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media: v4l: subdev: Move out subdev state lock macros outside CONFIG_MEDIA_CONTROLLER

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The subdev state locking macros and macros to get the active state are
currently behind CONFIG_MEDIA_CONTROLLER. This makes sense, as there can
be no subdev state without MC.

However, we have code paths common to MC and non-MC cases which call
subdev operations that have subdev state as a parameter. In the non-MC
case the state parameter would always be NULL.

Thus it makes sense to allow, e.g.:

v4l2_subdev_call_state_active(sd, pad, get_fmt, fmt)

which for non-MC case would call the subdev passing NULL as the state.

This currently fails:
https://lore.kernel.org/oe-kbuild-all/202312061101.PLrz5NnJ-lkp@intel.com/

Fix the issue by moving the related macros to be outside
CONFIG_MEDIA_CONTROLLER. The v4l2_subdev_lock_state() and
v4l2_subdev_unlock_state() macros will crash if given NULL as the state,
but the other macros behave correctly even when there's no active state,
and they will only call the lock/unlock macros if there is a state.

An alternative fix would be to make another version of
v4l2_subdev_call_state_try() with ifdefs, which would not use any state
macros and would always pass NULL as the state. But having two version
of a macro/function is always more confusing than having just one, so I
went this way.

So, this fixes the v4l2_subdev_call_state_active() macro. But we also
have v4l2_subdev_call_state_try(). It would be possible to fix that
macro by additionally creating "no-op" variants of the state alloc and
free functions. However, v4l2_subdev_call_state_try() is only used by a
single driver (stm32-dcmi), which selects MC, and the macro is supposed
to be removed as soon as the users have been converted away from the
macro. Thus I have not touched the state alloc/free functions, and I
think it makes sense to keep alloc/free functions available only if
there's actually something that can be allocated or freed.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Link: https://lore.kernel.org/r/20231208-v4l2-state-mc-fix-v1-1-a0c8162557c6@ideasonboard.com
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
This commit is contained in:
Tomi Valkeinen 2023-12-13 17:00:03 +02:00 committed by Hans Verkuil
parent e4af84f34c
commit 08e5c36410
1 changed files with 83 additions and 83 deletions
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166
include/media/v4l2-subdev.h
View file

