Commit 18ae7d0c authored by Bjorn Andersson's avatar Bjorn Andersson Committed by Jeff Johnson
Browse files

wifi: ath12k: Avoid CPU busy-wait by handling VDEV_STAT and BCN_STAT 



When the ath12k driver is built without CONFIG_ATH12K_DEBUG, the
recently refactored stats code can cause any user space application
(such at NetworkManager) to consume 100% CPU for 3 seconds, every time
stats are read.

Commit 'b8a0d83f ("wifi: ath12k: move firmware stats out of
debugfs")' moved ath12k_debugfs_fw_stats_request() out of debugfs, by
merging the additional logic into ath12k_mac_get_fw_stats().

Among the added responsibility of ath12k_mac_get_fw_stats() was the
busy-wait for `fw_stats_done`.

Signalling of `fw_stats_done` happens when one of the
WMI_REQUEST_PDEV_STAT, WMI_REQUEST_VDEV_STAT, and WMI_REQUEST_BCN_STAT
messages are received, but the handling of the latter two commands remained
in the debugfs code. As `fw_stats_done` isn't signalled, the calling
processes will spin until the timeout (3 seconds) is reached.

Moving the handling of these two additional responses out of debugfs
resolves the issue.

Fixes: b8a0d83f ("wifi: ath12k: move firmware stats out of debugfs")
Signed-off-by: default avatarBjorn Andersson <bjorn.andersson@oss.qualcomm.com>
Tested-by: default avatarAbel Vesa <abel.vesa@linaro.org>
Link: https://patch.msgid.link/20250609-ath12k-fw-stats-done-v1-1-2b3624656697@oss.qualcomm.com


Signed-off-by: default avatarJeff Johnson <jeff.johnson@oss.qualcomm.com>
parent 27605c8c

drivers/net/wireless/ath/ath12k/debugfs.c

+0 −58
Original line number Diff line number Diff line
@@ -1251,64 +1251,6 @@ void ath12k_debugfs_soc_destroy(struct ath12k_base *ab) 
	 */

}



void

ath12k_debugfs_fw_stats_process(struct ath12k *ar,

				struct ath12k_fw_stats *stats)

{

	struct ath12k_base *ab = ar->ab;

	struct ath12k_pdev *pdev;

	bool is_end;

	static unsigned int num_vdev, num_bcn;

	size_t total_vdevs_started = 0;

	int i;



	if (stats->stats_id == WMI_REQUEST_VDEV_STAT) {

		if (list_empty(&stats->vdevs)) {

			ath12k_warn(ab, "empty vdev stats");

			return;

		}

		/* FW sends all the active VDEV stats irrespective of PDEV,

		 * hence limit until the count of all VDEVs started

		 */

		rcu_read_lock();

		for (i = 0; i < ab->num_radios; i++) {

			pdev = rcu_dereference(ab->pdevs_active[i]);

			if (pdev && pdev->ar)

				total_vdevs_started += pdev->ar->num_started_vdevs;

		}

		rcu_read_unlock();



		is_end = ((++num_vdev) == total_vdevs_started);



		list_splice_tail_init(&stats->vdevs,

				      &ar->fw_stats.vdevs);



		if (is_end) {

			ar->fw_stats.fw_stats_done = true;

			num_vdev = 0;

		}

		return;

	}

	if (stats->stats_id == WMI_REQUEST_BCN_STAT) {

		if (list_empty(&stats->bcn)) {

			ath12k_warn(ab, "empty beacon stats");

			return;

		}

		/* Mark end until we reached the count of all started VDEVs

		 * within the PDEV

		 */

		is_end = ((++num_bcn) == ar->num_started_vdevs);



		list_splice_tail_init(&stats->bcn,

				      &ar->fw_stats.bcn);



		if (is_end) {

			ar->fw_stats.fw_stats_done = true;

			num_bcn = 0;

		}

	}

}



static int ath12k_open_vdev_stats(struct inode *inode, struct file *file)

