-			slave->mtd.sync = part_sync;
+-		if (!i && master->suspend && master->resume) {
+-				slave->mtd.suspend = part_suspend;
+-				slave->mtd.resume = part_resume;
+-		}
+-		if (master->writev)
+-			slave->mtd.writev = part_writev;
+-		if (master->lock)
+-			slave->mtd.lock = part_lock;
+-		if (master->unlock)
+-			slave->mtd.unlock = part_unlock;
+-		if (master->block_isbad)
+-			slave->mtd.block_isbad = part_block_isbad;
+-		if (master->block_markbad)
+-			slave->mtd.block_markbad = part_block_markbad;
+-		slave->mtd.erase = part_erase;
+-		slave->master = master;
+-		slave->offset = parts[i].offset;
+-		slave->index = i;
+-
+-		if (slave->offset == MTDPART_OFS_APPEND)
+-			slave->offset = cur_offset;
+-		if (slave->offset == MTDPART_OFS_NXTBLK) {
+-			slave->offset = cur_offset;
+-			if ((cur_offset % master->erasesize) != 0) {
+-				/* Round up to next erasesize */
+-				slave->offset = ((cur_offset / master->erasesize) + 1) * master->erasesize;
+-				printk(KERN_NOTICE "Moving partition %d: "
+-				       "0x%08x -> 0x%08x\n", i,
+-				       cur_offset, slave->offset);
+-			}
+-		}
+-		if (slave->mtd.size == MTDPART_SIZ_FULL)
+-			slave->mtd.size = master->size - slave->offset;
+-		cur_offset = slave->offset + slave->mtd.size;
+-
+-		printk (KERN_NOTICE "0x%08x-0x%08x : \"%s\"\n", slave->offset,
+-			slave->offset + slave->mtd.size, slave->mtd.name);
+-
+-		/* let's do some sanity checks */
+-		if (slave->offset >= master->size) {
+-				/* let's register it anyway to preserve ordering */
+-			slave->offset = 0;
+-			slave->mtd.size = 0;
+-			printk ("mtd: partition \"%s\" is out of reach -- disabled\n",
+-				parts[i].name);
+-		}
+-		if (slave->offset + slave->mtd.size > master->size) {
+-			slave->mtd.size = master->size - slave->offset;
+-			printk ("mtd: partition \"%s\" extends beyond the end of device \"%s\" -- size truncated to %#x\n",
+-				parts[i].name, master->name, slave->mtd.size);
+-		}
+-		if (master->numeraseregions>1) {
+-			/* Deal with variable erase size stuff */
+-			int i;
+-			struct mtd_erase_region_info *regions = master->eraseregions;
+-
+-			/* Find the first erase regions which is part of this partition. */
+-			for (i=0; i < master->numeraseregions && slave->offset >= regions[i].offset; i++)
+-				;
+-
+-			for (i--; i < master->numeraseregions && slave->offset + slave->mtd.size > regions[i].offset; i++) {
+-				if (slave->mtd.erasesize < regions[i].erasesize) {
+-					slave->mtd.erasesize = regions[i].erasesize;
+-				}
++	for (i = 0, j = 0; i < nbparts; i++) {
++		part = (struct mtd_partition *) &parts[i];
++		ret = add_one_partition(master, part, j, &slave);
++		if (ret)
++			return ret;
++		j++;
++
++		if (strcmp(part->name, "rootfs") == 0 && slave->registered) {
++#ifdef CONFIG_MTD_ROOTFS_ROOT_DEV
++			if (ROOT_DEV == 0) {
++				printk(KERN_NOTICE "mtd: partition \"rootfs\" "
++					"set to be root filesystem\n");
++				ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, slave->mtd.index);
+ 			}
+-		} else {
+-			/* Single erase size */
+-			slave->mtd.erasesize = master->erasesize;
+-		}
+-
+-		if ((slave->mtd.flags & MTD_WRITEABLE) &&
+-		    (slave->offset % slave->mtd.erasesize)) {
+-			/* Doesn't start on a boundary of major erase size */
+-			/* FIXME: Let it be writable if it is on a boundary of _minor_ erase size though */
+-			slave->mtd.flags &= ~MTD_WRITEABLE;
+-			printk ("mtd: partition \"%s\" doesn't start on an erase block boundary -- force read-only\n",
