[PATCH v3 0/4] mtd: Preparation patches for the SPI NAND framework

[PATCH v3 0/4] mtd: Preparation patches for the SPI NAND framework

[Boris Brezillon]

Hello,

Here is a set of patches to prepare the introduction of the generic
NAND and SPI frameworks.

The last 2 patches have already been submitted here [1], and the first
two are new, and should also help simplify other drivers/frameworks
in providing generic code for already existing logic.

If you want to see the overall picture of the SPI NAND framework you can
have a look at this branch [2].

Regards,

Boris

[1]https://patchwork.ozlabs.org/patch/780477/
[2]https://github.com/bbrezillon/linux-0day/commits/nand/spi-nand-squashed

Boris Brezillon (4):
  mtd: Do not allow MTD devices with inconsistent erase properties
  mtd: Add an helper to make erase request aligned on ->erasesize
  mtd: Stop directly calling master ->_xxx() hooks from mtdpart code
  mtd: Fallback to ->_read/write_oob() when ->_read/write() is missing

 drivers/mtd/devices/docg3.c        |  65 -----------------
 drivers/mtd/mtdcore.c              |  36 +++++++++-
 drivers/mtd/mtdpart.c              | 141 ++++++++++++++-----------------------
 drivers/mtd/nand/nand_base.c       |  56 ---------------
 drivers/mtd/onenand/onenand_base.c |  63 -----------------
 include/linux/mtd/mtd.h            |  28 ++++++++
 6 files changed, 115 insertions(+), 274 deletions(-)

-- 
2.11.0

[PATCH v3 1/4] mtd: Do not allow MTD devices with inconsistent erase properties

[Boris Brezillon]

When mtd->erasesize is 0 or mtd->_erase is NULL, that means the device
does not support the erase operation, which in turn means it should
have the MTD_NO_ERASE flag set.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
---
Changes in v3:
- new patch
---
 drivers/mtd/mtdcore.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index f80e911b8843..642c35dde686 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -503,6 +503,11 @@ int add_mtd_device(struct mtd_info *mtd)
 		return -EEXIST;
 
 	BUG_ON(mtd->writesize == 0);
+
+	if (WARN_ON((!mtd->erasesize || !mtd->_erase) &&
+		    !(mtd->flags & MTD_NO_ERASE)))
+		return -EINVAL;
+
 	mutex_lock(&mtd_table_mutex);
 
 	i = idr_alloc(&mtd_idr, mtd, 0, 0, GFP_KERNEL);
-- 
2.11.0

[PATCH v3 2/4] mtd: Add an helper to make erase request aligned on ->erasesize

[Boris Brezillon]

There's currently nothing forcing alignment of einfo->addr and
einfo->len on mtd->erasesize. Since we don't know if automatically
aligning those field in mtd_erase() will hurt some drivers, we add an
helper function to let drivers that need such an alignment explicitly
ask for it.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
---
Changes in v3:
- new patch
---
 include/linux/mtd/mtd.h | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index cd55bf14ad51..205ededccc60 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -489,6 +489,34 @@ static inline uint32_t mtd_mod_by_eb(uint64_t sz, struct mtd_info *mtd)
 	return do_div(sz, mtd->erasesize);
 }
 
+/**
+ * mtd_align_erase_req - Adjust an erase request to align things on eraseblock
+ *			 boundaries.
+ * @mtd: the MTD device this erase request applies on
+ * @req: the erase request to adjust
+ *
+ * This function will adjust @req->addr and @req->len to align them on
+ * @mtd->erasesize. Of course we expect @mtd->erasesize to be != 0.
+ */
+static inline void mtd_align_erase_req(struct mtd_info *mtd,
+				       struct erase_info *req)
+{
+	u32 mod;
+
+	if (WARN_ON(!mtd->erasesize))
+		return;
+
+	mod = mtd_mod_by_eb(req->addr, mtd);
+	if (mod) {
+		req->addr -= mod;
+		req->len += mod;
+	}
+
+	mod = mtd_mod_by_eb(req->addr + req->len, mtd);
+	if (mod)
+		req->len += mtd->erasesize - mod;
+}
+
 static inline uint32_t mtd_div_by_ws(uint64_t sz, struct mtd_info *mtd)
 {
 	if (mtd->writesize_shift)
-- 
2.11.0

[PATCH v3 3/4] mtd: Stop directly calling master ->_xxx() hooks from mtdpart code

[Boris Brezillon]

The MTD layer provides several wrappers around mtd->_xxx() hooks. Call
these wrappers instead of directly dereferencing the associated ->_xxx()
pointer.

This change has been motivated by another rework letting the core
handle the case where ->_read/write_oob() are implemented but not
->_read/write(). In this case, we want mtd_read/write() to fall back to
->_read/write_oob() when ->_read/write() are NULL. The problem is,
mtdpart is directly calling the ->_xxx() instead of using the wrappers,
thus leading to a NULL pointer exception.

Even though we only need to do the change for part_read/write(), going
through those wrappers for all kind of part -> master operation
propagation is a good thing, because other wrappers might become
smarter over time, and the duplicated check overhead (parameters will
be checked at the partition and master level instead of only at the
partition level) should be negligible.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
---
Changes in v3:
- unconditionally assign part wrappers as suggested by Brian

Changes in v2:
- new patch needed to fix a NULL pointer dereference BUG
---
 drivers/mtd/mtdpart.c | 141 +++++++++++++++++++-------------------------------
 1 file changed, 53 insertions(+), 88 deletions(-)

diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index be088bccd593..e83c9d870b11 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -74,8 +74,7 @@ static int part_read(struct mtd_info *mtd, loff_t from, size_t len,
 	int res;
 
 	stats = part->parent->ecc_stats;
-	res = part->parent->_read(part->parent, from + part->offset, len,
-				  retlen, buf);
+	res = mtd_read(part->parent, from + part->offset, len, retlen, buf);
 	if (unlikely(mtd_is_eccerr(res)))
 		mtd->ecc_stats.failed +=
 			part->parent->ecc_stats.failed - stats.failed;
@@ -90,15 +89,15 @@ static int part_point(struct mtd_info *mtd, loff_t from, size_t len,
 {
 	struct mtd_part *part = mtd_to_part(mtd);
 
-	return part->parent->_point(part->parent, from + part->offset, len,
-				    retlen, virt, phys);
+	return mtd_point(part->parent, from + part->offset, len, retlen, virt,
+			 phys);
 }
 
 static int part_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
 
-	return part->parent->_unpoint(part->parent, from + part->offset, len);
+	return mtd_unpoint(part->parent, from + part->offset, len);
 }
 
 static int part_read_oob(struct mtd_info *mtd, loff_t from,
@@ -126,7 +125,7 @@ static int part_read_oob(struct mtd_info *mtd, loff_t from,
 			return -EINVAL;
 	}
 
-	res = part->parent->_read_oob(part->parent, from + part->offset, ops);
+	res = mtd_read_oob(part->parent, from + part->offset, ops);
 	if (unlikely(res)) {
 		if (mtd_is_bitflip(res))
 			mtd->ecc_stats.corrected++;
@@ -140,48 +139,43 @@ static int part_read_user_prot_reg(struct mtd_info *mtd, loff_t from,
 		size_t len, size_t *retlen, u_char *buf)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	return part->parent->_read_user_prot_reg(part->parent, from, len,
-						 retlen, buf);
+	return mtd_read_user_prot_reg(part->parent, from, len, retlen, buf);
 }
 
 static int part_get_user_prot_info(struct mtd_info *mtd, size_t len,
 				   size_t *retlen, struct otp_info *buf)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	return part->parent->_get_user_prot_info(part->parent, len, retlen,
-						 buf);
+	return mtd_get_user_prot_info(part->parent, len, retlen, buf);
 }
 
 static int part_read_fact_prot_reg(struct mtd_info *mtd, loff_t from,
 		size_t len, size_t *retlen, u_char *buf)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	return part->parent->_read_fact_prot_reg(part->parent, from, len,
-						 retlen, buf);
+	return mtd_read_fact_prot_reg(part->parent, from, len, retlen, buf);
 }
 
 static int part_get_fact_prot_info(struct mtd_info *mtd, size_t len,
 				   size_t *retlen, struct otp_info *buf)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	return part->parent->_get_fact_prot_info(part->parent, len, retlen,
-						 buf);
+	return mtd_get_fact_prot_info(part->parent, len, retlen, buf);
 }
 
 static int part_write(struct mtd_info *mtd, loff_t to, size_t len,
 		size_t *retlen, const u_char *buf)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	return part->parent->_write(part->parent, to + part->offset, len,
-				    retlen, buf);
+	return mtd_write(part->parent, to + part->offset, len, retlen, buf);
 }
 
 static int part_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
 		size_t *retlen, const u_char *buf)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	return part->parent->_panic_write(part->parent, to + part->offset, len,
-					  retlen, buf);
+	return mtd_panic_write(part->parent, to + part->offset, len, retlen,
+			       buf);
 }
 
 static int part_write_oob(struct mtd_info *mtd, loff_t to,
@@ -193,30 +187,29 @@ static int part_write_oob(struct mtd_info *mtd, loff_t to,
 		return -EINVAL;
 	if (ops->datbuf && to + ops->len > mtd->size)
 		return -EINVAL;
-	return part->parent->_write_oob(part->parent, to + part->offset, ops);
+	return mtd_write_oob(part->parent, to + part->offset, ops);
 }
 
 static int part_write_user_prot_reg(struct mtd_info *mtd, loff_t from,
 		size_t len, size_t *retlen, u_char *buf)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	return part->parent->_write_user_prot_reg(part->parent, from, len,
-						  retlen, buf);
+	return mtd_write_user_prot_reg(part->parent, from, len, retlen, buf);
 }
 
 static int part_lock_user_prot_reg(struct mtd_info *mtd, loff_t from,
 		size_t len)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	return part->parent->_lock_user_prot_reg(part->parent, from, len);
+	return mtd_lock_user_prot_reg(part->parent, from, len);
 }
 
 static int part_writev(struct mtd_info *mtd, const struct kvec *vecs,
 		unsigned long count, loff_t to, size_t *retlen)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	return part->parent->_writev(part->parent, vecs, count,
-				     to + part->offset, retlen);
+	return mtd_writev(part->parent, vecs, count, to + part->offset,
+			  retlen);
 }
 
 static int part_erase(struct mtd_info *mtd, struct erase_info *instr)
@@ -225,7 +218,7 @@ static int part_erase(struct mtd_info *mtd, struct erase_info *instr)
 	int ret;
 
 	instr->addr += part->offset;
-	ret = part->parent->_erase(part->parent, instr);
+	ret = mtd_erase(part->parent, instr);
 	if (ret) {
 		if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
 			instr->fail_addr -= part->offset;
@@ -251,51 +244,51 @@ EXPORT_SYMBOL_GPL(mtd_erase_callback);
 static int part_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	return part->parent->_lock(part->parent, ofs + part->offset, len);
+	return mtd_lock(part->parent, ofs + part->offset, len);
 }
 
 static int part_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	return part->parent->_unlock(part->parent, ofs + part->offset, len);
+	return mtd_unlock(part->parent, ofs + part->offset, len);
 }
 
 static int part_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	return part->parent->_is_locked(part->parent, ofs + part->offset, len);
+	return mtd_is_locked(part->parent, ofs + part->offset, len);
 }
 
 static void part_sync(struct mtd_info *mtd)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	part->parent->_sync(part->parent);
+	mtd_sync(part->parent);
 }
 
 static int part_suspend(struct mtd_info *mtd)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	return part->parent->_suspend(part->parent);
+	return mtd_suspend(part->parent);
 }
 
 static void part_resume(struct mtd_info *mtd)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	part->parent->_resume(part->parent);
+	mtd_resume(part->parent);
 }
 
 static int part_block_isreserved(struct mtd_info *mtd, loff_t ofs)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
 	ofs += part->offset;
-	return part->parent->_block_isreserved(part->parent, ofs);
+	return mtd_block_isreserved(part->parent, ofs);
 }
 
 static int part_block_isbad(struct mtd_info *mtd, loff_t ofs)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
 	ofs += part->offset;
-	return part->parent->_block_isbad(part->parent, ofs);
+	return mtd_block_isbad(part->parent, ofs);
 }
 
 static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
@@ -304,7 +297,7 @@ static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
 	int res;
 
 	ofs += part->offset;
-	res = part->parent->_block_markbad(part->parent, ofs);
+	res = mtd_block_markbad(part->parent, ofs);
 	if (!res)
 		mtd->ecc_stats.badblocks++;
 	return res;
@@ -313,13 +306,13 @@ static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
 static int part_get_device(struct mtd_info *mtd)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	return part->parent->_get_device(part->parent);
+	return __get_mtd_device(part->parent);
 }
 
 static void part_put_device(struct mtd_info *mtd)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
-	part->parent->_put_device(part->parent);
+	__put_mtd_device(part->parent);
 }
 
 static int part_ooblayout_ecc(struct mtd_info *mtd, int section,
@@ -347,8 +340,7 @@ static int part_max_bad_blocks(struct mtd_info *mtd, loff_t ofs, size_t len)
 {
 	struct mtd_part *part = mtd_to_part(mtd);
 
