diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 1cb22bf..0236539 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -565,7 +565,7 @@
 		}
 
 	ubi = ubi_devices[ubi_devices_cnt] = kzalloc(sizeof(struct ubi_device),
-						      GFP_KERNEL);
+						     GFP_KERNEL);
 	if (!ubi) {
 		err = -ENOMEM;
 		goto out_mtd;
@@ -583,6 +583,22 @@
 	if (err)
 		goto out_free;
 
+	mutex_init(&ubi->buf_mutex);
+	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;
+
+#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;
+#endif
+
 	err = attach_by_scanning(ubi);
 	if (err) {
 		dbg_err("failed to attach by scanning, error %d", err);
@@ -630,6 +646,11 @@
 	ubi_wl_close(ubi);
 	vfree(ubi->vtbl);
 out_free:
+	vfree(ubi->peb_buf1);
+	vfree(ubi->peb_buf2);
+#ifdef CONFIG_MTD_UBI_DEBUG
+	vfree(ubi->dbg_peb_buf);
+#endif
 	kfree(ubi);
 out_mtd:
 	put_mtd_device(mtd);
@@ -651,6 +672,11 @@
 	ubi_wl_close(ubi);
 	vfree(ubi->vtbl);
 	put_mtd_device(ubi->mtd);
+	vfree(ubi->peb_buf1);
+	vfree(ubi->peb_buf2);
+#ifdef CONFIG_MTD_UBI_DEBUG
+	vfree(ubi->dbg_peb_buf);
+#endif
 	kfree(ubi_devices[ubi_num]);
 	ubi_devices[ubi_num] = NULL;
 	ubi_devices_cnt -= 1;
diff --git a/drivers/mtd/ubi/debug.c b/drivers/mtd/ubi/debug.c
index 310341e..56956ec 100644
--- a/drivers/mtd/ubi/debug.c
+++ b/drivers/mtd/ubi/debug.c
@@ -42,7 +42,8 @@
 	dbg_msg("data_offset    %d",    be32_to_cpu(ec_hdr->data_offset));
 	dbg_msg("hdr_crc        %#08x", be32_to_cpu(ec_hdr->hdr_crc));
 	dbg_msg("erase counter header hexdump:");
-	ubi_dbg_hexdump(ec_hdr, UBI_EC_HDR_SIZE);
+	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
+		       ec_hdr, UBI_EC_HDR_SIZE, 1);
 }
 
 /**
@@ -187,38 +188,4 @@
 	dbg_msg("the 1st 16 characters of the name: %s", nm);
 }
 
-#define BYTES_PER_LINE 32
-
-/**
- * ubi_dbg_hexdump - dump a buffer.
- * @ptr: the buffer to dump
- * @size: buffer size which must be multiple of 4 bytes
- */
-void ubi_dbg_hexdump(const void *ptr, int size)
-{
-	int i, k = 0, rows, columns;
-	const uint8_t *p = ptr;
-
-	size = ALIGN(size, 4);
-	rows = size/BYTES_PER_LINE + size % BYTES_PER_LINE;
-	for (i = 0; i < rows; i++) {
-		int j;
-
-		cond_resched();
-		columns = min(size - k, BYTES_PER_LINE) / 4;
-		if (columns == 0)
-			break;
-		printk(KERN_DEBUG "%5d:  ", i * BYTES_PER_LINE);
-		for (j = 0; j < columns; j++) {
-			int n, N;
-
-			N = size - k > 4 ? 4 : size - k;
-			for (n = 0; n < N; n++)
-				printk("%02x", p[k++]);
-			printk(" ");
-		}
-		printk("\n");
-	}
-}
-
 #endif /* CONFIG_MTD_UBI_DEBUG_MSG */
diff --git a/drivers/mtd/ubi/debug.h b/drivers/mtd/ubi/debug.h
index ff8f395..467722e 100644
--- a/drivers/mtd/ubi/debug.h
+++ b/drivers/mtd/ubi/debug.h
@@ -59,7 +59,6 @@
 void ubi_dbg_dump_sv(const struct ubi_scan_volume *sv);
 void ubi_dbg_dump_seb(const struct ubi_scan_leb *seb, int type);
 void ubi_dbg_dump_mkvol_req(const struct ubi_mkvol_req *req);
-void ubi_dbg_hexdump(const void *buf, int size);
 
 #else
 
@@ -72,7 +71,6 @@
 #define ubi_dbg_dump_sv(sv)              ({})
 #define ubi_dbg_dump_seb(seb, type)      ({})
 #define ubi_dbg_dump_mkvol_req(req)      ({})
-#define ubi_dbg_hexdump(buf, size)       ({})
 
 #endif /* CONFIG_MTD_UBI_DEBUG_MSG */
 
diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index 7c5e29e..1297732 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -46,6 +46,9 @@
 #include <linux/err.h>
 #include "ubi.h"
 
+/* Number of physical eraseblocks reserved for atomic LEB change operation */
+#define EBA_RESERVED_PEBS 1
+
 /**
  * struct ltree_entry - an entry in the lock tree.
  * @rb: links RB-tree nodes
@@ -157,7 +160,7 @@
 {
 	struct ltree_entry *le, *le1, *le_free;
 
-	le = kmem_cache_alloc(ltree_slab, GFP_KERNEL);
+	le = kmem_cache_alloc(ltree_slab, GFP_NOFS);
 	if (!le)
 		return ERR_PTR(-ENOMEM);
 
@@ -397,7 +400,7 @@
 
 retry:
 	if (check) {
-		vid_hdr = ubi_zalloc_vid_hdr(ubi);
+		vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
 		if (!vid_hdr) {
 			err = -ENOMEM;
 			goto out_unlock;
@@ -495,16 +498,18 @@
 	int err, idx = vol_id2idx(ubi, vol_id), new_pnum, data_size, tries = 0;
 	struct ubi_volume *vol = ubi->volumes[idx];
 	struct ubi_vid_hdr *vid_hdr;
-	unsigned char *new_buf;
 
-	vid_hdr = ubi_zalloc_vid_hdr(ubi);
+	vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
 	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;
 	}
@@ -524,31 +529,22 @@
 		goto write_error;
 
 	data_size = offset + len;
-	new_buf = vmalloc(data_size);
-	if (!new_buf) {
-		err = -ENOMEM;
-		goto out_put;
-	}
-	memset(new_buf + offset, 0xFF, len);
+	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, new_buf, pnum, 0, offset);
-		if (err && err != UBI_IO_BITFLIPS) {
-			vfree(new_buf);
+		err = ubi_io_read_data(ubi, ubi->peb_buf1, pnum, 0, offset);
+		if (err && err != UBI_IO_BITFLIPS)
 			goto out_put;
-		}
 	}
 
-	memcpy(new_buf + offset, buf, len);
+	memcpy(ubi->peb_buf1 + offset, buf, len);
 
-	err = ubi_io_write_data(ubi, new_buf, new_pnum, 0, data_size);
-	if (err) {
-		vfree(new_buf);
+	err = ubi_io_write_data(ubi, ubi->peb_buf1, new_pnum, 0, data_size);
+	if (err)
 		goto write_error;
-	}
 
