Merge branch 'master' into next

Conflicts:
	fs/namei.c

Manually merged per:

diff --cc fs/namei.c
index 734f2b5,bbc15c2..0000000
--- a/fs/namei.c
+++ b/fs/namei.c
@@@ -860,9 -848,8 +849,10 @@@ static int __link_path_walk(const char
  		nd->flags |= LOOKUP_CONTINUE;
  		err = exec_permission_lite(inode);
  		if (err == -EAGAIN)
- 			err = vfs_permission(nd, MAY_EXEC);
+ 			err = inode_permission(nd->path.dentry->d_inode,
+ 					       MAY_EXEC);
 +		if (!err)
 +			err = ima_path_check(&nd->path, MAY_EXEC);
   		if (err)
  			break;

@@@ -1525,14 -1506,9 +1509,14 @@@ int may_open(struct path *path, int acc
  		flag &= ~O_TRUNC;
  	}

- 	error = vfs_permission(nd, acc_mode);
+ 	error = inode_permission(inode, acc_mode);
  	if (error)
  		return error;
 +
- 	error = ima_path_check(&nd->path,
++	error = ima_path_check(path,
 +			       acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC));
 +	if (error)
 +		return error;
  	/*
  	 * An append-only file must be opened in append mode for writing.
  	 */

Signed-off-by: James Morris <jmorris@namei.org>

15 files changed, 497 insertions, 460 deletions

diff --git a/drivers/mtd/ubi/Kconfig.debug b/drivers/mtd/ubi/Kconfig.debug
index 1e2ee22edeff..2246f154e2f7 100644
--- a/drivers/mtd/ubi/Kconfig.debug
+++ b/drivers/mtd/ubi/Kconfig.debug
@@ -33,16 +33,6 @@ config MTD_UBI_DEBUG_DISABLE_BGT
 	  This option switches the background thread off by default. The thread
 	  may be also be enabled/disabled via UBI sysfs.
 
-config MTD_UBI_DEBUG_USERSPACE_IO
-	bool "Direct user-space write/erase support"
-	default n
-	depends on MTD_UBI_DEBUG
-	help
-	  By default, users cannot directly write and erase individual
-	  eraseblocks of dynamic volumes, and have to use update operation
-	  instead. This option enables this capability - it is very useful for
-	  debugging and testing.
-
 config MTD_UBI_DEBUG_EMULATE_BITFLIPS
 	bool "Emulate flash bit-flips"
 	depends on MTD_UBI_DEBUG
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index c7630a228310..4048db83aef6 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -263,8 +263,12 @@ static ssize_t dev_attribute_show(struct device *dev,
 	return ret;
 }
 
-/* Fake "release" method for UBI devices */
-static void dev_release(struct device *dev) { }
+static void dev_release(struct device *dev)
+{
+	struct ubi_device *ubi = container_of(dev, struct ubi_device, dev);
+
+	kfree(ubi);
+}
 
 /**
  * ubi_sysfs_init - initialize sysfs for an UBI device.
@@ -280,7 +284,7 @@ static int ubi_sysfs_init(struct ubi_device *ubi)
 	ubi->dev.release = dev_release;
 	ubi->dev.devt = ubi->cdev.dev;
 	ubi->dev.class = ubi_class;
-	sprintf(&ubi->dev.bus_id[0], UBI_NAME_STR"%d", ubi->ubi_num);
+	dev_set_name(&ubi->dev, UBI_NAME_STR"%d", ubi->ubi_num);
 	err = device_register(&ubi->dev);
 	if (err)
 		return err;
@@ -380,7 +384,7 @@ static void free_user_volumes(struct ubi_device *ubi)
  */
 static int uif_init(struct ubi_device *ubi)
 {
-	int i, err, do_free = 0;
+	int i, err;
 	dev_t dev;
 
 	sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);
@@ -427,13 +431,10 @@ static int uif_init(struct ubi_device *ubi)
 
 out_volumes:
 	kill_volumes(ubi);
-	do_free = 0;
 out_sysfs:
 	ubi_sysfs_close(ubi);
 	cdev_del(&ubi->cdev);
 out_unreg:
-	if (do_free)
-		free_user_volumes(ubi);
 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
 	ubi_err("cannot initialize UBI %s, error %d", ubi->ubi_name, err);
 	return err;
@@ -561,7 +562,7 @@ static int io_init(struct ubi_device *ubi)
 	 */
 
 	ubi->peb_size   = ubi->mtd->erasesize;
-	ubi->peb_count  = ubi->mtd->size / ubi->mtd->erasesize;
+	ubi->peb_count  = mtd_div_by_eb(ubi->mtd->size, ubi->mtd);
 	ubi->flash_size = ubi->mtd->size;
 
 	if (ubi->mtd->block_isbad && ubi->mtd->block_markbad)
@@ -815,19 +816,20 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset)
 	if (err)
 		goto out_free;
 
+	err = -ENOMEM;
 	ubi->peb_buf1 = vmalloc(ubi->peb_size);
 	if (!ubi->peb_buf1)
 		goto out_free;
 
 	ubi->peb_buf2 = vmalloc(ubi->peb_size);
 	if (!ubi->peb_buf2)
-		 goto out_free;
+		goto out_free;
 
 #ifdef CONFIG_MTD_UBI_DEBUG
 	mutex_init(&ubi->dbg_buf_mutex);
 	ubi->dbg_peb_buf = vmalloc(ubi->peb_size);
 	if (!ubi->dbg_peb_buf)
-		 goto out_free;
+		goto out_free;
 #endif
 
 	err = attach_by_scanning(ubi);
@@ -946,6 +948,12 @@ int ubi_detach_mtd_dev(int ubi_num, int anyway)
 	if (ubi->bgt_thread)
 		kthread_stop(ubi->bgt_thread);
 
+	/*
+	 * Get a reference to the device in order to prevent 'dev_release()'
+	 * from freeing @ubi object.
+	 */
+	get_device(&ubi->dev);
+
 	uif_close(ubi);
 	ubi_wl_close(ubi);
 	free_internal_volumes(ubi);
@@ -957,7 +965,7 @@ int ubi_detach_mtd_dev(int ubi_num, int anyway)
 	vfree(ubi->dbg_peb_buf);
 #endif
 	ubi_msg("mtd%d is detached from ubi%d", ubi->mtd->index, ubi->ubi_num);
-	kfree(ubi);
+	put_device(&ubi->dev);
 	return 0;
 }
 
diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index b30a0b83d7f1..e63c8fc3df3a 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -40,9 +40,9 @@
 #include <linux/ioctl.h>
 #include <linux/capability.h>
 #include <linux/uaccess.h>
-#include <linux/smp_lock.h>
+#include <linux/compat.h>
+#include <linux/math64.h>
 #include <mtd/ubi-user.h>
-#include <asm/div64.h>
 #include "ubi.h"
 
 /**
@@ -195,7 +195,6 @@ static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
 	int err, lnum, off, len,  tbuf_size;
 	size_t count_save = count;
 	void *tbuf;
-	uint64_t tmp;
 
 	dbg_gen("read %zd bytes from offset %lld of volume %d",
 		count, *offp, vol->vol_id);
@@ -225,10 +224,7 @@ static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
 		return -ENOMEM;
 
 	len = count > tbuf_size ? tbuf_size : count;
-
-	tmp = *offp;
-	off = do_div(tmp, vol->usable_leb_size);
-	lnum = tmp;
+	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
 
 	do {
 		cond_resched();
@@ -263,12 +259,9 @@ static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
 	return err ? err : count_save - count;
 }
 
-#ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
-
 /*
  * This function allows to directly write to dynamic UBI volumes, without
- * issuing the volume update operation. Available only as a debugging feature.
- * Very useful for testing UBI.
+ * issuing the volume update operation.
  */
 static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
 				     size_t count, loff_t *offp)
@@ -279,7 +272,9 @@ static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
 	int lnum, off, len, tbuf_size, err = 0;
 	size_t count_save = count;
 	char *tbuf;
-	uint64_t tmp;
+
+	if (!vol->direct_writes)
+		return -EPERM;
 
 	dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
 		count, *offp, vol->vol_id);
@@ -287,10 +282,7 @@ static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
 	if (vol->vol_type == UBI_STATIC_VOLUME)
 		return -EROFS;
 
-	tmp = *offp;
-	off = do_div(tmp, vol->usable_leb_size);
-	lnum = tmp;
-
+	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
 	if (off & (ubi->min_io_size - 1)) {
 		dbg_err("unaligned position");
 		return -EINVAL;
@@ -347,10 +339,6 @@ static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
 	return err ? err : count_save - count;
 }
 
-#else
-#define vol_cdev_direct_write(file, buf, count, offp) (-EPERM)
-#endif /* CONFIG_MTD_UBI_DEBUG_USERSPACE_IO */
-
 static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
 			      size_t count, loff_t *offp)
 {
@@ -402,8 +390,8 @@ static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
 	return count;
 }
 
-static int vol_cdev_ioctl(struct inode *inode, struct file *file,
-			  unsigned int cmd, unsigned long arg)
+static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
+			   unsigned long arg)
 {
 	int err = 0;
 	struct ubi_volume_desc *desc = file->private_data;
@@ -487,7 +475,6 @@ static int vol_cdev_ioctl(struct inode *inode, struct file *file,
 		break;
 	}
 
-#ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
 	/* Logical eraseblock erasure command */
 	case UBI_IOCEBER:
 	{
@@ -518,13 +505,77 @@ static int vol_cdev_ioctl(struct inode *inode, struct file *file,
 		err = ubi_wl_flush(ubi);
 		break;
 	}
-#endif
+
+	/* Logical eraseblock map command */
+	case UBI_IOCEBMAP:
+	{
+		struct ubi_map_req req;
+
+		err = copy_from_user(&req, argp, sizeof(struct ubi_map_req));
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+		err = ubi_leb_map(desc, req.lnum, req.dtype);
+		break;
+	}
+
+	/* Logical eraseblock un-map command */
+	case UBI_IOCEBUNMAP:
+	{
+		int32_t lnum;
+
+		err = get_user(lnum, (__user int32_t *)argp);
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+		err = ubi_leb_unmap(desc, lnum);
+		break;
+	}
+
+	/* Check if logical eraseblock is mapped command */
+	case UBI_IOCEBISMAP:
+	{
+		int32_t lnum;
+
+		err = get_user(lnum, (__user int32_t *)argp);
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+		err = ubi_is_mapped(desc, lnum);
+		break;
+	}
+
+	/* Set volume property command*/
+	case UBI_IOCSETPROP:
+	{
+		struct ubi_set_prop_req req;
+
+		err = copy_from_user(&req, argp,
+				sizeof(struct ubi_set_prop_req));
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+		switch (req.property) {
+		case UBI_PROP_DIRECT_WRITE:
+			mutex_lock(&ubi->volumes_mutex);
+			desc->vol->direct_writes = !!req.value;
+			mutex_unlock(&ubi->volumes_mutex);
+			break;
+		default:
+			err = -EINVAL;
+			break;
+		}
+		break;
+	}
 
 	default:
 		err = -ENOTTY;
 		break;
 	}
-
 	return err;
 }
 
@@ -721,7 +772,8 @@ static int rename_volumes(struct ubi_device *ubi,
 		 * It seems we need to remove volume with name @re->new_name,
 		 * if it exists.
 		 */
-		desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name, UBI_EXCLUSIVE);
+		desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name,
+					  UBI_EXCLUSIVE);
 		if (IS_ERR(desc)) {
 			err = PTR_ERR(desc);
 			if (err == -ENODEV)
@@ -761,8 +813,8 @@ out_free:
 	return err;
 }
 