-	return part->parent->_max_bad_blocks(part->parent,
-					     ofs + part->offset, len);
+	return mtd_max_bad_blocks(part->parent, ofs + part->offset, len);
 }
 
 static inline void free_partition(struct mtd_part *p)
@@ -437,59 +429,32 @@ static struct mtd_part *allocate_partition(struct mtd_info *parent,
 
 	slave->mtd._read = part_read;
 	slave->mtd._write = part_write;
-
-	if (parent->_panic_write)
-		slave->mtd._panic_write = part_panic_write;
-
-	if (parent->_point && parent->_unpoint) {
-		slave->mtd._point = part_point;
-		slave->mtd._unpoint = part_unpoint;
-	}
-
-	if (parent->_read_oob)
-		slave->mtd._read_oob = part_read_oob;
-	if (parent->_write_oob)
-		slave->mtd._write_oob = part_write_oob;
-	if (parent->_read_user_prot_reg)
-		slave->mtd._read_user_prot_reg = part_read_user_prot_reg;
-	if (parent->_read_fact_prot_reg)
-		slave->mtd._read_fact_prot_reg = part_read_fact_prot_reg;
-	if (parent->_write_user_prot_reg)
-		slave->mtd._write_user_prot_reg = part_write_user_prot_reg;
-	if (parent->_lock_user_prot_reg)
-		slave->mtd._lock_user_prot_reg = part_lock_user_prot_reg;
-	if (parent->_get_user_prot_info)
-		slave->mtd._get_user_prot_info = part_get_user_prot_info;
-	if (parent->_get_fact_prot_info)
-		slave->mtd._get_fact_prot_info = part_get_fact_prot_info;
-	if (parent->_sync)
-		slave->mtd._sync = part_sync;
-	if (!partno && !parent->dev.class && parent->_suspend &&
-	    parent->_resume) {
+	slave->mtd._panic_write = part_panic_write;
+	slave->mtd._point = part_point;
+	slave->mtd._unpoint = part_unpoint;
+	slave->mtd._read_oob = part_read_oob;
+	slave->mtd._write_oob = part_write_oob;
+	slave->mtd._read_user_prot_reg = part_read_user_prot_reg;
+	slave->mtd._read_fact_prot_reg = part_read_fact_prot_reg;
+	slave->mtd._write_user_prot_reg = part_write_user_prot_reg;
+	slave->mtd._lock_user_prot_reg = part_lock_user_prot_reg;
+	slave->mtd._get_user_prot_info = part_get_user_prot_info;
+	slave->mtd._get_fact_prot_info = part_get_fact_prot_info;
+	slave->mtd._sync = part_sync;
+	if (!partno && !parent->dev.class) {
 		slave->mtd._suspend = part_suspend;
 		slave->mtd._resume = part_resume;
 	}
-	if (parent->_writev)
-		slave->mtd._writev = part_writev;
-	if (parent->_lock)
-		slave->mtd._lock = part_lock;
-	if (parent->_unlock)
-		slave->mtd._unlock = part_unlock;
-	if (parent->_is_locked)
-		slave->mtd._is_locked = part_is_locked;
-	if (parent->_block_isreserved)
-		slave->mtd._block_isreserved = part_block_isreserved;
-	if (parent->_block_isbad)
-		slave->mtd._block_isbad = part_block_isbad;
-	if (parent->_block_markbad)
-		slave->mtd._block_markbad = part_block_markbad;
-	if (parent->_max_bad_blocks)
-		slave->mtd._max_bad_blocks = part_max_bad_blocks;
-
-	if (parent->_get_device)
-		slave->mtd._get_device = part_get_device;
-	if (parent->_put_device)
-		slave->mtd._put_device = part_put_device;
+	slave->mtd._writev = part_writev;
+	slave->mtd._lock = part_lock;
+	slave->mtd._unlock = part_unlock;
+	slave->mtd._is_locked = part_is_locked;
+	slave->mtd._block_isreserved = part_block_isreserved;
+	slave->mtd._block_isbad = part_block_isbad;
+	slave->mtd._block_markbad = part_block_markbad;
+	slave->mtd._max_bad_blocks = part_max_bad_blocks;
+	slave->mtd._get_device = part_get_device;
+	slave->mtd._put_device = part_put_device;
 
 	slave->mtd._erase = part_erase;
 	slave->parent = parent;
-- 
2.11.0

[PATCH v3 4/4] mtd: Fallback to ->_read/write_oob() when ->_read/write() is missing

[Boris Brezillon]

Some MTD sublayers/drivers are implementing ->_read/write_oob() and
provide dummy wrappers for their ->_read/write() implementations.
Let the core handle this case instead of duplicating the logic.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Acked-by: Brian Norris <computersforpeace@gmail.com>
---
Changes in v3:
- none

Changes in v2:
- none
---
 drivers/mtd/devices/docg3.c        | 65 --------------------------------------
 drivers/mtd/mtdcore.c              | 31 ++++++++++++++++--
 drivers/mtd/nand/nand_base.c       | 56 --------------------------------
 drivers/mtd/onenand/onenand_base.c | 63 ------------------------------------
 4 files changed, 29 insertions(+), 186 deletions(-)

diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
index 0806f72102c0..5fb5e93d1547 100644
--- a/drivers/mtd/devices/docg3.c
+++ b/drivers/mtd/devices/docg3.c
@@ -990,36 +990,6 @@ static int doc_read_oob(struct mtd_info *mtd, loff_t from,
 	goto out;
 }
 
-/**
- * doc_read - Read bytes from flash
- * @mtd: the device
- * @from: the offset from first block and first page, in bytes, aligned on page
- *        size
- * @len: the number of bytes to read (must be a multiple of 4)
- * @retlen: the number of bytes actually read
- * @buf: the filled in buffer
- *
- * Reads flash memory pages. This function does not read the OOB chunk, but only
- * the page data.
- *
- * Returns 0 if read successful, of -EIO, -EINVAL if an error occurred
- */
-static int doc_read(struct mtd_info *mtd, loff_t from, size_t len,
-	     size_t *retlen, u_char *buf)
-{
-	struct mtd_oob_ops ops;
-	size_t ret;
-
-	memset(&ops, 0, sizeof(ops));
-	ops.datbuf = buf;
-	ops.len = len;
-	ops.mode = MTD_OPS_AUTO_OOB;
-
-	ret = doc_read_oob(mtd, from, &ops);
-	*retlen = ops.retlen;
-	return ret;
-}
-
 static int doc_reload_bbt(struct docg3 *docg3)
 {
 	int block = DOC_LAYOUT_BLOCK_BBT;
@@ -1513,39 +1483,6 @@ static int doc_write_oob(struct mtd_info *mtd, loff_t ofs,
 	return ret;
 }
 
-/**
- * doc_write - Write a buffer to the chip
- * @mtd: the device
- * @to: the offset from first block and first page, in bytes, aligned on page
- *      size
- * @len: the number of bytes to write (must be a full page size, ie. 512)
- * @retlen: the number of bytes actually written (0 or 512)
- * @buf: the buffer to get bytes from
- *
- * Writes data to the chip.
- *
- * Returns 0 if write successful, -EIO if write error
- */
-static int doc_write(struct mtd_info *mtd, loff_t to, size_t len,
-		     size_t *retlen, const u_char *buf)
-{
-	struct docg3 *docg3 = mtd->priv;
-	int ret;
-	struct mtd_oob_ops ops;
-
-	doc_dbg("doc_write(to=%lld, len=%zu)\n", to, len);
-	ops.datbuf = (char *)buf;
-	ops.len = len;
-	ops.mode = MTD_OPS_PLACE_OOB;
-	ops.oobbuf = NULL;
-	ops.ooblen = 0;
-	ops.ooboffs = 0;
-
-	ret = doc_write_oob(mtd, to, &ops);
-	*retlen = ops.retlen;
-	return ret;
-}
-
 static struct docg3 *sysfs_dev2docg3(struct device *dev,
 				     struct device_attribute *attr)
 {
@@ -1866,8 +1803,6 @@ static int __init doc_set_driver_info(int chip_id, struct mtd_info *mtd)
 	mtd->writebufsize = mtd->writesize = DOC_LAYOUT_PAGE_SIZE;
 	mtd->oobsize = DOC_LAYOUT_OOB_SIZE;
 	mtd->_erase = doc_erase;
-	mtd->_read = doc_read;
-	mtd->_write = doc_write;
 	mtd->_read_oob = doc_read_oob;
 	mtd->_write_oob = doc_write_oob;
 	mtd->_block_isbad = doc_block_isbad;
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 642c35dde686..d7ab091b36b2 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -1058,7 +1058,20 @@ int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
 	 * representing the maximum number of bitflips that were corrected on
 	 * any one ecc region (if applicable; zero otherwise).
 	 */
-	ret_code = mtd->_read(mtd, from, len, retlen, buf);
+	if (mtd->_read) {
+		ret_code = mtd->_read(mtd, from, len, retlen, buf);
+	} else if (mtd->_read_oob) {
+		struct mtd_oob_ops ops = {
+			.len = len,
+			.datbuf = buf,
+		};
+
+		ret_code = mtd->_read_oob(mtd, from, &ops);
+		*retlen = ops.retlen;
+	} else {
+		return -ENOTSUPP;
+	}
+
 	if (unlikely(ret_code < 0))
 		return ret_code;
 	if (mtd->ecc_strength == 0)
@@ -1073,11 +1086,25 @@ int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
 	*retlen = 0;
 	if (to < 0 || to >= mtd->size || len > mtd->size - to)
 		return -EINVAL;
-	if (!mtd->_write || !(mtd->flags & MTD_WRITEABLE))
+	if ((!mtd->_write && !mtd->_write_oob) ||
+	    !(mtd->flags & MTD_WRITEABLE))
 		return -EROFS;
 	if (!len)
 		return 0;
 	ledtrig_mtd_activity();
+
+	if (!mtd->_write) {
+		struct mtd_oob_ops ops = {
+			.len = len,
+			.datbuf = (u8 *)buf,
+		};
+		int ret;
+
+		ret = mtd->_write_oob(mtd, to, &ops);
+		*retlen = ops.retlen;
+		return ret;
+	}
+
 	return mtd->_write(mtd, to, len, retlen, buf);
 }
 EXPORT_SYMBOL_GPL(mtd_write);
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 6135d007a068..889ceadbf607 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2027,33 +2027,6 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
 }
 
