[PATCH ath-next v4] wifi: ath12k: avoid dynamic alloc when parsing wmi tb

[Rameshkumar Sundaram]

On 3/17/2026 2:17 PM, Nicolas Escande wrote:
> On each WMI message received from the hardware, we alloc a temporary array
> of WMI_TAG_MAX entries of type void *. This array is then populated with
> pointers of parsed structs depending on the WMI type, and then freed. This
> alloc can fail when memory pressure in the system is high enough.
> 
> Given the fact that it is scheduled in softirq with the system_bh_wq, we
> should not be able to parse more than one WMI message per CPU at any time.
> 
> So instead lets move to a per cpu allocated array, that is reused across
> calls: ath12K_wmi_tb that lives in wmi.c of the ath12K module. To alloc &
> free we added two new module_init/exit functions for the module and two
> new wmi functions to alloc/free this memory.
> 
> ath12k_wmi_tlv_parse_alloc() and ath12k_wmi_tlv_parse() are merged
> together as it no longer allocs mem but returns the existing per-cpu one.
> 
> Signed-off-by: Nicolas Escande <nico.escande at gmail.com>
> ---
> changes from v3:
>    - simplified ath12k_core_init() with a single statement
>    - move perpcu.h include directly to wmi.c
> 
> changes from v2:
>    - removed now superfluous return in ath12k_wmi_event_teardown_complete()
>    - moved ath12k_wmi_tb declaration to wmi.c & added two functions to
>      alloc / free it
>    - removed useless error message on memory allocation failure
> 
> changes from v1:
>    - rebased on ath-next 27401c9b1432
>    - changed wording according to Jeff's comment
>    - moved alloc/cleanup to new module_init/exit functions in the
>      ath12k module as per Baochen's comment
> 
> changes from RFC:
>    - rebased on ath-next 8e0ab5b9adb7
>    - converted missing call sites ath12k_wmi_obss_color_collision_event()
>      & ath12k_wmi_pdev_temperature_event()
>    - changed alloc order & cleanup path in ath12k_core_alloc() as it seems
>      it confused people
>    - used sizeof(*tb) in ath12k_wmi_tlv_parse()
> ---
>   drivers/net/wireless/ath/ath12k/core.c |  13 ++
>   drivers/net/wireless/ath/ath12k/wmi.c  | 201 ++++++++-----------------
>   drivers/net/wireless/ath/ath12k/wmi.h  |   3 +
>   3 files changed, 78 insertions(+), 139 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath12k/core.c b/drivers/net/wireless/ath/ath12k/core.c
> index c31c47fb5a73..6c034071cc6d 100644
> --- a/drivers/net/wireless/ath/ath12k/core.c
> +++ b/drivers/net/wireless/ath/ath12k/core.c
> @@ -2321,5 +2321,18 @@ struct ath12k_base *ath12k_core_alloc(struct device *dev, size_t priv_size,
>   	return NULL;
>   }
>   
> +static int ath12k_init(void)
> +{
> +	return ath12k_wmi_alloc();


Since CONFIG_ATH12K is tristate, a built-in boot can continue past a 
failed ath12k_init() and still run ath12k_wifi7_init().

Please ensure that later initialization path is guarded against 
allocation failure.

Or may be have this allocated on first device probe and free it on last 
device deinit ?


> +}
> +
> +static void ath12k_exit(void)
> +{
> +	ath12k_wmi_free();
> +}
> +
> +module_init(ath12k_init);
> +module_exit(ath12k_exit);
> +
>   MODULE_DESCRIPTION("Driver support for Qualcomm Technologies WLAN devices");
>   MODULE_LICENSE("Dual BSD/GPL");
--
Ramesh