Re: [PATCH] drm/i915/gt: Refactor uabi engine class/instance list creation

2024-04-23 Thread Andi Shyti
Hi Nirmoy,

On Tue, Apr 23, 2024 at 11:02:06AM +0200, Nirmoy Das wrote:
> On 4/17/2024 12:49 AM, Andi Shyti wrote:

...

>  void intel_engines_driver_register(struct drm_i915_private *i915)
>  {
> -   u16 name_instance, other_instance = 0;
> +   u16 class_instance[I915_LAST_UABI_ENGINE_CLASS + 2] = { };
> 
> +2 is confusing here. I think we need a better macro.

This is to avoid buffer overflow, otherwise we will always hit
the GEM_BUG_ON below.

> struct legacy_ring ring = {};
> struct list_head *it, *next;
> struct rb_node **p, *prev;

...

> +   GEM_BUG_ON(uabi_class >=
> +  ARRAY_SIZE(i915->engine_uabi_class_count));
> +   i915->engine_uabi_class_count[uabi_class]++;
> 
> Shouldn't this be  i915->engine_uabi_class_count[uabi_class] =  class_instance
> [uabi_class]; ?

that's mostly a counter, we don't really need to be on sync with
the real instance of the engines.

> What I see is that this patch mainly adding this class_instance array and rest
> looks the same.
> May be it make sense to add other upcoming  patches to better understand why 
> we
> need this patch.

yes, this patch simplifies the coming patches and the logic
inside, as well.

I just wanted to anticipate some of the refactorings so that we
could speed up the reviews. There is no functional change in
here, that's why I thought it was harmless.

Thanks for taking a look into it.

Andi


Re: [PATCH] drm/i915/gt: Refactor uabi engine class/instance list creation

2024-04-23 Thread Nirmoy Das

Hi Andi,

On 4/17/2024 12:49 AM, Andi Shyti wrote:

For the upcoming changes we need a cleaner way to build the list
of uabi engines.

Suggested-by: Tvrtko Ursulin
Signed-off-by: Andi Shyti
---
Hi,

just sending this patch to unburden the coming series from this
single patch inherited from a previously sent series.

Andi

  drivers/gpu/drm/i915/gt/intel_engine_user.c | 29 -
  1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c 
b/drivers/gpu/drm/i915/gt/intel_engine_user.c
index 833987015b8b..11cc06c0c785 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_user.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c
@@ -203,7 +203,7 @@ static void engine_rename(struct intel_engine_cs *engine, 
const char *name, u16
  
  void intel_engines_driver_register(struct drm_i915_private *i915)

  {
-   u16 name_instance, other_instance = 0;
+   u16 class_instance[I915_LAST_UABI_ENGINE_CLASS + 2] = { };

+2 is confusing here. I think we need a better macro.

struct legacy_ring ring = {};
struct list_head *it, *next;
struct rb_node **p, *prev;
@@ -214,6 +214,8 @@ void intel_engines_driver_register(struct drm_i915_private 
*i915)
prev = NULL;
p = >uabi_engines.rb_node;
list_for_each_safe(it, next, ) {
+   u16 uabi_class;
+
struct intel_engine_cs *engine =
container_of(it, typeof(*engine), uabi_list);
  
@@ -222,15 +224,14 @@ void intel_engines_driver_register(struct drm_i915_private *i915)
  
  		GEM_BUG_ON(engine->class >= ARRAY_SIZE(uabi_classes));

engine->uabi_class = uabi_classes[engine->class];
-   if (engine->uabi_class == I915_NO_UABI_CLASS) {
-   name_instance = other_instance++;
-   } else {
-   GEM_BUG_ON(engine->uabi_class >=
-  ARRAY_SIZE(i915->engine_uabi_class_count));
-   name_instance =
-   
i915->engine_uabi_class_count[engine->uabi_class]++;
-   }
-   engine->uabi_instance = name_instance;
+
+   if (engine->uabi_class == I915_NO_UABI_CLASS)
+   uabi_class = I915_LAST_UABI_ENGINE_CLASS + 1;
+   else
+   uabi_class = engine->uabi_class;
+
+   GEM_BUG_ON(uabi_class >= ARRAY_SIZE(class_instance));
+   engine->uabi_instance = class_instance[uabi_class]++;
  