 /**
- * nand_read - [MTD Interface] MTD compatibility function for nand_do_read_ecc
- * @mtd: MTD device structure
- * @from: offset to read from
- * @len: number of bytes to read
- * @retlen: pointer to variable to store the number of read bytes
- * @buf: the databuffer to put data
- *
- * Get hold of the chip and call nand_do_read.
- */
-static int nand_read(struct mtd_info *mtd, loff_t from, size_t len,
-		     size_t *retlen, uint8_t *buf)
-{
-	struct mtd_oob_ops ops;
-	int ret;
-
-	nand_get_device(mtd, FL_READING);
-	memset(&ops, 0, sizeof(ops));
-	ops.len = len;
-	ops.datbuf = buf;
-	ops.mode = MTD_OPS_PLACE_OOB;
-	ret = nand_do_read_ops(mtd, from, &ops);
-	*retlen = ops.retlen;
-	nand_release_device(mtd);
-	return ret;
-}
-
-/**
  * nand_read_oob_std - [REPLACEABLE] the most common OOB data read function
  * @mtd: mtd info structure
  * @chip: nand chip info structure
@@ -2822,33 +2795,6 @@ static int panic_nand_write(struct mtd_info *mtd, loff_t to, size_t len,
 }
 
 /**
- * nand_write - [MTD Interface] NAND write with ECC
- * @mtd: MTD device structure
- * @to: offset to write to
- * @len: number of bytes to write
- * @retlen: pointer to variable to store the number of written bytes
- * @buf: the data to write
- *
- * NAND write with ECC.
- */
-static int nand_write(struct mtd_info *mtd, loff_t to, size_t len,
-			  size_t *retlen, const uint8_t *buf)
-{
-	struct mtd_oob_ops ops;
-	int ret;
-
-	nand_get_device(mtd, FL_WRITING);
-	memset(&ops, 0, sizeof(ops));
-	ops.len = len;
-	ops.datbuf = (uint8_t *)buf;
-	ops.mode = MTD_OPS_PLACE_OOB;
-	ret = nand_do_write_ops(mtd, to, &ops);
-	*retlen = ops.retlen;
-	nand_release_device(mtd);
-	return ret;
-}
-
-/**
  * nand_do_write_oob - [MTD Interface] NAND write out-of-band
  * @mtd: MTD device structure
  * @to: offset to write to
@@ -4917,8 +4863,6 @@ int nand_scan_tail(struct mtd_info *mtd)
 	mtd->_erase = nand_erase;
 	mtd->_point = NULL;
 	mtd->_unpoint = NULL;
-	mtd->_read = nand_read;
-	mtd->_write = nand_write;
 	mtd->_panic_write = panic_nand_write;
 	mtd->_read_oob = nand_read_oob;
 	mtd->_write_oob = nand_write_oob;
diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
index 1a6d0e367b89..050ba8a87543 100644
--- a/drivers/mtd/onenand/onenand_base.c
+++ b/drivers/mtd/onenand/onenand_base.c
@@ -1448,38 +1448,6 @@ static int onenand_read_oob_nolock(struct mtd_info *mtd, loff_t from,
 }
 
 /**
- * onenand_read - [MTD Interface] Read data from flash
- * @param mtd		MTD device structure
- * @param from		offset to read from
- * @param len		number of bytes to read
- * @param retlen	pointer to variable to store the number of read bytes
- * @param buf		the databuffer to put data
- *
- * Read with ecc
-*/
-static int onenand_read(struct mtd_info *mtd, loff_t from, size_t len,
-	size_t *retlen, u_char *buf)
-{
-	struct onenand_chip *this = mtd->priv;
-	struct mtd_oob_ops ops = {
-		.len	= len,
-		.ooblen	= 0,
-		.datbuf	= buf,
-		.oobbuf	= NULL,
-	};
-	int ret;
-
-	onenand_get_device(mtd, FL_READING);
-	ret = ONENAND_IS_4KB_PAGE(this) ?
-		onenand_mlc_read_ops_nolock(mtd, from, &ops) :
-		onenand_read_ops_nolock(mtd, from, &ops);
-	onenand_release_device(mtd);
-
-	*retlen = ops.retlen;
-	return ret;
-}
-
-/**
  * onenand_read_oob - [MTD Interface] Read main and/or out-of-band
  * @param mtd:		MTD device structure
  * @param from:		offset to read from
@@ -2129,35 +2097,6 @@ static int onenand_write_oob_nolock(struct mtd_info *mtd, loff_t to,
 }
 
 /**
- * onenand_write - [MTD Interface] write buffer to FLASH
- * @param mtd		MTD device structure
- * @param to		offset to write to
- * @param len		number of bytes to write
- * @param retlen	pointer to variable to store the number of written bytes
- * @param buf		the data to write
- *
- * Write with ECC
- */
-static int onenand_write(struct mtd_info *mtd, loff_t to, size_t len,
-	size_t *retlen, const u_char *buf)
-{
-	struct mtd_oob_ops ops = {
-		.len	= len,
-		.ooblen	= 0,
-		.datbuf	= (u_char *) buf,
-		.oobbuf	= NULL,
-	};
-	int ret;
-
-	onenand_get_device(mtd, FL_WRITING);
-	ret = onenand_write_ops_nolock(mtd, to, &ops);
-	onenand_release_device(mtd);
-
-	*retlen = ops.retlen;
-	return ret;
-}
-
-/**
  * onenand_write_oob - [MTD Interface] NAND write data and/or out-of-band
  * @param mtd:		MTD device structure
  * @param to:		offset to write
@@ -4038,8 +3977,6 @@ int onenand_scan(struct mtd_info *mtd, int maxchips)
 	mtd->_erase = onenand_erase;
 	mtd->_point = NULL;
 	mtd->_unpoint = NULL;
-	mtd->_read = onenand_read;
-	mtd->_write = onenand_write;
 	mtd->_read_oob = onenand_read_oob;
 	mtd->_write_oob = onenand_write_oob;
 	mtd->_panic_write = onenand_panic_write;
-- 
2.11.0

Re: [PATCH v3 0/4] mtd: Preparation patches for the SPI NAND framework

[Miquel RAYNAL]

Hello Boris,

On Fri, 15 Dec 2017 13:39:50 +0100
Boris Brezillon <boris.brezillon@free-electrons.com> wrote:

> Hello,
> 
> Here is a set of patches to prepare the introduction of the generic
> NAND and SPI frameworks.
> 
> The last 2 patches have already been submitted here [1], and the first
> two are new, and should also help simplify other drivers/frameworks
> in providing generic code for already existing logic.
> 
> If you want to see the overall picture of the SPI NAND framework you
> can have a look at this branch [2].
> 
> Regards,
> 
> Boris
> 
> [1]https://patchwork.ozlabs.org/patch/780477/
> [2]https://github.com/bbrezillon/linux-0day/commits/nand/spi-nand-squashed
> 
> Boris Brezillon (4):
>   mtd: Do not allow MTD devices with inconsistent erase properties
>   mtd: Add an helper to make erase request aligned on ->erasesize
>   mtd: Stop directly calling master ->_xxx() hooks from mtdpart code
>   mtd: Fallback to ->_read/write_oob() when ->_read/write() is missing

I did not spot anything strange on the four patches :) so for the
series:

Reviewed-by: Miquel Raynal <miquel.raynal@free-electrons.com>

Thank you,
Miquèl

> 
>  drivers/mtd/devices/docg3.c        |  65 -----------------
>  drivers/mtd/mtdcore.c              |  36 +++++++++-
>  drivers/mtd/mtdpart.c              | 141
> ++++++++++++++-----------------------
> drivers/mtd/nand/nand_base.c       |  56 ---------------
> drivers/mtd/onenand/onenand_base.c |  63 -----------------
> include/linux/mtd/mtd.h            |  28 ++++++++ 6 files changed,
> 115 insertions(+), 274 deletions(-)
> 



-- 
Miquel Raynal, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

Re: [PATCH v3 3/4] mtd: Stop directly calling master ->_xxx() hooks from mtdpart code

[Peter Pan]

Hi Boris,

On Fri, Dec 15, 2017 at 8:39 PM, Boris Brezillon
<boris.brezillon@free-electrons.com> wrote:
> The MTD layer provides several wrappers around mtd->_xxx() hooks. Call
> these wrappers instead of directly dereferencing the associated ->_xxx()
> pointer.
>
> This change has been motivated by another rework letting the core
> handle the case where ->_read/write_oob() are implemented but not
> ->_read/write(). In this case, we want mtd_read/write() to fall back to
> ->_read/write_oob() when ->_read/write() are NULL. The problem is,
> mtdpart is directly calling the ->_xxx() instead of using the wrappers,
> thus leading to a NULL pointer exception.
>
> Even though we only need to do the change for part_read/write(), going
> through those wrappers for all kind of part -> master operation
> propagation is a good thing, because other wrappers might become
> smarter over time, and the duplicated check overhead (parameters will
> be checked at the partition and master level instead of only at the
> partition level) should be negligible.
>
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> ---
> Changes in v3:
> - unconditionally assign part wrappers as suggested by Brian
>
> Changes in v2:
> - new patch needed to fix a NULL pointer dereference BUG
> ---
>  drivers/mtd/mtdpart.c | 141 +++++++++++++++++++-------------------------------
>  1 file changed, 53 insertions(+), 88 deletions(-)
>
> diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> index be088bccd593..e83c9d870b11 100644
> --- a/drivers/mtd/mtdpart.c
> +++ b/drivers/mtd/mtdpart.c
> @@ -74,8 +74,7 @@ static int part_read(struct mtd_info *mtd, loff_t from, size_t len,
>         int res;
>

This is not about your modification. But shouldn't we add check to prevent
part_read/write/write_oob from accessing  past the end of partition?
There is a check in part_read_oob() only.