-	vfree(new_buf);
+	mutex_unlock(&ubi->buf_mutex);
 	ubi_free_vid_hdr(ubi, vid_hdr);
 
 	vol->eba_tbl[lnum] = new_pnum;
@@ -558,6 +554,7 @@
 	return 0;
 
 out_put:
+	mutex_unlock(&ubi->buf_mutex);
 	ubi_wl_put_peb(ubi, new_pnum, 1);
 	ubi_free_vid_hdr(ubi, vid_hdr);
 	return err;
@@ -570,6 +567,7 @@
 	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;
 	}
@@ -627,7 +625,7 @@
 	 * The logical eraseblock is not mapped. We have to get a free physical
 	 * eraseblock and write the volume identifier header there first.
 	 */
-	vid_hdr = ubi_zalloc_vid_hdr(ubi);
+	vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
 	if (!vid_hdr) {
 		leb_write_unlock(ubi, vol_id, lnum);
 		return -ENOMEM;
@@ -738,7 +736,7 @@
 	else
 		ubi_assert(len % ubi->min_io_size == 0);
 
-	vid_hdr = ubi_zalloc_vid_hdr(ubi);
+	vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
 	if (!vid_hdr)
 		return -ENOMEM;
 
@@ -832,6 +830,9 @@
  * data, which has to be aligned. This function guarantees that in case of an
  * unclean reboot the old contents is preserved. Returns zero in case of
  * success and a negative error code in case of failure.
+ *
+ * UBI reserves one LEB for the "atomic LEB change" operation, so only one
+ * LEB change may be done at a time. This is ensured by @ubi->alc_mutex.
  */
 int ubi_eba_atomic_leb_change(struct ubi_device *ubi, int vol_id, int lnum,
 			      const void *buf, int len, int dtype)
@@ -844,15 +845,14 @@
 	if (ubi->ro_mode)
 		return -EROFS;
 
-	vid_hdr = ubi_zalloc_vid_hdr(ubi);
+	vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
 	if (!vid_hdr)
 		return -ENOMEM;
 
+	mutex_lock(&ubi->alc_mutex);
 	err = leb_write_lock(ubi, vol_id, lnum);
-	if (err) {
-		ubi_free_vid_hdr(ubi, vid_hdr);
-		return err;
-	}
+	if (err)
+		goto out_mutex;
 
 	vid_hdr->sqnum = cpu_to_be64(next_sqnum(ubi));
 	vid_hdr->vol_id = cpu_to_be32(vol_id);
@@ -869,9 +869,8 @@
 retry:
 	pnum = ubi_wl_get_peb(ubi, dtype);
 	if (pnum < 0) {
-		ubi_free_vid_hdr(ubi, vid_hdr);
-		leb_write_unlock(ubi, vol_id, lnum);
-		return pnum;
+		err = pnum;
+		goto out_leb_unlock;
 	}
 
 	dbg_eba("change LEB %d:%d, PEB %d, write VID hdr to PEB %d",
@@ -893,17 +892,18 @@
 
 	if (vol->eba_tbl[lnum] >= 0) {
 		err = ubi_wl_put_peb(ubi, vol->eba_tbl[lnum], 1);
-		if (err) {
-			ubi_free_vid_hdr(ubi, vid_hdr);
-			leb_write_unlock(ubi, vol_id, lnum);
-			return err;
-		}
+		if (err)
+			goto out_leb_unlock;
 	}
 
 	vol->eba_tbl[lnum] = pnum;
+
+out_leb_unlock:
 	leb_write_unlock(ubi, vol_id, lnum);
+out_mutex:
+	mutex_unlock(&ubi->alc_mutex);
 	ubi_free_vid_hdr(ubi, vid_hdr);
-	return 0;
+	return err;
 
 write_error:
 	if (err != -EIO || !ubi->bad_allowed) {
@@ -913,17 +913,13 @@
 		 * mode just in case.
 		 */
 		ubi_ro_mode(ubi);
-		leb_write_unlock(ubi, vol_id, lnum);
-		ubi_free_vid_hdr(ubi, vid_hdr);
-		return err;
+		goto out_leb_unlock;
 	}
 
 	err = ubi_wl_put_peb(ubi, pnum, 1);
 	if (err || ++tries > UBI_IO_RETRIES) {
 		ubi_ro_mode(ubi);
-		leb_write_unlock(ubi, vol_id, lnum);
-		ubi_free_vid_hdr(ubi, vid_hdr);
-		return err;
+		goto out_leb_unlock;
 	}
 
 	vid_hdr->sqnum = cpu_to_be64(next_sqnum(ubi));
@@ -965,7 +961,6 @@
 	int err, vol_id, lnum, data_size, aldata_size, pnum, idx;
 	struct ubi_volume *vol;
 	uint32_t crc;
-	void *buf, *buf1 = NULL;
 
 	vol_id = be32_to_cpu(vid_hdr->vol_id);
 	lnum = be32_to_cpu(vid_hdr->lnum);
@@ -979,19 +974,15 @@
 		data_size = aldata_size =
 			    ubi->leb_size - be32_to_cpu(vid_hdr->data_pad);
 
-	buf = vmalloc(aldata_size);
-	if (!buf)
-		return -ENOMEM;
-
 	/*
 	 * We do not want anybody to write to this logical eraseblock while we
 	 * are moving it, so we lock it.
 	 */
 	err = leb_write_lock(ubi, vol_id, lnum);
-	if (err) {
-		vfree(buf);
+	if (err)
 		return err;
-	}
+
+	mutex_lock(&ubi->buf_mutex);
 
 	/*
 	 * But the logical eraseblock might have been put by this time.
@@ -1023,7 +1014,7 @@
 	/* OK, now the LEB is locked and we can safely start moving it */
 
 	dbg_eba("read %d bytes of data", aldata_size);
-	err = ubi_io_read_data(ubi, buf, from, 0, aldata_size);
+	err = ubi_io_read_data(ubi, ubi->peb_buf1, from, 0, aldata_size);
 	if (err && err != UBI_IO_BITFLIPS) {
 		ubi_warn("error %d while reading data from PEB %d",
 			 err, from);
@@ -1042,10 +1033,10 @@
 	 */
 	if (vid_hdr->vol_type == UBI_VID_DYNAMIC)
 		aldata_size = data_size =
-				ubi_calc_data_len(ubi, buf, data_size);
+			ubi_calc_data_len(ubi, ubi->peb_buf1, data_size);
 
 	cond_resched();
-	crc = crc32(UBI_CRC32_INIT, buf, data_size);
+	crc = crc32(UBI_CRC32_INIT, ubi->peb_buf1, data_size);
 	cond_resched();
 
 	/*
@@ -1076,23 +1067,18 @@
 	}
 
 	if (data_size > 0) {
-		err = ubi_io_write_data(ubi, buf, to, 0, aldata_size);
+		err = ubi_io_write_data(ubi, ubi->peb_buf1, to, 0, aldata_size);
 		if (err)
 			goto out_unlock;
 
+		cond_resched();
+
 		/*
 		 * We've written the data and are going to read it back to make
 		 * sure it was written correctly.
 		 */
-		buf1 = vmalloc(aldata_size);
-		if (!buf1) {
-			err = -ENOMEM;
-			goto out_unlock;
-		}
 