-static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
-			  unsigned int cmd, unsigned long arg)
+static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
+			   unsigned long arg)
 {
 	int err = 0;
 	struct ubi_device *ubi;
@@ -772,7 +824,7 @@ static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
 	if (!capable(CAP_SYS_RESOURCE))
 		return -EPERM;
 
-	ubi = ubi_get_by_major(imajor(inode));
+	ubi = ubi_get_by_major(imajor(file->f_mapping->host));
 	if (!ubi)
 		return -ENODEV;
 
@@ -842,7 +894,6 @@ static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
 	case UBI_IOCRSVOL:
 	{
 		int pebs;
-		uint64_t tmp;
 		struct ubi_rsvol_req req;
 
 		dbg_gen("re-size volume");
@@ -862,9 +913,8 @@ static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
 			break;
 		}
 
-		tmp = req.bytes;
-		pebs = !!do_div(tmp, desc->vol->usable_leb_size);
-		pebs += tmp;
+		pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
+			       desc->vol->usable_leb_size);
 
 		mutex_lock(&ubi->volumes_mutex);
 		err = ubi_resize_volume(desc, pebs);
@@ -908,8 +958,8 @@ static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
 	return err;
 }
 
-static int ctrl_cdev_ioctl(struct inode *inode, struct file *file,
-			   unsigned int cmd, unsigned long arg)
+static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
+			    unsigned long arg)
 {
 	int err = 0;
 	void __user *argp = (void __user *)arg;
@@ -985,26 +1035,59 @@ static int ctrl_cdev_ioctl(struct inode *inode, struct file *file,
 	return err;
 }
 
-/* UBI control character device operations */
-struct file_operations ubi_ctrl_cdev_operations = {
-	.ioctl = ctrl_cdev_ioctl,
-	.owner = THIS_MODULE,
+#ifdef CONFIG_COMPAT
+static long vol_cdev_compat_ioctl(struct file *file, unsigned int cmd,
+				  unsigned long arg)
+{
+	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
+
+	return vol_cdev_ioctl(file, cmd, translated_arg);
+}
+
+static long ubi_cdev_compat_ioctl(struct file *file, unsigned int cmd,
+				  unsigned long arg)
+{
+	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
+
+	return ubi_cdev_ioctl(file, cmd, translated_arg);
+}
+
+static long ctrl_cdev_compat_ioctl(struct file *file, unsigned int cmd,
+				   unsigned long arg)
+{
+	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
+
+	return ctrl_cdev_ioctl(file, cmd, translated_arg);
+}
+#else
+#define vol_cdev_compat_ioctl  NULL
+#define ubi_cdev_compat_ioctl  NULL
+#define ctrl_cdev_compat_ioctl NULL
+#endif
+
+/* UBI volume character device operations */
+const struct file_operations ubi_vol_cdev_operations = {
+	.owner          = THIS_MODULE,
+	.open           = vol_cdev_open,
+	.release        = vol_cdev_release,
+	.llseek         = vol_cdev_llseek,
+	.read           = vol_cdev_read,
+	.write          = vol_cdev_write,
+	.unlocked_ioctl = vol_cdev_ioctl,
+	.compat_ioctl   = vol_cdev_compat_ioctl,
 };
 
 /* UBI character device operations */
-struct file_operations ubi_cdev_operations = {
-	.owner = THIS_MODULE,
-	.ioctl = ubi_cdev_ioctl,
-	.llseek = no_llseek,
+const struct file_operations ubi_cdev_operations = {
+	.owner          = THIS_MODULE,
+	.llseek         = no_llseek,
+	.unlocked_ioctl = ubi_cdev_ioctl,
+	.compat_ioctl   = ubi_cdev_compat_ioctl,
 };
 
-/* UBI volume character device operations */
-struct file_operations ubi_vol_cdev_operations = {
-	.owner   = THIS_MODULE,
-	.open    = vol_cdev_open,
-	.release = vol_cdev_release,
-	.llseek  = vol_cdev_llseek,
-	.read    = vol_cdev_read,
-	.write   = vol_cdev_write,
-	.ioctl   = vol_cdev_ioctl,
+/* UBI control character device operations */
+const struct file_operations ubi_ctrl_cdev_operations = {
+	.owner          = THIS_MODULE,
+	.unlocked_ioctl = ctrl_cdev_ioctl,
+	.compat_ioctl   = ctrl_cdev_compat_ioctl,
 };
diff --git a/drivers/mtd/ubi/debug.h b/drivers/mtd/ubi/debug.h
index 78e914d23ece..13777e5beac9 100644
--- a/drivers/mtd/ubi/debug.h
+++ b/drivers/mtd/ubi/debug.h
@@ -27,11 +27,11 @@
 #define dbg_err(fmt, ...) ubi_err(fmt, ##__VA_ARGS__)
 
 #define ubi_assert(expr)  do {                                               \
-        if (unlikely(!(expr))) {                                             \
-                printk(KERN_CRIT "UBI assert failed in %s at %u (pid %d)\n", \
-                       __func__, __LINE__, current->pid);                    \
-                ubi_dbg_dump_stack();                                        \
-        }                                                                    \
+	if (unlikely(!(expr))) {                                             \
+		printk(KERN_CRIT "UBI assert failed in %s at %u (pid %d)\n", \
+		       __func__, __LINE__, current->pid);                    \
+		ubi_dbg_dump_stack();                                        \
+	}                                                                    \
 } while (0)
 
 #define dbg_msg(fmt, ...)                                    \
diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index d8966bae0e0b..25def348e5ba 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -504,12 +504,9 @@ static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
 	if (!vid_hdr)
 		return -ENOMEM;
 
-	mutex_lock(&ubi->buf_mutex);
-
 retry:
 	new_pnum = ubi_wl_get_peb(ubi, UBI_UNKNOWN);
 	if (new_pnum < 0) {
-		mutex_unlock(&ubi->buf_mutex);
 		ubi_free_vid_hdr(ubi, vid_hdr);
 		return new_pnum;
 	}
@@ -529,20 +526,23 @@ retry:
 		goto write_error;
 
 	data_size = offset + len;
+	mutex_lock(&ubi->buf_mutex);
 	memset(ubi->peb_buf1 + offset, 0xFF, len);
 
 	/* Read everything before the area where the write failure happened */
 	if (offset > 0) {
 		err = ubi_io_read_data(ubi, ubi->peb_buf1, pnum, 0, offset);
 		if (err && err != UBI_IO_BITFLIPS)
-			goto out_put;
+			goto out_unlock;
 	}
 
 	memcpy(ubi->peb_buf1 + offset, buf, len);
 
 	err = ubi_io_write_data(ubi, ubi->peb_buf1, new_pnum, 0, data_size);
-	if (err)
+	if (err) {
+		mutex_unlock(&ubi->buf_mutex);
 		goto write_error;
+	}
 
 	mutex_unlock(&ubi->buf_mutex);
 	ubi_free_vid_hdr(ubi, vid_hdr);
@@ -553,8 +553,9 @@ retry:
 	ubi_msg("data was successfully recovered");
 	return 0;
 
-out_put:
+out_unlock:
 	mutex_unlock(&ubi->buf_mutex);
+out_put:
 	ubi_wl_put_peb(ubi, new_pnum, 1);
 	ubi_free_vid_hdr(ubi, vid_hdr);
 	return err;
@@ -567,7 +568,6 @@ write_error:
 	ubi_warn("failed to write to PEB %d", new_pnum);
 	ubi_wl_put_peb(ubi, new_pnum, 1);
 	if (++tries > UBI_IO_RETRIES) {
-		mutex_unlock(&ubi->buf_mutex);
 		ubi_free_vid_hdr(ubi, vid_hdr);
 		return err;
 	}
@@ -717,7 +717,7 @@ write_error:
  * to the real data size, although the @buf buffer has to contain the
  * alignment. In all other cases, @len has to be aligned.
  *
- * It is prohibited to write more then once to logical eraseblocks of static
+ * It is prohibited to write more than once to logical eraseblocks of static
  * volumes. This function returns zero in case of success and a negative error
  * code in case of failure.
  */
@@ -949,10 +949,14 @@ write_error:
  * This function copies logical eraseblock from physical eraseblock @from to
  * physical eraseblock @to. The @vid_hdr buffer may be changed by this
  * function. Returns:
- *   o %0  in case of success;
- *   o %1 if the operation was canceled and should be tried later (e.g.,
- *     because a bit-flip was detected at the target PEB);
- *   o %2 if the volume is being deleted and this LEB should not be moved.
+ *   o %0 in case of success;
+ *   o %1 if the operation was canceled because the volume is being deleted
+ *        or because the PEB was put meanwhile;
+ *   o %2 if the operation was canceled because there was a write error to the
+ *        target PEB;
+ *   o %-EAGAIN if the operation was canceled because a bit-flip was detected
+ *     in the target PEB;
+ *   o a negative error code in case of failure.
  */
 int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 		     struct ubi_vid_hdr *vid_hdr)
@@ -978,7 +982,7 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 	/*
 	 * Note, we may race with volume deletion, which means that the volume
 	 * this logical eraseblock belongs to might be being deleted. Since the
-	 * volume deletion unmaps all the volume's logical eraseblocks, it will
+	 * volume deletion un-maps all the volume's logical eraseblocks, it will
 	 * be locked in 'ubi_wl_put_peb()' and wait for the WL worker to finish.
 	 */
 	vol = ubi->volumes[idx];
@@ -986,7 +990,7 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 		/* No need to do further work, cancel */
 		dbg_eba("volume %d is being removed, cancel", vol_id);
 		spin_unlock(&ubi->volumes_lock);
-		return 2;
+		return 1;
 	}
 	spin_unlock(&ubi->volumes_lock);
 
