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authorChris Lesiak <chris.lesiak@licor.com>2019-03-07 20:39:00 +0000
committerMark Brown <broonie@kernel.org>2019-03-11 16:40:00 +0000
commit5442dcaa0d90fc376bdfc179a018931a8f43dea4 (patch)
tree534004708e588143978eee01bac91227cad942cb /drivers/spi/spi.c
parent0e836c3bea7da04cd4e2ed22d8c20654d5a09273 (diff)
spi: Fix zero length xfer bug
This fixes a bug for messages containing both zero length and unidirectional xfers. The function spi_map_msg will allocate dummy tx and/or rx buffers for use with unidirectional transfers when the hardware can only do a bidirectional transfer. That dummy buffer will be used in place of a NULL buffer even when the xfer length is 0. Then in the function __spi_map_msg, if he hardware can dma, the zero length xfer will have spi_map_buf called on the dummy buffer. Eventually, __sg_alloc_table is called and returns -EINVAL because nents == 0. This fix prevents the error by not using the dummy buffer when the xfer length is zero. Signed-off-by: Chris Lesiak <chris.lesiak@licor.com> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi.c')
-rw-r--r--drivers/spi/spi.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 93986f879b09..2be394d3bc59 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1039,6 +1039,8 @@ static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
if (max_tx || max_rx) {
list_for_each_entry(xfer, &msg->transfers,
transfer_list) {
+ if (!xfer->len)
+ continue;
if (!xfer->tx_buf)
xfer->tx_buf = ctlr->dummy_tx;
if (!xfer->rx_buf)