[PATCH 5.9 143/757] media: i2c: max9286: Allocate v4l2_async_subdev dynamically

Greg Kroah-Hartman
2020-10-27T15:43:35Z

From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

[ Upstream commit 86d37bf31af647760f1f17e7c1afa1bdba075198 ]

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>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/i2c/max9286.c | 40 +++++++++++++++++++------------------
1 file changed, 21 insertions(+), 19 deletions(-)

diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
index b364a3f604861..c82c1493e099d 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;
@@ -481,7 +487,7 @@ 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;
@@ -545,7 +551,7 @@ 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;
@@ -570,23 +576,19 @@ static int max9286_v4l2_notifier_register(struct max9286_priv *priv)

for_each_source(priv, source) {
unsigned int i = to_index(priv, source);
-
- 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);
+ struct v4l2_async_subdev *asd;
+
+ 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;
--
2.25.1