From: Martin Sperl <kernel@martin.sperl.org>
Date: Sat, 30 Mar 2019 09:30:59 +0000 (+0000)
Subject: spi: bcm2835aux: remove dangerous uncontrolled read of fifo
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=c7de8500fd8ecbb544846dd5f11dca578c3777e1;p=android-x86%2Fkernel.git

spi: bcm2835aux: remove dangerous uncontrolled read of fifo

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: 1ea29b39f4c812ec ("spi: bcm2835aux: add bcm2835 auxiliary spi device...")
Suggested-by: Hubert Denkmair <h.denkmair@intence.de>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---

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)