+-				parts[i].name);
+-		}
+-		if ((slave->mtd.flags & MTD_WRITEABLE) &&
+-		    (slave->mtd.size % slave->mtd.erasesize)) {
+-			slave->mtd.flags &= ~MTD_WRITEABLE;
+-			printk ("mtd: partition \"%s\" doesn't end on an erase block -- force read-only\n",
+-				parts[i].name);
+-		}
+-
+-		slave->mtd.ecclayout = master->ecclayout;
+-		if (master->block_isbad) {
+-			uint32_t offs = 0;
+-
+-			while(offs < slave->mtd.size) {
+-				if (master->block_isbad(master,
+-							offs + slave->offset))
+-					slave->mtd.ecc_stats.badblocks++;
+-				offs += slave->mtd.erasesize;
+-			}
+-		}
+-
+-		if(parts[i].mtdp)
+-		{	/* store the object pointer (caller may or may not register it */
+-			*parts[i].mtdp = &slave->mtd;
+-			slave->registered = 0;
+-		}
+-		else
+-		{
+-			/* register our partition */
+-			add_mtd_device(&slave->mtd);
+-			slave->registered = 1;
++#endif
++#ifdef CONFIG_MTD_ROOTFS_SPLIT
++			ret = split_rootfs_data(master, &slave->mtd, part, j);
++			if (ret == 0)
++				j++;
++#endif
+ 		}
+ 	}
+ 
+@@ -574,6 +746,32 @@
+ 	return ret;
+ }
+ 
++int refresh_mtd_partitions(struct mtd_info *mtd)
++{
++	int ret = 0;
++
++	if (IS_PART(mtd)) {
++		struct mtd_part *part;
++		struct mtd_info *master;
++
++		part = PART(mtd);
++		master = part->master;
++		if (master->refresh_device)
++			ret = master->refresh_device(master);
++	}
++
++	if (!ret && mtd->refresh_device)
++		ret = mtd->refresh_device(mtd);
++
++#ifdef CONFIG_MTD_ROOTFS_SPLIT
++	if (!ret && IS_PART(mtd) && !strcmp(mtd->name, "rootfs"))
++		refresh_rootfs_split(mtd);
++#endif
++
++	return 0;
++}
++
+ EXPORT_SYMBOL_GPL(parse_mtd_partitions);
++EXPORT_SYMBOL_GPL(refresh_mtd_partitions);
+ EXPORT_SYMBOL_GPL(register_mtd_parser);
+ EXPORT_SYMBOL_GPL(deregister_mtd_parser);
+--- a/drivers/mtd/devices/block2mtd.c
++++ b/drivers/mtd/devices/block2mtd.c
+@@ -34,6 +34,8 @@
+ 	struct block_device *blkdev;
+ 	struct mtd_info mtd;
+ 	struct mutex write_mutex;
++	rwlock_t bdev_mutex;
++	char devname[0];
+ };
+ 
+ 
+@@ -86,6 +88,12 @@
+ 	size_t len = instr->len;
+ 	int err;
+ 
++	read_lock(&dev->bdev_mutex);
++	if (!dev->blkdev) {
++		err = -EINVAL;
++		goto done;
++	}
++
+ 	instr->state = MTD_ERASING;
+ 	mutex_lock(&dev->write_mutex);
+ 	err = _block2mtd_erase(dev, from, len);
+@@ -98,6 +106,10 @@
+ 
+ 	instr->state = MTD_ERASE_DONE;
+ 	mtd_erase_callback(instr);
++
++done:
++	read_unlock(&dev->bdev_mutex);
++
+ 	return err;
+ }
+ 
+@@ -109,10 +121,14 @@
+ 	struct page *page;
+ 	int index = from >> PAGE_SHIFT;
+ 	int offset = from & (PAGE_SIZE-1);
+-	int cpylen;
++	int cpylen, err = 0;
++
++	read_lock(&dev->bdev_mutex);
++	if (!dev->blkdev || (from > mtd->size)) {
++		err = -EINVAL;
++		goto done;
++	}
+ 
+-	if (from > mtd->size)
+-		return -EINVAL;
+ 	if (from + len > mtd->size)
+ 		len = mtd->size - from;
+ 
+@@ -127,10 +143,14 @@
+ 		len = len - cpylen;
+ 
+ 		page = page_read(dev->blkdev->bd_inode->i_mapping, index);
+-		if (!page)
+-			return -ENOMEM;
+-		if (IS_ERR(page))
+-			return PTR_ERR(page);
++		if (!page) {
++			err = -ENOMEM;
++			goto done;
++		}
++		if (IS_ERR(page)) {
++			err = PTR_ERR(page);
++			goto done;
++		}
+ 
+ 		memcpy(buf, page_address(page) + offset, cpylen);
+ 		page_cache_release(page);
+@@ -141,7 +161,10 @@
+ 		offset = 0;
+ 		index++;
+ 	}
+-	return 0;
++
++done:
++	read_unlock(&dev->bdev_mutex);
++	return err;
+ }
+ 
+ 
+@@ -193,12 +216,22 @@