-		cond_resched();
-
-		err = ubi_io_read_data(ubi, buf1, to, 0, aldata_size);
+		err = ubi_io_read_data(ubi, ubi->peb_buf2, to, 0, aldata_size);
 		if (err) {
 			if (err != UBI_IO_BITFLIPS)
 				ubi_warn("cannot read data back from PEB %d",
@@ -1102,7 +1088,7 @@
 
 		cond_resched();
 
-		if (memcmp(buf, buf1, aldata_size)) {
+		if (memcmp(ubi->peb_buf1, ubi->peb_buf2, aldata_size)) {
 			ubi_warn("read data back from PEB %d - it is different",
 				 to);
 			goto out_unlock;
@@ -1112,16 +1098,9 @@
 	ubi_assert(vol->eba_tbl[lnum] == from);
 	vol->eba_tbl[lnum] = to;
 
-	leb_write_unlock(ubi, vol_id, lnum);
-	vfree(buf);
-	vfree(buf1);
-
-	return 0;
-
 out_unlock:
+	mutex_unlock(&ubi->buf_mutex);
 	leb_write_unlock(ubi, vol_id, lnum);
-	vfree(buf);
-	vfree(buf1);
 	return err;
 }
 
@@ -1144,6 +1123,7 @@
 	dbg_eba("initialize EBA unit");
 
 	spin_lock_init(&ubi->ltree_lock);
+	mutex_init(&ubi->alc_mutex);
 	ubi->ltree = RB_ROOT;
 
 	if (ubi_devices_cnt == 0) {
@@ -1205,6 +1185,15 @@
 		ubi->rsvd_pebs  += ubi->beb_rsvd_pebs;
 	}
 
+	if (ubi->avail_pebs < EBA_RESERVED_PEBS) {
+		ubi_err("no enough physical eraseblocks (%d, need %d)",
+			ubi->avail_pebs, EBA_RESERVED_PEBS);
+		err = -ENOSPC;
+		goto out_free;
+	}
+	ubi->avail_pebs -= EBA_RESERVED_PEBS;
+	ubi->rsvd_pebs += EBA_RESERVED_PEBS;
+
 	dbg_eba("EBA unit is initialized");
 	return 0;
 
diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index b0d8f4c..7c304eec 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -98,8 +98,8 @@
 static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum);
 static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
 				  const struct ubi_vid_hdr *vid_hdr);
-static int paranoid_check_all_ff(const struct ubi_device *ubi, int pnum,
-				 int offset, int len);
+static int paranoid_check_all_ff(struct ubi_device *ubi, int pnum, int offset,
+				 int len);
 #else
 #define paranoid_check_not_bad(ubi, pnum) 0
 #define paranoid_check_peb_ec_hdr(ubi, pnum)  0
@@ -202,8 +202,8 @@
  * Note, in case of an error, it is possible that something was still written
  * to the flash media, but may be some garbage.
  */
-int ubi_io_write(const struct ubi_device *ubi, const void *buf, int pnum,
-		 int offset, int len)
+int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
+		 int len)
 {
 	int err;
 	size_t written;
@@ -285,7 +285,7 @@
  * zero in case of success and a negative error code in case of failure. If
  * %-EIO is returned, the physical eraseblock most probably went bad.
  */
-static int do_sync_erase(const struct ubi_device *ubi, int pnum)
+static int do_sync_erase(struct ubi_device *ubi, int pnum)
 {
 	int err, retries = 0;
 	struct erase_info ei;
@@ -377,29 +377,25 @@
  * test, a positive number of erase operations done if the test was
  * successfully passed, and other negative error codes in case of other errors.
  */
-static int torture_peb(const struct ubi_device *ubi, int pnum)
+static int torture_peb(struct ubi_device *ubi, int pnum)
 {
-	void *buf;
 	int err, i, patt_count;
 
-	buf = vmalloc(ubi->peb_size);
-	if (!buf)
-		return -ENOMEM;
-
 	patt_count = ARRAY_SIZE(patterns);
 	ubi_assert(patt_count > 0);
 
+	mutex_lock(&ubi->buf_mutex);
 	for (i = 0; i < patt_count; i++) {
 		err = do_sync_erase(ubi, pnum);
 		if (err)
 			goto out;
 
 		/* Make sure the PEB contains only 0xFF bytes */
-		err = ubi_io_read(ubi, buf, pnum, 0, ubi->peb_size);
+		err = ubi_io_read(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
 		if (err)
 			goto out;
 
-		err = check_pattern(buf, 0xFF, ubi->peb_size);
+		err = check_pattern(ubi->peb_buf1, 0xFF, ubi->peb_size);
 		if (err == 0) {
 			ubi_err("erased PEB %d, but a non-0xFF byte found",
 				pnum);
@@ -408,17 +404,17 @@
 		}
 
 		/* Write a pattern and check it */
-		memset(buf, patterns[i], ubi->peb_size);
-		err = ubi_io_write(ubi, buf, pnum, 0, ubi->peb_size);
+		memset(ubi->peb_buf1, patterns[i], ubi->peb_size);
+		err = ubi_io_write(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
 		if (err)
 			goto out;
 
-		memset(buf, ~patterns[i], ubi->peb_size);
-		err = ubi_io_read(ubi, buf, pnum, 0, ubi->peb_size);
+		memset(ubi->peb_buf1, ~patterns[i], ubi->peb_size);
+		err = ubi_io_read(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
 		if (err)
 			goto out;
 
-		err = check_pattern(buf, patterns[i], ubi->peb_size);
+		err = check_pattern(ubi->peb_buf1, patterns[i], ubi->peb_size);
 		if (err == 0) {
 			ubi_err("pattern %x checking failed for PEB %d",
 				patterns[i], pnum);
@@ -430,14 +426,17 @@
 	err = patt_count;
 
 out:
-	if (err == UBI_IO_BITFLIPS || err == -EBADMSG)
+	mutex_unlock(&ubi->buf_mutex);
+	if (err == UBI_IO_BITFLIPS || err == -EBADMSG) {
 		/*
 		 * If a bit-flip or data integrity error was detected, the test
 		 * has not passed because it happened on a freshly erased
 		 * physical eraseblock which means something is wrong with it.
 		 */
+		ubi_err("read problems on freshly erased PEB %d, must be bad",
+			pnum);
 		err = -EIO;
-	vfree(buf);
+	}
 	return err;
 }
 
@@ -457,7 +456,7 @@
  * codes in case of other errors. Note, %-EIO means that the physical
  * eraseblock is bad.
  */
-int ubi_io_sync_erase(const struct ubi_device *ubi, int pnum, int torture)
+int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture)
 {
 	int err, ret = 0;
 
