diff mbox

spi: davinci: fix spurious i/o error

Message ID 108883742c4b44d338ea0816abeeb2901a2afcd5.1448361028.git.nsekhar@ti.com
State Accepted
Commit 7f3ac71ac3b05aaa2c55c266448f973188275a8c
Headers show

Commit Message

Sekhar Nori Nov. 24, 2015, 10:34 a.m. UTC
davinci_spi_bufs() uses wait_for_completion_interruptible()
without bothering to handle -ERESTARTSYS. Due to this,
sometime, it returns prematurely when a signal is received.
Since the return value is never checked, userspace eventually
receives a spurious -EIO.

To fix this, use un-interruptible wait_for_completion_timeout().

Signed-off-by: Sekhar Nori <nsekhar@ti.com>

---
 drivers/spi/spi-davinci.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

-- 
2.4.4.408.g16da57c

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Comments

Sekhar Nori Nov. 24, 2015, 12:27 p.m. UTC | #1
On Tuesday 24 November 2015 04:04 PM, Sekhar Nori wrote:
> davinci_spi_bufs() uses wait_for_completion_interruptible()

> without bothering to handle -ERESTARTSYS. Due to this,

> sometime, it returns prematurely when a signal is received.

> Since the return value is never checked, userspace eventually

> receives a spurious -EIO.

> 

> To fix this, use un-interruptible wait_for_completion_timeout().

> 

> Signed-off-by: Sekhar Nori <nsekhar@ti.com>

> ---

>  drivers/spi/spi-davinci.c | 5 ++++-

>  1 file changed, 4 insertions(+), 1 deletion(-)

> 

> diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c

> index 7d3af3eacf57..38026aa1afd7 100644

> --- a/drivers/spi/spi-davinci.c

> +++ b/drivers/spi/spi-davinci.c

> @@ -703,7 +703,10 @@ static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)

>  

>  	/* Wait for the transfer to complete */

>  	if (spicfg->io_type != SPI_IO_TYPE_POLL) {

> -		wait_for_completion_interruptible(&(dspi->done));

> +		if (wait_for_completion_timeout(&dspi->done, HZ) == 0) {

> +			dev_err(&spi->dev, "spi transfer timeout\n");

> +			return -ETIMEDOUT;


Grygorii pointed out offline that this does not recover correctly in DMA
case. I will fix and send a v2.

Thanks,
Sekhar
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diff mbox

Patch

diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c
index 7d3af3eacf57..38026aa1afd7 100644
--- a/drivers/spi/spi-davinci.c
+++ b/drivers/spi/spi-davinci.c
@@ -703,7 +703,10 @@  static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
 
 	/* Wait for the transfer to complete */
 	if (spicfg->io_type != SPI_IO_TYPE_POLL) {
-		wait_for_completion_interruptible(&(dspi->done));
+		if (wait_for_completion_timeout(&dspi->done, HZ) == 0) {
+			dev_err(&spi->dev, "spi transfer timeout\n");
+			return -ETIMEDOUT;
+		}
 	} else {
 		while (dspi->rcount > 0 || dspi->wcount > 0) {
 			errors = davinci_spi_process_events(dspi);