+ 		size_t *retlen, const u_char *buf)
+ {
+ 	struct block2mtd_dev *dev = mtd->priv;
+-	int err;
++	int err = 0;
++
++	read_lock(&dev->bdev_mutex);
++	if (!dev->blkdev) {
++		err = -EINVAL;
++		goto done;
++	}
+ 
+ 	if (!len)
+-		return 0;
+-	if (to >= mtd->size)
+-		return -ENOSPC;
++		goto done;
++
++	if (to >= mtd->size) {
++		err = -ENOSPC;
++		goto done;
++	}
++
+ 	if (to + len > mtd->size)
+ 		len = mtd->size - to;
+ 
+@@ -207,6 +240,9 @@
+ 	mutex_unlock(&dev->write_mutex);
+ 	if (err > 0)
+ 		err = 0;
++
++done:
++	read_unlock(&dev->bdev_mutex);
+ 	return err;
+ }
+ 
+@@ -215,51 +251,29 @@
+ static void block2mtd_sync(struct mtd_info *mtd)
+ {
+ 	struct block2mtd_dev *dev = mtd->priv;
+-	sync_blockdev(dev->blkdev);
+-	return;
+-}
+-
+-
+-static void block2mtd_free_device(struct block2mtd_dev *dev)
+-{
+-	if (!dev)
+-		return;
+-
+-	kfree(dev->mtd.name);
+ 
+-	if (dev->blkdev) {
+-		invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping,
+-					0, -1);
+-		close_bdev_excl(dev->blkdev);
+-	}
++	read_lock(&dev->bdev_mutex);
++	if (dev->blkdev)
++		sync_blockdev(dev->blkdev);
++	read_unlock(&dev->bdev_mutex);
+ 
+-	kfree(dev);
++	return;
+ }
+ 
+ 
+-/* FIXME: ensure that mtd->size % erase_size == 0 */
+-static struct block2mtd_dev *add_device(char *devname, int erase_size, char *mtdname)
++static int _open_bdev(struct block2mtd_dev *dev)
+ {
+ 	struct block_device *bdev;
+-	struct block2mtd_dev *dev;
+-	struct mtd_partition *part;
+-
+-	if (!devname)
+-		return NULL;
+-
+-	dev = kzalloc(sizeof(struct block2mtd_dev), GFP_KERNEL);
+-	if (!dev)
+-		return NULL;
+ 
+ 	/* Get a handle on the device */
+-	bdev = open_bdev_excl(devname, O_RDWR, NULL);
++	bdev = open_bdev_excl(dev->devname, O_RDWR, NULL);
+ #ifndef MODULE
+ 	if (IS_ERR(bdev)) {
+ 
+ 		/* We might not have rootfs mounted at this point. Try
+ 		   to resolve the device name by other means. */
+ 
+-		dev_t devt = name_to_dev_t(devname);
++		dev_t devt = name_to_dev_t(dev->devname);
+ 		if (devt) {
+ 			bdev = open_by_devnum(devt, FMODE_WRITE | FMODE_READ);
+ 		}
+@@ -267,17 +281,96 @@
+ #endif
+ 
+ 	if (IS_ERR(bdev)) {
+-		ERROR("error: cannot open device %s", devname);
+-		goto devinit_err;
++		ERROR("error: cannot open device %s", dev->devname);
++		return 1;
+ 	}
+ 	dev->blkdev = bdev;
+ 
+ 	if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
+ 		ERROR("attempting to use an MTD device as a block device");
+-		goto devinit_err;
++		return 1;
+ 	}
+ 
++	return 0;
++}
++
++static void _close_bdev(struct block2mtd_dev *dev)
++{
++	struct block_device *bdev;
++
++	if (!dev->blkdev)
++		return;
++
++	bdev = dev->blkdev;
++	invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping, 0, -1);
++	close_bdev_excl(dev->blkdev);
++	dev->blkdev = NULL;
++}
++
++static void block2mtd_free_device(struct block2mtd_dev *dev)
++{
++	if (!dev)
++		return;
++
++	kfree(dev->mtd.name);
++	_close_bdev(dev);
++	kfree(dev);
++}
++
++
++static int block2mtd_refresh(struct mtd_info *mtd)
++{
++	struct block2mtd_dev *dev = mtd->priv;
++	struct block_device *bdev;
++	dev_t devt;
++	int err = 0;
++
++	/* no other mtd function can run at this point */
++	write_lock(&dev->bdev_mutex);
++
++	/* get the device number for the whole disk */
++	devt = MKDEV(MAJOR(dev->blkdev->bd_dev), 0);
++
++	/* close the old block device */
++	_close_bdev(dev);
++
++	/* open the whole disk, issue a partition rescan, then */
