13 files changed, 21 insertions, 76 deletions

diff --git a/drivers/mtd/chips/cfi_cmdset_0001.c b/drivers/mtd/chips/cfi_cmdset_0001.c
index dc66df6ab58a..2d9669047ed4 100644
--- a/drivers/mtd/chips/cfi_cmdset_0001.c
+++ b/drivers/mtd/chips/cfi_cmdset_0001.c
@@ -1566,9 +1566,6 @@ static int cfi_intelext_write_words (struct mtd_info *mtd, loff_t to , size_t le
 	int chipnum;
 	unsigned long ofs;
 
-	if (!len)
-		return 0;
-
 	chipnum = to >> cfi->chipshift;
 	ofs = to  - (chipnum << cfi->chipshift);
 
diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
index a89d899efad4..c1d4624ce6e7 100644
--- a/drivers/mtd/chips/cfi_cmdset_0002.c
+++ b/drivers/mtd/chips/cfi_cmdset_0002.c
@@ -1246,9 +1246,6 @@ static int cfi_amdstd_write_words(struct mtd_info *mtd, loff_t to, size_t len,
 	unsigned long ofs, chipstart;
 	DECLARE_WAITQUEUE(wait, current);
 
-	if (!len)
-		return 0;
-
 	chipnum = to >> cfi->chipshift;
 	ofs = to  - (chipnum << cfi->chipshift);
 	chipstart = cfi->chips[chipnum].start;
@@ -1487,9 +1484,6 @@ static int cfi_amdstd_write_buffers(struct mtd_info *mtd, loff_t to, size_t len,
 	int chipnum;
 	unsigned long ofs;
 
-	if (!len)
-		return 0;
-
 	chipnum = to >> cfi->chipshift;
 	ofs = to  - (chipnum << cfi->chipshift);
 
@@ -1697,9 +1691,6 @@ static int cfi_amdstd_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
 	int ret = 0;
 	int chipnum;
 
-	if (!len)
-		return 0;
-
 	chipnum = to >> cfi->chipshift;
 	ofs = to - (chipnum << cfi->chipshift);
 	chipstart = cfi->chips[chipnum].start;
diff --git a/drivers/mtd/chips/cfi_cmdset_0020.c b/drivers/mtd/chips/cfi_cmdset_0020.c
index d690b7d6952b..096993f9711e 100644
--- a/drivers/mtd/chips/cfi_cmdset_0020.c
+++ b/drivers/mtd/chips/cfi_cmdset_0020.c
@@ -615,9 +615,6 @@ static int cfi_staa_write_buffers (struct mtd_info *mtd, loff_t to,
 	int chipnum;
 	unsigned long ofs;
 
-	if (!len)
-		return 0;
-
 	chipnum = to >> cfi->chipshift;
 	ofs = to  - (chipnum << cfi->chipshift);
 
diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index ba2d74b01c7e..a4a80b742e65 100644
--- a/drivers/mtd/devices/block2mtd.c
+++ b/drivers/mtd/devices/block2mtd.c
@@ -178,9 +178,6 @@ static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
 	struct block2mtd_dev *dev = mtd->priv;
 	int err;
 
-	if (!len)
-		return 0;
-
 	mutex_lock(&dev->write_mutex);
 	err = _block2mtd_write(dev, buf, to, len, retlen);
 	mutex_unlock(&dev->write_mutex);
diff --git a/drivers/mtd/devices/lart.c b/drivers/mtd/devices/lart.c
index 6fb8dba76959..82bd00af5cc3 100644
--- a/drivers/mtd/devices/lart.c
+++ b/drivers/mtd/devices/lart.c
@@ -437,9 +437,6 @@ static int flash_read (struct mtd_info *mtd,loff_t from,size_t len,size_t *retle
    printk (KERN_DEBUG "%s(from = 0x%.8x, len = %d)\n", __func__, (__u32)from, len);
 #endif
 
-   /* sanity checks */
-   if (!len) return (0);
-
    /* we always read len bytes */
    *retlen = len;
 
diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index 45cc4a1ae5b0..1924d247c1cb 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -346,10 +346,6 @@ static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
 	pr_debug("%s: %s from 0x%08x, len %zd\n", dev_name(&flash->spi->dev),
 			__func__, (u32)from, len);
 
-	/* sanity checks */
-	if (!len)
-		return 0;
-
 	spi_message_init(&m);
 	memset(t, 0, (sizeof t));
 
@@ -408,10 +404,6 @@ static int m25p80_write(struct mtd_info *mtd, loff_t to, size_t len,
 	pr_debug("%s: %s to 0x%08x, len %zd\n", dev_name(&flash->spi->dev),
 			__func__, (u32)to, len);
 
-	/* sanity checks */
-	if (!len)
-		return(0);
-
 	spi_message_init(&m);
 	memset(t, 0, (sizeof t));
 