@@ -614,7 +613,7 @@
  * o %UBI_IO_PEB_EMPTY if the physical eraseblock is empty;
  * o a negative error code in case of failure.
  */
-int ubi_io_read_ec_hdr(const struct ubi_device *ubi, int pnum,
+int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 		       struct ubi_ec_hdr *ec_hdr, int verbose)
 {
 	int err, read_err = 0;
@@ -720,7 +719,7 @@
  * case of failure. If %-EIO is returned, the physical eraseblock most probably
  * went bad.
  */
-int ubi_io_write_ec_hdr(const struct ubi_device *ubi, int pnum,
+int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
 			struct ubi_ec_hdr *ec_hdr)
 {
 	int err;
@@ -886,7 +885,7 @@
  *   header there);
  * o a negative error code in case of failure.
  */
-int ubi_io_read_vid_hdr(const struct ubi_device *ubi, int pnum,
+int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 			struct ubi_vid_hdr *vid_hdr, int verbose)
 {
 	int err, read_err = 0;
@@ -993,7 +992,7 @@
  * case of failure. If %-EIO is returned, the physical eraseblock probably went
  * bad.
  */
-int ubi_io_write_vid_hdr(const struct ubi_device *ubi, int pnum,
+int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
 			 struct ubi_vid_hdr *vid_hdr)
 {
 	int err;
@@ -1096,7 +1095,7 @@
 	uint32_t crc, hdr_crc;
 	struct ubi_ec_hdr *ec_hdr;
 
-	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
+	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
 	if (!ec_hdr)
 		return -ENOMEM;
 
@@ -1176,7 +1175,7 @@
 	struct ubi_vid_hdr *vid_hdr;
 	void *p;
 
-	vid_hdr = ubi_zalloc_vid_hdr(ubi);
+	vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
 	if (!vid_hdr)
 		return -ENOMEM;
 
@@ -1216,44 +1215,40 @@
  * @offset of the physical eraseblock @pnum, %1 if not, and a negative error
  * code if an error occurred.
  */
-static int paranoid_check_all_ff(const struct ubi_device *ubi, int pnum,
-				 int offset, int len)
+static int paranoid_check_all_ff(struct ubi_device *ubi, int pnum, int offset,
+				 int len)
 {
 	size_t read;
 	int err;
-	void *buf;
 	loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
 
-	buf = vmalloc(len);
-	if (!buf)
-		return -ENOMEM;
-	memset(buf, 0, len);
-
-	err = ubi->mtd->read(ubi->mtd, addr, len, &read, buf);
+	mutex_lock(&ubi->dbg_buf_mutex);
+	err = ubi->mtd->read(ubi->mtd, addr, len, &read, ubi->dbg_peb_buf);
 	if (err && err != -EUCLEAN) {
 		ubi_err("error %d while reading %d bytes from PEB %d:%d, "
 			"read %zd bytes", err, len, pnum, offset, read);
 		goto error;
 	}
 
-	err = check_pattern(buf, 0xFF, len);
+	err = check_pattern(ubi->dbg_peb_buf, 0xFF, len);
 	if (err == 0) {
 		ubi_err("flash region at PEB %d:%d, length %d does not "
 			"contain all 0xFF bytes", pnum, offset, len);
 		goto fail;
 	}
+	mutex_unlock(&ubi->dbg_buf_mutex);
 
-	vfree(buf);
 	return 0;
 
 fail:
 	ubi_err("paranoid check failed for PEB %d", pnum);
 	dbg_msg("hex dump of the %d-%d region", offset, offset + len);
-	ubi_dbg_hexdump(buf, len);
+	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
+		       ubi->dbg_peb_buf, len, 1);
 	err = 1;
 error:
 	ubi_dbg_dump_stack();
-	vfree(buf);
+	mutex_unlock(&ubi->dbg_buf_mutex);
 	return err;
 }
 
diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c
index 4a458e8..03c774f 100644
--- a/drivers/mtd/ubi/kapi.c
+++ b/drivers/mtd/ubi/kapi.c
@@ -99,16 +99,21 @@
 {
 	int err;
 	struct ubi_volume_desc *desc;
-	struct ubi_device *ubi = ubi_devices[ubi_num];
+	struct ubi_device *ubi;
 	struct ubi_volume *vol;
 
 	dbg_msg("open device %d volume %d, mode %d", ubi_num, vol_id, mode);
 
 	err = -ENODEV;
+	if (ubi_num < 0)
+		return ERR_PTR(err);
+
+	ubi = ubi_devices[ubi_num];
+
 	if (!try_module_get(THIS_MODULE))
 		return ERR_PTR(err);
 
-	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES || !ubi)
+	if (ubi_num >= UBI_MAX_DEVICES || !ubi)
 		goto out_put;
 
 	err = -EINVAL;
diff --git a/drivers/mtd/ubi/scan.c b/drivers/mtd/ubi/scan.c
index 29c41ee..c7b0afc 100644
--- a/drivers/mtd/ubi/scan.c
+++ b/drivers/mtd/ubi/scan.c
@@ -45,8 +45,7 @@
 #include "ubi.h"
 
 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
-static int paranoid_check_si(const struct ubi_device *ubi,
-			     struct ubi_scan_info *si);
+static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si);
 #else
 #define paranoid_check_si(ubi, si) 0
 #endif
@@ -259,14 +258,13 @@
  *     o bit 2 is cleared: the older LEB is not corrupted;
  *     o bit 2 is set: the older LEB is corrupted.
  */
-static int compare_lebs(const struct ubi_device *ubi,
-			const struct ubi_scan_leb *seb, int pnum,
-			const struct ubi_vid_hdr *vid_hdr)
+static int compare_lebs(struct ubi_device *ubi, const struct ubi_scan_leb *seb,
+			int pnum, const struct ubi_vid_hdr *vid_hdr)
 {
 	void *buf;
 	int len, err, second_is_newer, bitflips = 0, corrupted = 0;
 	uint32_t data_crc, crc;
-	struct ubi_vid_hdr *vidh = NULL;
+	struct ubi_vid_hdr *vh = NULL;
 	unsigned long long sqnum2 = be64_to_cpu(vid_hdr->sqnum);
 
 	if (seb->sqnum == 0 && sqnum2 == 0) {
@@ -323,11 +321,11 @@
 	} else {
 		pnum = seb->pnum;
 
-		vidh = ubi_zalloc_vid_hdr(ubi);
-		if (!vidh)
+		vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
+		if (!vh)
 			return -ENOMEM;
 
-		err = ubi_io_read_vid_hdr(ubi, pnum, vidh, 0);
+		err = ubi_io_read_vid_hdr(ubi, pnum, vh, 0);
 		if (err) {
 			if (err == UBI_IO_BITFLIPS)
 				bitflips = 1;
@@ -341,7 +339,7 @@
 			}
 		}
 
-		if (!vidh->copy_flag) {
+		if (!vh->copy_flag) {
 			/* It is not a copy, so it is newer */
 			dbg_bld("first PEB %d is newer, copy_flag is unset",
 				pnum);
@@ -349,7 +347,7 @@
 			goto out_free_vidh;
 		}
 
-		vid_hdr = vidh;
+		vid_hdr = vh;
 	}
 
 	/* Read the data of the copy and check the CRC */
@@ -379,7 +377,7 @@
 	}
 
 	vfree(buf);
-	ubi_free_vid_hdr(ubi, vidh);
+	ubi_free_vid_hdr(ubi, vh);
 
 	if (second_is_newer)
 		dbg_bld("second PEB %d is newer, copy_flag is set", pnum);
@@ -391,7 +389,7 @@
 out_free_buf:
 	vfree(buf);
 out_free_vidh:
-	ubi_free_vid_hdr(ubi, vidh);
+	ubi_free_vid_hdr(ubi, vh);
 	ubi_assert(err < 0);
 	return err;
 }
@@ -413,7 +411,7 @@
  * to be picked, while the older one has to be dropped. This function returns
  * zero in case of success and a negative error code in case of failure.
  */
-int ubi_scan_add_used(const struct ubi_device *ubi, struct ubi_scan_info *si,
+int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
 		      int pnum, int ec, const struct ubi_vid_hdr *vid_hdr,
 		      int bitflips)
 {
@@ -667,16 +665,12 @@
  * function returns zero in case of success and a negative error code in case
  * of failure.
  */
-int ubi_scan_erase_peb(const struct ubi_device *ubi,
-		       const struct ubi_scan_info *si, int pnum, int ec)
+int ubi_scan_erase_peb(struct ubi_device *ubi, const struct ubi_scan_info *si,
+		       int pnum, int ec)
 {
 	int err;
 	struct ubi_ec_hdr *ec_hdr;
 