++	bdev = open_by_devnum(devt, FMODE_WRITE | FMODE_READ);
++	if (!bdev || !bdev->bd_disk)
++		err = -EINVAL;
++	else {
++		err = rescan_partitions(bdev->bd_disk, bdev);
++	}
++	if (bdev)
++		close_bdev_excl(bdev);
++
++	/* try to open the partition block device again */
++	_open_bdev(dev);
++	write_unlock(&dev->bdev_mutex);
++
++	return err;
++}
++
++/* FIXME: ensure that mtd->size % erase_size == 0 */
++static struct block2mtd_dev *add_device(char *devname, int erase_size, char *mtdname)
++{
++	struct block2mtd_dev *dev;
++	struct mtd_partition *part;
++
++	if (!devname)
++		return NULL;
++
++	dev = kzalloc(sizeof(struct block2mtd_dev) + strlen(devname) + 1, GFP_KERNEL);
++	if (!dev)
++		return NULL;
++
++	strcpy(dev->devname, devname);
++
++	if (_open_bdev(dev))
++		goto devinit_err;
++
+ 	mutex_init(&dev->write_mutex);
++	rwlock_init(&dev->bdev_mutex);
+ 
+ 	/* Setup the MTD structure */
+ 	/* make the name contain the block device in */
+@@ -304,6 +397,7 @@
+ 	dev->mtd.read = block2mtd_read;
+ 	dev->mtd.priv = dev;
+ 	dev->mtd.owner = THIS_MODULE;
++	dev->mtd.refresh_device = block2mtd_refresh;
+ 	
+ 	part = kzalloc(sizeof(struct mtd_partition), GFP_KERNEL);
+ 	part->name = dev->mtd.name;
+--- a/drivers/mtd/mtdchar.c
++++ b/drivers/mtd/mtdchar.c
+@@ -17,6 +17,7 @@
+ 
+ #include <linux/mtd/mtd.h>
+ #include <linux/mtd/compatmac.h>
++#include <linux/mtd/partitions.h>
+ 
+ #include <asm/uaccess.h>
+ 
+@@ -756,6 +757,13 @@
+ 		file->f_pos = 0;
+ 		break;
+ 	}
++#ifdef CONFIG_MTD_PARTITIONS
++	case MTDREFRESH:
++	{
++		ret = refresh_mtd_partitions(mtd);
++		break;
++	}
++#endif
+ 
+ 	default:
+ 		ret = -ENOTTY;
+--- a/include/linux/mtd/mtd.h
++++ b/include/linux/mtd/mtd.h
+@@ -98,6 +98,7 @@
+ 	uint8_t		*oobbuf;
+ };
+ 
++struct mtd_info;
+ struct mtd_info {
+ 	u_char type;
+ 	u_int32_t flags;
+@@ -211,6 +212,9 @@
+ 	struct module *owner;
+ 	int usecount;
+ 
++	int (*refresh_device)(struct mtd_info *mtd);
++	struct mtd_info *split;
++
+ 	/* If the driver is something smart, like UBI, it may need to maintain
+ 	 * its own reference counting. The below functions are only for driver.
+ 	 * The driver may register its callbacks. These callbacks are not
+--- a/include/linux/mtd/partitions.h
++++ b/include/linux/mtd/partitions.h
+@@ -36,6 +36,7 @@
+  * erasesize aligned (e.g. use MTDPART_OFS_NEXTBLK).
+  */
+ 
++struct mtd_partition;
+ struct mtd_partition {
+ 	char *name;			/* identifier string */
+ 	u_int32_t size;			/* partition size */
+@@ -43,6 +44,7 @@
+ 	u_int32_t mask_flags;		/* master MTD flags to mask out for this partition */
+ 	struct nand_ecclayout *ecclayout;	/* out of band layout for this partition (NAND only)*/
+ 	struct mtd_info **mtdp;		/* pointer to store the MTD object */
++	int (*refresh_partition)(struct mtd_info *);
+ };
+ 
+ #define MTDPART_OFS_NXTBLK	(-2)
+@@ -52,6 +54,7 @@
+ 
+ int add_mtd_partitions(struct mtd_info *, const struct mtd_partition *, int);
+ int del_mtd_partitions(struct mtd_info *);
++int refresh_mtd_partitions(struct mtd_info *);
+ 
+ /*
+  * Functions dealing with the various ways of partitioning the space
+--- a/include/mtd/mtd-abi.h
++++ b/include/mtd/mtd-abi.h
+@@ -95,6 +95,7 @@
+ #define ECCGETLAYOUT		_IOR('M', 17, struct nand_ecclayout)
+ #define ECCGETSTATS		_IOR('M', 18, struct mtd_ecc_stats)
+ #define MTDFILEMODE		_IO('M', 19)
++#define MTDREFRESH		_IO('M', 23)
+ 
+ /*
+  * Obsolete legacy interface. Keep it in order not to break userspace