mtd: move zero length verification to MTD API functions

In many places in drivers we verify for the zero length, but this is very
inconsistent across drivers. This is obviously the right thing to do, though.
This patch moves the check to the MTD API functions instead and removes a lot
of duplication.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Reviewed-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

6 files changed, 0 insertions, 42 deletions

diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index ba2d74b..a4a80b7 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 6fb8dba..82bd00a 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 45cc4a1..1924d24 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 c76b446..928fb0e 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 2cdbcc6..f45dd37 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 5c2613c..51b2df3 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;