Thanks
Peter Pan

>         stats = part->parent->ecc_stats;
> -       res = part->parent->_read(part->parent, from + part->offset, len,
> -                                 retlen, buf);
> +       res = mtd_read(part->parent, from + part->offset, len, retlen, buf);
>         if (unlikely(mtd_is_eccerr(res)))
>                 mtd->ecc_stats.failed +=
>                         part->parent->ecc_stats.failed - stats.failed;
> @@ -90,15 +89,15 @@ static int part_point(struct mtd_info *mtd, loff_t from, size_t len,
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
>
> -       return part->parent->_point(part->parent, from + part->offset, len,
> -                                   retlen, virt, phys);
> +       return mtd_point(part->parent, from + part->offset, len, retlen, virt,
> +                        phys);
>  }
>
>  static int part_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
>
> -       return part->parent->_unpoint(part->parent, from + part->offset, len);
> +       return mtd_unpoint(part->parent, from + part->offset, len);
>  }
>
>  static int part_read_oob(struct mtd_info *mtd, loff_t from,
> @@ -126,7 +125,7 @@ static int part_read_oob(struct mtd_info *mtd, loff_t from,
>                         return -EINVAL;
>         }
>
> -       res = part->parent->_read_oob(part->parent, from + part->offset, ops);
> +       res = mtd_read_oob(part->parent, from + part->offset, ops);
>         if (unlikely(res)) {
>                 if (mtd_is_bitflip(res))
>                         mtd->ecc_stats.corrected++;
> @@ -140,48 +139,43 @@ static int part_read_user_prot_reg(struct mtd_info *mtd, loff_t from,
>                 size_t len, size_t *retlen, u_char *buf)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       return part->parent->_read_user_prot_reg(part->parent, from, len,
> -                                                retlen, buf);
> +       return mtd_read_user_prot_reg(part->parent, from, len, retlen, buf);
>  }
>
>  static int part_get_user_prot_info(struct mtd_info *mtd, size_t len,
>                                    size_t *retlen, struct otp_info *buf)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       return part->parent->_get_user_prot_info(part->parent, len, retlen,
> -                                                buf);
> +       return mtd_get_user_prot_info(part->parent, len, retlen, buf);
>  }
>
>  static int part_read_fact_prot_reg(struct mtd_info *mtd, loff_t from,
>                 size_t len, size_t *retlen, u_char *buf)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       return part->parent->_read_fact_prot_reg(part->parent, from, len,
> -                                                retlen, buf);
> +       return mtd_read_fact_prot_reg(part->parent, from, len, retlen, buf);
>  }
>
>  static int part_get_fact_prot_info(struct mtd_info *mtd, size_t len,
>                                    size_t *retlen, struct otp_info *buf)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       return part->parent->_get_fact_prot_info(part->parent, len, retlen,
> -                                                buf);
> +       return mtd_get_fact_prot_info(part->parent, len, retlen, buf);
>  }
>
>  static int part_write(struct mtd_info *mtd, loff_t to, size_t len,
>                 size_t *retlen, const u_char *buf)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       return part->parent->_write(part->parent, to + part->offset, len,
> -                                   retlen, buf);
> +       return mtd_write(part->parent, to + part->offset, len, retlen, buf);
>  }
>
>  static int part_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
>                 size_t *retlen, const u_char *buf)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       return part->parent->_panic_write(part->parent, to + part->offset, len,
> -                                         retlen, buf);
> +       return mtd_panic_write(part->parent, to + part->offset, len, retlen,
> +                              buf);
>  }
>
>  static int part_write_oob(struct mtd_info *mtd, loff_t to,
> @@ -193,30 +187,29 @@ static int part_write_oob(struct mtd_info *mtd, loff_t to,
>                 return -EINVAL;
>         if (ops->datbuf && to + ops->len > mtd->size)
>                 return -EINVAL;
> -       return part->parent->_write_oob(part->parent, to + part->offset, ops);
> +       return mtd_write_oob(part->parent, to + part->offset, ops);
>  }
>
>  static int part_write_user_prot_reg(struct mtd_info *mtd, loff_t from,
>                 size_t len, size_t *retlen, u_char *buf)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       return part->parent->_write_user_prot_reg(part->parent, from, len,
> -                                                 retlen, buf);
> +       return mtd_write_user_prot_reg(part->parent, from, len, retlen, buf);
>  }
>
>  static int part_lock_user_prot_reg(struct mtd_info *mtd, loff_t from,
>                 size_t len)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       return part->parent->_lock_user_prot_reg(part->parent, from, len);
> +       return mtd_lock_user_prot_reg(part->parent, from, len);
>  }
>
>  static int part_writev(struct mtd_info *mtd, const struct kvec *vecs,
>                 unsigned long count, loff_t to, size_t *retlen)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       return part->parent->_writev(part->parent, vecs, count,
> -                                    to + part->offset, retlen);
> +       return mtd_writev(part->parent, vecs, count, to + part->offset,
> +                         retlen);
>  }
>
>  static int part_erase(struct mtd_info *mtd, struct erase_info *instr)
> @@ -225,7 +218,7 @@ static int part_erase(struct mtd_info *mtd, struct erase_info *instr)
>         int ret;
>
>         instr->addr += part->offset;
> -       ret = part->parent->_erase(part->parent, instr);
> +       ret = mtd_erase(part->parent, instr);
>         if (ret) {
>                 if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
>                         instr->fail_addr -= part->offset;
> @@ -251,51 +244,51 @@ EXPORT_SYMBOL_GPL(mtd_erase_callback);
>  static int part_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       return part->parent->_lock(part->parent, ofs + part->offset, len);
> +       return mtd_lock(part->parent, ofs + part->offset, len);
>  }
>
>  static int part_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       return part->parent->_unlock(part->parent, ofs + part->offset, len);
> +       return mtd_unlock(part->parent, ofs + part->offset, len);
>  }
>
>  static int part_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       return part->parent->_is_locked(part->parent, ofs + part->offset, len);
> +       return mtd_is_locked(part->parent, ofs + part->offset, len);
>  }
>
>  static void part_sync(struct mtd_info *mtd)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       part->parent->_sync(part->parent);
> +       mtd_sync(part->parent);
>  }
>
>  static int part_suspend(struct mtd_info *mtd)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       return part->parent->_suspend(part->parent);
> +       return mtd_suspend(part->parent);
>  }
>
>  static void part_resume(struct mtd_info *mtd)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       part->parent->_resume(part->parent);
> +       mtd_resume(part->parent);
>  }
>
>  static int part_block_isreserved(struct mtd_info *mtd, loff_t ofs)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
>         ofs += part->offset;
> -       return part->parent->_block_isreserved(part->parent, ofs);
> +       return mtd_block_isreserved(part->parent, ofs);
>  }
>
>  static int part_block_isbad(struct mtd_info *mtd, loff_t ofs)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
>         ofs += part->offset;
> -       return part->parent->_block_isbad(part->parent, ofs);
> +       return mtd_block_isbad(part->parent, ofs);
>  }
>
>  static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
> @@ -304,7 +297,7 @@ static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
>         int res;
>
>         ofs += part->offset;
> -       res = part->parent->_block_markbad(part->parent, ofs);
> +       res = mtd_block_markbad(part->parent, ofs);
>         if (!res)
>                 mtd->ecc_stats.badblocks++;
>         return res;
> @@ -313,13 +306,13 @@ static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
>  static int part_get_device(struct mtd_info *mtd)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       return part->parent->_get_device(part->parent);
> +       return __get_mtd_device(part->parent);
>  }
>
>  static void part_put_device(struct mtd_info *mtd)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
> -       part->parent->_put_device(part->parent);
> +       __put_mtd_device(part->parent);
>  }
>
>  static int part_ooblayout_ecc(struct mtd_info *mtd, int section,
> @@ -347,8 +340,7 @@ static int part_max_bad_blocks(struct mtd_info *mtd, loff_t ofs, size_t len)
>  {
>         struct mtd_part *part = mtd_to_part(mtd);
>
> -       return part->parent->_max_bad_blocks(part->parent,
> -                                            ofs + part->offset, len);
> +       return mtd_max_bad_blocks(part->parent, ofs + part->offset, len);
>  }
>
>  static inline void free_partition(struct mtd_part *p)
> @@ -437,59 +429,32 @@ static struct mtd_part *allocate_partition(struct mtd_info *parent,
>
>         slave->mtd._read = part_read;
>         slave->mtd._write = part_write;
> -
> -       if (parent->_panic_write)
> -               slave->mtd._panic_write = part_panic_write;
> -
> -       if (parent->_point && parent->_unpoint) {
> -               slave->mtd._point = part_point;
> -               slave->mtd._unpoint = part_unpoint;
> -       }
> -
> -       if (parent->_read_oob)
> -               slave->mtd._read_oob = part_read_oob;
> -       if (parent->_write_oob)
> -               slave->mtd._write_oob = part_write_oob;
> -       if (parent->_read_user_prot_reg)
> -               slave->mtd._read_user_prot_reg = part_read_user_prot_reg;
> -       if (parent->_read_fact_prot_reg)
> -               slave->mtd._read_fact_prot_reg = part_read_fact_prot_reg;
> -       if (parent->_write_user_prot_reg)
> -               slave->mtd._write_user_prot_reg = part_write_user_prot_reg;
> -       if (parent->_lock_user_prot_reg)
> -               slave->mtd._lock_user_prot_reg = part_lock_user_prot_reg;
> -       if (parent->_get_user_prot_info)
> -               slave->mtd._get_user_prot_info = part_get_user_prot_info;
> -       if (parent->_get_fact_prot_info)
> -               slave->mtd._get_fact_prot_info = part_get_fact_prot_info;
> -       if (parent->_sync)
> -               slave->mtd._sync = part_sync;
> -       if (!partno && !parent->dev.class && parent->_suspend &&
> -           parent->_resume) {
> +       slave->mtd._panic_write = part_panic_write;
> +       slave->mtd._point = part_point;
> +       slave->mtd._unpoint = part_unpoint;
> +       slave->mtd._read_oob = part_read_oob;
> +       slave->mtd._write_oob = part_write_oob;
> +       slave->mtd._read_user_prot_reg = part_read_user_prot_reg;
> +       slave->mtd._read_fact_prot_reg = part_read_fact_prot_reg;
> +       slave->mtd._write_user_prot_reg = part_write_user_prot_reg;
> +       slave->mtd._lock_user_prot_reg = part_lock_user_prot_reg;
> +       slave->mtd._get_user_prot_info = part_get_user_prot_info;
> +       slave->mtd._get_fact_prot_info = part_get_fact_prot_info;
> +       slave->mtd._sync = part_sync;
> +       if (!partno && !parent->dev.class) {
>                 slave->mtd._suspend = part_suspend;
>                 slave->mtd._resume = part_resume;
>         }
> -       if (parent->_writev)
> -               slave->mtd._writev = part_writev;
> -       if (parent->_lock)
> -               slave->mtd._lock = part_lock;
> -       if (parent->_unlock)
> -               slave->mtd._unlock = part_unlock;
> -       if (parent->_is_locked)
> -               slave->mtd._is_locked = part_is_locked;
> -       if (parent->_block_isreserved)
> -               slave->mtd._block_isreserved = part_block_isreserved;
> -       if (parent->_block_isbad)
> -               slave->mtd._block_isbad = part_block_isbad;
> -       if (parent->_block_markbad)
> -               slave->mtd._block_markbad = part_block_markbad;
> -       if (parent->_max_bad_blocks)
> -               slave->mtd._max_bad_blocks = part_max_bad_blocks;
> -
> -       if (parent->_get_device)
> -               slave->mtd._get_device = part_get_device;
> -       if (parent->_put_device)
> -               slave->mtd._put_device = part_put_device;
> +       slave->mtd._writev = part_writev;
> +       slave->mtd._lock = part_lock;
> +       slave->mtd._unlock = part_unlock;
> +       slave->mtd._is_locked = part_is_locked;
> +       slave->mtd._block_isreserved = part_block_isreserved;
> +       slave->mtd._block_isbad = part_block_isbad;
> +       slave->mtd._block_markbad = part_block_markbad;
> +       slave->mtd._max_bad_blocks = part_max_bad_blocks;
> +       slave->mtd._get_device = part_get_device;
> +       slave->mtd._put_device = part_put_device;
>
>         slave->mtd._erase = part_erase;
>         slave->parent = parent;
> --
> 2.11.0
>

Re: [PATCH v3 3/4] mtd: Stop directly calling master ->_xxx() hooks from mtdpart code

[Boris Brezillon]

On Fri, 22 Dec 2017 13:40:26 +0800
Peter Pan <peterpansjtu@gmail.com> wrote:

> Hi Boris,
> 
> On Fri, Dec 15, 2017 at 8:39 PM, Boris Brezillon
> <boris.brezillon@free-electrons.com> wrote:
> > The MTD layer provides several wrappers around mtd->_xxx() hooks. Call
> > these wrappers instead of directly dereferencing the associated ->_xxx()
> > pointer.
> >
> > This change has been motivated by another rework letting the core
> > handle the case where ->_read/write_oob() are implemented but not  
> > ->_read/write(). In this case, we want mtd_read/write() to fall back to
> > ->_read/write_oob() when ->_read/write() are NULL. The problem is,  
> > mtdpart is directly calling the ->_xxx() instead of using the wrappers,
> > thus leading to a NULL pointer exception.
> >
> > Even though we only need to do the change for part_read/write(), going
> > through those wrappers for all kind of part -> master operation
> > propagation is a good thing, because other wrappers might become
> > smarter over time, and the duplicated check overhead (parameters will
> > be checked at the partition and master level instead of only at the
> > partition level) should be negligible.
> >
> > Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> > ---
> > Changes in v3:
> > - unconditionally assign part wrappers as suggested by Brian
> >
> > Changes in v2:
> > - new patch needed to fix a NULL pointer dereference BUG
> > ---
> >  drivers/mtd/mtdpart.c | 141 +++++++++++++++++++-------------------------------
> >  1 file changed, 53 insertions(+), 88 deletions(-)
> >
> > diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> > index be088bccd593..e83c9d870b11 100644
> > --- a/drivers/mtd/mtdpart.c
> > +++ b/drivers/mtd/mtdpart.c
> > @@ -74,8 +74,7 @@ static int part_read(struct mtd_info *mtd, loff_t from, size_t len,
> >         int res;
> >  
> 
> This is not about your modification. But shouldn't we add check to prevent
> part_read/write/write_oob from accessing  past the end of partition?
> There is a check in part_read_oob() only.