-	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
-	if (!ec_hdr)
-		return -ENOMEM;
-
 	if ((long long)ec >= UBI_MAX_ERASECOUNTER) {
 		/*
 		 * Erase counter overflow. Upgrade UBI and use 64-bit
@@ -686,6 +680,10 @@
 		return -EINVAL;
 	}
 
+	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
+	if (!ec_hdr)
+		return -ENOMEM;
+
 	ec_hdr->ec = cpu_to_be64(ec);
 
 	err = ubi_io_sync_erase(ubi, pnum, 0);
@@ -712,7 +710,7 @@
  * This function returns scanning physical eraseblock information in case of
  * success and an error code in case of failure.
  */
-struct ubi_scan_leb *ubi_scan_get_free_peb(const struct ubi_device *ubi,
+struct ubi_scan_leb *ubi_scan_get_free_peb(struct ubi_device *ubi,
 					   struct ubi_scan_info *si)
 {
 	int err = 0, i;
@@ -948,7 +946,7 @@
 	if (!ech)
 		goto out_si;
 
-	vidh = ubi_zalloc_vid_hdr(ubi);
+	vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
 	if (!vidh)
 		goto out_ech;
 
@@ -1110,8 +1108,7 @@
  * This function returns zero if the scanning information is all right, %1 if
  * not and a negative error code if an error occurred.
  */
-static int paranoid_check_si(const struct ubi_device *ubi,
-			     struct ubi_scan_info *si)
+static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si)
 {
 	int pnum, err, vols_found = 0;
 	struct rb_node *rb1, *rb2;
diff --git a/drivers/mtd/ubi/scan.h b/drivers/mtd/ubi/scan.h
index 140e82e..46d444a 100644
--- a/drivers/mtd/ubi/scan.h
+++ b/drivers/mtd/ubi/scan.h
@@ -147,7 +147,7 @@
 		list_add_tail(&seb->u.list, list);
 }
 
-int ubi_scan_add_used(const struct ubi_device *ubi, struct ubi_scan_info *si,
+int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
 		      int pnum, int ec, const struct ubi_vid_hdr *vid_hdr,
 		      int bitflips);
 struct ubi_scan_volume *ubi_scan_find_sv(const struct ubi_scan_info *si,
@@ -155,10 +155,10 @@
 struct ubi_scan_leb *ubi_scan_find_seb(const struct ubi_scan_volume *sv,
 				       int lnum);
 void ubi_scan_rm_volume(struct ubi_scan_info *si, struct ubi_scan_volume *sv);
-struct ubi_scan_leb *ubi_scan_get_free_peb(const struct ubi_device *ubi,
+struct ubi_scan_leb *ubi_scan_get_free_peb(struct ubi_device *ubi,
 					   struct ubi_scan_info *si);
-int ubi_scan_erase_peb(const struct ubi_device *ubi,
-		       const struct ubi_scan_info *si, int pnum, int ec);
+int ubi_scan_erase_peb(struct ubi_device *ubi, const struct ubi_scan_info *si,
+		       int pnum, int ec);
 struct ubi_scan_info *ubi_scan(struct ubi_device *ubi);
 void ubi_scan_destroy_si(struct ubi_scan_info *si);
 
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 5959f91..5e941a6 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -221,14 +221,15 @@
  * @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
+ * @vtbl_mutex: protects on-flash volume table
  *
  * @max_ec: current highest erase counter value
  * @mean_ec: current mean erase counter value
  *
- * global_sqnum: global sequence number
+ * @global_sqnum: global sequence number
  * @ltree_lock: protects the lock tree and @global_sqnum
  * @ltree: the lock tree
- * @vtbl_mutex: protects on-flash volume table
+ * @alc_mutex: serializes "atomic LEB change" operations
  *
  * @used: RB-tree of used physical eraseblocks
  * @free: RB-tree of free physical eraseblocks
@@ -274,6 +275,12 @@
  * @bad_allowed: whether the MTD device admits of bad physical eraseblocks or
  * not
  * @mtd: MTD device descriptor
+ *
+ * @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
+ * @dbg_peb_buf:  buffer of PEB size used for debugging
+ * @dbg_buf_mutex: proptects @dbg_peb_buf
  */
 struct ubi_device {
 	struct cdev cdev;
@@ -302,6 +309,7 @@
 	unsigned long long global_sqnum;
 	spinlock_t ltree_lock;
 	struct rb_root ltree;
+	struct mutex alc_mutex;
 
 	/* Wear-leveling unit's stuff */
 	struct rb_root used;
@@ -343,6 +351,14 @@
 	int vid_hdr_shift;
 	int bad_allowed;
 	struct mtd_info *mtd;
+
+	void *peb_buf1;
+	void *peb_buf2;
+	struct mutex buf_mutex;
+#ifdef CONFIG_MTD_UBI_DEBUG
+	void *dbg_peb_buf;
+	struct mutex dbg_buf_mutex;
+#endif
 };
 
 extern struct file_operations ubi_cdev_operations;
@@ -409,18 +425,18 @@
 /* io.c */
 int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
 		int len);
-int ubi_io_write(const struct ubi_device *ubi, const void *buf, int pnum,
-		 int offset, int len);
-int ubi_io_sync_erase(const struct ubi_device *ubi, int pnum, int torture);
+int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
+		 int len);
+int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture);
 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum);
 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum);
-int ubi_io_read_ec_hdr(const struct ubi_device *ubi, int pnum,
+int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 		       struct ubi_ec_hdr *ec_hdr, int verbose);
-int ubi_io_write_ec_hdr(const struct ubi_device *ubi, int pnum,
+int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
 			struct ubi_ec_hdr *ec_hdr);
-int ubi_io_read_vid_hdr(const struct ubi_device *ubi, int pnum,
+int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 			struct ubi_vid_hdr *vid_hdr, int verbose);
-int ubi_io_write_vid_hdr(const struct ubi_device *ubi, int pnum,
+int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
 			 struct ubi_vid_hdr *vid_hdr);
 
 /*
@@ -439,16 +455,18 @@
 /**
  * ubi_zalloc_vid_hdr - allocate a volume identifier header object.
  * @ubi: UBI device description object
+ * @gfp_flags: GFP flags to allocate with
  *
  * This function returns a pointer to the newly allocated and zero-filled
  * volume identifier header object in case of success and %NULL in case of
  * failure.
  */
-static inline struct ubi_vid_hdr *ubi_zalloc_vid_hdr(const struct ubi_device *ubi)
+static inline struct ubi_vid_hdr *
+ubi_zalloc_vid_hdr(const struct ubi_device *ubi, gfp_t gfp_flags)
 {
 	void *vid_hdr;
 
