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[5/5] media: i2c: max9286: Allocate v4l2_async_subdev dynamically

Message ID 20200811205939.19550-6-laurent.pinchart+renesas@ideasonboard.com
State Accepted
Commit 86d37bf31af647760f1f17e7c1afa1bdba075198
Headers show
Series None | expand

Commit Message

Laurent Pinchart Aug. 11, 2020, 8:59 p.m. UTC
v4l2_async_notifier_add_subdev() requires the asd to be allocated
dynamically, but the max9286 driver embeds it in the max9286_source
structure. This causes memory corruption when the notifier is destroyed
at remove time with v4l2_async_notifier_cleanup().

Fix this issue by registering the asd with
v4l2_async_notifier_add_fwnode_subdev(), which allocates it dynamically
internally. A new max9286_asd structure is introduced, to store a
pointer to the corresonding max9286_source that needs to be accessed
from bound and unbind callbacks. There's no need to take an extra
explicit reference to the fwnode anymore as
v4l2_async_notifier_add_fwnode_subdev() does so internally.

While at it, use %u instead of %d to print the unsigned index in the
error message from the v4l2_async_notifier_add_fwnode_subdev() error
path.

Fixes: 66d8c9d2422d ("media: i2c: Add MAX9286 driver")
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
 drivers/media/i2c/max9286.c | 38 +++++++++++++++++++------------------
 1 file changed, 20 insertions(+), 18 deletions(-)

Comments

Laurent Pinchart Sept. 8, 2020, 5:08 a.m. UTC | #1
Gentle ping for reviews.

On Tue, Aug 11, 2020 at 11:59:39PM +0300, Laurent Pinchart wrote:
> v4l2_async_notifier_add_subdev() requires the asd to be allocated
> dynamically, but the max9286 driver embeds it in the max9286_source
> structure. This causes memory corruption when the notifier is destroyed
> at remove time with v4l2_async_notifier_cleanup().
> 
> Fix this issue by registering the asd with
> v4l2_async_notifier_add_fwnode_subdev(), which allocates it dynamically
> internally. A new max9286_asd structure is introduced, to store a
> pointer to the corresonding max9286_source that needs to be accessed
> from bound and unbind callbacks. There's no need to take an extra
> explicit reference to the fwnode anymore as
> v4l2_async_notifier_add_fwnode_subdev() does so internally.
> 
> While at it, use %u instead of %d to print the unsigned index in the
> error message from the v4l2_async_notifier_add_fwnode_subdev() error
> path.
> 
> Fixes: 66d8c9d2422d ("media: i2c: Add MAX9286 driver")
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> ---
>  drivers/media/i2c/max9286.c | 38 +++++++++++++++++++------------------
>  1 file changed, 20 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
> index 47f280518fdb..5d890dddb376 100644
> --- a/drivers/media/i2c/max9286.c
> +++ b/drivers/media/i2c/max9286.c
> @@ -135,13 +135,19 @@
>  #define MAX9286_SRC_PAD			4
>  
>  struct max9286_source {
> -	struct v4l2_async_subdev asd;
>  	struct v4l2_subdev *sd;
>  	struct fwnode_handle *fwnode;
>  };
>  
> -#define asd_to_max9286_source(_asd) \
> -	container_of(_asd, struct max9286_source, asd)
> +struct max9286_asd {
> +	struct v4l2_async_subdev base;
> +	struct max9286_source *source;
> +};
> +
> +static inline struct max9286_asd *to_max9286_asd(struct v4l2_async_subdev *asd)
> +{
> +	return container_of(asd, struct max9286_asd, base);
> +}
>  
>  struct max9286_priv {
>  	struct i2c_client *client;
> @@ -480,7 +486,7 @@ static int max9286_notify_bound(struct v4l2_async_notifier *notifier,
>  				struct v4l2_async_subdev *asd)
>  {
>  	struct max9286_priv *priv = sd_to_max9286(notifier->sd);
> -	struct max9286_source *source = asd_to_max9286_source(asd);
> +	struct max9286_source *source = to_max9286_asd(asd)->source;
>  	unsigned int index = to_index(priv, source);
>  	unsigned int src_pad;
>  	int ret;
> @@ -544,7 +550,7 @@ static void max9286_notify_unbind(struct v4l2_async_notifier *notifier,
>  				  struct v4l2_async_subdev *asd)
>  {
>  	struct max9286_priv *priv = sd_to_max9286(notifier->sd);
> -	struct max9286_source *source = asd_to_max9286_source(asd);
> +	struct max9286_source *source = to_max9286_asd(asd)->source;
>  	unsigned int index = to_index(priv, source);
>  
>  	source->sd = NULL;
> @@ -569,23 +575,19 @@ static int max9286_v4l2_notifier_register(struct max9286_priv *priv)
>  
>  	for_each_source(priv, source) {
>  		unsigned int i = to_index(priv, source);
> +		struct v4l2_async_subdev *asd;
>  
> -		source->asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
> -		source->asd.match.fwnode = source->fwnode;
> -
> -		ret = v4l2_async_notifier_add_subdev(&priv->notifier,
> -						     &source->asd);
> -		if (ret) {
> -			dev_err(dev, "Failed to add subdev for source %d", i);
> +		asd = v4l2_async_notifier_add_fwnode_subdev(&priv->notifier,
> +							    source->fwnode,
> +							    sizeof(*asd));
> +		if (IS_ERR(asd)) {
> +			dev_err(dev, "Failed to add subdev for source %u: %ld",
> +				i, PTR_ERR(asd));
>  			v4l2_async_notifier_cleanup(&priv->notifier);
> -			return ret;
> +			return PTR_ERR(asd);
>  		}
>  
> -		/*
> -		 * Balance the reference counting handled through
> -		 * v4l2_async_notifier_cleanup()
> -		 */
> -		fwnode_handle_get(source->fwnode);
> +		to_max9286_asd(asd)->source = source;
>  	}
>  
>  	priv->notifier.ops = &max9286_notify_ops;
diff mbox series