You should not call part_xxx() directly, and mtd_read/write{_oob}()
should already check that. If that's not the case, we should fix them.

Can you give a bit more details about what is wrong?

Thanks,

Boris

> 
> Thanks
> Peter Pan
> 
> >         stats = part->parent->ecc_stats;
> > -       res = part->parent->_read(part->parent, from + part->offset, len,
> > -                                 retlen, buf);
> > +       res = mtd_read(part->parent, from + part->offset, len, retlen, buf);
> >         if (unlikely(mtd_is_eccerr(res)))
> >                 mtd->ecc_stats.failed +=
> >                         part->parent->ecc_stats.failed - stats.failed;
> > @@ -90,15 +89,15 @@ static int part_point(struct mtd_info *mtd, loff_t from, size_t len,
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> >
> > -       return part->parent->_point(part->parent, from + part->offset, len,
> > -                                   retlen, virt, phys);
> > +       return mtd_point(part->parent, from + part->offset, len, retlen, virt,
> > +                        phys);
> >  }
> >
> >  static int part_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> >
> > -       return part->parent->_unpoint(part->parent, from + part->offset, len);
> > +       return mtd_unpoint(part->parent, from + part->offset, len);
> >  }
> >
> >  static int part_read_oob(struct mtd_info *mtd, loff_t from,
> > @@ -126,7 +125,7 @@ static int part_read_oob(struct mtd_info *mtd, loff_t from,
> >                         return -EINVAL;
> >         }
> >
> > -       res = part->parent->_read_oob(part->parent, from + part->offset, ops);
> > +       res = mtd_read_oob(part->parent, from + part->offset, ops);
> >         if (unlikely(res)) {
> >                 if (mtd_is_bitflip(res))
> >                         mtd->ecc_stats.corrected++;
> > @@ -140,48 +139,43 @@ static int part_read_user_prot_reg(struct mtd_info *mtd, loff_t from,
> >                 size_t len, size_t *retlen, u_char *buf)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       return part->parent->_read_user_prot_reg(part->parent, from, len,
> > -                                                retlen, buf);
> > +       return mtd_read_user_prot_reg(part->parent, from, len, retlen, buf);
> >  }
> >
> >  static int part_get_user_prot_info(struct mtd_info *mtd, size_t len,
> >                                    size_t *retlen, struct otp_info *buf)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       return part->parent->_get_user_prot_info(part->parent, len, retlen,
> > -                                                buf);
> > +       return mtd_get_user_prot_info(part->parent, len, retlen, buf);
> >  }
> >
> >  static int part_read_fact_prot_reg(struct mtd_info *mtd, loff_t from,
> >                 size_t len, size_t *retlen, u_char *buf)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       return part->parent->_read_fact_prot_reg(part->parent, from, len,
> > -                                                retlen, buf);
> > +       return mtd_read_fact_prot_reg(part->parent, from, len, retlen, buf);
> >  }
> >
> >  static int part_get_fact_prot_info(struct mtd_info *mtd, size_t len,
> >                                    size_t *retlen, struct otp_info *buf)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       return part->parent->_get_fact_prot_info(part->parent, len, retlen,
> > -                                                buf);
> > +       return mtd_get_fact_prot_info(part->parent, len, retlen, buf);
> >  }
> >
> >  static int part_write(struct mtd_info *mtd, loff_t to, size_t len,
> >                 size_t *retlen, const u_char *buf)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       return part->parent->_write(part->parent, to + part->offset, len,
> > -                                   retlen, buf);
> > +       return mtd_write(part->parent, to + part->offset, len, retlen, buf);
> >  }
> >
> >  static int part_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
> >                 size_t *retlen, const u_char *buf)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       return part->parent->_panic_write(part->parent, to + part->offset, len,
> > -                                         retlen, buf);
> > +       return mtd_panic_write(part->parent, to + part->offset, len, retlen,
> > +                              buf);
> >  }
> >
> >  static int part_write_oob(struct mtd_info *mtd, loff_t to,
> > @@ -193,30 +187,29 @@ static int part_write_oob(struct mtd_info *mtd, loff_t to,
> >                 return -EINVAL;
> >         if (ops->datbuf && to + ops->len > mtd->size)
> >                 return -EINVAL;
> > -       return part->parent->_write_oob(part->parent, to + part->offset, ops);
> > +       return mtd_write_oob(part->parent, to + part->offset, ops);
> >  }
> >
> >  static int part_write_user_prot_reg(struct mtd_info *mtd, loff_t from,
> >                 size_t len, size_t *retlen, u_char *buf)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       return part->parent->_write_user_prot_reg(part->parent, from, len,
> > -                                                 retlen, buf);
> > +       return mtd_write_user_prot_reg(part->parent, from, len, retlen, buf);
> >  }
> >
> >  static int part_lock_user_prot_reg(struct mtd_info *mtd, loff_t from,
> >                 size_t len)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       return part->parent->_lock_user_prot_reg(part->parent, from, len);
> > +       return mtd_lock_user_prot_reg(part->parent, from, len);
> >  }
> >
> >  static int part_writev(struct mtd_info *mtd, const struct kvec *vecs,
> >                 unsigned long count, loff_t to, size_t *retlen)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       return part->parent->_writev(part->parent, vecs, count,
> > -                                    to + part->offset, retlen);
> > +       return mtd_writev(part->parent, vecs, count, to + part->offset,
> > +                         retlen);
> >  }
> >
> >  static int part_erase(struct mtd_info *mtd, struct erase_info *instr)
> > @@ -225,7 +218,7 @@ static int part_erase(struct mtd_info *mtd, struct erase_info *instr)
> >         int ret;
> >
> >         instr->addr += part->offset;
> > -       ret = part->parent->_erase(part->parent, instr);
> > +       ret = mtd_erase(part->parent, instr);
> >         if (ret) {
> >                 if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
> >                         instr->fail_addr -= part->offset;
> > @@ -251,51 +244,51 @@ EXPORT_SYMBOL_GPL(mtd_erase_callback);
> >  static int part_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       return part->parent->_lock(part->parent, ofs + part->offset, len);
> > +       return mtd_lock(part->parent, ofs + part->offset, len);
> >  }
> >
> >  static int part_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       return part->parent->_unlock(part->parent, ofs + part->offset, len);
> > +       return mtd_unlock(part->parent, ofs + part->offset, len);
> >  }
> >
> >  static int part_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       return part->parent->_is_locked(part->parent, ofs + part->offset, len);
> > +       return mtd_is_locked(part->parent, ofs + part->offset, len);
> >  }
> >
> >  static void part_sync(struct mtd_info *mtd)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       part->parent->_sync(part->parent);
> > +       mtd_sync(part->parent);
> >  }
> >
> >  static int part_suspend(struct mtd_info *mtd)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       return part->parent->_suspend(part->parent);
> > +       return mtd_suspend(part->parent);
> >  }
> >
> >  static void part_resume(struct mtd_info *mtd)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       part->parent->_resume(part->parent);
> > +       mtd_resume(part->parent);
> >  }
> >
> >  static int part_block_isreserved(struct mtd_info *mtd, loff_t ofs)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> >         ofs += part->offset;
> > -       return part->parent->_block_isreserved(part->parent, ofs);
> > +       return mtd_block_isreserved(part->parent, ofs);
> >  }
> >
> >  static int part_block_isbad(struct mtd_info *mtd, loff_t ofs)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> >         ofs += part->offset;
> > -       return part->parent->_block_isbad(part->parent, ofs);
> > +       return mtd_block_isbad(part->parent, ofs);
> >  }
> >
> >  static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
> > @@ -304,7 +297,7 @@ static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
> >         int res;
> >
> >         ofs += part->offset;
> > -       res = part->parent->_block_markbad(part->parent, ofs);
> > +       res = mtd_block_markbad(part->parent, ofs);
> >         if (!res)
> >                 mtd->ecc_stats.badblocks++;
> >         return res;
> > @@ -313,13 +306,13 @@ static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
> >  static int part_get_device(struct mtd_info *mtd)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       return part->parent->_get_device(part->parent);
> > +       return __get_mtd_device(part->parent);
> >  }
> >
> >  static void part_put_device(struct mtd_info *mtd)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> > -       part->parent->_put_device(part->parent);
> > +       __put_mtd_device(part->parent);
> >  }
> >
> >  static int part_ooblayout_ecc(struct mtd_info *mtd, int section,
> > @@ -347,8 +340,7 @@ static int part_max_bad_blocks(struct mtd_info *mtd, loff_t ofs, size_t len)
> >  {
> >         struct mtd_part *part = mtd_to_part(mtd);
> >
> > -       return part->parent->_max_bad_blocks(part->parent,
> > -                                            ofs + part->offset, len);
> > +       return mtd_max_bad_blocks(part->parent, ofs + part->offset, len);
> >  }
> >
> >  static inline void free_partition(struct mtd_part *p)
> > @@ -437,59 +429,32 @@ static struct mtd_part *allocate_partition(struct mtd_info *parent,
> >
> >         slave->mtd._read = part_read;
> >         slave->mtd._write = part_write;
> > -
> > -       if (parent->_panic_write)
> > -               slave->mtd._panic_write = part_panic_write;
> > -
> > -       if (parent->_point && parent->_unpoint) {
> > -               slave->mtd._point = part_point;
> > -               slave->mtd._unpoint = part_unpoint;
> > -       }
> > -
> > -       if (parent->_read_oob)
> > -               slave->mtd._read_oob = part_read_oob;
> > -       if (parent->_write_oob)
> > -               slave->mtd._write_oob = part_write_oob;
> > -       if (parent->_read_user_prot_reg)
> > -               slave->mtd._read_user_prot_reg = part_read_user_prot_reg;
> > -       if (parent->_read_fact_prot_reg)
> > -               slave->mtd._read_fact_prot_reg = part_read_fact_prot_reg;
> > -       if (parent->_write_user_prot_reg)
> > -               slave->mtd._write_user_prot_reg = part_write_user_prot_reg;
> > -       if (parent->_lock_user_prot_reg)
> > -               slave->mtd._lock_user_prot_reg = part_lock_user_prot_reg;
> > -       if (parent->_get_user_prot_info)
> > -               slave->mtd._get_user_prot_info = part_get_user_prot_info;
> > -       if (parent->_get_fact_prot_info)
> > -               slave->mtd._get_fact_prot_info = part_get_fact_prot_info;
> > -       if (parent->_sync)
> > -               slave->mtd._sync = part_sync;
> > -       if (!partno && !parent->dev.class && parent->_suspend &&
> > -           parent->_resume) {
> > +       slave->mtd._panic_write = part_panic_write;
> > +       slave->mtd._point = part_point;
> > +       slave->mtd._unpoint = part_unpoint;
> > +       slave->mtd._read_oob = part_read_oob;
> > +       slave->mtd._write_oob = part_write_oob;
> > +       slave->mtd._read_user_prot_reg = part_read_user_prot_reg;
> > +       slave->mtd._read_fact_prot_reg = part_read_fact_prot_reg;
> > +       slave->mtd._write_user_prot_reg = part_write_user_prot_reg;
> > +       slave->mtd._lock_user_prot_reg = part_lock_user_prot_reg;
> > +       slave->mtd._get_user_prot_info = part_get_user_prot_info;
> > +       slave->mtd._get_fact_prot_info = part_get_fact_prot_info;
> > +       slave->mtd._sync = part_sync;
> > +       if (!partno && !parent->dev.class) {
> >                 slave->mtd._suspend = part_suspend;
> >                 slave->mtd._resume = part_resume;
> >         }
> > -       if (parent->_writev)
> > -               slave->mtd._writev = part_writev;
> > -       if (parent->_lock)
> > -               slave->mtd._lock = part_lock;
> > -       if (parent->_unlock)
> > -               slave->mtd._unlock = part_unlock;
> > -       if (parent->_is_locked)
> > -               slave->mtd._is_locked = part_is_locked;
> > -       if (parent->_block_isreserved)
> > -               slave->mtd._block_isreserved = part_block_isreserved;
> > -       if (parent->_block_isbad)
> > -               slave->mtd._block_isbad = part_block_isbad;
> > -       if (parent->_block_markbad)
> > -               slave->mtd._block_markbad = part_block_markbad;
> > -       if (parent->_max_bad_blocks)
> > -               slave->mtd._max_bad_blocks = part_max_bad_blocks;
> > -
> > -       if (parent->_get_device)
> > -               slave->mtd._get_device = part_get_device;
> > -       if (parent->_put_device)
> > -               slave->mtd._put_device = part_put_device;
> > +       slave->mtd._writev = part_writev;
> > +       slave->mtd._lock = part_lock;
> > +       slave->mtd._unlock = part_unlock;
> > +       slave->mtd._is_locked = part_is_locked;
> > +       slave->mtd._block_isreserved = part_block_isreserved;
> > +       slave->mtd._block_isbad = part_block_isbad;
> > +       slave->mtd._block_markbad = part_block_markbad;
> > +       slave->mtd._max_bad_blocks = part_max_bad_blocks;
> > +       slave->mtd._get_device = part_get_device;
> > +       slave->mtd._put_device = part_put_device;
> >
> >         slave->mtd._erase = part_erase;
> >         slave->parent = parent;
> > --
> > 2.11.0
> >  