-	vid_hdr = kzalloc(ubi->vid_hdr_alsize, GFP_KERNEL);
+	vid_hdr = kzalloc(ubi->vid_hdr_alsize, gfp_flags);
 	if (!vid_hdr)
 		return NULL;
 
@@ -492,7 +510,7 @@
  * the beginning of the logical eraseblock, not to the beginning of the
  * physical eraseblock.
  */
-static inline int ubi_io_write_data(const struct ubi_device *ubi, const void *buf,
+static inline int ubi_io_write_data(struct ubi_device *ubi, const void *buf,
 				    int pnum, int offset, int len)
 {
 	ubi_assert(offset >= 0);
diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
index ea0d5c8..88629a3 100644
--- a/drivers/mtd/ubi/vmt.c
+++ b/drivers/mtd/ubi/vmt.c
@@ -37,21 +37,21 @@
 				  struct device_attribute *attr, char *buf);
 
 /* Device attributes corresponding to files in '/<sysfs>/class/ubi/ubiX_Y' */
-static struct device_attribute vol_reserved_ebs =
+static struct device_attribute attr_vol_reserved_ebs =
 	__ATTR(reserved_ebs, S_IRUGO, vol_attribute_show, NULL);
-static struct device_attribute vol_type =
+static struct device_attribute attr_vol_type =
 	__ATTR(type, S_IRUGO, vol_attribute_show, NULL);
-static struct device_attribute vol_name =
+static struct device_attribute attr_vol_name =
 	__ATTR(name, S_IRUGO, vol_attribute_show, NULL);
-static struct device_attribute vol_corrupted =
+static struct device_attribute attr_vol_corrupted =
 	__ATTR(corrupted, S_IRUGO, vol_attribute_show, NULL);
-static struct device_attribute vol_alignment =
+static struct device_attribute attr_vol_alignment =
 	__ATTR(alignment, S_IRUGO, vol_attribute_show, NULL);
-static struct device_attribute vol_usable_eb_size =
+static struct device_attribute attr_vol_usable_eb_size =
 	__ATTR(usable_eb_size, S_IRUGO, vol_attribute_show, NULL);
-static struct device_attribute vol_data_bytes =
+static struct device_attribute attr_vol_data_bytes =
 	__ATTR(data_bytes, S_IRUGO, vol_attribute_show, NULL);
-static struct device_attribute vol_upd_marker =
+static struct device_attribute attr_vol_upd_marker =
 	__ATTR(upd_marker, S_IRUGO, vol_attribute_show, NULL);
 
 /*
@@ -78,23 +78,27 @@
 		spin_unlock(&vol->ubi->volumes_lock);
 		return -ENODEV;
 	}
-	if (attr == &vol_reserved_ebs)
+	if (attr == &attr_vol_reserved_ebs)
 		ret = sprintf(buf, "%d\n", vol->reserved_pebs);
-	else if (attr == &vol_type) {
+	else if (attr == &attr_vol_type) {
 		const char *tp;
-		tp = vol->vol_type == UBI_DYNAMIC_VOLUME ? "dynamic" : "static";
+
+		if (vol->vol_type == UBI_DYNAMIC_VOLUME)
+			tp = "dynamic";
+		else
+			tp = "static";
 		ret = sprintf(buf, "%s\n", tp);
-	} else if (attr == &vol_name)
+	} else if (attr == &attr_vol_name)
 		ret = sprintf(buf, "%s\n", vol->name);
-	else if (attr == &vol_corrupted)
+	else if (attr == &attr_vol_corrupted)
 		ret = sprintf(buf, "%d\n", vol->corrupted);
-	else if (attr == &vol_alignment)
+	else if (attr == &attr_vol_alignment)
 		ret = sprintf(buf, "%d\n", vol->alignment);
-	else if (attr == &vol_usable_eb_size) {
+	else if (attr == &attr_vol_usable_eb_size) {
 		ret = sprintf(buf, "%d\n", vol->usable_leb_size);
-	} else if (attr == &vol_data_bytes)
+	} else if (attr == &attr_vol_data_bytes)
 		ret = sprintf(buf, "%lld\n", vol->used_bytes);
-	else if (attr == &vol_upd_marker)
+	else if (attr == &attr_vol_upd_marker)
 		ret = sprintf(buf, "%d\n", vol->upd_marker);
 	else
 		BUG();
@@ -126,28 +130,28 @@
 {
 	int err;
 
-	err = device_create_file(&vol->dev, &vol_reserved_ebs);
+	err = device_create_file(&vol->dev, &attr_vol_reserved_ebs);
 	if (err)
 		return err;
-	err = device_create_file(&vol->dev, &vol_type);
+	err = device_create_file(&vol->dev, &attr_vol_type);
 	if (err)
 		return err;
-	err = device_create_file(&vol->dev, &vol_name);
+	err = device_create_file(&vol->dev, &attr_vol_name);
 	if (err)
 		return err;
-	err = device_create_file(&vol->dev, &vol_corrupted);
+	err = device_create_file(&vol->dev, &attr_vol_corrupted);
 	if (err)
 		return err;
-	err = device_create_file(&vol->dev, &vol_alignment);
+	err = device_create_file(&vol->dev, &attr_vol_alignment);
 	if (err)
 		return err;
-	err = device_create_file(&vol->dev, &vol_usable_eb_size);
+	err = device_create_file(&vol->dev, &attr_vol_usable_eb_size);
 	if (err)
 		return err;
-	err = device_create_file(&vol->dev, &vol_data_bytes);
+	err = device_create_file(&vol->dev, &attr_vol_data_bytes);
 	if (err)
 		return err;
-	err = device_create_file(&vol->dev, &vol_upd_marker);
+	err = device_create_file(&vol->dev, &attr_vol_upd_marker);
 	if (err)
 		return err;
 	return 0;
@@ -159,14 +163,14 @@
  */
 static void volume_sysfs_close(struct ubi_volume *vol)
 {
-	device_remove_file(&vol->dev, &vol_upd_marker);
-	device_remove_file(&vol->dev, &vol_data_bytes);
-	device_remove_file(&vol->dev, &vol_usable_eb_size);
-	device_remove_file(&vol->dev, &vol_alignment);
-	device_remove_file(&vol->dev, &vol_corrupted);
-	device_remove_file(&vol->dev, &vol_name);
-	device_remove_file(&vol->dev, &vol_type);
-	device_remove_file(&vol->dev, &vol_reserved_ebs);
+	device_remove_file(&vol->dev, &attr_vol_upd_marker);
+	device_remove_file(&vol->dev, &attr_vol_data_bytes);
+	device_remove_file(&vol->dev, &attr_vol_usable_eb_size);
+	device_remove_file(&vol->dev, &attr_vol_alignment);
+	device_remove_file(&vol->dev, &attr_vol_corrupted);
+	device_remove_file(&vol->dev, &attr_vol_name);
+	device_remove_file(&vol->dev, &attr_vol_type);
+	device_remove_file(&vol->dev, &attr_vol_reserved_ebs);
 	device_unregister(&vol->dev);
 }
 
diff --git a/drivers/mtd/ubi/vtbl.c b/drivers/mtd/ubi/vtbl.c
index bc5df50..25b3bd6 100644
--- a/drivers/mtd/ubi/vtbl.c
+++ b/drivers/mtd/ubi/vtbl.c
@@ -254,7 +254,7 @@
  * This function returns zero in case of success and a negative error code in
  * case of failure.
  */
-static int create_vtbl(const struct ubi_device *ubi, struct ubi_scan_info *si,
+static int create_vtbl(struct ubi_device *ubi, struct ubi_scan_info *si,
 		       int copy, void *vtbl)
 {
 	int err, tries = 0;
@@ -264,7 +264,7 @@
 
 	ubi_msg("create volume table (copy #%d)", copy + 1);
 
