1 files changed, 28 insertions, 17 deletions

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index ca935df80c88..e19512ffc40e 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -552,6 +552,9 @@ int spi_register_board_info(struct spi_board_info const *info, unsigned n)
         struct boardinfo *bi;
         int i;
 
+        if (!n)
+                return -EINVAL;
+
         bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
         if (!bi)
                 return -ENOMEM;
@@ -789,27 +792,35 @@ static int spi_transfer_one_message(struct spi_master *master,
         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
                 trace_spi_transfer_start(msg, xfer);
 
-                reinit_completion(&master->xfer_completion);
+                if (xfer->tx_buf || xfer->rx_buf) {
+                        reinit_completion(&master->xfer_completion);
 
-                ret = master->transfer_one(master, msg->spi, xfer);
-                if (ret < 0) {
-                        dev_err(&msg->spi->dev,
-                                "SPI transfer failed: %d\n", ret);
-                        goto out;
-                }
+                        ret = master->transfer_one(master, msg->spi, xfer);
+                        if (ret < 0) {
+                                dev_err(&msg->spi->dev,
+                                        "SPI transfer failed: %d\n", ret);
+                                goto out;
+                        }
 
-                if (ret > 0) {
-                        ret = 0;
-                        ms = xfer->len * 8 * 1000 / xfer->speed_hz;
-                        ms += ms + 100; /* some tolerance */
+                        if (ret > 0) {
+                                ret = 0;
+                                ms = xfer->len * 8 * 1000 / xfer->speed_hz;
+                                ms += ms + 100; /* some tolerance */
 
-                        ms = wait_for_completion_timeout(&master->xfer_completion,
-                                                         msecs_to_jiffies(ms));
-                }
+                                ms = wait_for_completion_timeout(&master->xfer_completion,
+                                                                 msecs_to_jiffies(ms));
+                        }
 
-                if (ms == 0) {
-                        dev_err(&msg->spi->dev, "SPI transfer timed out\n");
-                        msg->status = -ETIMEDOUT;
+                        if (ms == 0) {
+                                dev_err(&msg->spi->dev,
+                                        "SPI transfer timed out\n");
+                                msg->status = -ETIMEDOUT;
+                        }
+                } else {
+                        if (xfer->len)
+                                dev_err(&msg->spi->dev,
+                                        "Bufferless transfer has length %u\n",
+                                        xfer->len);
                 }
 
                 trace_spi_transfer_stop(msg, xfer);