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| author | Chris Lesiak <chris.lesiak@licor.com> | 2019-03-07 21:39:00 +0100 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2019-03-11 17:40:00 +0100 |
| commit | 5442dcaa0d90fc376bdfc179a018931a8f43dea4 (patch) | |
| tree | 534004708e588143978eee01bac91227cad942cb /drivers/spi/spi.c | |
| parent | spi: sh-msiof: Restrict bits per word to 8/16/24/32 on R-Car Gen2/3 (diff) | |
| download | linux-5442dcaa0d90fc376bdfc179a018931a8f43dea4.tar.xz linux-5442dcaa0d90fc376bdfc179a018931a8f43dea4.zip | |
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.c | 2 |
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) |