drm: Reduce scope of 'state' variable

Smaller scope reduces visibility of variable and makes usage of uninitialized variable less possible.

---
 drivers/gpu/drm/drm_atomic.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

drivers/gpu/drm/drm_atomic.c +0 -0

index f32506a..ea5a9a7 100644

drivers/gpu/drm/drm_atomic.c +1 -0

+
 		if (!state)
 			return NULL;
 		if (drm_atomic_state_init(dev, state) < 0) {

Quoted 16 lines · Dawid Kurek

Smaller scope reduces visibility of variable and makes usage of uninitialized variable less possible.

---
 drivers/gpu/drm/drm_atomic.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

drivers/gpu/drm/drm_atomic.c +0 -1

index f32506a..ea5a9a7 100644
@@ -108,10 +108,11 @@ struct drm_atomic_state *
 drm_atomic_state_alloc(struct drm_device *dev)
 {
 	struct drm_mode_config *config = &dev->mode_config;
-	struct drm_atomic_state *state;
 

drivers/gpu/drm/drm_atomic.c struct drm_atomic_state * · line 114

Quoted 4 lines

drivers/gpu/drm/drm_atomic.c +2 -1

 	if (!config->funcs->atomic_state_alloc) {
-		state = kzalloc(sizeof(*state), GFP_KERNEL);
+		struct drm_atomic_state *state
+			= kzalloc(sizeof(*state), GFP_KERNEL);

Separate declaration and initialization would lead to a cleaner patch and result.

BR,
Jani.

Quoted 4 lines

drivers/gpu/drm/drm_atomic.c +1 -0

+
 		if (!state)
 			return NULL;
 		if (drm_atomic_state_init(dev, state) < 0) {

Signature · 1 line

Jani Nikula, Intel Open Source Technology Center

Quoted 2 lines · Jani Nikula

Separate declaration and initialization would lead to a cleaner patch and result.

I saw combining declaration and initialization is quite common, i.e. in drm_atomic file. Personally, I also prefer those in one statement. But yes, it looks cleaner here, in two lines.

Quoted 4 lines · Dawid Kurek

Quoted 2 lines · Jani Nikula

Separate declaration and initialization would lead to a cleaner patch and result.

Quoted 3 lines

I saw combining declaration and initialization is quite common, i.e. in drm_atomic file. Personally, I also prefer those in one statement. But yes, it looks cleaner here, in two lines.

I'd say the rule of thumb is that combined declaration and initialization is fine if the initialization is trivial, in particular can never fail. If you need to check the return value, like in this case, I'd prefer separate initialization.