Patch

diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
index 47f280518fdb..5d890dddb376 100644
--- a/drivers/media/i2c/max9286.c
+++ b/drivers/media/i2c/max9286.c
@@ -135,13 +135,19 @@ 
 #define MAX9286_SRC_PAD			4
 
 struct max9286_source {
-	struct v4l2_async_subdev asd;
 	struct v4l2_subdev *sd;
 	struct fwnode_handle *fwnode;
 };
 
-#define asd_to_max9286_source(_asd) \
-	container_of(_asd, struct max9286_source, asd)
+struct max9286_asd {
+	struct v4l2_async_subdev base;
+	struct max9286_source *source;
+};
+
+static inline struct max9286_asd *to_max9286_asd(struct v4l2_async_subdev *asd)
+{
+	return container_of(asd, struct max9286_asd, base);
+}
 
 struct max9286_priv {
 	struct i2c_client *client;
@@ -480,7 +486,7 @@  static int max9286_notify_bound(struct v4l2_async_notifier *notifier,
 				struct v4l2_async_subdev *asd)
 {
 	struct max9286_priv *priv = sd_to_max9286(notifier->sd);
-	struct max9286_source *source = asd_to_max9286_source(asd);
+	struct max9286_source *source = to_max9286_asd(asd)->source;
 	unsigned int index = to_index(priv, source);
 	unsigned int src_pad;
 	int ret;
@@ -544,7 +550,7 @@  static void max9286_notify_unbind(struct v4l2_async_notifier *notifier,
 				  struct v4l2_async_subdev *asd)
 {
 	struct max9286_priv *priv = sd_to_max9286(notifier->sd);
-	struct max9286_source *source = asd_to_max9286_source(asd);
+	struct max9286_source *source = to_max9286_asd(asd)->source;
 	unsigned int index = to_index(priv, source);
 
 	source->sd = NULL;
@@ -569,23 +575,19 @@  static int max9286_v4l2_notifier_register(struct max9286_priv *priv)
 
 	for_each_source(priv, source) {
 		unsigned int i = to_index(priv, source);
+		struct v4l2_async_subdev *asd;
 
-		source->asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
-		source->asd.match.fwnode = source->fwnode;
-
-		ret = v4l2_async_notifier_add_subdev(&priv->notifier,
-						     &source->asd);
-		if (ret) {
-			dev_err(dev, "Failed to add subdev for source %d", i);
+		asd = v4l2_async_notifier_add_fwnode_subdev(&priv->notifier,
+							    source->fwnode,
+							    sizeof(*asd));
+		if (IS_ERR(asd)) {
+			dev_err(dev, "Failed to add subdev for source %u: %ld",
+				i, PTR_ERR(asd));
 			v4l2_async_notifier_cleanup(&priv->notifier);
-			return ret;
+			return PTR_ERR(asd);
 		}
 
-		/*
-		 * Balance the reference counting handled through
-		 * v4l2_async_notifier_cleanup()
-		 */
-		fwnode_handle_get(source->fwnode);
+		to_max9286_asd(asd)->source = source;
 	}
 
 	priv->notifier.ops = &max9286_notify_ops;