Re: [PATCH v3 3/4] mtd: Stop directly calling master ->_xxx() hooks from mtdpart code

[Peter Pan]

Boris,

On Fri, Dec 22, 2017 at 4:37 PM, Boris Brezillon
<boris.brezillon@free-electrons.com> wrote:
> On Fri, 22 Dec 2017 13:40:26 +0800
> Peter Pan <peterpansjtu@gmail.com> wrote:
>
>> Hi Boris,
>>
>> On Fri, Dec 15, 2017 at 8:39 PM, Boris Brezillon
>> <boris.brezillon@free-electrons.com> wrote:
>> > The MTD layer provides several wrappers around mtd->_xxx() hooks. Call
>> > these wrappers instead of directly dereferencing the associated ->_xxx()
>> > pointer.
>> >
>> > This change has been motivated by another rework letting the core
>> > handle the case where ->_read/write_oob() are implemented but not
>> > ->_read/write(). In this case, we want mtd_read/write() to fall back to
>> > ->_read/write_oob() when ->_read/write() are NULL. The problem is,
>> > mtdpart is directly calling the ->_xxx() instead of using the wrappers,
>> > thus leading to a NULL pointer exception.
>> >
>> > Even though we only need to do the change for part_read/write(), going
>> > through those wrappers for all kind of part -> master operation
>> > propagation is a good thing, because other wrappers might become
>> > smarter over time, and the duplicated check overhead (parameters will
>> > be checked at the partition and master level instead of only at the
>> > partition level) should be negligible.
>> >
>> > Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
>> > ---
>> > Changes in v3:
>> > - unconditionally assign part wrappers as suggested by Brian
>> >
>> > Changes in v2:
>> > - new patch needed to fix a NULL pointer dereference BUG
>> > ---
>> >  drivers/mtd/mtdpart.c | 141 +++++++++++++++++++-------------------------------
>> >  1 file changed, 53 insertions(+), 88 deletions(-)
>> >
>> > diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
>> > index be088bccd593..e83c9d870b11 100644
>> > --- a/drivers/mtd/mtdpart.c
>> > +++ b/drivers/mtd/mtdpart.c
>> > @@ -74,8 +74,7 @@ static int part_read(struct mtd_info *mtd, loff_t from, size_t len,
>> >         int res;
>> >
>>
>> This is not about your modification. But shouldn't we add check to prevent
>> part_read/write/write_oob from accessing  past the end of partition?
>> There is a check in part_read_oob() only.
>
> You should not call part_xxx() directly, and mtd_read/write{_oob}()
> should already check that. If that's not the case, we should fix them.
>
> Can you give a bit more details about what is wrong?

Sorry for late reply. My failure is due to failed to assign mtd->oobavail.
We don't have problem in OOB ops checking.
But since we already check it in mtd_read/write_oob(), shouln't we
remove the check in part_read/write_oob() ?

Thanks
Peter Pan


>
> Thanks,
>
> Boris
>
>>
>> Thanks
>> Peter Pan
>>
>> >         stats = part->parent->ecc_stats;
>> > -       res = part->parent->_read(part->parent, from + part->offset, len,
>> > -                                 retlen, buf);
>> > +       res = mtd_read(part->parent, from + part->offset, len, retlen, buf);
>> >         if (unlikely(mtd_is_eccerr(res)))
>> >                 mtd->ecc_stats.failed +=
>> >                         part->parent->ecc_stats.failed - stats.failed;
>> > @@ -90,15 +89,15 @@ static int part_point(struct mtd_info *mtd, loff_t from, size_t len,
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> >
>> > -       return part->parent->_point(part->parent, from + part->offset, len,
>> > -                                   retlen, virt, phys);
>> > +       return mtd_point(part->parent, from + part->offset, len, retlen, virt,
>> > +                        phys);
>> >  }
>> >
>> >  static int part_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> >
>> > -       return part->parent->_unpoint(part->parent, from + part->offset, len);
>> > +       return mtd_unpoint(part->parent, from + part->offset, len);
>> >  }
>> >
>> >  static int part_read_oob(struct mtd_info *mtd, loff_t from,
>> > @@ -126,7 +125,7 @@ static int part_read_oob(struct mtd_info *mtd, loff_t from,
>> >                         return -EINVAL;
>> >         }
>> >
>> > -       res = part->parent->_read_oob(part->parent, from + part->offset, ops);
>> > +       res = mtd_read_oob(part->parent, from + part->offset, ops);
>> >         if (unlikely(res)) {
>> >                 if (mtd_is_bitflip(res))
>> >                         mtd->ecc_stats.corrected++;
>> > @@ -140,48 +139,43 @@ static int part_read_user_prot_reg(struct mtd_info *mtd, loff_t from,
>> >                 size_t len, size_t *retlen, u_char *buf)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       return part->parent->_read_user_prot_reg(part->parent, from, len,
>> > -                                                retlen, buf);
>> > +       return mtd_read_user_prot_reg(part->parent, from, len, retlen, buf);
>> >  }
>> >
>> >  static int part_get_user_prot_info(struct mtd_info *mtd, size_t len,
>> >                                    size_t *retlen, struct otp_info *buf)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       return part->parent->_get_user_prot_info(part->parent, len, retlen,
>> > -                                                buf);
>> > +       return mtd_get_user_prot_info(part->parent, len, retlen, buf);
>> >  }
>> >
>> >  static int part_read_fact_prot_reg(struct mtd_info *mtd, loff_t from,
>> >                 size_t len, size_t *retlen, u_char *buf)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       return part->parent->_read_fact_prot_reg(part->parent, from, len,
>> > -                                                retlen, buf);
>> > +       return mtd_read_fact_prot_reg(part->parent, from, len, retlen, buf);
>> >  }
>> >
>> >  static int part_get_fact_prot_info(struct mtd_info *mtd, size_t len,
>> >                                    size_t *retlen, struct otp_info *buf)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       return part->parent->_get_fact_prot_info(part->parent, len, retlen,
>> > -                                                buf);
>> > +       return mtd_get_fact_prot_info(part->parent, len, retlen, buf);
>> >  }
>> >
>> >  static int part_write(struct mtd_info *mtd, loff_t to, size_t len,
>> >                 size_t *retlen, const u_char *buf)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       return part->parent->_write(part->parent, to + part->offset, len,
>> > -                                   retlen, buf);
>> > +       return mtd_write(part->parent, to + part->offset, len, retlen, buf);
>> >  }
>> >
>> >  static int part_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
>> >                 size_t *retlen, const u_char *buf)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       return part->parent->_panic_write(part->parent, to + part->offset, len,
>> > -                                         retlen, buf);
>> > +       return mtd_panic_write(part->parent, to + part->offset, len, retlen,
>> > +                              buf);
>> >  }
>> >
>> >  static int part_write_oob(struct mtd_info *mtd, loff_t to,
>> > @@ -193,30 +187,29 @@ static int part_write_oob(struct mtd_info *mtd, loff_t to,
>> >                 return -EINVAL;
>> >         if (ops->datbuf && to + ops->len > mtd->size)
>> >                 return -EINVAL;
>> > -       return part->parent->_write_oob(part->parent, to + part->offset, ops);
>> > +       return mtd_write_oob(part->parent, to + part->offset, ops);
>> >  }
>> >
>> >  static int part_write_user_prot_reg(struct mtd_info *mtd, loff_t from,
>> >                 size_t len, size_t *retlen, u_char *buf)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       return part->parent->_write_user_prot_reg(part->parent, from, len,
>> > -                                                 retlen, buf);
>> > +       return mtd_write_user_prot_reg(part->parent, from, len, retlen, buf);
>> >  }
>> >
>> >  static int part_lock_user_prot_reg(struct mtd_info *mtd, loff_t from,
>> >                 size_t len)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       return part->parent->_lock_user_prot_reg(part->parent, from, len);
>> > +       return mtd_lock_user_prot_reg(part->parent, from, len);
>> >  }
>> >
>> >  static int part_writev(struct mtd_info *mtd, const struct kvec *vecs,
>> >                 unsigned long count, loff_t to, size_t *retlen)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       return part->parent->_writev(part->parent, vecs, count,
>> > -                                    to + part->offset, retlen);
>> > +       return mtd_writev(part->parent, vecs, count, to + part->offset,
>> > +                         retlen);
>> >  }
>> >
>> >  static int part_erase(struct mtd_info *mtd, struct erase_info *instr)
>> > @@ -225,7 +218,7 @@ static int part_erase(struct mtd_info *mtd, struct erase_info *instr)
>> >         int ret;
>> >
>> >         instr->addr += part->offset;
>> > -       ret = part->parent->_erase(part->parent, instr);
>> > +       ret = mtd_erase(part->parent, instr);
>> >         if (ret) {
>> >                 if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
>> >                         instr->fail_addr -= part->offset;
>> > @@ -251,51 +244,51 @@ EXPORT_SYMBOL_GPL(mtd_erase_callback);
>> >  static int part_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       return part->parent->_lock(part->parent, ofs + part->offset, len);
>> > +       return mtd_lock(part->parent, ofs + part->offset, len);
>> >  }
>> >
>> >  static int part_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       return part->parent->_unlock(part->parent, ofs + part->offset, len);
>> > +       return mtd_unlock(part->parent, ofs + part->offset, len);
>> >  }
>> >
>> >  static int part_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       return part->parent->_is_locked(part->parent, ofs + part->offset, len);
>> > +       return mtd_is_locked(part->parent, ofs + part->offset, len);
>> >  }
>> >
>> >  static void part_sync(struct mtd_info *mtd)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       part->parent->_sync(part->parent);
>> > +       mtd_sync(part->parent);
>> >  }
>> >
>> >  static int part_suspend(struct mtd_info *mtd)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       return part->parent->_suspend(part->parent);
>> > +       return mtd_suspend(part->parent);
>> >  }
>> >
>> >  static void part_resume(struct mtd_info *mtd)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       part->parent->_resume(part->parent);
>> > +       mtd_resume(part->parent);
>> >  }
>> >
>> >  static int part_block_isreserved(struct mtd_info *mtd, loff_t ofs)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> >         ofs += part->offset;
>> > -       return part->parent->_block_isreserved(part->parent, ofs);
>> > +       return mtd_block_isreserved(part->parent, ofs);
>> >  }
>> >
>> >  static int part_block_isbad(struct mtd_info *mtd, loff_t ofs)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> >         ofs += part->offset;
>> > -       return part->parent->_block_isbad(part->parent, ofs);
>> > +       return mtd_block_isbad(part->parent, ofs);
>> >  }
>> >
>> >  static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
>> > @@ -304,7 +297,7 @@ static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
>> >         int res;
>> >
>> >         ofs += part->offset;
>> > -       res = part->parent->_block_markbad(part->parent, ofs);
>> > +       res = mtd_block_markbad(part->parent, ofs);
>> >         if (!res)
>> >                 mtd->ecc_stats.badblocks++;
>> >         return res;
>> > @@ -313,13 +306,13 @@ static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
>> >  static int part_get_device(struct mtd_info *mtd)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       return part->parent->_get_device(part->parent);
>> > +       return __get_mtd_device(part->parent);
>> >  }
>> >
>> >  static void part_put_device(struct mtd_info *mtd)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> > -       part->parent->_put_device(part->parent);
>> > +       __put_mtd_device(part->parent);
>> >  }
>> >
>> >  static int part_ooblayout_ecc(struct mtd_info *mtd, int section,
>> > @@ -347,8 +340,7 @@ static int part_max_bad_blocks(struct mtd_info *mtd, loff_t ofs, size_t len)
>> >  {
>> >         struct mtd_part *part = mtd_to_part(mtd);
>> >
>> > -       return part->parent->_max_bad_blocks(part->parent,
>> > -                                            ofs + part->offset, len);
>> > +       return mtd_max_bad_blocks(part->parent, ofs + part->offset, len);
>> >  }
>> >
>> >  static inline void free_partition(struct mtd_part *p)
>> > @@ -437,59 +429,32 @@ static struct mtd_part *allocate_partition(struct mtd_info *parent,
>> >
>> >         slave->mtd._read = part_read;
>> >         slave->mtd._write = part_write;
>> > -
>> > -       if (parent->_panic_write)
>> > -               slave->mtd._panic_write = part_panic_write;
>> > -
>> > -       if (parent->_point && parent->_unpoint) {
>> > -               slave->mtd._point = part_point;
>> > -               slave->mtd._unpoint = part_unpoint;
>> > -       }
>> > -
>> > -       if (parent->_read_oob)
>> > -               slave->mtd._read_oob = part_read_oob;
>> > -       if (parent->_write_oob)
>> > -               slave->mtd._write_oob = part_write_oob;
>> > -       if (parent->_read_user_prot_reg)
>> > -               slave->mtd._read_user_prot_reg = part_read_user_prot_reg;
>> > -       if (parent->_read_fact_prot_reg)
>> > -               slave->mtd._read_fact_prot_reg = part_read_fact_prot_reg;
>> > -       if (parent->_write_user_prot_reg)
>> > -               slave->mtd._write_user_prot_reg = part_write_user_prot_reg;
>> > -       if (parent->_lock_user_prot_reg)
>> > -               slave->mtd._lock_user_prot_reg = part_lock_user_prot_reg;
>> > -       if (parent->_get_user_prot_info)
>> > -               slave->mtd._get_user_prot_info = part_get_user_prot_info;
>> > -       if (parent->_get_fact_prot_info)
>> > -               slave->mtd._get_fact_prot_info = part_get_fact_prot_info;
>> > -       if (parent->_sync)
>> > -               slave->mtd._sync = part_sync;
>> > -       if (!partno && !parent->dev.class && parent->_suspend &&
>> > -           parent->_resume) {
>> > +       slave->mtd._panic_write = part_panic_write;
>> > +       slave->mtd._point = part_point;
>> > +       slave->mtd._unpoint = part_unpoint;
>> > +       slave->mtd._read_oob = part_read_oob;
>> > +       slave->mtd._write_oob = part_write_oob;
>> > +       slave->mtd._read_user_prot_reg = part_read_user_prot_reg;
>> > +       slave->mtd._read_fact_prot_reg = part_read_fact_prot_reg;
>> > +       slave->mtd._write_user_prot_reg = part_write_user_prot_reg;
>> > +       slave->mtd._lock_user_prot_reg = part_lock_user_prot_reg;
>> > +       slave->mtd._get_user_prot_info = part_get_user_prot_info;
>> > +       slave->mtd._get_fact_prot_info = part_get_fact_prot_info;
>> > +       slave->mtd._sync = part_sync;
>> > +       if (!partno && !parent->dev.class) {
>> >                 slave->mtd._suspend = part_suspend;
>> >                 slave->mtd._resume = part_resume;
>> >         }
>> > -       if (parent->_writev)
>> > -               slave->mtd._writev = part_writev;
>> > -       if (parent->_lock)
>> > -               slave->mtd._lock = part_lock;
>> > -       if (parent->_unlock)
>> > -               slave->mtd._unlock = part_unlock;
>> > -       if (parent->_is_locked)
>> > -               slave->mtd._is_locked = part_is_locked;
>> > -       if (parent->_block_isreserved)
>> > -               slave->mtd._block_isreserved = part_block_isreserved;
>> > -       if (parent->_block_isbad)
>> > -               slave->mtd._block_isbad = part_block_isbad;
>> > -       if (parent->_block_markbad)
>> > -               slave->mtd._block_markbad = part_block_markbad;
>> > -       if (parent->_max_bad_blocks)
>> > -               slave->mtd._max_bad_blocks = part_max_bad_blocks;
>> > -
>> > -       if (parent->_get_device)
>> > -               slave->mtd._get_device = part_get_device;
>> > -       if (parent->_put_device)
>> > -               slave->mtd._put_device = part_put_device;
>> > +       slave->mtd._writev = part_writev;
>> > +       slave->mtd._lock = part_lock;
>> > +       slave->mtd._unlock = part_unlock;
>> > +       slave->mtd._is_locked = part_is_locked;
>> > +       slave->mtd._block_isreserved = part_block_isreserved;
>> > +       slave->mtd._block_isbad = part_block_isbad;
>> > +       slave->mtd._block_markbad = part_block_markbad;
>> > +       slave->mtd._max_bad_blocks = part_max_bad_blocks;
>> > +       slave->mtd._get_device = part_get_device;
>> > +       slave->mtd._put_device = part_put_device;
>> >
>> >         slave->mtd._erase = part_erase;
>> >         slave->parent = parent;
>> > --
>> > 2.11.0
>> >
>

