[PATCHv2 ath-next] wifi: ath12k: use kzalloc_flex

[PATCHv2 ath-next] wifi: ath12k: use kzalloc_flex

[Rosen Penev]

Convert kzalloc_obj + kcalloc to kzalloc_flex to save an allocation.

Add __counted_by to get extra runtime analysis. Move counting variable
assignment immediately after allocation before any potential accesses.
kzalloc_flex does this anyway for GCC >= 15.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
---
 v2: reword last comment.
 drivers/net/wireless/ath/ath12k/mac.c | 29 +++++++--------------------
 drivers/net/wireless/ath/ath12k/wmi.h |  2 +-
 2 files changed, 8 insertions(+), 23 deletions(-)

diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
index fbdfe6424fd7..32d590504a80 100644
--- a/drivers/net/wireless/ath/ath12k/mac.c
+++ b/drivers/net/wireless/ath/ath12k/mac.c
@@ -5611,12 +5611,14 @@ static int ath12k_mac_initiate_hw_scan(struct ieee80211_hw *hw,
 	if (ret)
 		goto exit;

-	arg = kzalloc_obj(*arg);
+	arg = kzalloc_flex(*arg, chan_list, n_channels);
 	if (!arg) {
 		ret = -ENOMEM;
 		goto exit;
 	}

+	arg->num_chan = n_channels;
+
 	ath12k_wmi_start_scan_init(ar, arg);
 	arg->vdev_id = arvif->vdev_id;
 	arg->scan_id = ATH12K_SCAN_ID;
@@ -5638,18 +5640,8 @@ static int ath12k_mac_initiate_hw_scan(struct ieee80211_hw *hw,
 		arg->scan_f_passive = 1;
 	}

-	if (n_channels) {
-		arg->num_chan = n_channels;
-		arg->chan_list = kcalloc(arg->num_chan, sizeof(*arg->chan_list),
-					 GFP_KERNEL);
-		if (!arg->chan_list) {
-			ret = -ENOMEM;
-			goto exit;
-		}
-
-		for (i = 0; i < arg->num_chan; i++)
-			arg->chan_list[i] = chan_list[i]->center_freq;
-	}
+	for (i = 0; i < arg->num_chan; i++)
+		arg->chan_list[i] = chan_list[i]->center_freq;

 	ret = ath12k_start_scan(ar, arg);
 	if (ret) {
@@ -5674,7 +5666,6 @@ static int ath12k_mac_initiate_hw_scan(struct ieee80211_hw *hw,

 exit:
 	if (arg) {
-		kfree(arg->chan_list);
 		kfree(arg->extraie.ptr);
 		kfree(arg);
 	}
@@ -13735,19 +13726,13 @@ int ath12k_mac_op_remain_on_channel(struct ieee80211_hw *hw,
 	scan_time_msec = hw->wiphy->max_remain_on_channel_duration * 2;

 	struct ath12k_wmi_scan_req_arg *arg __free(kfree) =
-					kzalloc_obj(*arg);
+					kzalloc_flex(*arg, chan_list, 1);
 	if (!arg)
 		return -ENOMEM;

-	ath12k_wmi_start_scan_init(ar, arg);
 	arg->num_chan = 1;
+	ath12k_wmi_start_scan_init(ar, arg);

-	u32 *chan_list __free(kfree) = kcalloc(arg->num_chan, sizeof(*chan_list),
-					       GFP_KERNEL);
-	if (!chan_list)
-		return -ENOMEM;
-
-	arg->chan_list = chan_list;
 	arg->vdev_id = arvif->vdev_id;
 	arg->scan_id = ATH12K_SCAN_ID;
 	arg->chan_list[0] = chan->center_freq;
diff --git a/drivers/net/wireless/ath/ath12k/wmi.h b/drivers/net/wireless/ath/ath12k/wmi.h
index 5ba9b7d3a888..5f150f21c146 100644
--- a/drivers/net/wireless/ath/ath12k/wmi.h
+++ b/drivers/net/wireless/ath/ath12k/wmi.h
@@ -3586,7 +3586,6 @@ struct ath12k_wmi_scan_req_arg {
 	u32 num_bssid;
 	u32 num_ssids;
 	u32 n_probes;
-	u32 *chan_list;
 	u32 notify_scan_events;
 	struct cfg80211_ssid ssid[WLAN_SCAN_MAX_NUM_SSID];
 	struct ath12k_wmi_mac_addr_params bssid_list[WLAN_SCAN_MAX_NUM_BSSID];
@@ -3595,6 +3594,7 @@ struct ath12k_wmi_scan_req_arg {
 	u32 num_hint_bssid;
 	struct ath12k_wmi_hint_short_ssid_arg hint_s_ssid[WLAN_SCAN_MAX_HINT_S_SSID];
 	struct ath12k_wmi_hint_bssid_arg hint_bssid[WLAN_SCAN_MAX_HINT_BSSID];
+	u32 chan_list[] __counted_by(num_chan);
 };

 struct wmi_ssid_arg {
--
2.53.0

Re: [PATCHv2 ath-next] wifi: ath12k: use kzalloc_flex

[Rameshkumar Sundaram]

On 4/22/2026 3:05 AM, Rosen Penev wrote:
> Convert kzalloc_obj + kcalloc to kzalloc_flex to save an allocation.
> 
> Add __counted_by to get extra runtime analysis. Move counting variable
> assignment immediately after allocation before any potential accesses.
> kzalloc_flex does this anyway for GCC >= 15.
> 
> Signed-off-by: Rosen Penev <rosenp@gmail.com>
> Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Reviewed-by: Rameshkumar Sundaram <rameshkumar.sundaram@oss.qualcomm.com>