[PATCH V2 2/9] spi: bcm2835aux: remove dangerous uncontrolled read of fifo

kernel
2019-03-24T17:51:04Z

This read of the fifo is a potential candidate for a race condition
as the spi transfer is not necessarily finished and so can lead to
an early read of the fifo that still misses data.

So it has been removed.

Fixes: 1ea29b39f4c812ece2f936065a0a3d6fe44a263e

Suggested-by: Hubert Denkmair <h.denkmair@intence.de>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
---
drivers/spi/spi-bcm2835aux.c | 7 -------
1 file changed, 7 deletions(-)

diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c
index 41366d0a16af..0838dbda57c7 100644
--- a/drivers/spi/spi-bcm2835aux.c
+++ b/drivers/spi/spi-bcm2835aux.c
@@ -194,13 +194,6 @@ static void bcm2835aux_spi_transfer_helper(struct bcm2835aux_spi *bs)
BCM2835_AUX_SPI_STAT_TX_FULL))) {
bcm2835aux_wr_fifo(bs);
}
-
- /* and check if we have reached "done" */
- while (bs->rx_len &&
- (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT) &
- BCM2835_AUX_SPI_STAT_BUSY))) {
- bcm2835aux_rd_fifo(bs);
- }
}

static irqreturn_t bcm2835aux_spi_interrupt(int irq, void *dev_id)