diff options
| author | Chris Lesiak <chris.lesiak@licor.com> | 2019-03-07 20:39:00 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-31 06:46:34 -0700 |
| commit | cc211863ac79517b2df1d00f14d1cb803081fa67 (patch) | |
| tree | 5bd85d50d1cc139705192f4a9c1f60841b260a37 | |
| parent | 8f7f333af9f6f799930c5d66b40a59501122003d (diff) | |
| download | linux-stable-cc211863ac79517b2df1d00f14d1cb803081fa67.tar.gz linux-stable-cc211863ac79517b2df1d00f14d1cb803081fa67.tar.bz2 linux-stable-cc211863ac79517b2df1d00f14d1cb803081fa67.zip | |
spi: Fix zero length xfer bug
[ Upstream commit 5442dcaa0d90fc376bdfc179a018931a8f43dea4 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/spi/spi.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 9da0bc5a036c..88a8a8edd44b 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -982,6 +982,8 @@ 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) |