1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index cb6c5cb0df0b..38af18645133 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -2258,7 +2258,8 @@ EXPORT_SYMBOL(i2c_put_adapter);
 /**
  * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
  * @msg: the message to be checked
- * @threshold: the minimum number of bytes for which using DMA makes sense
+ * @threshold: the minimum number of bytes for which using DMA makes sense.
+ *             Should at least be 1.
  *
  * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
  *         Or a valid pointer to be used with DMA. After use, release it by
@@ -2268,7 +2269,11 @@ EXPORT_SYMBOL(i2c_put_adapter);
  */
 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
 {
-        if (msg->len < threshold)
+        /* also skip 0-length msgs for bogus thresholds of 0 */
+        if (!threshold)
+                pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
+                         msg->addr);
+        if (msg->len < threshold || msg->len == 0)
                 return NULL;
 
         if (msg->flags & I2C_M_DMA_SAFE)