[PATCH] net: marvell: prestera: use kzalloc_flex

[PATCH] net: marvell: prestera: use kzalloc_flex

[Rosen Penev]

Simplify allocation by using a flexible array member in this struct. No
need to free separately.

Add __counted_by to get extra runtime analysis. Move counting variable
assignment to right after allocation as required by __counted_by.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 .../ethernet/marvell/prestera/prestera_devlink.c | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/marvell/prestera/prestera_devlink.c b/drivers/net/ethernet/marvell/prestera/prestera_devlink.c
index 06b876f6b27f..9c043cddb0f9 100644
--- a/drivers/net/ethernet/marvell/prestera/prestera_devlink.c
+++ b/drivers/net/ethernet/marvell/prestera/prestera_devlink.c
@@ -125,8 +125,8 @@ struct prestera_trap_item {
 
 struct prestera_trap_data {
 	struct prestera_switch *sw;
-	struct prestera_trap_item *trap_items_arr;
 	u32 traps_count;
+	struct prestera_trap_item trap_items_arr[] __counted_by(traps_count);
 };
 
 #define PRESTERA_TRAP_METADATA DEVLINK_TRAP_METADATA_TYPE_F_IN_PORT
@@ -451,19 +451,12 @@ int prestera_devlink_traps_register(struct prestera_switch *sw)
 	struct prestera_trap *prestera_trap;
 	int err, i;
 
-	trap_data = kzalloc_obj(*trap_data);
+	trap_data = kzalloc_flex(*trap_data, trap_items_arr, traps_count);
 	if (!trap_data)
 		return -ENOMEM;
 
-	trap_data->trap_items_arr = kzalloc_objs(struct prestera_trap_item,
-						 traps_count);
-	if (!trap_data->trap_items_arr) {
-		err = -ENOMEM;
-		goto err_trap_items_alloc;
-	}
-
-	trap_data->sw = sw;
 	trap_data->traps_count = traps_count;
+	trap_data->sw = sw;
 	sw->trap_data = trap_data;
 
 	err = devlink_trap_groups_register(devlink, prestera_trap_groups_arr,
@@ -489,8 +482,6 @@ int prestera_devlink_traps_register(struct prestera_switch *sw)
 	devlink_trap_groups_unregister(devlink, prestera_trap_groups_arr,
 				       groups_count);
 err_groups_register:
-	kfree(trap_data->trap_items_arr);
-err_trap_items_alloc:
 	kfree(trap_data);
 	return err;
 }
@@ -594,6 +585,5 @@ void prestera_devlink_traps_unregister(struct prestera_switch *sw)
 
 	devlink_trap_groups_unregister(dl, prestera_trap_groups_arr,
 				       ARRAY_SIZE(prestera_trap_groups_arr));
-	kfree(trap_data->trap_items_arr);
 	kfree(trap_data);
 }
-- 
2.53.0

RE: [EXTERNAL] [PATCH] net: marvell: prestera: use kzalloc_flex

[Elad Nachman]

> Simplify allocation by using a flexible array member in this struct. No
> need to free separately.
> 
> Add __counted_by to get extra runtime analysis. Move counting variable
> assignment to right after allocation as required by __counted_by.
> 
> Signed-off-by: Rosen Penev <rosenp@gmail.com>
> ---
>  .../ethernet/marvell/prestera/prestera_devlink.c | 16 +++-------------
>  1 file changed, 3 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/net/ethernet/marvell/prestera/prestera_devlink.c b/drivers/net/ethernet/marvell/prestera/prestera_devlink.c
> index 06b876f6b27f..9c043cddb0f9 100644
> --- a/drivers/net/ethernet/marvell/prestera/prestera_devlink.c
> +++ b/drivers/net/ethernet/marvell/prestera/prestera_devlink.c
> @@ -125,8 +125,8 @@ struct prestera_trap_item {
> 
>  struct prestera_trap_data {
>  	struct prestera_switch *sw;
> -	struct prestera_trap_item *trap_items_arr;
>  	u32 traps_count;
> +	struct prestera_trap_item trap_items_arr[] __counted_by(traps_count);
>  };
> 
>  #define PRESTERA_TRAP_METADATA DEVLINK_TRAP_METADATA_TYPE_F_IN_PORT
> @@ -451,19 +451,12 @@ int prestera_devlink_traps_register(struct prestera_switch *sw)
>  	struct prestera_trap *prestera_trap;
>  	int err, i;
> 
> -	trap_data = kzalloc_obj(*trap_data);
> +	trap_data = kzalloc_flex(*trap_data, trap_items_arr, traps_count);
>  	if (!trap_data)
>  		return -ENOMEM;
> 
> -	trap_data->trap_items_arr = kzalloc_objs(struct prestera_trap_item,
> -						 traps_count);
> -	if (!trap_data->trap_items_arr) {
> -		err = -ENOMEM;
> -		goto err_trap_items_alloc;
> -	}
> -
> -	trap_data->sw = sw;
>  	trap_data->traps_count = traps_count;
> +	trap_data->sw = sw;
>  	sw->trap_data = trap_data;
> 
>  	err = devlink_trap_groups_register(devlink, prestera_trap_groups_arr,
> @@ -489,8 +482,6 @@ int prestera_devlink_traps_register(struct prestera_switch *sw)
>  	devlink_trap_groups_unregister(devlink, prestera_trap_groups_arr,
>  				       groups_count);
>  err_groups_register:
> -	kfree(trap_data->trap_items_arr);
> -err_trap_items_alloc:
>  	kfree(trap_data);
>  	return err;
>  }
> @@ -594,6 +585,5 @@ void prestera_devlink_traps_unregister(struct prestera_switch *sw)
> 
>  	devlink_trap_groups_unregister(dl, prestera_trap_groups_arr,
>  				       ARRAY_SIZE(prestera_trap_groups_arr));
> -	kfree(trap_data->trap_items_arr);
>  	kfree(trap_data);
>  }
> --
> 2.53.0
>

Acked-by: Elad Nachman <enachman@marvell.com>

Re: [PATCH] net: marvell: prestera: use kzalloc_flex

[Jakub Kicinski]

On Wed, 18 Mar 2026 12:21:11 -0700 Rosen Penev wrote:
> Simplify allocation by using a flexible array member in this struct. No
> need to free separately.
> 
> Add __counted_by to get extra runtime analysis. Move counting variable
> assignment to right after allocation as required by __counted_by.

Quoting documentation:

  Clean-up patches
  ~~~~~~~~~~~~~~~~
  
  Netdev discourages patches which perform simple clean-ups, which are not in
  the context of other work.
  
See: https://www.kernel.org/doc/html/next/process/maintainer-netdev.html#clean-up-patches
-- 
pw-bot: reject