@@ -1023,7 +1027,7 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 
 	/*
 	 * OK, now the LEB is locked and we can safely start moving it. Since
-	 * this function utilizes thie @ubi->peb1_buf buffer which is shared
+	 * this function utilizes the @ubi->peb1_buf buffer which is shared
 	 * with some other functions, so lock the buffer by taking the
 	 * @ubi->buf_mutex.
 	 */
@@ -1068,8 +1072,11 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 	vid_hdr->sqnum = cpu_to_be64(next_sqnum(ubi));
 
 	err = ubi_io_write_vid_hdr(ubi, to, vid_hdr);
-	if (err)
+	if (err) {
+		if (err == -EIO)
+			err = 2;
 		goto out_unlock_buf;
+	}
 
 	cond_resched();
 
@@ -1079,14 +1086,17 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 		if (err != UBI_IO_BITFLIPS)
 			ubi_warn("cannot read VID header back from PEB %d", to);
 		else
-			err = 1;
+			err = -EAGAIN;
 		goto out_unlock_buf;
 	}
 
 	if (data_size > 0) {
 		err = ubi_io_write_data(ubi, ubi->peb_buf1, to, 0, aldata_size);
-		if (err)
+		if (err) {
+			if (err == -EIO)
+				err = 2;
 			goto out_unlock_buf;
+		}
 
 		cond_resched();
 
@@ -1101,15 +1111,16 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 				ubi_warn("cannot read data back from PEB %d",
 					 to);
 			else
-				err = 1;
+				err = -EAGAIN;
 			goto out_unlock_buf;
 		}
 
 		cond_resched();
 
 		if (memcmp(ubi->peb_buf1, ubi->peb_buf2, aldata_size)) {
-			ubi_warn("read data back from PEB %d - it is different",
-				 to);
+			ubi_warn("read data back from PEB %d and it is "
+				 "different", to);
+			err = -EINVAL;
 			goto out_unlock_buf;
 		}
 	}
diff --git a/drivers/mtd/ubi/gluebi.c b/drivers/mtd/ubi/gluebi.c
index 605812bb0b1a..49cd55ade9c8 100644
--- a/drivers/mtd/ubi/gluebi.c
+++ b/drivers/mtd/ubi/gluebi.c
@@ -28,7 +28,7 @@
  * eraseblock size is equivalent to the logical eraseblock size of the volume.
  */
 
-#include <asm/div64.h>
+#include <linux/math64.h>
 #include "ubi.h"
 
 /**
@@ -109,7 +109,6 @@ static int gluebi_read(struct mtd_info *mtd, loff_t from, size_t len,
 	int err = 0, lnum, offs, total_read;
 	struct ubi_volume *vol;
 	struct ubi_device *ubi;
-	uint64_t tmp = from;
 
 	dbg_gen("read %zd bytes from offset %lld", len, from);
 
@@ -119,9 +118,7 @@ static int gluebi_read(struct mtd_info *mtd, loff_t from, size_t len,
 	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
 	ubi = vol->ubi;
 
-	offs = do_div(tmp, mtd->erasesize);
-	lnum = tmp;
-
+	lnum = div_u64_rem(from, mtd->erasesize, &offs);
 	total_read = len;
 	while (total_read) {
 		size_t to_read = mtd->erasesize - offs;
@@ -160,7 +157,6 @@ static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len,
 	int err = 0, lnum, offs, total_written;
 	struct ubi_volume *vol;
 	struct ubi_device *ubi;
-	uint64_t tmp = to;
 
 	dbg_gen("write %zd bytes to offset %lld", len, to);
 
@@ -173,8 +169,7 @@ static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len,
 	if (ubi->ro_mode)
 		return -EROFS;
 
-	offs = do_div(tmp, mtd->erasesize);
-	lnum = tmp;
+	lnum = div_u64_rem(to, mtd->erasesize, &offs);
 
 	if (len % mtd->writesize || offs % mtd->writesize)
 		return -EINVAL;
@@ -215,7 +210,8 @@ static int gluebi_erase(struct mtd_info *mtd, struct erase_info *instr)
 	struct ubi_volume *vol;
 	struct ubi_device *ubi;
 
-	dbg_gen("erase %u bytes at offset %u", instr->len, instr->addr);
+	dbg_gen("erase %llu bytes at offset %llu", (unsigned long long)instr->len,
+		 (unsigned long long)instr->addr);
 
 	if (instr->addr < 0 || instr->addr > mtd->size - mtd->erasesize)
 		return -EINVAL;
@@ -223,11 +219,11 @@ static int gluebi_erase(struct mtd_info *mtd, struct erase_info *instr)
 	if (instr->len < 0 || instr->addr + instr->len > mtd->size)
 		return -EINVAL;
 
-	if (instr->addr % mtd->writesize || instr->len % mtd->writesize)
+	if (mtd_mod_by_ws(instr->addr, mtd) || mtd_mod_by_ws(instr->len, mtd))
 		return -EINVAL;
 
-	lnum = instr->addr / mtd->erasesize;
-	count = instr->len / mtd->erasesize;
+	lnum = mtd_div_by_eb(instr->addr, mtd);
+	count = mtd_div_by_eb(instr->len, mtd);
 
 	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
 	ubi = vol->ubi;
@@ -255,7 +251,7 @@ static int gluebi_erase(struct mtd_info *mtd, struct erase_info *instr)
 
 out_err:
 	instr->state = MTD_ERASE_FAILED;
-	instr->fail_addr = lnum * mtd->erasesize;
+	instr->fail_addr = (long long)lnum * mtd->erasesize;
 	return err;
 }
 
@@ -294,7 +290,7 @@ int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol)
 	 * bytes.
 	 */
 	if (vol->vol_type == UBI_DYNAMIC_VOLUME)
-		mtd->size = vol->usable_leb_size * vol->reserved_pebs;
+		mtd->size = (long long)vol->usable_leb_size * vol->reserved_pebs;
 	else
 		mtd->size = vol->used_bytes;
 
@@ -304,8 +300,8 @@ int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol)
 		return -ENFILE;
 	}
 
-	dbg_gen("added mtd%d (\"%s\"), size %u, EB size %u",
-		mtd->index, mtd->name, mtd->size, mtd->erasesize);
+	dbg_gen("added mtd%d (\"%s\"), size %llu, EB size %u",
+		mtd->index, mtd->name, (unsigned long long)mtd->size, mtd->erasesize);
 	return 0;
 }
 
diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index 2fb64be44f1b..fe81039f2a7c 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -465,7 +465,7 @@ out:
  * This function synchronously erases physical eraseblock @pnum. If @torture
  * flag is not zero, the physical eraseblock is checked by means of writing
  * different patterns to it and reading them back. If the torturing is enabled,
- * the physical eraseblock is erased more then once.
+ * the physical eraseblock is erased more than once.
  *
  * This function returns the number of erasures made in case of success, %-EIO
  * if the erasure failed or the torturing test failed, and other negative error
@@ -637,8 +637,6 @@ int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 
 	dbg_io("read EC header from PEB %d", pnum);
 	ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
-	if (UBI_IO_DEBUG)
-		verbose = 1;
 
 	err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
 	if (err) {
@@ -685,6 +683,9 @@ int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 			if (verbose)
 				ubi_warn("no EC header found at PEB %d, "
 					 "only 0xFF bytes", pnum);
+			else if (UBI_IO_DEBUG)
+				dbg_msg("no EC header found at PEB %d, "
+					"only 0xFF bytes", pnum);
 			return UBI_IO_PEB_EMPTY;
 		}
 
@@ -696,7 +697,9 @@ int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 			ubi_warn("bad magic number at PEB %d: %08x instead of "
 				 "%08x", pnum, magic, UBI_EC_HDR_MAGIC);
 			ubi_dbg_dump_ec_hdr(ec_hdr);
-		}
+		} else if (UBI_IO_DEBUG)
+			dbg_msg("bad magic number at PEB %d: %08x instead of "
+				"%08x", pnum, magic, UBI_EC_HDR_MAGIC);
 		return UBI_IO_BAD_EC_HDR;
 	}
 
@@ -708,7 +711,9 @@ int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 			ubi_warn("bad EC header CRC at PEB %d, calculated "
 				 "%#08x, read %#08x", pnum, crc, hdr_crc);
 			ubi_dbg_dump_ec_hdr(ec_hdr);
-		}
+		} else if (UBI_IO_DEBUG)
+			dbg_msg("bad EC header CRC at PEB %d, calculated "
+				"%#08x, read %#08x", pnum, crc, hdr_crc);
 		return UBI_IO_BAD_EC_HDR;
 	}
 
@@ -912,8 +917,6 @@ int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 
 	dbg_io("read VID header from PEB %d", pnum);
 	ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
-	if (UBI_IO_DEBUG)
-		verbose = 1;
 
 	p = (char *)vid_hdr - ubi->vid_hdr_shift;
 	err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
@@ -960,6 +963,9 @@ int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 			if (verbose)
 				ubi_warn("no VID header found at PEB %d, "
 					 "only 0xFF bytes", pnum);
+			else if (UBI_IO_DEBUG)
+				dbg_msg("no VID header found at PEB %d, "
+					"only 0xFF bytes", pnum);
 			return UBI_IO_PEB_FREE;
 		}
 
@@ -971,7 +977,9 @@ int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 			ubi_warn("bad magic number at PEB %d: %08x instead of "
 				 "%08x", pnum, magic, UBI_VID_HDR_MAGIC);
 			ubi_dbg_dump_vid_hdr(vid_hdr);
-		}
+		} else if (UBI_IO_DEBUG)
+			dbg_msg("bad magic number at PEB %d: %08x instead of "
+				"%08x", pnum, magic, UBI_VID_HDR_MAGIC);
 		return UBI_IO_BAD_VID_HDR;
 	}
 
@@ -983,7 +991,9 @@ int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 			ubi_warn("bad CRC at PEB %d, calculated %#08x, "
 				 "read %#08x", pnum, crc, hdr_crc);
 			ubi_dbg_dump_vid_hdr(vid_hdr);
-		}
+		} else if (UBI_IO_DEBUG)
+			dbg_msg("bad CRC at PEB %d, calculated %#08x, "
+				"read %#08x", pnum, crc, hdr_crc);
 		return UBI_IO_BAD_VID_HDR;
 	}
 