{

	struct ath12k *ar = inode->i_private;

drivers/net/wireless/ath/ath12k/debugfs.h

+0 −7
Original line number Diff line number Diff line
@@ -12,8 +12,6 @@ void ath12k_debugfs_soc_create(struct ath12k_base *ab); 
void ath12k_debugfs_soc_destroy(struct ath12k_base *ab);

void ath12k_debugfs_register(struct ath12k *ar);

void ath12k_debugfs_unregister(struct ath12k *ar);

void ath12k_debugfs_fw_stats_process(struct ath12k *ar,

				     struct ath12k_fw_stats *stats);

void ath12k_debugfs_op_vif_add(struct ieee80211_hw *hw,

			       struct ieee80211_vif *vif);

void ath12k_debugfs_pdev_create(struct ath12k_base *ab);
@@ -126,11 +124,6 @@ static inline void ath12k_debugfs_unregister(struct ath12k *ar) 
{

}



static inline void ath12k_debugfs_fw_stats_process(struct ath12k *ar,

						   struct ath12k_fw_stats *stats)

{

}



static inline bool ath12k_debugfs_is_extd_rx_stats_enabled(struct ath12k *ar)

{

	return false;

drivers/net/wireless/ath/ath12k/wmi.c

+60 −7
Original line number Diff line number Diff line
@@ -7626,6 +7626,63 @@ static int ath12k_wmi_pull_fw_stats(struct ath12k_base *ab, struct sk_buff *skb, 
				   &parse);

}



static void ath12k_wmi_fw_stats_process(struct ath12k *ar,

					struct ath12k_fw_stats *stats)

{

	struct ath12k_base *ab = ar->ab;

	struct ath12k_pdev *pdev;

	bool is_end;

	static unsigned int num_vdev, num_bcn;

	size_t total_vdevs_started = 0;

	int i;



	if (stats->stats_id == WMI_REQUEST_VDEV_STAT) {

		if (list_empty(&stats->vdevs)) {

			ath12k_warn(ab, "empty vdev stats");

			return;

		}

		/* FW sends all the active VDEV stats irrespective of PDEV,

		 * hence limit until the count of all VDEVs started

		 */

		rcu_read_lock();

		for (i = 0; i < ab->num_radios; i++) {

			pdev = rcu_dereference(ab->pdevs_active[i]);

			if (pdev && pdev->ar)

				total_vdevs_started += pdev->ar->num_started_vdevs;

		}

		rcu_read_unlock();



		is_end = ((++num_vdev) == total_vdevs_started);



		list_splice_tail_init(&stats->vdevs,

				      &ar->fw_stats.vdevs);



		if (is_end) {

			ar->fw_stats.fw_stats_done = true;

			num_vdev = 0;

		}

		return;

	}

	if (stats->stats_id == WMI_REQUEST_BCN_STAT) {

		if (list_empty(&stats->bcn)) {

			ath12k_warn(ab, "empty beacon stats");

			return;

		}

		/* Mark end until we reached the count of all started VDEVs

		 * within the PDEV

		 */

		is_end = ((++num_bcn) == ar->num_started_vdevs);



		list_splice_tail_init(&stats->bcn,

				      &ar->fw_stats.bcn);



		if (is_end) {

			ar->fw_stats.fw_stats_done = true;

			num_bcn = 0;

		}

	}

}



static void ath12k_update_stats_event(struct ath12k_base *ab, struct sk_buff *skb)

{

	struct ath12k_fw_stats stats = {};
@@ -7655,19 +7712,15 @@ static void ath12k_update_stats_event(struct ath12k_base *ab, struct sk_buff *sk 


	spin_lock_bh(&ar->data_lock);



	/* WMI_REQUEST_PDEV_STAT can be requested via .get_txpower mac ops or via

	 * debugfs fw stats. Therefore, processing it separately.

	 */

	/* Handle WMI_REQUEST_PDEV_STAT status update */

	if (stats.stats_id == WMI_REQUEST_PDEV_STAT) {

		list_splice_tail_init(&stats.pdevs, &ar->fw_stats.pdevs);

		ar->fw_stats.fw_stats_done = true;

		goto complete;

	}



	/* WMI_REQUEST_VDEV_STAT and WMI_REQUEST_BCN_STAT are currently requested only

	 * via debugfs fw stats. Hence, processing these in debugfs context.

	 */

	ath12k_debugfs_fw_stats_process(ar, &stats);

	/* Handle WMI_REQUEST_VDEV_STAT and WMI_REQUEST_BCN_STAT updates. */

	ath12k_wmi_fw_stats_process(ar, &stats);



complete:

	complete(&ar->fw_stats_complete);