Re: [PATCH v3 0/4] mtd: Preparation patches for the SPI NAND framework

[Boris Brezillon]

On Fri, 15 Dec 2017 13:39:50 +0100
Boris Brezillon <boris.brezillon@free-electrons.com> wrote:

> Hello,
> 
> Here is a set of patches to prepare the introduction of the generic
> NAND and SPI frameworks.
> 
> The last 2 patches have already been submitted here [1], and the first
> two are new, and should also help simplify other drivers/frameworks
> in providing generic code for already existing logic.
> 
> If you want to see the overall picture of the SPI NAND framework you can
> have a look at this branch [2].
> 
> Regards,
> 
> Boris
> 
> [1]https://patchwork.ozlabs.org/patch/780477/
> [2]https://github.com/bbrezillon/linux-0day/commits/nand/spi-nand-squashed
> 
> Boris Brezillon (4):
>   mtd: Do not allow MTD devices with inconsistent erase properties
>   mtd: Add an helper to make erase request aligned on ->erasesize
>   mtd: Stop directly calling master ->_xxx() hooks from mtdpart code
>   mtd: Fallback to ->_read/write_oob() when ->_read/write() is missing

Applied the whole series. I'm preparing a patch to remove unneeded
checks done in part_read/write_oob() (as suggested by Peter).

> 
>  drivers/mtd/devices/docg3.c        |  65 -----------------
>  drivers/mtd/mtdcore.c              |  36 +++++++++-
>  drivers/mtd/mtdpart.c              | 141 ++++++++++++++-----------------------
>  drivers/mtd/nand/nand_base.c       |  56 ---------------
>  drivers/mtd/onenand/onenand_base.c |  63 -----------------
>  include/linux/mtd/mtd.h            |  28 ++++++++
>  6 files changed, 115 insertions(+), 274 deletions(-)
> 

Re: [PATCH v3 3/4] mtd: Stop directly calling master ->_xxx() hooks from mtdpart code

[Boris Brezillon]

+Ladislav

On Fri, 15 Dec 2017 13:39:53 +0100
Boris Brezillon <boris.brezillon@free-electrons.com> wrote:

> The MTD layer provides several wrappers around mtd->_xxx() hooks. Call
> these wrappers instead of directly dereferencing the associated ->_xxx()
> pointer.
> 
> This change has been motivated by another rework letting the core
> handle the case where ->_read/write_oob() are implemented but not
> ->_read/write(). In this case, we want mtd_read/write() to fall back to
> ->_read/write_oob() when ->_read/write() are NULL. The problem is,  
> mtdpart is directly calling the ->_xxx() instead of using the wrappers,
> thus leading to a NULL pointer exception.
> 
> Even though we only need to do the change for part_read/write(), going
> through those wrappers for all kind of part -> master operation
> propagation is a good thing, because other wrappers might become
> smarter over time, and the duplicated check overhead (parameters will
> be checked at the partition and master level instead of only at the
> partition level) should be negligible.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> ---
> Changes in v3:
> - unconditionally assign part wrappers as suggested by Brian
> 
> Changes in v2:
> - new patch needed to fix a NULL pointer dereference BUG
> ---
>  drivers/mtd/mtdpart.c | 141 +++++++++++++++++++-------------------------------
>  1 file changed, 53 insertions(+), 88 deletions(-)
> 
> diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> index be088bccd593..e83c9d870b11 100644
> --- a/drivers/mtd/mtdpart.c
> +++ b/drivers/mtd/mtdpart.c
> @@ -74,8 +74,7 @@ static int part_read(struct mtd_info *mtd, loff_t from, size_t len,
>  	int res;
>  
>  	stats = part->parent->ecc_stats;
> -	res = part->parent->_read(part->parent, from + part->offset, len,
> -				  retlen, buf);
> +	res = mtd_read(part->parent, from + part->offset, len, retlen, buf);

This change introduced a regression (reported by Ladislav) because
mtd_read() does not return the number of bitflips and instead returns 0
if we are below ->bitflips_threshold and -EUCLEAN if we're equal
or above. That's a problem in 2 situations:
1/ when ->bitflips_threshold is customized for a specific partition,
   the custom value is ignored in favor of the one set on the master MTD
   device
2/ when PARTITIONED_MASTER is not defined, ->bitflip_threshold is not
   initialized (->bitflip_threshold = 0), thus triggering -EUCLEAN
   every time we read a page

I fear this patch might introduce other subtle regression so I plan to
drop it entirely.

Regards,

Boris

>  	if (unlikely(mtd_is_eccerr(res)))
>  		mtd->ecc_stats.failed +=
>  			part->parent->ecc_stats.failed - stats.failed;

Re: [PATCH v3 4/4] mtd: Fallback to ->_read/write_oob() when ->_read/write() is missing

[Boris Brezillon]

On Fri, 15 Dec 2017 13:39:54 +0100
Boris Brezillon <boris.brezillon@free-electrons.com> wrote:

> Some MTD sublayers/drivers are implementing ->_read/write_oob() and
> provide dummy wrappers for their ->_read/write() implementations.
> Let the core handle this case instead of duplicating the logic.

Also dropped this patch since it depends on patch 3. I'll send a new
version soon.