@@ -1024,7 +1034,7 @@ int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
 
 	err = paranoid_check_peb_ec_hdr(ubi, pnum);
 	if (err)
-		return err > 0 ? -EINVAL: err;
+		return err > 0 ? -EINVAL : err;
 
 	vid_hdr->magic = cpu_to_be32(UBI_VID_HDR_MAGIC);
 	vid_hdr->version = UBI_VERSION;
diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c
index 5d9bcf109c13..4abbe573fa40 100644
--- a/drivers/mtd/ubi/kapi.c
+++ b/drivers/mtd/ubi/kapi.c
@@ -564,7 +564,7 @@ EXPORT_SYMBOL_GPL(ubi_leb_unmap);
  * @dtype: expected data type
  *
  * This function maps an un-mapped logical eraseblock @lnum to a physical
- * eraseblock. This means, that after a successfull invocation of this
+ * eraseblock. This means, that after a successful invocation of this
  * function the logical eraseblock @lnum will be empty (contain only %0xFF
  * bytes) and be mapped to a physical eraseblock, even if an unclean reboot
  * happens.
diff --git a/drivers/mtd/ubi/scan.c b/drivers/mtd/ubi/scan.c
index 41d47e1cf15c..c3d653ba5ca0 100644
--- a/drivers/mtd/ubi/scan.c
+++ b/drivers/mtd/ubi/scan.c
@@ -42,7 +42,7 @@
 
 #include <linux/err.h>
 #include <linux/crc32.h>
-#include <asm/div64.h>
+#include <linux/math64.h>
 #include "ubi.h"
 
 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
@@ -478,7 +478,7 @@ int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
 			return 0;
 		} else {
 			/*
-			 * This logical eraseblock is older then the one found
+			 * This logical eraseblock is older than the one found
 			 * previously.
 			 */
 			if (cmp_res & 4)
@@ -904,10 +904,8 @@ struct ubi_scan_info *ubi_scan(struct ubi_device *ubi)
 	dbg_msg("scanning is finished");
 
 	/* Calculate mean erase counter */
-	if (si->ec_count) {
-		do_div(si->ec_sum, si->ec_count);
-		si->mean_ec = si->ec_sum;
-	}
+	if (si->ec_count)
+		si->mean_ec = div_u64(si->ec_sum, si->ec_count);
 
 	if (si->is_empty)
 		ubi_msg("empty MTD device detected");
diff --git a/drivers/mtd/ubi/ubi-media.h b/drivers/mtd/ubi/ubi-media.h
index 2ad940409053..8419fdccc79c 100644
--- a/drivers/mtd/ubi/ubi-media.h
+++ b/drivers/mtd/ubi/ubi-media.h
@@ -135,7 +135,7 @@ enum {
  * The erase counter header takes 64 bytes and has a plenty of unused space for
  * future usage. The unused fields are zeroed. The @version field is used to
  * indicate the version of UBI implementation which is supposed to be able to
- * work with this UBI image. If @version is greater then the current UBI
+ * work with this UBI image. If @version is greater than the current UBI
  * version, the image is rejected. This may be useful in future if something
  * is changed radically. This field is duplicated in the volume identifier
  * header.
@@ -187,7 +187,7 @@ struct ubi_ec_hdr {
  * (sequence number) is used to distinguish between older and newer versions of
  * logical eraseblocks.
  *
- * There are 2 situations when there may be more then one physical eraseblock
+ * There are 2 situations when there may be more than one physical eraseblock
  * corresponding to the same logical eraseblock, i.e., having the same @vol_id
  * and @lnum values in the volume identifier header. Suppose we have a logical
  * eraseblock L and it is mapped to the physical eraseblock P.
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 1c3fa18c26a7..c055511bb1b2 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -74,6 +74,13 @@
 #define UBI_IO_RETRIES 3
 
 /*
+ * Length of the protection queue. The length is effectively equivalent to the
+ * number of (global) erase cycles PEBs are protected from the wear-leveling
+ * worker.
+ */
+#define UBI_PROT_QUEUE_LEN 10
+
+/*
  * Error codes returned by the I/O sub-system.
  *
  * UBI_IO_PEB_EMPTY: the physical eraseblock is empty, i.e. it contains only
@@ -95,7 +102,8 @@ enum {
 
 /**
  * struct ubi_wl_entry - wear-leveling entry.
- * @rb: link in the corresponding RB-tree
+ * @u.rb: link in the corresponding (free/used) RB-tree
+ * @u.list: link in the protection queue
  * @ec: erase counter
  * @pnum: physical eraseblock number
  *
@@ -104,7 +112,10 @@ enum {
  * RB-trees. See WL sub-system for details.
  */
 struct ubi_wl_entry {
-	struct rb_node rb;
+	union {
+		struct rb_node rb;
+		struct list_head list;
+	} u;
 	int ec;
 	int pnum;
 };
@@ -195,6 +206,7 @@ struct ubi_volume_desc;
  * @upd_marker: %1 if the update marker is set for this volume
  * @updating: %1 if the volume is being updated
  * @changing_leb: %1 if the atomic LEB change ioctl command is in progress
+ * @direct_writes: %1 if direct writes are enabled for this volume
  *
  * @gluebi_desc: gluebi UBI volume descriptor
  * @gluebi_refcount: reference count of the gluebi MTD device
@@ -242,6 +254,7 @@ struct ubi_volume {
 	unsigned int upd_marker:1;
 	unsigned int updating:1;
 	unsigned int changing_leb:1;
+	unsigned int direct_writes:1;
 
 #ifdef CONFIG_MTD_UBI_GLUEBI
 	/*
@@ -288,12 +301,13 @@ struct ubi_wl_entry;
  * @beb_rsvd_level: normal level of PEBs reserved for bad PEB handling
  *
  * @autoresize_vol_id: ID of the volume which has to be auto-resized at the end
- *                     of UBI ititializetion
+ *                     of UBI initialization
  * @vtbl_slots: how many slots are available in the volume table
  * @vtbl_size: size of the volume table in bytes
  * @vtbl: in-RAM volume table copy
  * @volumes_mutex: protects on-flash volume table and serializes volume
- *                 changes, like creation, deletion, update, re-size and re-name
+ *                 changes, like creation, deletion, update, re-size,
+ *                 re-name and set property
  *
  * @max_ec: current highest erase counter value
  * @mean_ec: current mean erase counter value
@@ -306,18 +320,17 @@ struct ubi_wl_entry;
  * @used: RB-tree of used physical eraseblocks
  * @free: RB-tree of free physical eraseblocks
  * @scrub: RB-tree of physical eraseblocks which need scrubbing
- * @prot: protection trees
- * @prot.pnum: protection tree indexed by physical eraseblock numbers
- * @prot.aec: protection tree indexed by absolute erase counter value
- * @wl_lock: protects the @used, @free, @prot, @lookuptbl, @abs_ec, @move_from,
- *           @move_to, @move_to_put @erase_pending, @wl_scheduled, and @works
- *           fields
+ * @pq: protection queue (contain physical eraseblocks which are temporarily
+ *      protected from the wear-leveling worker)
+ * @pq_head: protection queue head
+ * @wl_lock: protects the @used, @free, @pq, @pq_head, @lookuptbl, @move_from,
+ * 	     @move_to, @move_to_put @erase_pending, @wl_scheduled and @works
+ * 	     fields
  * @move_mutex: serializes eraseblock moves
- * @work_sem: sycnhronizes the WL worker with use tasks
+ * @work_sem: synchronizes the WL worker with use tasks
  * @wl_scheduled: non-zero if the wear-leveling was scheduled
  * @lookuptbl: a table to quickly find a &struct ubi_wl_entry object for any
  *             physical eraseblock
- * @abs_ec: absolute erase counter
  * @move_from: physical eraseblock from where the data is being moved
  * @move_to: physical eraseblock where the data is being moved to
  * @move_to_put: if the "to" PEB was put
@@ -351,11 +364,11 @@ struct ubi_wl_entry;
  *
  * @peb_buf1: a buffer of PEB size used for different purposes
  * @peb_buf2: another buffer of PEB size used for different purposes
- * @buf_mutex: proptects @peb_buf1 and @peb_buf2
+ * @buf_mutex: protects @peb_buf1 and @peb_buf2
  * @ckvol_mutex: serializes static volume checking when opening
- * @mult_mutex: serializes operations on multiple volumes, like re-nameing
+ * @mult_mutex: serializes operations on multiple volumes, like re-naming
  * @dbg_peb_buf: buffer of PEB size used for debugging
- * @dbg_buf_mutex: proptects @dbg_peb_buf
+ * @dbg_buf_mutex: protects @dbg_peb_buf
  */
 struct ubi_device {
 	struct cdev cdev;
@@ -392,16 +405,13 @@ struct ubi_device {
 	struct rb_root used;
 	struct rb_root free;
 	struct rb_root scrub;
-	struct {
-		struct rb_root pnum;
-		struct rb_root aec;
-	} prot;
+	struct list_head pq[UBI_PROT_QUEUE_LEN];
+	int pq_head;
 	spinlock_t wl_lock;
 	struct mutex move_mutex;
 	struct rw_semaphore work_sem;
 	int wl_scheduled;
 	struct ubi_wl_entry **lookuptbl;
-	unsigned long long abs_ec;
 	struct ubi_wl_entry *move_from;
 	struct ubi_wl_entry *move_to;
 	int move_to_put;
@@ -442,9 +452,9 @@ struct ubi_device {
 };
 
 extern struct kmem_cache *ubi_wl_entry_slab;
-extern struct file_operations ubi_ctrl_cdev_operations;
-extern struct file_operations ubi_cdev_operations;
-extern struct file_operations ubi_vol_cdev_operations;
+extern const struct file_operations ubi_ctrl_cdev_operations;
+extern const struct file_operations ubi_cdev_operations;
+extern const struct file_operations ubi_vol_cdev_operations;
 extern struct class *ubi_class;
 extern struct mutex ubi_devices_mutex;
 
diff --git a/drivers/mtd/ubi/upd.c b/drivers/mtd/ubi/upd.c
index 8b89cc18ff0b..6b4d1ae891ae 100644
--- a/drivers/mtd/ubi/upd.c
+++ b/drivers/mtd/ubi/upd.c
@@ -40,7 +40,7 @@
 
 #include <linux/err.h>
 #include <linux/uaccess.h>
-#include <asm/div64.h>
+#include <linux/math64.h>
 #include "ubi.h"
 
