diff mbox series

[4.19,09/78] iio: adc: mcp3422: fix locking on error path

Message ID 20200915140634.010489871@linuxfoundation.org
State Superseded
Headers show
Series None | expand

Commit Message

Greg KH Sept. 15, 2020, 2:12 p.m. UTC 
From: Angelo Compagnucci <angelo.compagnucci@gmail.com>

[ Upstream commit a139ffa40f0c24b753838b8ef3dcf6ad10eb7854 ]

Reading from the chip should be unlocked on error path else the lock
could never being released.

Fixes: 07914c84ba30 ("iio: adc: Add driver for Microchip MCP3422/3/4 high resolution ADC")
Fixes: 3f1093d83d71 ("iio: adc: mcp3422: fix locking scope")
Acked-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Angelo Compagnucci <angelo.compagnucci@gmail.com>
Link: https://lore.kernel.org/r/20200901093218.1500845-1-angelo.compagnucci@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/iio/adc/mcp3422.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Pavel Machek Sept. 16, 2020, 7:31 a.m. UTC | #1 
Hi!

> [ Upstream commit a139ffa40f0c24b753838b8ef3dcf6ad10eb7854 ]

> 

> Reading from the chip should be unlocked on error path else the lock

> could never being released.

> 

> Fixes: 07914c84ba30 ("iio: adc: Add driver for Microchip MCP3422/3/4 high resolution ADC")

> Fixes: 3f1093d83d71 ("iio: adc: mcp3422: fix locking scope")


Well, 3f1093d83d71 is only applied later in the stable series, so this
introduces spurious unlock.

Ideally this should go just after 3f1093d83d71 ("iio: adc: mcp3422:
fix locking scope").

Best regards,
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
Sasha Levin Sept. 17, 2020, 1:41 a.m. UTC | #2 
On Wed, Sep 16, 2020 at 09:31:00AM +0200, Pavel Machek wrote:
>Hi!

>

>> [ Upstream commit a139ffa40f0c24b753838b8ef3dcf6ad10eb7854 ]

>>

>> Reading from the chip should be unlocked on error path else the lock

>> could never being released.

>>

>> Fixes: 07914c84ba30 ("iio: adc: Add driver for Microchip MCP3422/3/4 high resolution ADC")

>> Fixes: 3f1093d83d71 ("iio: adc: mcp3422: fix locking scope")

>

>Well, 3f1093d83d71 is only applied later in the stable series, so this

>introduces spurious unlock.

>

>Ideally this should go just after 3f1093d83d71 ("iio: adc: mcp3422:

>fix locking scope").


Patches rearranged, thanks!

-- 
Thanks,
Sasha
diff mbox series

Patch

diff --git a/drivers/iio/adc/mcp3422.c b/drivers/iio/adc/mcp3422.c
index 819f260115005..a5a687257c0b8 100644
--- a/drivers/iio/adc/mcp3422.c
+++ b/drivers/iio/adc/mcp3422.c
@@ -148,8 +148,10 @@  static int mcp3422_read_channel(struct mcp3422 *adc,
 		config &= ~MCP3422_PGA_MASK;
 		config |= MCP3422_PGA_VALUE(adc->pga[req_channel]);
 		ret = mcp3422_update_config(adc, config);
-		if (ret < 0)
+		if (ret < 0) {
+			mutex_unlock(&adc->lock);
 			return ret;
+		}
 		msleep(mcp3422_read_times[MCP3422_SAMPLE_RATE(adc->config)]);
 	}