  		/*

 * Replace the internal name with the final user and log facing
@@ -238,11 +239,15 @@ void intel_engines_driver_register(struct 
drm_i915_private *i915)
 */
engine_rename(engine,
  intel_engine_class_repr(engine->class),
- name_instance);
+ engine->uabi_instance);
  
-		if (engine->uabi_class == I915_NO_UABI_CLASS)

+   if (uabi_class > I915_LAST_UABI_ENGINE_CLASS)
continue;
  
+		GEM_BUG_ON(uabi_class >=

+  ARRAY_SIZE(i915->engine_uabi_class_count));
+   i915->engine_uabi_class_count[uabi_class]++;
Shouldn't this be  i915->engine_uabi_class_count[uabi_class] = 
class_instance[uabi_class]; ?


What I see is that this patch mainly adding this class_instance array 
and rest looks the same.
May be it make sense to add other upcoming  patches to better understand 
why we need this patch.


Regards,
Nirmoy


+
rb_link_node(>uabi_node, prev, p);
rb_insert_color(>uabi_node, >uabi_engines);
  

[PATCH] drm/i915/gt: Refactor uabi engine class/instance list creation

2024-04-16 Thread Andi Shyti
For the upcoming changes we need a cleaner way to build the list
of uabi engines.

Suggested-by: Tvrtko Ursulin 
Signed-off-by: Andi Shyti 
---
Hi,

just sending this patch to unburden the coming series from this
single patch inherited from a previously sent series.

Andi

 drivers/gpu/drm/i915/gt/intel_engine_user.c | 29 -
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c 
b/drivers/gpu/drm/i915/gt/intel_engine_user.c
index 833987015b8b..11cc06c0c785 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_user.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c
@@ -203,7 +203,7 @@ static void engine_rename(struct intel_engine_cs *engine, 
const char *name, u16
 
 void intel_engines_driver_register(struct drm_i915_private *i915)
 {
-   u16 name_instance, other_instance = 0;
+   u16 class_instance[I915_LAST_UABI_ENGINE_CLASS + 2] = { };
struct legacy_ring ring = {};
struct list_head *it, *next;
struct rb_node **p, *prev;
@@ -214,6 +214,8 @@ void intel_engines_driver_register(struct drm_i915_private 
*i915)
prev = NULL;
p = >uabi_engines.rb_node;
list_for_each_safe(it, next, ) {
+   u16 uabi_class;
+
struct intel_engine_cs *engine =
container_of(it, typeof(*engine), uabi_list);
 
@@ -222,15 +224,14 @@ void intel_engines_driver_register(struct 
drm_i915_private *i915)
 
GEM_BUG_ON(engine->class >= ARRAY_SIZE(uabi_classes));
engine->uabi_class = uabi_classes[engine->class];
-   if (engine->uabi_class == I915_NO_UABI_CLASS) {
-   name_instance = other_instance++;
-   } else {
-   GEM_BUG_ON(engine->uabi_class >=
-  ARRAY_SIZE(i915->engine_uabi_class_count));
-   name_instance =
-   
i915->engine_uabi_class_count[engine->uabi_class]++;
-   }
-   engine->uabi_instance = name_instance;
+
+   if (engine->uabi_class == I915_NO_UABI_CLASS)
+   uabi_class = I915_LAST_UABI_ENGINE_CLASS + 1;
+   else
+   uabi_class = engine->uabi_class;
+
+   GEM_BUG_ON(uabi_class >= ARRAY_SIZE(class_instance));
+   engine->uabi_instance = class_instance[uabi_class]++;
 
/*
 * Replace the internal name with the final user and log facing
@@ -238,11 +239,15 @@ void intel_engines_driver_register(struct 
drm_i915_private *i915)
 */
engine_rename(engine,
  intel_engine_class_repr(engine->class),
- name_instance);
+ engine->uabi_instance);
 
-   if (engine->uabi_class == I915_NO_UABI_CLASS)
+   if (uabi_class > I915_LAST_UABI_ENGINE_CLASS)
continue;
 
+   GEM_BUG_ON(uabi_class >=
+  ARRAY_SIZE(i915->engine_uabi_class_count));
+   i915->engine_uabi_class_count[uabi_class]++;
+
rb_link_node(>uabi_node, prev, p);
rb_insert_color(>uabi_node, >uabi_engines);
 
-- 
2.43.0