-	vid_hdr = ubi_zalloc_vid_hdr(ubi);
+	vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
 	if (!vid_hdr)
 		return -ENOMEM;
 
@@ -339,7 +339,7 @@
  * not corrupted, and recovering from corruptions if needed. Returns volume
  * table in case of success and a negative error code in case of failure.
  */
-static struct ubi_vtbl_record *process_lvol(const struct ubi_device *ubi,
+static struct ubi_vtbl_record *process_lvol(struct ubi_device *ubi,
 					    struct ubi_scan_info *si,
 					    struct ubi_scan_volume *sv)
 {
@@ -453,7 +453,7 @@
  * This function returns volume table contents in case of success and a
  * negative error code in case of failure.
  */
-static struct ubi_vtbl_record *create_empty_lvol(const struct ubi_device *ubi,
+static struct ubi_vtbl_record *create_empty_lvol(struct ubi_device *ubi,
 						 struct ubi_scan_info *si)
 {
 	int i;
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index a5a9b8d..a4f1bf3 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -208,7 +208,7 @@
 };
 
 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
-static int paranoid_check_ec(const struct ubi_device *ubi, int pnum, int ec);
+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);
 #else
@@ -220,17 +220,6 @@
 static struct kmem_cache *wl_entries_slab;
 
 /**
- * tree_empty - a helper function to check if an RB-tree is empty.
- * @root: the root of the tree
- *
- * This function returns non-zero if the RB-tree is empty and zero if not.
- */
-static inline int tree_empty(struct rb_root *root)
-{
-	return root->rb_node == NULL;
-}
-
-/**
  * wl_tree_add - add a wear-leveling entry to a WL RB-tree.
  * @e: the wear-leveling entry to add
  * @root: the root of the tree
@@ -266,45 +255,6 @@
 	rb_insert_color(&e->rb, root);
 }
 
-
-/*
- * Helper functions to add and delete wear-leveling entries from different
- * trees.
- */
-
-static void free_tree_add(struct ubi_device *ubi, struct ubi_wl_entry *e)
-{
-	wl_tree_add(e, &ubi->free);
-}
-static inline void used_tree_add(struct ubi_device *ubi,
-				 struct ubi_wl_entry *e)
-{
-	wl_tree_add(e, &ubi->used);
-}
-static inline void scrub_tree_add(struct ubi_device *ubi,
-				  struct ubi_wl_entry *e)
-{
-	wl_tree_add(e, &ubi->scrub);
-}
-static inline void free_tree_del(struct ubi_device *ubi,
-				 struct ubi_wl_entry *e)
-{
-	paranoid_check_in_wl_tree(e, &ubi->free);
-	rb_erase(&e->rb, &ubi->free);
-}
-static inline void used_tree_del(struct ubi_device *ubi,
-				 struct ubi_wl_entry *e)
-{
-	paranoid_check_in_wl_tree(e, &ubi->used);
-	rb_erase(&e->rb, &ubi->used);
-}
-static inline void scrub_tree_del(struct ubi_device *ubi,
-				  struct ubi_wl_entry *e)
-{
-	paranoid_check_in_wl_tree(e, &ubi->scrub);
-	rb_erase(&e->rb, &ubi->scrub);
-}
-
 /**
  * do_work - do one pending work.
  * @ubi: UBI device description object
@@ -358,7 +308,7 @@
 	int err;
 
 	spin_lock(&ubi->wl_lock);
-	while (tree_empty(&ubi->free)) {
+	while (!ubi->free.rb_node) {
 		spin_unlock(&ubi->wl_lock);
 
 		dbg_wl("do one work synchronously");
@@ -508,13 +458,13 @@
 	ubi_assert(dtype == UBI_LONGTERM || dtype == UBI_SHORTTERM ||
 		   dtype == UBI_UNKNOWN);
 
-	pe = kmalloc(sizeof(struct ubi_wl_prot_entry), GFP_KERNEL);
+	pe = kmalloc(sizeof(struct ubi_wl_prot_entry), GFP_NOFS);
 	if (!pe)
 		return -ENOMEM;
 
 retry:
 	spin_lock(&ubi->wl_lock);
-	if (tree_empty(&ubi->free)) {
+	if (!ubi->free.rb_node) {
 		if (ubi->works_count == 0) {
 			ubi_assert(list_empty(&ubi->works));
 			ubi_err("no free eraseblocks");
@@ -585,7 +535,8 @@
 	 * Move the physical eraseblock to the protection trees where it will
 	 * be protected from being moved for some time.
 	 */
-	free_tree_del(ubi, e);
+	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);
@@ -645,7 +596,7 @@
 	if (err > 0)
 		return -EINVAL;
 
-	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
+	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
 	if (!ec_hdr)
 		return -ENOMEM;
 
@@ -704,7 +655,7 @@
 	 */
 	while (1) {
 		spin_lock(&ubi->wl_lock);
-		if (tree_empty(&ubi->prot.aec)) {
+		if (!ubi->prot.aec.rb_node) {
 			spin_unlock(&ubi->wl_lock);
 			break;
 		}
@@ -721,7 +672,7 @@
 		       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);
-		used_tree_add(ubi, pe->e);
+		wl_tree_add(pe->e, &ubi->used);
 		spin_unlock(&ubi->wl_lock);
 
 		kfree(pe);
@@ -768,7 +719,7 @@
 	dbg_wl("schedule erasure of PEB %d, EC %d, torture %d",
 	       e->pnum, e->ec, torture);
 
-	wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_KERNEL);
+	wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
 	if (!wl_wrk)
 		return -ENOMEM;
 
@@ -802,7 +753,7 @@
 	if (cancel)
 		return 0;
 
-	vid_hdr = ubi_zalloc_vid_hdr(ubi);
+	vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
 	if (!vid_hdr)
 		return -ENOMEM;
 
@@ -812,8 +763,8 @@
 	 * Only one WL worker at a time is supported at this implementation, so
 	 * make sure a PEB is not being moved already.
 	 */
-	if (ubi->move_to || tree_empty(&ubi->free) ||
-	    (tree_empty(&ubi->used) && tree_empty(&ubi->scrub))) {
+	if (ubi->move_to || !ubi->free.rb_node ||
+	    (!ubi->used.rb_node && !ubi->scrub.rb_node)) {
 		/*
 		 * Only one WL worker at a time is supported at this
 		 * implementation, so if a LEB is already being moved, cancel.
@@ -828,14 +779,14 @@
 		 * triggered again.
 		 */
 		dbg_wl("cancel WL, a list is empty: free %d, used %d",
-		       tree_empty(&ubi->free), tree_empty(&ubi->used));
+		       !ubi->free.rb_node, !ubi->used.rb_node);
 		ubi->wl_scheduled = 0;
 		spin_unlock(&ubi->wl_lock);
 		ubi_free_vid_hdr(ubi, vid_hdr);
 		return 0;
 	}
 
