i2c: ismt: use correct length when copy buffer

commit 979bbf7b upstream.

In block write mode, when encapsulating dma_buffer, first element is
'command', the rest is data buffer, so only copy actual data buffer
starting from block[1] with the size indicating by block[0].
Signed-off-by: Fan Du <fan.du@intel.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/i2c/busses/i2c-ismt.c

@@ -497,7 +497,7 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr,
 			desc->wr_len_cmd = dma_size;
 			desc->control |= ISMT_DESC_BLK;
 			priv->dma_buffer[0] = command;
-			memcpy(&priv->dma_buffer[1], &data->block[1], dma_size);
+			memcpy(&priv->dma_buffer[1], &data->block[1], dma_size - 1);
 		} else {
 			/* Block Read */
 			dev_dbg(dev, "I2C_SMBUS_BLOCK_DATA:  READ\n");
@@ -525,7 +525,7 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr,
 			desc->wr_len_cmd = dma_size;
 			desc->control |= ISMT_DESC_I2C;
 			priv->dma_buffer[0] = command;
-			memcpy(&priv->dma_buffer[1], &data->block[1], dma_size);
+			memcpy(&priv->dma_buffer[1], &data->block[1], dma_size - 1);
 		} else {
 			/* i2c Block Read */
 			dev_dbg(dev, "I2C_SMBUS_I2C_BLOCK_DATA:  READ\n");