@@ -495,10 +487,6 @@ static int sst_write(struct mtd_info *mtd, loff_t to, size_t len,
 	pr_debug("%s: %s to 0x%08x, len %zd\n", dev_name(&flash->spi->dev),
 			__func__, (u32)to, len);
 
-	/* sanity checks */
-	if (!len)
-		return 0;
-
 	spi_message_init(&m);
 	memset(t, 0, (sizeof t));
 
diff --git a/drivers/mtd/devices/mtd_dataflash.c b/drivers/mtd/devices/mtd_dataflash.c
index c76b4464e8b9..928fb0e6d73a 100644
--- a/drivers/mtd/devices/mtd_dataflash.c
+++ b/drivers/mtd/devices/mtd_dataflash.c
@@ -249,10 +249,6 @@ static int dataflash_read(struct mtd_info *mtd, loff_t from, size_t len,
 	pr_debug("%s: read 0x%x..0x%x\n", dev_name(&priv->spi->dev),
 			(unsigned)from, (unsigned)(from + len));
 
-	/* Sanity checks */
-	if (!len)
-		return 0;
-
 	/* Calculate flash page/byte address */
 	addr = (((unsigned)from / priv->page_size) << priv->page_offset)
 		+ ((unsigned)from % priv->page_size);
@@ -321,10 +317,6 @@ static int dataflash_write(struct mtd_info *mtd, loff_t to, size_t len,
 	pr_debug("%s: write 0x%x..0x%x\n",
 		dev_name(&spi->dev), (unsigned)to, (unsigned)(to + len));
 
-	/* Sanity checks */
-	if (!len)
-		return 0;
-
 	spi_message_init(&msg);
 
 	x[0].tx_buf = command = priv->command;
@@ -479,8 +471,6 @@ static ssize_t otp_read(struct spi_device *spi, unsigned base,
 
 	if ((off + len) > 64)
 		len = 64 - off;
-	if (len == 0)
-		return len;
 
 	spi_message_init(&m);
 
diff --git a/drivers/mtd/devices/spear_smi.c b/drivers/mtd/devices/spear_smi.c
index 2cdbcc65b39f..f45dd37b771e 100644
--- a/drivers/mtd/devices/spear_smi.c
+++ b/drivers/mtd/devices/spear_smi.c
@@ -563,9 +563,6 @@ static int spear_mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
 	u32 ctrlreg1, val;
 	int ret;
 
-	if (!len)
-		return 0;
-
 	if (!flash || !dev)
 		return -ENODEV;
 
@@ -662,9 +659,6 @@ static int spear_mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
 	if (!flash || !dev)
 		return -ENODEV;
 
-	if (!len)
-		return 0;
-
 	if (flash->bank > dev->num_flashes - 1) {
 		dev_err(&dev->pdev->dev, "Invalid Bank Num");
 		return -EINVAL;
diff --git a/drivers/mtd/devices/sst25l.c b/drivers/mtd/devices/sst25l.c
index 5c2613c99e4a..51b2df33b8e9 100644
--- a/drivers/mtd/devices/sst25l.c
+++ b/drivers/mtd/devices/sst25l.c
@@ -220,10 +220,6 @@ static int sst25l_read(struct mtd_info *mtd, loff_t from, size_t len,
 	unsigned char command[4];
 	int ret;
 
-	/* Sanity checking */
-	if (len == 0)
-		return 0;
-
 	spi_message_init(&message);
 	memset(&transfer, 0, sizeof(transfer));
 
@@ -265,10 +261,6 @@ static int sst25l_write(struct mtd_info *mtd, loff_t to, size_t len,
 	int i, j, ret, bytes, copied = 0;
 	unsigned char command[5];
 
-	/* Sanity checks */
-	if (!len)
-		return 0;
-
 	if ((uint32_t)to % mtd->writesize)
 		return -EINVAL;
 
diff --git a/drivers/mtd/lpddr/lpddr_cmds.c b/drivers/mtd/lpddr/lpddr_cmds.c
index a92906ba535d..d3cfe26beeaa 100644
--- a/drivers/mtd/lpddr/lpddr_cmds.c
+++ b/drivers/mtd/lpddr/lpddr_cmds.c
@@ -639,7 +639,6 @@ static int lpddr_writev(struct mtd_info *mtd, const struct kvec *vecs,
 	int chipnum;
 	unsigned long ofs, vec_seek, i;
 	int wbufsize = 1 << lpddr->qinfo->BufSizeShift;
-
 	size_t len = 0;
 
 	for (i = 0; i < count; i++)
diff --git a/drivers/mtd/maps/vmu-flash.c b/drivers/mtd/maps/vmu-flash.c
index 48a803e2cd2e..2e2b0945edc7 100644
--- a/drivers/mtd/maps/vmu-flash.c
+++ b/drivers/mtd/maps/vmu-flash.c
@@ -360,9 +360,6 @@ static int vmu_flash_read(struct mtd_info *mtd, loff_t from, size_t len,
 	int index = 0, retval, partition, leftover, numblocks;
 	unsigned char cx;
 