 /**
@@ -89,7 +89,6 @@ static int clear_update_marker(struct ubi_device *ubi, struct ubi_volume *vol,
 			       long long bytes)
 {
 	int err;
-	uint64_t tmp;
 	struct ubi_vtbl_record vtbl_rec;
 
 	dbg_gen("clear update marker for volume %d", vol->vol_id);
@@ -101,9 +100,9 @@ static int clear_update_marker(struct ubi_device *ubi, struct ubi_volume *vol,
 
 	if (vol->vol_type == UBI_STATIC_VOLUME) {
 		vol->corrupted = 0;
-		vol->used_bytes = tmp = bytes;
-		vol->last_eb_bytes = do_div(tmp, vol->usable_leb_size);
-		vol->used_ebs = tmp;
+		vol->used_bytes = bytes;
+		vol->used_ebs = div_u64_rem(bytes, vol->usable_leb_size,
+					    &vol->last_eb_bytes);
 		if (vol->last_eb_bytes)
 			vol->used_ebs += 1;
 		else
@@ -131,7 +130,6 @@ int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
 		     long long bytes)
 {
 	int i, err;
-	uint64_t tmp;
 
 	dbg_gen("start update of volume %d, %llu bytes", vol->vol_id, bytes);
 	ubi_assert(!vol->updating && !vol->changing_leb);
@@ -161,9 +159,8 @@ int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
 	if (!vol->upd_buf)
 		return -ENOMEM;
 
-	tmp = bytes;
-	vol->upd_ebs = !!do_div(tmp, vol->usable_leb_size);
-	vol->upd_ebs += tmp;
+	vol->upd_ebs = div_u64(bytes + vol->usable_leb_size - 1,
+			       vol->usable_leb_size);
 	vol->upd_bytes = bytes;
 	vol->upd_received = 0;
 	return 0;
@@ -282,7 +279,6 @@ static int write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
 int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
 			 const void __user *buf, int count)
 {
-	uint64_t tmp;
 	int lnum, offs, err = 0, len, to_write = count;
 
 	dbg_gen("write %d of %lld bytes, %lld already passed",
@@ -291,10 +287,7 @@ int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
 	if (ubi->ro_mode)
 		return -EROFS;
 
-	tmp = vol->upd_received;
-	offs = do_div(tmp, vol->usable_leb_size);
-	lnum = tmp;
-
+	lnum = div_u64_rem(vol->upd_received,  vol->usable_leb_size, &offs);
 	if (vol->upd_received + count > vol->upd_bytes)
 		to_write = count = vol->upd_bytes - vol->upd_received;
 
diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
index 3531ca9a1e24..df5483562b7a 100644
--- a/drivers/mtd/ubi/vmt.c
+++ b/drivers/mtd/ubi/vmt.c
@@ -24,7 +24,7 @@
  */
 
 #include <linux/err.h>
-#include <asm/div64.h>
+#include <linux/math64.h>
 #include "ubi.h"
 
 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
@@ -205,7 +205,6 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
 	int i, err, vol_id = req->vol_id, do_free = 1;
 	struct ubi_volume *vol;
 	struct ubi_vtbl_record vtbl_rec;
-	uint64_t bytes;
 	dev_t dev;
 
 	if (ubi->ro_mode)
@@ -255,10 +254,8 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
 
 	/* Calculate how many eraseblocks are requested */
 	vol->usable_leb_size = ubi->leb_size - ubi->leb_size % req->alignment;
-	bytes = req->bytes;
-	if (do_div(bytes, vol->usable_leb_size))
-		vol->reserved_pebs = 1;
-	vol->reserved_pebs += bytes;
+	vol->reserved_pebs += div_u64(req->bytes + vol->usable_leb_size - 1,
+				      vol->usable_leb_size);
 
 	/* Reserve physical eraseblocks */
 	if (vol->reserved_pebs > ubi->avail_pebs) {
@@ -301,10 +298,10 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
 		vol->used_bytes =
 			(long long)vol->used_ebs * vol->usable_leb_size;
 	} else {
-		bytes = vol->used_bytes;
-		vol->last_eb_bytes = do_div(bytes, vol->usable_leb_size);
-		vol->used_ebs = bytes;
-		if (vol->last_eb_bytes)
+		vol->used_ebs = div_u64_rem(vol->used_bytes,
+					    vol->usable_leb_size,
+					    &vol->last_eb_bytes);
+		if (vol->last_eb_bytes != 0)
 			vol->used_ebs += 1;
 		else
 			vol->last_eb_bytes = vol->usable_leb_size;
@@ -329,7 +326,7 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
 	vol->dev.devt = dev;
 	vol->dev.class = ubi_class;
 
-	sprintf(&vol->dev.bus_id[0], "%s_%d", ubi->ubi_name, vol->vol_id);
+	dev_set_name(&vol->dev, "%s_%d", ubi->ubi_name, vol->vol_id);
 	err = device_register(&vol->dev);
 	if (err) {
 		ubi_err("cannot register device");
@@ -678,7 +675,7 @@ int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol)
 	vol->dev.parent = &ubi->dev;
 	vol->dev.devt = dev;
 	vol->dev.class = ubi_class;
-	sprintf(&vol->dev.bus_id[0], "%s_%d", ubi->ubi_name, vol->vol_id);
+	dev_set_name(&vol->dev, "%s_%d", ubi->ubi_name, vol->vol_id);
 	err = device_register(&vol->dev);
 	if (err)
 		goto out_gluebi;
diff --git a/drivers/mtd/ubi/vtbl.c b/drivers/mtd/ubi/vtbl.c
index 333c8941552f..1afc61e7455d 100644
--- a/drivers/mtd/ubi/vtbl.c
+++ b/drivers/mtd/ubi/vtbl.c
@@ -577,7 +577,7 @@ static int init_volumes(struct ubi_device *ubi, const struct ubi_scan_info *si,
 		if (vtbl[i].flags & UBI_VTBL_AUTORESIZE_FLG) {
 			/* Auto re-size flag may be set only for one volume */
 			if (ubi->autoresize_vol_id != -1) {
-				ubi_err("more then one auto-resize volume (%d "
+				ubi_err("more than one auto-resize volume (%d "
 					"and %d)", ubi->autoresize_vol_id, i);
 				kfree(vol);
 				return -EINVAL;
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index dcb6dac1dc54..891534f8210d 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -22,7 +22,7 @@
  * UBI wear-leveling sub-system.
  *
  * This sub-system is responsible for wear-leveling. It works in terms of
- * physical* eraseblocks and erase counters and knows nothing about logical
+ * physical eraseblocks and erase counters and knows nothing about logical
  * eraseblocks, volumes, etc. From this sub-system's perspective all physical
  * eraseblocks are of two types - used and free. Used physical eraseblocks are
  * those that were "get" by the 'ubi_wl_get_peb()' function, and free physical
@@ -55,8 +55,39 @@
  *
  * As it was said, for the UBI sub-system all physical eraseblocks are either
  * "free" or "used". Free eraseblock are kept in the @wl->free RB-tree, while
- * used eraseblocks are kept in a set of different RB-trees: @wl->used,
- * @wl->prot.pnum, @wl->prot.aec, and @wl->scrub.
+ * used eraseblocks are kept in @wl->used or @wl->scrub RB-trees, or
+ * (temporarily) in the @wl->pq queue.
+ *
+ * When the WL sub-system returns a physical eraseblock, the physical
+ * eraseblock is protected from being moved for some "time". For this reason,
+ * the physical eraseblock is not directly moved from the @wl->free tree to the
+ * @wl->used tree. There is a protection queue in between where this
+ * physical eraseblock is temporarily stored (@wl->pq).
+ *
+ * All this protection stuff is needed because:
+ *  o we don't want to move physical eraseblocks just after we have given them
+ *    to the user; instead, we first want to let users fill them up with data;
+ *
+ *  o there is a chance that the user will put the physical eraseblock very
+ *    soon, so it makes sense not to move it for some time, but wait; this is
+ *    especially important in case of "short term" physical eraseblocks.
+ *
+ * Physical eraseblocks stay protected only for limited time. But the "time" is
+ * measured in erase cycles in this case. This is implemented with help of the
+ * protection queue. Eraseblocks are put to the tail of this queue when they
+ * are returned by the 'ubi_wl_get_peb()', and eraseblocks are removed from the
+ * head of the queue on each erase operation (for any eraseblock). So the
+ * length of the queue defines how may (global) erase cycles PEBs are protected.
+ *
+ * To put it differently, each physical eraseblock has 2 main states: free and
+ * used. The former state corresponds to the @wl->free tree. The latter state
+ * is split up on several sub-states:
+ * o the WL movement is allowed (@wl->used tree);
+ * o the WL movement is temporarily prohibited (@wl->pq queue);
+ * o scrubbing is needed (@wl->scrub tree).
+ *
+ * Depending on the sub-state, wear-leveling entries of the used physical
+ * eraseblocks may be kept in one of those structures.
  *
  * Note, in this implementation, we keep a small in-RAM object for each physical
  * eraseblock. This is surely not a scalable solution. But it appears to be good
@@ -70,9 +101,6 @@
  * target PEB, we pick a PEB with the highest EC if our PEB is "old" and we
  * pick target PEB with an average EC if our PEB is not very "old". This is a
  * room for future re-works of the WL sub-system.
- *
- * Note: the stuff with protection trees looks too complex and is difficult to
- * understand. Should be fixed.
  */
 
 #include <linux/slab.h>
@@ -85,14 +113,6 @@
 #define WL_RESERVED_PEBS 1
 
 /*
- * How many erase cycles are short term, unknown, and long term physical
- * eraseblocks protected.
- */
-#define ST_PROTECTION 16
-#define U_PROTECTION  10
-#define LT_PROTECTION 4
-
-/*
  * Maximum difference between two erase counters. If this threshold is
  * exceeded, the WL sub-system starts moving data from used physical
  * eraseblocks with low erase counter to free physical eraseblocks with high
@@ -108,7 +128,7 @@
  * situation when the picked physical eraseblock is constantly erased after the
  * data is written to it. So, we have a constant which limits the highest erase
  * counter of the free physical eraseblock to pick. Namely, the WL sub-system
- * does not pick eraseblocks with erase counter greater then the lowest erase
+ * does not pick eraseblocks with erase counter greater than the lowest erase
  * counter plus %WL_FREE_MAX_DIFF.
  */
 #define WL_FREE_MAX_DIFF (2*UBI_WL_THRESHOLD)
@@ -120,64 +140,9 @@
 #define WL_MAX_FAILURES 32
 