-	if (tree_empty(&ubi->scrub)) {
+	if (!ubi->scrub.rb_node) {
 		/*
 		 * Now pick the least worn-out used physical eraseblock and a
 		 * highly worn-out free physical eraseblock. If the erase
@@ -852,17 +803,20 @@
 			ubi_free_vid_hdr(ubi, vid_hdr);
 			return 0;
 		}
-		used_tree_del(ubi, e1);
+		paranoid_check_in_wl_tree(e1, &ubi->used);
+		rb_erase(&e1->rb, &ubi->used);
 		dbg_wl("move PEB %d EC %d to PEB %d EC %d",
 		       e1->pnum, e1->ec, e2->pnum, e2->ec);
 	} else {
 		e1 = rb_entry(rb_first(&ubi->scrub), struct ubi_wl_entry, rb);
 		e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
-		scrub_tree_del(ubi, e1);
+		paranoid_check_in_wl_tree(e1, &ubi->scrub);
+	rb_erase(&e1->rb, &ubi->scrub);
 		dbg_wl("scrub PEB %d to PEB %d", e1->pnum, e2->pnum);
 	}
 
-	free_tree_del(ubi, e2);
+	paranoid_check_in_wl_tree(e2, &ubi->free);
+	rb_erase(&e2->rb, &ubi->free);
 	ubi_assert(!ubi->move_from && !ubi->move_to);
 	ubi_assert(!ubi->move_to_put && !ubi->move_from_put);
 	ubi->move_from = e1;
@@ -908,7 +862,7 @@
 	ubi_free_vid_hdr(ubi, vid_hdr);
 	spin_lock(&ubi->wl_lock);
 	if (!ubi->move_to_put)
-		used_tree_add(ubi, e2);
+		wl_tree_add(e2, &ubi->used);
 	else
 		put = 1;
 	ubi->move_from = ubi->move_to = NULL;
@@ -953,7 +907,7 @@
 	if (ubi->move_from_put)
 		put = 1;
 	else
-		used_tree_add(ubi, e1);
+		wl_tree_add(e1, &ubi->used);
 	ubi->move_from = ubi->move_to = NULL;
 	ubi->move_from_put = ubi->move_to_put = 0;
 	spin_unlock(&ubi->wl_lock);
@@ -1005,8 +959,8 @@
 	 * If the ubi->scrub tree is not empty, scrubbing is needed, and the
 	 * the WL worker has to be scheduled anyway.
 	 */
-	if (tree_empty(&ubi->scrub)) {
-		if (tree_empty(&ubi->used) || tree_empty(&ubi->free))
+	if (!ubi->scrub.rb_node) {
+		if (!ubi->used.rb_node || !ubi->free.rb_node)
 			/* No physical eraseblocks - no deal */
 			goto out_unlock;
 
@@ -1028,7 +982,7 @@
 	ubi->wl_scheduled = 1;
 	spin_unlock(&ubi->wl_lock);
 
-	wrk = kmalloc(sizeof(struct ubi_work), GFP_KERNEL);
+	wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
 	if (!wrk) {
 		err = -ENOMEM;
 		goto out_cancel;
@@ -1079,7 +1033,7 @@
 
 		spin_lock(&ubi->wl_lock);
 		ubi->abs_ec += 1;
-		free_tree_add(ubi, e);
+		wl_tree_add(e, &ubi->free);
 		spin_unlock(&ubi->wl_lock);
 
 		/*
@@ -1093,6 +1047,7 @@
 		return err;
 	}
 
+	ubi_err("failed to erase PEB %d, error %d", pnum, err);
 	kfree(wl_wrk);
 	kmem_cache_free(wl_entries_slab, e);
 
@@ -1211,11 +1166,13 @@
 		spin_unlock(&ubi->wl_lock);
 		return 0;
 	} else {
-		if (in_wl_tree(e, &ubi->used))
-			used_tree_del(ubi, e);
-		else if (in_wl_tree(e, &ubi->scrub))
-			scrub_tree_del(ubi, e);
-		else
+		if (in_wl_tree(e, &ubi->used)) {
+			paranoid_check_in_wl_tree(e, &ubi->used);
+			rb_erase(&e->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);
+		} else
 			prot_tree_del(ubi, e->pnum);
 	}
 	spin_unlock(&ubi->wl_lock);
@@ -1223,7 +1180,7 @@
 	err = schedule_erase(ubi, e, torture);
 	if (err) {
 		spin_lock(&ubi->wl_lock);
-		used_tree_add(ubi, e);
+		wl_tree_add(e, &ubi->used);
 		spin_unlock(&ubi->wl_lock);
 	}
 
@@ -1267,12 +1224,13 @@
 		goto retry;
 	}
 
-	if (in_wl_tree(e, &ubi->used))
-		used_tree_del(ubi, e);
-	else
+	if (in_wl_tree(e, &ubi->used)) {
+		paranoid_check_in_wl_tree(e, &ubi->used);
+		rb_erase(&e->rb, &ubi->used);
+	} else
 		prot_tree_del(ubi, pnum);
 
-	scrub_tree_add(ubi, e);
+	wl_tree_add(e, &ubi->scrub);
 	spin_unlock(&ubi->wl_lock);
 
 	/*
@@ -1488,7 +1446,7 @@
 		e->pnum = seb->pnum;
 		e->ec = seb->ec;
 		ubi_assert(e->ec >= 0);
-		free_tree_add(ubi, e);
+		wl_tree_add(e, &ubi->free);
 		ubi->lookuptbl[e->pnum] = e;
 	}
 
@@ -1522,16 +1480,16 @@
 			if (!seb->scrub) {
 				dbg_wl("add PEB %d EC %d to the used tree",
 				       e->pnum, e->ec);
-				used_tree_add(ubi, e);
+				wl_tree_add(e, &ubi->used);
 			} else {
 				dbg_wl("add PEB %d EC %d to the scrub tree",
 				       e->pnum, e->ec);
-				scrub_tree_add(ubi, e);
+				wl_tree_add(e, &ubi->scrub);
 			}
 		}
 	}
 
-	if (WL_RESERVED_PEBS > ubi->avail_pebs) {
+	if (ubi->avail_pebs < WL_RESERVED_PEBS) {
 		ubi_err("no enough physical eraseblocks (%d, need %d)",
 			ubi->avail_pebs, WL_RESERVED_PEBS);
 		goto out_free;
@@ -1624,13 +1582,13 @@
  * is equivalent to @ec, %1 if not, and a negative error code if an error
  * occurred.
  */
-static int paranoid_check_ec(const struct ubi_device *ubi, int pnum, int ec)
+static int paranoid_check_ec(struct ubi_device *ubi, int pnum, int ec)
 {
 	int err;
 	long long read_ec;
 	struct ubi_ec_hdr *ec_hdr;
 
-	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
+	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
 	if (!ec_hdr)
 		return -ENOMEM;