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;