> 
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
> Acked-by: Brian Norris <computersforpeace@gmail.com>
> ---
> Changes in v3:
> - none
> 
> Changes in v2:
> - none
> ---
>  drivers/mtd/devices/docg3.c        | 65 --------------------------------------
>  drivers/mtd/mtdcore.c              | 31 ++++++++++++++++--
>  drivers/mtd/nand/nand_base.c       | 56 --------------------------------
>  drivers/mtd/onenand/onenand_base.c | 63 ------------------------------------
>  4 files changed, 29 insertions(+), 186 deletions(-)
> 
> diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
> index 0806f72102c0..5fb5e93d1547 100644
> --- a/drivers/mtd/devices/docg3.c
> +++ b/drivers/mtd/devices/docg3.c
> @@ -990,36 +990,6 @@ static int doc_read_oob(struct mtd_info *mtd, loff_t from,
>  	goto out;
>  }
>  
> -/**
> - * doc_read - Read bytes from flash
> - * @mtd: the device
> - * @from: the offset from first block and first page, in bytes, aligned on page
> - *        size
> - * @len: the number of bytes to read (must be a multiple of 4)
> - * @retlen: the number of bytes actually read
> - * @buf: the filled in buffer
> - *
> - * Reads flash memory pages. This function does not read the OOB chunk, but only
> - * the page data.
> - *
> - * Returns 0 if read successful, of -EIO, -EINVAL if an error occurred
> - */
> -static int doc_read(struct mtd_info *mtd, loff_t from, size_t len,
> -	     size_t *retlen, u_char *buf)
> -{
> -	struct mtd_oob_ops ops;
> -	size_t ret;
> -
> -	memset(&ops, 0, sizeof(ops));
> -	ops.datbuf = buf;
> -	ops.len = len;
> -	ops.mode = MTD_OPS_AUTO_OOB;
> -
> -	ret = doc_read_oob(mtd, from, &ops);
> -	*retlen = ops.retlen;
> -	return ret;
> -}
> -
>  static int doc_reload_bbt(struct docg3 *docg3)
>  {
>  	int block = DOC_LAYOUT_BLOCK_BBT;
> @@ -1513,39 +1483,6 @@ static int doc_write_oob(struct mtd_info *mtd, loff_t ofs,
>  	return ret;
>  }
>  
> -/**
> - * doc_write - Write a buffer to the chip
> - * @mtd: the device
> - * @to: the offset from first block and first page, in bytes, aligned on page
> - *      size
> - * @len: the number of bytes to write (must be a full page size, ie. 512)
> - * @retlen: the number of bytes actually written (0 or 512)
> - * @buf: the buffer to get bytes from
> - *
> - * Writes data to the chip.
> - *
> - * Returns 0 if write successful, -EIO if write error
> - */
> -static int doc_write(struct mtd_info *mtd, loff_t to, size_t len,
> -		     size_t *retlen, const u_char *buf)
> -{
> -	struct docg3 *docg3 = mtd->priv;
> -	int ret;
> -	struct mtd_oob_ops ops;
> -
> -	doc_dbg("doc_write(to=%lld, len=%zu)\n", to, len);
> -	ops.datbuf = (char *)buf;
> -	ops.len = len;
> -	ops.mode = MTD_OPS_PLACE_OOB;
> -	ops.oobbuf = NULL;
> -	ops.ooblen = 0;
> -	ops.ooboffs = 0;
> -
> -	ret = doc_write_oob(mtd, to, &ops);
> -	*retlen = ops.retlen;
> -	return ret;
> -}
> -
>  static struct docg3 *sysfs_dev2docg3(struct device *dev,
>  				     struct device_attribute *attr)
>  {
> @@ -1866,8 +1803,6 @@ static int __init doc_set_driver_info(int chip_id, struct mtd_info *mtd)
>  	mtd->writebufsize = mtd->writesize = DOC_LAYOUT_PAGE_SIZE;
>  	mtd->oobsize = DOC_LAYOUT_OOB_SIZE;
>  	mtd->_erase = doc_erase;
> -	mtd->_read = doc_read;
> -	mtd->_write = doc_write;
>  	mtd->_read_oob = doc_read_oob;
>  	mtd->_write_oob = doc_write_oob;
>  	mtd->_block_isbad = doc_block_isbad;
> diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
> index 642c35dde686..d7ab091b36b2 100644
> --- a/drivers/mtd/mtdcore.c
> +++ b/drivers/mtd/mtdcore.c
> @@ -1058,7 +1058,20 @@ int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
>  	 * representing the maximum number of bitflips that were corrected on
>  	 * any one ecc region (if applicable; zero otherwise).
>  	 */
> -	ret_code = mtd->_read(mtd, from, len, retlen, buf);
> +	if (mtd->_read) {
> +		ret_code = mtd->_read(mtd, from, len, retlen, buf);
> +	} else if (mtd->_read_oob) {
> +		struct mtd_oob_ops ops = {
> +			.len = len,
> +			.datbuf = buf,
> +		};
> +
> +		ret_code = mtd->_read_oob(mtd, from, &ops);
> +		*retlen = ops.retlen;
> +	} else {
> +		return -ENOTSUPP;
> +	}
> +
>  	if (unlikely(ret_code < 0))
>  		return ret_code;
>  	if (mtd->ecc_strength == 0)
> @@ -1073,11 +1086,25 @@ int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
>  	*retlen = 0;
>  	if (to < 0 || to >= mtd->size || len > mtd->size - to)
>  		return -EINVAL;
> -	if (!mtd->_write || !(mtd->flags & MTD_WRITEABLE))
> +	if ((!mtd->_write && !mtd->_write_oob) ||
> +	    !(mtd->flags & MTD_WRITEABLE))
>  		return -EROFS;
>  	if (!len)
>  		return 0;
>  	ledtrig_mtd_activity();
> +
> +	if (!mtd->_write) {
> +		struct mtd_oob_ops ops = {
> +			.len = len,
> +			.datbuf = (u8 *)buf,
> +		};
> +		int ret;
> +
> +		ret = mtd->_write_oob(mtd, to, &ops);
> +		*retlen = ops.retlen;
> +		return ret;
> +	}
> +
>  	return mtd->_write(mtd, to, len, retlen, buf);
>  }
>  EXPORT_SYMBOL_GPL(mtd_write);
> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
> index 6135d007a068..889ceadbf607 100644
> --- a/drivers/mtd/nand/nand_base.c
> +++ b/drivers/mtd/nand/nand_base.c
> @@ -2027,33 +2027,6 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
>  }
>  
>  /**
> - * nand_read - [MTD Interface] MTD compatibility function for nand_do_read_ecc
> - * @mtd: MTD device structure
> - * @from: offset to read from
> - * @len: number of bytes to read
> - * @retlen: pointer to variable to store the number of read bytes
> - * @buf: the databuffer to put data
> - *
> - * Get hold of the chip and call nand_do_read.
> - */
> -static int nand_read(struct mtd_info *mtd, loff_t from, size_t len,
> -		     size_t *retlen, uint8_t *buf)
> -{
> -	struct mtd_oob_ops ops;
> -	int ret;
> -
> -	nand_get_device(mtd, FL_READING);
> -	memset(&ops, 0, sizeof(ops));
> -	ops.len = len;
> -	ops.datbuf = buf;
> -	ops.mode = MTD_OPS_PLACE_OOB;
> -	ret = nand_do_read_ops(mtd, from, &ops);
> -	*retlen = ops.retlen;
> -	nand_release_device(mtd);
> -	return ret;
> -}
> -
> -/**
>   * nand_read_oob_std - [REPLACEABLE] the most common OOB data read function
>   * @mtd: mtd info structure
>   * @chip: nand chip info structure
> @@ -2822,33 +2795,6 @@ static int panic_nand_write(struct mtd_info *mtd, loff_t to, size_t len,
>  }
>  
>  /**
> - * nand_write - [MTD Interface] NAND write with ECC
> - * @mtd: MTD device structure
> - * @to: offset to write to
> - * @len: number of bytes to write
> - * @retlen: pointer to variable to store the number of written bytes
> - * @buf: the data to write
> - *
> - * NAND write with ECC.
> - */
> -static int nand_write(struct mtd_info *mtd, loff_t to, size_t len,
> -			  size_t *retlen, const uint8_t *buf)
> -{
> -	struct mtd_oob_ops ops;
> -	int ret;
> -
> -	nand_get_device(mtd, FL_WRITING);
> -	memset(&ops, 0, sizeof(ops));
> -	ops.len = len;
> -	ops.datbuf = (uint8_t *)buf;
> -	ops.mode = MTD_OPS_PLACE_OOB;
> -	ret = nand_do_write_ops(mtd, to, &ops);
> -	*retlen = ops.retlen;
> -	nand_release_device(mtd);
> -	return ret;
> -}
> -
> -/**
>   * nand_do_write_oob - [MTD Interface] NAND write out-of-band
>   * @mtd: MTD device structure
>   * @to: offset to write to
> @@ -4917,8 +4863,6 @@ int nand_scan_tail(struct mtd_info *mtd)
>  	mtd->_erase = nand_erase;
>  	mtd->_point = NULL;
>  	mtd->_unpoint = NULL;
> -	mtd->_read = nand_read;
> -	mtd->_write = nand_write;
>  	mtd->_panic_write = panic_nand_write;
>  	mtd->_read_oob = nand_read_oob;
>  	mtd->_write_oob = nand_write_oob;
> diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
> index 1a6d0e367b89..050ba8a87543 100644
> --- a/drivers/mtd/onenand/onenand_base.c
> +++ b/drivers/mtd/onenand/onenand_base.c
> @@ -1448,38 +1448,6 @@ static int onenand_read_oob_nolock(struct mtd_info *mtd, loff_t from,
>  }
>  
>  /**
> - * onenand_read - [MTD Interface] Read data from flash
> - * @param mtd		MTD device structure
> - * @param from		offset to read from
> - * @param len		number of bytes to read
> - * @param retlen	pointer to variable to store the number of read bytes
> - * @param buf		the databuffer to put data
> - *
> - * Read with ecc
> -*/
> -static int onenand_read(struct mtd_info *mtd, loff_t from, size_t len,
> -	size_t *retlen, u_char *buf)
> -{
> -	struct onenand_chip *this = mtd->priv;
> -	struct mtd_oob_ops ops = {
> -		.len	= len,
> -		.ooblen	= 0,
> -		.datbuf	= buf,
> -		.oobbuf	= NULL,
> -	};
> -	int ret;
> -
> -	onenand_get_device(mtd, FL_READING);
> -	ret = ONENAND_IS_4KB_PAGE(this) ?
> -		onenand_mlc_read_ops_nolock(mtd, from, &ops) :
> -		onenand_read_ops_nolock(mtd, from, &ops);
> -	onenand_release_device(mtd);
> -
> -	*retlen = ops.retlen;
> -	return ret;
> -}
> -
> -/**
>   * onenand_read_oob - [MTD Interface] Read main and/or out-of-band
>   * @param mtd:		MTD device structure
>   * @param from:		offset to read from
> @@ -2129,35 +2097,6 @@ static int onenand_write_oob_nolock(struct mtd_info *mtd, loff_t to,
>  }
>  
>  /**
> - * onenand_write - [MTD Interface] write buffer to FLASH
> - * @param mtd		MTD device structure
> - * @param to		offset to write to
> - * @param len		number of bytes to write
> - * @param retlen	pointer to variable to store the number of written bytes
> - * @param buf		the data to write
> - *
> - * Write with ECC
> - */
> -static int onenand_write(struct mtd_info *mtd, loff_t to, size_t len,
> -	size_t *retlen, const u_char *buf)
> -{
> -	struct mtd_oob_ops ops = {
> -		.len	= len,
> -		.ooblen	= 0,
> -		.datbuf	= (u_char *) buf,
> -		.oobbuf	= NULL,
> -	};
> -	int ret;
> -
> -	onenand_get_device(mtd, FL_WRITING);
> -	ret = onenand_write_ops_nolock(mtd, to, &ops);
> -	onenand_release_device(mtd);
> -
> -	*retlen = ops.retlen;
> -	return ret;
> -}
> -
> -/**
>   * onenand_write_oob - [MTD Interface] NAND write data and/or out-of-band
>   * @param mtd:		MTD device structure
>   * @param to:		offset to write
> @@ -4038,8 +3977,6 @@ int onenand_scan(struct mtd_info *mtd, int maxchips)
>  	mtd->_erase = onenand_erase;
>  	mtd->_point = NULL;
>  	mtd->_unpoint = NULL;
> -	mtd->_read = onenand_read;
> -	mtd->_write = onenand_write;
>  	mtd->_read_oob = onenand_read_oob;
>  	mtd->_write_oob = onenand_write_oob;
>  	mtd->_panic_write = onenand_panic_write;