 /**
- * struct ubi_wl_prot_entry - PEB protection entry.
- * @rb_pnum: link in the @wl->prot.pnum RB-tree
- * @rb_aec: link in the @wl->prot.aec RB-tree
- * @abs_ec: the absolute erase counter value when the protection ends
- * @e: the wear-leveling entry of the physical eraseblock under protection
- *
- * When the WL sub-system returns a physical eraseblock, the physical
- * eraseblock is protected from being moved for some "time". For this reason,
- * the physical eraseblock is not directly moved from the @wl->free tree to the
- * @wl->used tree. There is one more tree in between where this physical
- * eraseblock is temporarily stored (@wl->prot).
- *
- * All this protection stuff is needed because:
- *  o we don't want to move physical eraseblocks just after we have given them
- *    to the user; instead, we first want to let users fill them up with data;
- *
- *  o there is a chance that the user will put the physical eraseblock very
- *    soon, so it makes sense not to move it for some time, but wait; this is
- *    especially important in case of "short term" physical eraseblocks.
- *
- * Physical eraseblocks stay protected only for limited time. But the "time" is
- * measured in erase cycles in this case. This is implemented with help of the
- * absolute erase counter (@wl->abs_ec). When it reaches certain value, the
- * physical eraseblocks are moved from the protection trees (@wl->prot.*) to
- * the @wl->used tree.
- *
- * Protected physical eraseblocks are searched by physical eraseblock number
- * (when they are put) and by the absolute erase counter (to check if it is
- * time to move them to the @wl->used tree). So there are actually 2 RB-trees
- * storing the protected physical eraseblocks: @wl->prot.pnum and
- * @wl->prot.aec. They are referred to as the "protection" trees. The
- * first one is indexed by the physical eraseblock number. The second one is
- * indexed by the absolute erase counter. Both trees store
- * &struct ubi_wl_prot_entry objects.
- *
- * Each physical eraseblock has 2 main states: free and used. The former state
- * corresponds to the @wl->free tree. The latter state is split up on several
- * sub-states:
- * o the WL movement is allowed (@wl->used tree);
- * o the WL movement is temporarily prohibited (@wl->prot.pnum and
- * @wl->prot.aec trees);
- * o scrubbing is needed (@wl->scrub tree).
- *
- * Depending on the sub-state, wear-leveling entries of the used physical
- * eraseblocks may be kept in one of those trees.
- */
-struct ubi_wl_prot_entry {
-	struct rb_node rb_pnum;
-	struct rb_node rb_aec;
-	unsigned long long abs_ec;
-	struct ubi_wl_entry *e;
-};
-
-/**
  * struct ubi_work - UBI work description data structure.
  * @list: a link in the list of pending works
  * @func: worker function
- * @priv: private data of the worker function
  * @e: physical eraseblock to erase
  * @torture: if the physical eraseblock has to be tortured
  *
@@ -198,9 +163,11 @@ struct ubi_work {
 static int paranoid_check_ec(struct ubi_device *ubi, int pnum, int ec);
 static int paranoid_check_in_wl_tree(struct ubi_wl_entry *e,
 				     struct rb_root *root);
+static int paranoid_check_in_pq(struct ubi_device *ubi, struct ubi_wl_entry *e);
 #else
 #define paranoid_check_ec(ubi, pnum, ec) 0
 #define paranoid_check_in_wl_tree(e, root)
+#define paranoid_check_in_pq(ubi, e) 0
 #endif
 
 /**
@@ -220,7 +187,7 @@ static void wl_tree_add(struct ubi_wl_entry *e, struct rb_root *root)
 		struct ubi_wl_entry *e1;
 
 		parent = *p;
-		e1 = rb_entry(parent, struct ubi_wl_entry, rb);
+		e1 = rb_entry(parent, struct ubi_wl_entry, u.rb);
 
 		if (e->ec < e1->ec)
 			p = &(*p)->rb_left;
@@ -235,8 +202,8 @@ static void wl_tree_add(struct ubi_wl_entry *e, struct rb_root *root)
 		}
 	}
 
-	rb_link_node(&e->rb, parent, p);
-	rb_insert_color(&e->rb, root);
+	rb_link_node(&e->u.rb, parent, p);
+	rb_insert_color(&e->u.rb, root);
 }
 
 /**
@@ -331,7 +298,7 @@ static int in_wl_tree(struct ubi_wl_entry *e, struct rb_root *root)
 	while (p) {
 		struct ubi_wl_entry *e1;
 
-		e1 = rb_entry(p, struct ubi_wl_entry, rb);
+		e1 = rb_entry(p, struct ubi_wl_entry, u.rb);
 
 		if (e->pnum == e1->pnum) {
 			ubi_assert(e == e1);
@@ -355,50 +322,24 @@ static int in_wl_tree(struct ubi_wl_entry *e, struct rb_root *root)
 }
 
 /**
- * prot_tree_add - add physical eraseblock to protection trees.
+ * prot_queue_add - add physical eraseblock to the protection queue.
  * @ubi: UBI device description object
  * @e: the physical eraseblock to add
- * @pe: protection entry object to use
- * @abs_ec: absolute erase counter value when this physical eraseblock has
- * to be removed from the protection trees.
  *
- * @wl->lock has to be locked.
+ * This function adds @e to the tail of the protection queue @ubi->pq, where
+ * @e will stay for %UBI_PROT_QUEUE_LEN erase operations and will be
+ * temporarily protected from the wear-leveling worker. Note, @wl->lock has to
+ * be locked.
  */
-static void prot_tree_add(struct ubi_device *ubi, struct ubi_wl_entry *e,
-			  struct ubi_wl_prot_entry *pe, int abs_ec)
+static void prot_queue_add(struct ubi_device *ubi, struct ubi_wl_entry *e)
 {
-	struct rb_node **p, *parent = NULL;
-	struct ubi_wl_prot_entry *pe1;
-
-	pe->e = e;
-	pe->abs_ec = ubi->abs_ec + abs_ec;
-
-	p = &ubi->prot.pnum.rb_node;
-	while (*p) {
-		parent = *p;
-		pe1 = rb_entry(parent, struct ubi_wl_prot_entry, rb_pnum);
-
-		if (e->pnum < pe1->e->pnum)
-			p = &(*p)->rb_left;
-		else
-			p = &(*p)->rb_right;
-	}
-	rb_link_node(&pe->rb_pnum, parent, p);
-	rb_insert_color(&pe->rb_pnum, &ubi->prot.pnum);
-
-	p = &ubi->prot.aec.rb_node;
-	parent = NULL;
-	while (*p) {
-		parent = *p;
-		pe1 = rb_entry(parent, struct ubi_wl_prot_entry, rb_aec);
+	int pq_tail = ubi->pq_head - 1;
 
-		if (pe->abs_ec < pe1->abs_ec)
-			p = &(*p)->rb_left;
-		else
-			p = &(*p)->rb_right;
-	}
-	rb_link_node(&pe->rb_aec, parent, p);
-	rb_insert_color(&pe->rb_aec, &ubi->prot.aec);
+	if (pq_tail < 0)
+		pq_tail = UBI_PROT_QUEUE_LEN - 1;
+	ubi_assert(pq_tail >= 0 && pq_tail < UBI_PROT_QUEUE_LEN);
+	list_add_tail(&e->u.list, &ubi->pq[pq_tail]);
+	dbg_wl("added PEB %d EC %d to the protection queue", e->pnum, e->ec);
 }
 
 /**
@@ -414,14 +355,14 @@ static struct ubi_wl_entry *find_wl_entry(struct rb_root *root, int max)
 	struct rb_node *p;
 	struct ubi_wl_entry *e;
 
-	e = rb_entry(rb_first(root), struct ubi_wl_entry, rb);
+	e = rb_entry(rb_first(root), struct ubi_wl_entry, u.rb);
 	max += e->ec;
 
 	p = root->rb_node;
 	while (p) {
 		struct ubi_wl_entry *e1;
 
-		e1 = rb_entry(p, struct ubi_wl_entry, rb);
+		e1 = rb_entry(p, struct ubi_wl_entry, u.rb);
 		if (e1->ec >= max)
 			p = p->rb_left;
 		else {
@@ -443,17 +384,12 @@ static struct ubi_wl_entry *find_wl_entry(struct rb_root *root, int max)
  */
 int ubi_wl_get_peb(struct ubi_device *ubi, int dtype)
 {
-	int err, protect, medium_ec;
+	int err, medium_ec;
 	struct ubi_wl_entry *e, *first, *last;
-	struct ubi_wl_prot_entry *pe;
 
 	ubi_assert(dtype == UBI_LONGTERM || dtype == UBI_SHORTTERM ||
 		   dtype == UBI_UNKNOWN);
 
-	pe = kmalloc(sizeof(struct ubi_wl_prot_entry), GFP_NOFS);
-	if (!pe)
-		return -ENOMEM;
-
 retry:
 	spin_lock(&ubi->wl_lock);
 	if (!ubi->free.rb_node) {
@@ -461,16 +397,13 @@ retry:
 			ubi_assert(list_empty(&ubi->works));
 			ubi_err("no free eraseblocks");
 			spin_unlock(&ubi->wl_lock);
-			kfree(pe);
 			return -ENOSPC;
 		}
 		spin_unlock(&ubi->wl_lock);
 
 		err = produce_free_peb(ubi);
-		if (err < 0) {
-			kfree(pe);
+		if (err < 0)
 			return err;
-		}
 		goto retry;
 	}
 
@@ -483,7 +416,6 @@ retry:
 		 * %WL_FREE_MAX_DIFF.
 		 */
 		e = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
-		protect = LT_PROTECTION;
 		break;
 	case UBI_UNKNOWN:
 		/*
@@ -492,81 +424,63 @@ retry:
 		 * eraseblock with erase counter greater or equivalent than the
 		 * lowest erase counter plus %WL_FREE_MAX_DIFF.
 		 */
-		first = rb_entry(rb_first(&ubi->free), struct ubi_wl_entry, rb);
-		last = rb_entry(rb_last(&ubi->free), struct ubi_wl_entry, rb);
+		first = rb_entry(rb_first(&ubi->free), struct ubi_wl_entry,
+					u.rb);
+		last = rb_entry(rb_last(&ubi->free), struct ubi_wl_entry, u.rb);
 
 		if (last->ec - first->ec < WL_FREE_MAX_DIFF)
 			e = rb_entry(ubi->free.rb_node,
-					struct ubi_wl_entry, rb);
+					struct ubi_wl_entry, u.rb);
 		else {
 			medium_ec = (first->ec + WL_FREE_MAX_DIFF)/2;
 			e = find_wl_entry(&ubi->free, medium_ec);
 		}
-		protect = U_PROTECTION;
 		break;
 	case UBI_SHORTTERM:
 		/*
 		 * For short term data we pick a physical eraseblock with the
 		 * lowest erase counter as we expect it will be erased soon.
 		 */
-		e = rb_entry(rb_first(&ubi->free), struct ubi_wl_entry, rb);
-		protect = ST_PROTECTION;
+		e = rb_entry(rb_first(&ubi->free), struct ubi_wl_entry, u.rb);
 		break;
 	default:
-		protect = 0;
-		e = NULL;
 		BUG();
 	}
 
