[PATCH v4 4/5] media: Add flags to tell whether to take graph mutex for an IOCTL

Sakari Ailus
2016-08-11T20:30:34Z

New IOCTLs (especially for the request API) do not necessarily need the
graph mutex acquired. Leave this up to the drivers.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
drivers/media/media-device.c | 47 ++++++++++++++++++++++++++------------------
1 file changed, 28 insertions(+), 19 deletions(-)

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index d1b47a4..6f565a2 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -381,31 +381,36 @@ static long copy_arg_to_user(void __user *uarg, void *karg, unsigned int cmd)
return 0;
}

-#define MEDIA_IOC_ARG(__cmd, func, from_user, to_user) \
- [_IOC_NR(MEDIA_IOC_##__cmd)] = { \
- .cmd = MEDIA_IOC_##__cmd, \
+/* Do acquire the graph mutex */
+#define MEDIA_IOC_FL_GRAPH_MUTEX BIT(0)
+
+#define MEDIA_IOC_ARG(__cmd, func, fl, from_user, to_user) \
+ [_IOC_NR(MEDIA_IOC_##__cmd)] = { \
+ .cmd = MEDIA_IOC_##__cmd, \
.fn = (long (*)(struct media_device *, void *))func, \
- .arg_from_user = from_user, \
- .arg_to_user = to_user, \
+ .flags = fl, \
+ .arg_from_user = from_user, \
+ .arg_to_user = to_user, \
}

-#define MEDIA_IOC(__cmd, func) \
- MEDIA_IOC_ARG(__cmd, func, copy_arg_from_user, copy_arg_to_user)
+#define MEDIA_IOC(__cmd, func, fl) \
+ MEDIA_IOC_ARG(__cmd, func, fl, copy_arg_from_user, copy_arg_to_user)

/* the table is indexed by _IOC_NR(cmd) */
struct media_ioctl_info {
unsigned int cmd;
+ unsigned short flags;
long (*fn)(struct media_device *dev, void *arg);
long (*arg_from_user)(void *karg, void __user *uarg, unsigned int cmd);
long (*arg_to_user)(void __user *uarg, void *karg, unsigned int cmd);
};

static const struct media_ioctl_info ioctl_info[] = {
- MEDIA_IOC(DEVICE_INFO, media_device_get_info),
- MEDIA_IOC(ENUM_ENTITIES, media_device_enum_entities),
- MEDIA_IOC(ENUM_LINKS, media_device_enum_links),
- MEDIA_IOC(SETUP_LINK, media_device_setup_link),
- MEDIA_IOC(G_TOPOLOGY, media_device_get_topology),
+ MEDIA_IOC(DEVICE_INFO, media_device_get_info, MEDIA_IOC_FL_GRAPH_MUTEX),
+ MEDIA_IOC(ENUM_ENTITIES, media_device_enum_entities, MEDIA_IOC_FL_GRAPH_MUTEX),
+ MEDIA_IOC(ENUM_LINKS, media_device_enum_links, MEDIA_IOC_FL_GRAPH_MUTEX),
+ MEDIA_IOC(SETUP_LINK, media_device_setup_link, MEDIA_IOC_FL_GRAPH_MUTEX),
+ MEDIA_IOC(G_TOPOLOGY, media_device_get_topology, MEDIA_IOC_FL_GRAPH_MUTEX),
};

static inline long is_valid_ioctl(const struct media_ioctl_info *info,
@@ -443,9 +448,13 @@ static long __media_device_ioctl(
goto out_free;
}

- mutex_lock(&dev->graph_mutex);
+ if (info->flags & MEDIA_IOC_FL_GRAPH_MUTEX)
+ mutex_lock(&dev->graph_mutex);
+
ret = info->fn(dev, karg);
- mutex_unlock(&dev->graph_mutex);
+
+ if (info->flags & MEDIA_IOC_FL_GRAPH_MUTEX)
+ mutex_unlock(&dev->graph_mutex);

if (!ret && info->arg_to_user)
ret = info->arg_to_user(arg, karg, cmd);
@@ -496,11 +505,11 @@ static long from_user_enum_links32(void *karg, void __user *uarg,
#define MEDIA_IOC_ENUM_LINKS32 _IOWR('|', 0x02, struct media_links_enum32)

static const struct media_ioctl_info compat_ioctl_info[] = {
- MEDIA_IOC(DEVICE_INFO, media_device_get_info),
- MEDIA_IOC(ENUM_ENTITIES, media_device_enum_entities),
- MEDIA_IOC_ARG(ENUM_LINKS32, media_device_enum_links, from_user_enum_links32, NULL),
- MEDIA_IOC(SETUP_LINK, media_device_setup_link),
- MEDIA_IOC(G_TOPOLOGY, media_device_get_topology),
+ MEDIA_IOC(DEVICE_INFO, media_device_get_info, MEDIA_IOC_FL_GRAPH_MUTEX),
+ MEDIA_IOC(ENUM_ENTITIES, media_device_enum_entities, MEDIA_IOC_FL_GRAPH_MUTEX),
+ MEDIA_IOC_ARG(ENUM_LINKS32, media_device_enum_links, MEDIA_IOC_FL_GRAPH_MUTEX, from_user_enum_links32, NULL),
+ MEDIA_IOC(SETUP_LINK, media_device_setup_link, MEDIA_IOC_FL_GRAPH_MUTEX),
+ MEDIA_IOC(G_TOPOLOGY, media_device_get_topology, MEDIA_IOC_FL_GRAPH_MUTEX),
};

static long media_device_compat_ioctl(struct file *filp, unsigned int cmd,
--
2.7.4