@ -1311,89 +1311,6 @@ int __v4l2_subdev_init_finalize(struct v4l2_subdev *sd, const char *name,
*/
void v4l2_subdev_cleanup(struct v4l2_subdev *sd);
/**
* v4l2_subdev_lock_state() - Locks the subdev state
* @state: The subdevice state
*
* Locks the given subdev state.
*
* The state must be unlocked with v4l2_subdev_unlock_state() after use.
*/
static inline void v4l2_subdev_lock_state(struct v4l2_subdev_state *state)
{
mutex_lock(state->lock);
}
/**
* v4l2_subdev_unlock_state() - Unlocks the subdev state
* @state: The subdevice state
*
* Unlocks the given subdev state.
*/
static inline void v4l2_subdev_unlock_state(struct v4l2_subdev_state *state)
{
mutex_unlock(state->lock);
}
/**
* v4l2_subdev_get_unlocked_active_state() - Checks that the active subdev state
* is unlocked and returns it
* @sd: The subdevice
*
* Returns the active state for the subdevice, or NULL if the subdev does not
* support active state. If the state is not NULL, calls
* lockdep_assert_not_held() to issue a warning if the state is locked.
*
* This function is to be used e.g. when getting the active state for the sole
* purpose of passing it forward, without accessing the state fields.
*/
static inline struct v4l2_subdev_state *
v4l2_subdev_get_unlocked_active_state(struct v4l2_subdev *sd)
{
if (sd->active_state)
lockdep_assert_not_held(sd->active_state->lock);
return sd->active_state;
}
/**
* v4l2_subdev_get_locked_active_state() - Checks that the active subdev state
* is locked and returns it
*
* @sd: The subdevice
*
* Returns the active state for the subdevice, or NULL if the subdev does not
* support active state. If the state is not NULL, calls lockdep_assert_held()
* to issue a warning if the state is not locked.
*
* This function is to be used when the caller knows that the active state is
* already locked.
*/
static inline struct v4l2_subdev_state *
v4l2_subdev_get_locked_active_state(struct v4l2_subdev *sd)
{
if (sd->active_state)
lockdep_assert_held(sd->active_state->lock);
return sd->active_state;
}
/**
* v4l2_subdev_lock_and_get_active_state() - Locks and returns the active subdev
* state for the subdevice
* @sd: The subdevice
*
* Returns the locked active state for the subdevice, or NULL if the subdev
* does not support active state.
*
* The state must be unlocked with v4l2_subdev_unlock_state() after use.
*/
static inline struct v4l2_subdev_state *
v4l2_subdev_lock_and_get_active_state(struct v4l2_subdev *sd)
{
if (sd->active_state)
v4l2_subdev_lock_state(sd->active_state);
return sd->active_state;
}
/*
* A macro to generate the macro or function name for sub-devices state access
* wrapper macros below.
@ -1738,6 +1655,89 @@ int v4l2_subdev_s_stream_helper(struct v4l2_subdev *sd, int enable);
#endif /* CONFIG_MEDIA_CONTROLLER */
/**
* v4l2_subdev_lock_state() - Locks the subdev state
* @state: The subdevice state
*
* Locks the given subdev state.
*
* The state must be unlocked with v4l2_subdev_unlock_state() after use.
*/
static inline void v4l2_subdev_lock_state(struct v4l2_subdev_state *state)
{
mutex_lock(state->lock);
}
/**
* v4l2_subdev_unlock_state() - Unlocks the subdev state
* @state: The subdevice state
*
* Unlocks the given subdev state.
*/
static inline void v4l2_subdev_unlock_state(struct v4l2_subdev_state *state)
{
mutex_unlock(state->lock);
}
/**
* v4l2_subdev_get_unlocked_active_state() - Checks that the active subdev state
* is unlocked and returns it
* @sd: The subdevice
*
* Returns the active state for the subdevice, or NULL if the subdev does not
* support active state. If the state is not NULL, calls
* lockdep_assert_not_held() to issue a warning if the state is locked.
*
* This function is to be used e.g. when getting the active state for the sole
* purpose of passing it forward, without accessing the state fields.
*/
static inline struct v4l2_subdev_state *
v4l2_subdev_get_unlocked_active_state(struct v4l2_subdev *sd)
{
if (sd->active_state)
lockdep_assert_not_held(sd->active_state->lock);
return sd->active_state;
}
/**
* v4l2_subdev_get_locked_active_state() - Checks that the active subdev state
* is locked and returns it
*
* @sd: The subdevice
*
* Returns the active state for the subdevice, or NULL if the subdev does not
* support active state. If the state is not NULL, calls lockdep_assert_held()
* to issue a warning if the state is not locked.
*
* This function is to be used when the caller knows that the active state is
* already locked.
*/
static inline struct v4l2_subdev_state *
v4l2_subdev_get_locked_active_state(struct v4l2_subdev *sd)
{
if (sd->active_state)
lockdep_assert_held(sd->active_state->lock);
return sd->active_state;
}
/**
* v4l2_subdev_lock_and_get_active_state() - Locks and returns the active subdev
* state for the subdevice
* @sd: The subdevice
*
* Returns the locked active state for the subdevice, or NULL if the subdev
* does not support active state.
*
* The state must be unlocked with v4l2_subdev_unlock_state() after use.
*/
static inline struct v4l2_subdev_state *
v4l2_subdev_lock_and_get_active_state(struct v4l2_subdev *sd)
{
if (sd->active_state)
v4l2_subdev_lock_state(sd->active_state);
return sd->active_state;
}
/**
* v4l2_subdev_init - initializes the sub-device struct
*