+	paranoid_check_in_wl_tree(e, &ubi->free);
+
 	/*
-	 * Move the physical eraseblock to the protection trees where it will
+	 * Move the physical eraseblock to the protection queue where it will
 	 * be protected from being moved for some time.
 	 */
-	paranoid_check_in_wl_tree(e, &ubi->free);
-	rb_erase(&e->rb, &ubi->free);
-	prot_tree_add(ubi, e, pe, protect);
-
-	dbg_wl("PEB %d EC %d, protection %d", e->pnum, e->ec, protect);
+	rb_erase(&e->u.rb, &ubi->free);
+	dbg_wl("PEB %d EC %d", e->pnum, e->ec);
+	prot_queue_add(ubi, e);
 	spin_unlock(&ubi->wl_lock);
-
 	return e->pnum;
 }
 
 /**
- * prot_tree_del - remove a physical eraseblock from the protection trees
+ * prot_queue_del - remove a physical eraseblock from the protection queue.
  * @ubi: UBI device description object
  * @pnum: the physical eraseblock to remove
  *
- * This function returns PEB @pnum from the protection trees and returns zero
- * in case of success and %-ENODEV if the PEB was not found in the protection
- * trees.
+ * This function deletes PEB @pnum from the protection queue and returns zero
+ * in case of success and %-ENODEV if the PEB was not found.
  */
-static int prot_tree_del(struct ubi_device *ubi, int pnum)
+static int prot_queue_del(struct ubi_device *ubi, int pnum)
 {
-	struct rb_node *p;
-	struct ubi_wl_prot_entry *pe = NULL;
-
-	p = ubi->prot.pnum.rb_node;
-	while (p) {
-
-		pe = rb_entry(p, struct ubi_wl_prot_entry, rb_pnum);
-
-		if (pnum == pe->e->pnum)
-			goto found;
+	struct ubi_wl_entry *e;
 
-		if (pnum < pe->e->pnum)
-			p = p->rb_left;
-		else
-			p = p->rb_right;
-	}
+	e = ubi->lookuptbl[pnum];
+	if (!e)
+		return -ENODEV;
 
-	return -ENODEV;
+	if (paranoid_check_in_pq(ubi, e))
+		return -ENODEV;
 
-found:
-	ubi_assert(pe->e->pnum == pnum);
-	rb_erase(&pe->rb_aec, &ubi->prot.aec);
-	rb_erase(&pe->rb_pnum, &ubi->prot.pnum);
-	kfree(pe);
+	list_del(&e->u.list);
+	dbg_wl("deleted PEB %d from the protection queue", e->pnum);
 	return 0;
 }
 
@@ -632,47 +546,47 @@ out_free:
 }
 
 /**
- * check_protection_over - check if it is time to stop protecting some PEBs.
+ * serve_prot_queue - check if it is time to stop protecting PEBs.
  * @ubi: UBI device description object
  *
- * This function is called after each erase operation, when the absolute erase
- * counter is incremented, to check if some physical eraseblock  have not to be
- * protected any longer. These physical eraseblocks are moved from the
- * protection trees to the used tree.
+ * This function is called after each erase operation and removes PEBs from the
+ * tail of the protection queue. These PEBs have been protected for long enough
+ * and should be moved to the used tree.
  */
-static void check_protection_over(struct ubi_device *ubi)
+static void serve_prot_queue(struct ubi_device *ubi)
 {
-	struct ubi_wl_prot_entry *pe;
+	struct ubi_wl_entry *e, *tmp;
+	int count;
 
 	/*
 	 * There may be several protected physical eraseblock to remove,
 	 * process them all.
 	 */
-	while (1) {
-		spin_lock(&ubi->wl_lock);
-		if (!ubi->prot.aec.rb_node) {
-			spin_unlock(&ubi->wl_lock);
-			break;
-		}
-
-		pe = rb_entry(rb_first(&ubi->prot.aec),
-			      struct ubi_wl_prot_entry, rb_aec);
+repeat:
+	count = 0;
+	spin_lock(&ubi->wl_lock);
+	list_for_each_entry_safe(e, tmp, &ubi->pq[ubi->pq_head], u.list) {
+		dbg_wl("PEB %d EC %d protection over, move to used tree",
+			e->pnum, e->ec);
 
-		if (pe->abs_ec > ubi->abs_ec) {
+		list_del(&e->u.list);
+		wl_tree_add(e, &ubi->used);
+		if (count++ > 32) {
+			/*
+			 * Let's be nice and avoid holding the spinlock for
+			 * too long.
+			 */
 			spin_unlock(&ubi->wl_lock);
-			break;
+			cond_resched();
+			goto repeat;
 		}
-
-		dbg_wl("PEB %d protection over, abs_ec %llu, PEB abs_ec %llu",
-		       pe->e->pnum, ubi->abs_ec, pe->abs_ec);
-		rb_erase(&pe->rb_aec, &ubi->prot.aec);
-		rb_erase(&pe->rb_pnum, &ubi->prot.pnum);
-		wl_tree_add(pe->e, &ubi->used);
-		spin_unlock(&ubi->wl_lock);
-
-		kfree(pe);
-		cond_resched();
 	}
+
+	ubi->pq_head += 1;
+	if (ubi->pq_head == UBI_PROT_QUEUE_LEN)
+		ubi->pq_head = 0;
+	ubi_assert(ubi->pq_head >= 0 && ubi->pq_head < UBI_PROT_QUEUE_LEN);
+	spin_unlock(&ubi->wl_lock);
 }
 
 /**
@@ -680,8 +594,8 @@ static void check_protection_over(struct ubi_device *ubi)
  * @ubi: UBI device description object
  * @wrk: the work to schedule
  *
- * This function enqueues a work defined by @wrk to the tail of the pending
- * works list.
+ * This function adds a work defined by @wrk to the tail of the pending works
+ * list.
  */
 static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
 {
@@ -739,13 +653,11 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
 static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
 				int cancel)
 {
-	int err, put = 0, scrubbing = 0, protect = 0;
-	struct ubi_wl_prot_entry *uninitialized_var(pe);
+	int err, scrubbing = 0, torture = 0;
 	struct ubi_wl_entry *e1, *e2;
 	struct ubi_vid_hdr *vid_hdr;
 
 	kfree(wrk);
-
 	if (cancel)
 		return 0;
 
@@ -781,7 +693,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
 		 * highly worn-out free physical eraseblock. If the erase
 		 * counters differ much enough, start wear-leveling.
 		 */
-		e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, rb);
+		e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
 		e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
 
 		if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD)) {
@@ -790,21 +702,21 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
 			goto out_cancel;
 		}
 		paranoid_check_in_wl_tree(e1, &ubi->used);
-		rb_erase(&e1->rb, &ubi->used);
+		rb_erase(&e1->u.rb, &ubi->used);
 		dbg_wl("move PEB %d EC %d to PEB %d EC %d",
 		       e1->pnum, e1->ec, e2->pnum, e2->ec);
 	} else {
 		/* Perform scrubbing */
 		scrubbing = 1;
-		e1 = rb_entry(rb_first(&ubi->scrub), struct ubi_wl_entry, rb);
+		e1 = rb_entry(rb_first(&ubi->scrub), struct ubi_wl_entry, u.rb);
 		e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
 		paranoid_check_in_wl_tree(e1, &ubi->scrub);
-		rb_erase(&e1->rb, &ubi->scrub);
+		rb_erase(&e1->u.rb, &ubi->scrub);
 		dbg_wl("scrub PEB %d to PEB %d", e1->pnum, e2->pnum);
 	}
 
 	paranoid_check_in_wl_tree(e2, &ubi->free);
-	rb_erase(&e2->rb, &ubi->free);
+	rb_erase(&e2->u.rb, &ubi->free);
 	ubi->move_from = e1;
 	ubi->move_to = e2;
 	spin_unlock(&ubi->wl_lock);
@@ -844,46 +756,67 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
 
 	err = ubi_eba_copy_leb(ubi, e1->pnum, e2->pnum, vid_hdr);
 	if (err) {
-
+		if (err == -EAGAIN)
+			goto out_not_moved;
 		if (err < 0)
 			goto out_error;
-		if (err == 1)
+		if (err == 2) {
+			/* Target PEB write error, torture it */
+			torture = 1;
 			goto out_not_moved;
+		}
 
 		/*
-		 * For some reason the LEB was not moved - it might be because
-		 * the volume is being deleted. We should prevent this PEB from
-		 * being selected for wear-levelling movement for some "time",
-		 * so put it to the protection tree.
+		 * The LEB has not been moved because the volume is being
+		 * deleted or the PEB has been put meanwhile. We should prevent
+		 * this PEB from being selected for wear-leveling movement
+		 * again, so put it to the protection queue.
 		 */
 
-		dbg_wl("cancelled moving PEB %d", e1->pnum);
-		pe = kmalloc(sizeof(struct ubi_wl_prot_entry), GFP_NOFS);
-		if (!pe) {
-			err = -ENOMEM;
-			goto out_error;
-		}
+		dbg_wl("canceled moving PEB %d", e1->pnum);
+		ubi_assert(err == 1);
+
+		ubi_free_vid_hdr(ubi, vid_hdr);
+		vid_hdr = NULL;
+
+		spin_lock(&ubi->wl_lock);
+		prot_queue_add(ubi, e1);
+		ubi_assert(!ubi->move_to_put);
+		ubi->move_from = ubi->move_to = NULL;
+		ubi->wl_scheduled = 0;
+		spin_unlock(&ubi->wl_lock);
 
-		protect = 1;
+		e1 = NULL;
+		err = schedule_erase(ubi, e2, 0);
+		if (err)
+			goto out_error;
+		mutex_unlock(&ubi->move_mutex);
+		return 0;
 	}
 