-	if (len < 1)
-		return -EIO;
-
 	mpart = mtd->priv;
 	mdev = mpart->mdev;
 	partition = mpart->partition;
@@ -434,11 +431,6 @@ static int vmu_flash_write(struct mtd_info *mtd, loff_t to, size_t len,
 	partition = mpart->partition;
 	card = maple_get_drvdata(mdev);
 
-	/* simple sanity checks */
-	if (len < 1) {
-		error = -EIO;
-		goto failed;
-	}
 	numblocks = card->parts[partition].numblocks;
 	if (to + len > numblocks * card->blocklen)
 		len = numblocks * card->blocklen - to;
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index b20346e9fecb..6acc4fb254e2 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -695,6 +695,11 @@ int mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
 		return -EINVAL;
 	if (!(mtd->flags & MTD_WRITEABLE))
 		return -EROFS;
+	if (!instr->len) {
+		instr->state = MTD_ERASE_DONE;
+		mtd_erase_callback(instr);
+		return 0;
+	}
 	return mtd->_erase(mtd, instr);
 }
 EXPORT_SYMBOL_GPL(mtd_erase);
@@ -713,6 +718,8 @@ int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
 		return -EOPNOTSUPP;
 	if (from < 0 || from > mtd->size || len > mtd->size - from)
 		return -EINVAL;
+	if (!len)
+		return 0;
 	return mtd->_point(mtd, from, len, retlen, virt, phys);
 }
 EXPORT_SYMBOL_GPL(mtd_point);
@@ -724,6 +731,8 @@ int mtd_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
 		return -EOPNOTSUPP;
 	if (from < 0 || from > mtd->size || len > mtd->size - from)
 		return -EINVAL;
+	if (!len)
+		return 0;
 	return mtd->_unpoint(mtd, from, len);
 }
 EXPORT_SYMBOL_GPL(mtd_unpoint);
@@ -750,6 +759,8 @@ int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
 	*retlen = 0;
 	if (from < 0 || from > mtd->size || len > mtd->size - from)
 		return -EINVAL;
+	if (!len)
+		return 0;
 	return mtd->_read(mtd, from, len, retlen, buf);
 }
 EXPORT_SYMBOL_GPL(mtd_read);
@@ -762,6 +773,8 @@ int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
 		return -EINVAL;
 	if (!mtd->_write || !(mtd->flags & MTD_WRITEABLE))
 		return -EROFS;
+	if (!len)
+		return 0;
 	return mtd->_write(mtd, to, len, retlen, buf);
 }
 EXPORT_SYMBOL_GPL(mtd_write);
@@ -783,6 +796,8 @@ int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
 		return -EINVAL;
 	if (!(mtd->flags & MTD_WRITEABLE))
 		return -EROFS;
+	if (!len)
+		return 0;
 	return mtd->_panic_write(mtd, to, len, retlen, buf);
 }
 EXPORT_SYMBOL_GPL(mtd_panic_write);
@@ -794,6 +809,8 @@ int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 		return -EOPNOTSUPP;
 	if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
 		return -EINVAL;
+	if (!len)
+		return 0;
 	return mtd->_lock(mtd, ofs, len);
 }
 EXPORT_SYMBOL_GPL(mtd_lock);
@@ -804,6 +821,8 @@ int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 		return -EOPNOTSUPP;
 	if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
 		return -EINVAL;
+	if (!len)
+		return 0;
 	return mtd->_unlock(mtd, ofs, len);
 }
 EXPORT_SYMBOL_GPL(mtd_unlock);
@@ -814,6 +833,8 @@ int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 		return -EOPNOTSUPP;
 	if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
 		return -EINVAL;
+	if (!len)
+		return 0;
 	return mtd->_is_locked(mtd, ofs, len);
 }
 EXPORT_SYMBOL_GPL(mtd_is_locked);
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index dd182c8591a9..5822e3a47ded 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -1614,9 +1614,6 @@ static int nand_read(struct mtd_info *mtd, loff_t from, size_t len,
 	struct mtd_oob_ops ops;
 	int ret;
 
-	if (!len)
-		return 0;
-
 	nand_get_device(chip, mtd, FL_READING);
 	ops.len = len;
 	ops.datbuf = buf;
@@ -2313,10 +2310,6 @@ static int panic_nand_write(struct mtd_info *mtd, loff_t to, size_t len,
 	struct mtd_oob_ops ops;
 	int ret;
 
-	/* Do not allow reads past end of device */
-	if (!len)
-		return 0;
-
 	/* Wait for the device to get ready */
 	panic_nand_wait(mtd, chip, 400);
 
@@ -2351,9 +2344,6 @@ static int nand_write(struct mtd_info *mtd, loff_t to, size_t len,
 	struct mtd_oob_ops ops;
 	int ret;
 
-	if (!len)
-		return 0;
-
 	nand_get_device(chip, mtd, FL_WRITING);
 	ops.len = len;
 	ops.datbuf = (uint8_t *)buf;