+	/* The PEB has been successfully moved */
 	ubi_free_vid_hdr(ubi, vid_hdr);
-	if (scrubbing && !protect)
+	vid_hdr = NULL;
+	if (scrubbing)
 		ubi_msg("scrubbed PEB %d, data moved to PEB %d",
 			e1->pnum, e2->pnum);
 
 	spin_lock(&ubi->wl_lock);
-	if (protect)
-		prot_tree_add(ubi, e1, pe, protect);
-	if (!ubi->move_to_put)
+	if (!ubi->move_to_put) {
 		wl_tree_add(e2, &ubi->used);
-	else
-		put = 1;
+		e2 = NULL;
+	}
 	ubi->move_from = ubi->move_to = NULL;
 	ubi->move_to_put = ubi->wl_scheduled = 0;
 	spin_unlock(&ubi->wl_lock);
 
-	if (put) {
+	err = schedule_erase(ubi, e1, 0);
+	if (err) {
+		e1 = NULL;
+		goto out_error;
+	}
+
+	if (e2) {
 		/*
 		 * Well, the target PEB was put meanwhile, schedule it for
 		 * erasure.
@@ -894,13 +827,6 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
 			goto out_error;
 	}
 
-	if (!protect) {
-		err = schedule_erase(ubi, e1, 0);
-		if (err)
-			goto out_error;
-	}
-
-
 	dbg_wl("done");
 	mutex_unlock(&ubi->move_mutex);
 	return 0;
@@ -908,20 +834,24 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
 	/*
 	 * For some reasons the LEB was not moved, might be an error, might be
 	 * something else. @e1 was not changed, so return it back. @e2 might
-	 * be changed, schedule it for erasure.
+	 * have been changed, schedule it for erasure.
 	 */
 out_not_moved:
+	dbg_wl("canceled moving PEB %d", e1->pnum);
 	ubi_free_vid_hdr(ubi, vid_hdr);
+	vid_hdr = NULL;
 	spin_lock(&ubi->wl_lock);
 	if (scrubbing)
 		wl_tree_add(e1, &ubi->scrub);
 	else
 		wl_tree_add(e1, &ubi->used);
+	ubi_assert(!ubi->move_to_put);
 	ubi->move_from = ubi->move_to = NULL;
-	ubi->move_to_put = ubi->wl_scheduled = 0;
+	ubi->wl_scheduled = 0;
 	spin_unlock(&ubi->wl_lock);
 
-	err = schedule_erase(ubi, e2, 0);
+	e1 = NULL;
+	err = schedule_erase(ubi, e2, torture);
 	if (err)
 		goto out_error;
 
@@ -938,8 +868,10 @@ out_error:
 	ubi->move_to_put = ubi->wl_scheduled = 0;
 	spin_unlock(&ubi->wl_lock);
 
-	kmem_cache_free(ubi_wl_entry_slab, e1);
-	kmem_cache_free(ubi_wl_entry_slab, e2);
+	if (e1)
+		kmem_cache_free(ubi_wl_entry_slab, e1);
+	if (e2)
+		kmem_cache_free(ubi_wl_entry_slab, e2);
 	ubi_ro_mode(ubi);
 
 	mutex_unlock(&ubi->move_mutex);
@@ -985,10 +917,10 @@ static int ensure_wear_leveling(struct ubi_device *ubi)
 		/*
 		 * We schedule wear-leveling only if the difference between the
 		 * lowest erase counter of used physical eraseblocks and a high
-		 * erase counter of free physical eraseblocks is greater then
+		 * erase counter of free physical eraseblocks is greater than
 		 * %UBI_WL_THRESHOLD.
 		 */
-		e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, rb);
+		e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
 		e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
 
 		if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD))
@@ -1050,7 +982,6 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
 		kfree(wl_wrk);
 
 		spin_lock(&ubi->wl_lock);
-		ubi->abs_ec += 1;
 		wl_tree_add(e, &ubi->free);
 		spin_unlock(&ubi->wl_lock);
 
@@ -1058,7 +989,7 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
 		 * One more erase operation has happened, take care about
 		 * protected physical eraseblocks.
 		 */
-		check_protection_over(ubi);
+		serve_prot_queue(ubi);
 
 		/* And take care about wear-leveling */
 		err = ensure_wear_leveling(ubi);
@@ -1190,12 +1121,12 @@ retry:
 	} else {
 		if (in_wl_tree(e, &ubi->used)) {
 			paranoid_check_in_wl_tree(e, &ubi->used);
-			rb_erase(&e->rb, &ubi->used);
+			rb_erase(&e->u.rb, &ubi->used);
 		} else if (in_wl_tree(e, &ubi->scrub)) {
 			paranoid_check_in_wl_tree(e, &ubi->scrub);
-			rb_erase(&e->rb, &ubi->scrub);
+			rb_erase(&e->u.rb, &ubi->scrub);
 		} else {
-			err = prot_tree_del(ubi, e->pnum);
+			err = prot_queue_del(ubi, e->pnum);
 			if (err) {
 				ubi_err("PEB %d not found", pnum);
 				ubi_ro_mode(ubi);
@@ -1255,11 +1186,11 @@ retry:
 
 	if (in_wl_tree(e, &ubi->used)) {
 		paranoid_check_in_wl_tree(e, &ubi->used);
-		rb_erase(&e->rb, &ubi->used);
+		rb_erase(&e->u.rb, &ubi->used);
 	} else {
 		int err;
 
-		err = prot_tree_del(ubi, e->pnum);
+		err = prot_queue_del(ubi, e->pnum);
 		if (err) {
 			ubi_err("PEB %d not found", pnum);
 			ubi_ro_mode(ubi);
@@ -1290,7 +1221,7 @@ int ubi_wl_flush(struct ubi_device *ubi)
 	int err;
 
 	/*
-	 * Erase while the pending works queue is not empty, but not more then
+	 * Erase while the pending works queue is not empty, but not more than
 	 * the number of currently pending works.
 	 */
 	dbg_wl("flush (%d pending works)", ubi->works_count);
@@ -1308,7 +1239,7 @@ int ubi_wl_flush(struct ubi_device *ubi)
 	up_write(&ubi->work_sem);
 
 	/*
-	 * And in case last was the WL worker and it cancelled the LEB
+	 * And in case last was the WL worker and it canceled the LEB
 	 * movement, flush again.
 	 */
 	while (ubi->works_count) {
@@ -1337,11 +1268,11 @@ static void tree_destroy(struct rb_root *root)
 		else if (rb->rb_right)
 			rb = rb->rb_right;
 		else {
-			e = rb_entry(rb, struct ubi_wl_entry, rb);
+			e = rb_entry(rb, struct ubi_wl_entry, u.rb);
 
 			rb = rb_parent(rb);
 			if (rb) {
-				if (rb->rb_left == &e->rb)
+				if (rb->rb_left == &e->u.rb)
 					rb->rb_left = NULL;
 				else
 					rb->rb_right = NULL;
@@ -1436,15 +1367,13 @@ static void cancel_pending(struct ubi_device *ubi)
  */
 int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si)
 {
-	int err;
+	int err, i;
 	struct rb_node *rb1, *rb2;
 	struct ubi_scan_volume *sv;
 	struct ubi_scan_leb *seb, *tmp;
 	struct ubi_wl_entry *e;
 
-
 	ubi->used = ubi->free = ubi->scrub = RB_ROOT;
-	ubi->prot.pnum = ubi->prot.aec = RB_ROOT;
 	spin_lock_init(&ubi->wl_lock);
 	mutex_init(&ubi->move_mutex);
 	init_rwsem(&ubi->work_sem);
@@ -1458,6 +1387,10 @@ int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si)
 	if (!ubi->lookuptbl)
 		return err;
 
+	for (i = 0; i < UBI_PROT_QUEUE_LEN; i++)
+		INIT_LIST_HEAD(&ubi->pq[i]);
+	ubi->pq_head = 0;
+
 	list_for_each_entry_safe(seb, tmp, &si->erase, u.list) {
 		cond_resched();
 
@@ -1552,33 +1485,18 @@ out_free:
 }
 
 /**
- * protection_trees_destroy - destroy the protection RB-trees.
+ * protection_queue_destroy - destroy the protection queue.
  * @ubi: UBI device description object
  */
-static void protection_trees_destroy(struct ubi_device *ubi)
+static void protection_queue_destroy(struct ubi_device *ubi)
 {
-	struct rb_node *rb;
-	struct ubi_wl_prot_entry *pe;
-
-	rb = ubi->prot.aec.rb_node;
-	while (rb) {
-		if (rb->rb_left)
-			rb = rb->rb_left;
-		else if (rb->rb_right)
-			rb = rb->rb_right;
-		else {
-			pe = rb_entry(rb, struct ubi_wl_prot_entry, rb_aec);
-
-			rb = rb_parent(rb);
-			if (rb) {
-				if (rb->rb_left == &pe->rb_aec)
-					rb->rb_left = NULL;
-				else
-					rb->rb_right = NULL;
-			}
+	int i;
+	struct ubi_wl_entry *e, *tmp;
 
-			kmem_cache_free(ubi_wl_entry_slab, pe->e);
-			kfree(pe);
+	for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i) {
+		list_for_each_entry_safe(e, tmp, &ubi->pq[i], u.list) {
+			list_del(&e->u.list);
+			kmem_cache_free(ubi_wl_entry_slab, e);
 		}
 	}
 }
@@ -1591,7 +1509,7 @@ void ubi_wl_close(struct ubi_device *ubi)
 {
 	dbg_wl("close the WL sub-system");
 	cancel_pending(ubi);
-	protection_trees_destroy(ubi);
+	protection_queue_destroy(ubi);
 	tree_destroy(&ubi->used);
 	tree_destroy(&ubi->free);
 	tree_destroy(&ubi->scrub);
@@ -1661,4 +1579,27 @@ static int paranoid_check_in_wl_tree(struct ubi_wl_entry *e,
 	return 1;
 }
 
+/**
+ * paranoid_check_in_pq - check if wear-leveling entry is in the protection
+ *                        queue.
+ * @ubi: UBI device description object
+ * @e: the wear-leveling entry to check
+ *
+ * This function returns zero if @e is in @ubi->pq and %1 if it is not.
+ */
+static int paranoid_check_in_pq(struct ubi_device *ubi, struct ubi_wl_entry *e)
+{
+	struct ubi_wl_entry *p;
+	int i;
+
+	for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i)
+		list_for_each_entry(p, &ubi->pq[i], u.list)
+			if (p == e)
+				return 0;
+
+	ubi_err("paranoid check failed for PEB %d, EC %d, Protect queue",
+		e->pnum, e->ec);
+	ubi_dbg_dump_stack();
+	return 1;
+}
 #endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */