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Date:   Fri, 8 Apr 2022 11:49:49 +0200 (CEST)
From:   Julia Lawall <julia.lawall@inria.fr>
To:     Jaehee Park <jhpark1013@gmail.com>
cc:     =?ISO-8859-15?Q?J=E9r=F4me_Pouiller?= <jerome.pouiller@silabs.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org,
        outreachy@lists.linux.dev, Stefano Brivio <sbrivio@redhat.com>
Subject: Re: [PATCH] staging: wfx: use container_of() to get vif
In-Reply-To: <20220407204128.GA1810425@jaehee-ThinkPad-X1-Extreme>
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References: <20220407204128.GA1810425@jaehee-ThinkPad-X1-Extreme>
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On Thu, 7 Apr 2022, Jaehee Park wrote:

> Use container_of() to get vif. This improves the code in two ways:
> [1] it speeds up the compilation because container_of() saves steps to
> retrieve vif (the representation of ieee80211_vif), and

I don't understand this part.

julia

> [2] it eliminates the need to define multiple pointers. Previously,
> after setting the pointer to drv_priv, another pointer had to be
> defined by vif in struct wfx_vif to point back to ieee80211_vif.
> Remove vif from the struct wfx_vif, define a macro wvif_to_vif(ptr)
> for container_of(), and replace all wvif->vif with the newly defined
> container_of() construct.
>
> Signed-off-by: Jaehee Park <jhpark1013@gmail.com>
> ---
> Questions:
> - These changes built for me, but it would be great if someone can test it on the actual hardware.
> - We noticed that the?development of the wfx driver is happening in netdev instead of the staging directory. Do you suggest that I use the net-next tree for this change?
> ?
>  drivers/staging/wfx/data_rx.c |  4 ++--
>  drivers/staging/wfx/data_tx.c |  2 +-
>  drivers/staging/wfx/key.c     |  3 +--
>  drivers/staging/wfx/queue.c   |  2 +-
>  drivers/staging/wfx/scan.c    |  6 ++---
>  drivers/staging/wfx/sta.c     | 45 ++++++++++++++++-------------------
>  drivers/staging/wfx/wfx.h     |  3 ++-
>  7 files changed, 31 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/staging/wfx/data_rx.c b/drivers/staging/wfx/data_rx.c
> index a4b5ffe158e4..98c2223089b8 100644
> --- a/drivers/staging/wfx/data_rx.c
> +++ b/drivers/staging/wfx/data_rx.c
> @@ -24,12 +24,12 @@ static void wfx_rx_handle_ba(struct wfx_vif *wvif, struct ieee80211_mgmt *mgmt)
>  	case WLAN_ACTION_ADDBA_REQ:
>  		params = le16_to_cpu(mgmt->u.action.u.addba_req.capab);
>  		tid = (params & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
> -		ieee80211_start_rx_ba_session_offl(wvif->vif, mgmt->sa, tid);
> +		ieee80211_start_rx_ba_session_offl(wvif_to_vif(wvif), mgmt->sa, tid);
>  		break;
>  	case WLAN_ACTION_DELBA:
>  		params = le16_to_cpu(mgmt->u.action.u.delba.params);
>  		tid = (params &  IEEE80211_DELBA_PARAM_TID_MASK) >> 12;
> -		ieee80211_stop_rx_ba_session_offl(wvif->vif, mgmt->sa, tid);
> +		ieee80211_stop_rx_ba_session_offl(wvif_to_vif(wvif), mgmt->sa, tid);
>  		break;
>  	}
>  }
> diff --git a/drivers/staging/wfx/data_tx.c b/drivers/staging/wfx/data_tx.c
> index e07381b2ff4d..fd79e03a08c5 100644
> --- a/drivers/staging/wfx/data_tx.c
> +++ b/drivers/staging/wfx/data_tx.c
> @@ -216,7 +216,7 @@ static u8 wfx_tx_get_link_id(struct wfx_vif *wvif, struct ieee80211_sta *sta,
>
>  	if (sta_priv && sta_priv->link_id)
>  		return sta_priv->link_id;
> -	if (wvif->vif->type != NL80211_IFTYPE_AP)
> +	if (wvif_to_vif(wvif)->type != NL80211_IFTYPE_AP)
>  		return 0;
>  	if (is_multicast_ether_addr(da))
>  		return 0;
> diff --git a/drivers/staging/wfx/key.c b/drivers/staging/wfx/key.c
> index 8f23e8d42bd4..71b1fca70248 100644
> --- a/drivers/staging/wfx/key.c
> +++ b/drivers/staging/wfx/key.c
> @@ -174,7 +174,7 @@ static int wfx_add_key(struct wfx_vif *wvif, struct ieee80211_sta *sta,
>  			k.type = fill_tkip_pair(&k.key.tkip_pairwise_key, key, sta->addr);
>  		else
>  			k.type = fill_tkip_group(&k.key.tkip_group_key, key, &seq,
> -						 wvif->vif->type);
> +						 wvif_to_vif(wvif)->type);
>  	} else if (key->cipher == WLAN_CIPHER_SUITE_CCMP) {
>  		if (pairwise)
>  			k.type = fill_ccmp_pair(&k.key.aes_pairwise_key, key, sta->addr);
> @@ -224,4 +224,3 @@ int wfx_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd, struct ieee80211_
>  	mutex_unlock(&wvif->wdev->conf_mutex);
>  	return ret;
>  }
> -
> diff --git a/drivers/staging/wfx/queue.c b/drivers/staging/wfx/queue.c
> index 729825230db2..a2745d1024c6 100644
> --- a/drivers/staging/wfx/queue.c
> +++ b/drivers/staging/wfx/queue.c
> @@ -207,7 +207,7 @@ bool wfx_tx_queues_has_cab(struct wfx_vif *wvif)
>  {
>  	int i;
>
> -	if (wvif->vif->type != NL80211_IFTYPE_AP)
> +	if (wvif_to_vif(wvif)->type != NL80211_IFTYPE_AP)
>  		return false;
>  	for (i = 0; i < IEEE80211_NUM_ACS; ++i)
>  		/* Note: since only AP can have mcast frames in queue and only one vif can be AP,
> diff --git a/drivers/staging/wfx/scan.c b/drivers/staging/wfx/scan.c
> index 7f34f0d322f9..5c25fde3fc41 100644
> --- a/drivers/staging/wfx/scan.c
> +++ b/drivers/staging/wfx/scan.c
> @@ -25,7 +25,7 @@ static int update_probe_tmpl(struct wfx_vif *wvif, struct cfg80211_scan_request
>  {
>  	struct sk_buff *skb;
>
> -	skb = ieee80211_probereq_get(wvif->wdev->hw, wvif->vif->addr, NULL, 0, req->ie_len);
> +	skb = ieee80211_probereq_get(wvif->wdev->hw, wvif_to_vif(wvif)->addr, NULL, 0, req->ie_len);
>  	if (!skb)
>  		return -ENOMEM;
>
> @@ -75,8 +75,8 @@ static int send_scan_req(struct wfx_vif *wvif, struct cfg80211_scan_request *req
>  	} else {
>  		ret = wvif->scan_nb_chan_done;
>  	}
> -	if (req->channels[start_idx]->max_power != wvif->vif->bss_conf.txpower)
> -		wfx_hif_set_output_power(wvif, wvif->vif->bss_conf.txpower);
> +	if (req->channels[start_idx]->max_power != wvif_to_vif(wvif)->bss_conf.txpower)
> +		wfx_hif_set_output_power(wvif, wvif_to_vif(wvif)->bss_conf.txpower);
>  	wfx_tx_unlock(wvif->wdev);
>  	return ret;
>  }
> diff --git a/drivers/staging/wfx/sta.c b/drivers/staging/wfx/sta.c
> index 03025ef7f1be..b634c8e004db 100644
> --- a/drivers/staging/wfx/sta.c
> +++ b/drivers/staging/wfx/sta.c
> @@ -132,7 +132,7 @@ void wfx_configure_filter(struct ieee80211_hw *hw, unsigned int changed_flags,
>  			filter_bssid = true;
>
>  		/* In AP mode, chip can reply to probe request itself */
> -		if (*total_flags & FIF_PROBE_REQ && wvif->vif->type == NL80211_IFTYPE_AP) {
> +		if (*total_flags & FIF_PROBE_REQ && wvif_to_vif(wvif)->type == NL80211_IFTYPE_AP) {
>  			dev_dbg(wdev->dev, "do not forward probe request in AP mode\n");
>  			*total_flags &= ~FIF_PROBE_REQ;
>  		}
> @@ -153,18 +153,18 @@ static int wfx_get_ps_timeout(struct wfx_vif *wvif, bool *enable_ps)
>  	struct ieee80211_channel *chan0 = NULL, *chan1 = NULL;
>  	struct ieee80211_conf *conf = &wvif->wdev->hw->conf;
>
> -	WARN(!wvif->vif->bss_conf.assoc && enable_ps,
> +	WARN(!wvif_to_vif(wvif)->bss_conf.assoc && enable_ps,
>  	     "enable_ps is reliable only if associated");
>  	if (wdev_to_wvif(wvif->wdev, 0))
> -		chan0 = wdev_to_wvif(wvif->wdev, 0)->vif->bss_conf.chandef.chan;
> +		chan0 = wvif_to_vif(wdev_to_wvif(wvif->wdev, 0))->bss_conf.chandef.chan;
>  	if (wdev_to_wvif(wvif->wdev, 1))
> -		chan1 = wdev_to_wvif(wvif->wdev, 1)->vif->bss_conf.chandef.chan;
> -	if (chan0 && chan1 && wvif->vif->type != NL80211_IFTYPE_AP) {
> +		chan1 = wvif_to_vif(wdev_to_wvif(wvif->wdev, 1))->bss_conf.chandef.chan;
> +	if (chan0 && chan1 && wvif_to_vif(wvif)->type != NL80211_IFTYPE_AP) {
>  		if (chan0->hw_value == chan1->hw_value) {
>  			/* It is useless to enable PS if channels are the same. */
>  			if (enable_ps)
>  				*enable_ps = false;
> -			if (wvif->vif->bss_conf.assoc && wvif->vif->bss_conf.ps)
> +			if (wvif_to_vif(wvif)->bss_conf.assoc && wvif_to_vif(wvif)->bss_conf.ps)
>  				dev_info(wvif->wdev->dev, "ignoring requested PS mode");
>  			return -1;
>  		}
> @@ -177,8 +177,8 @@ static int wfx_get_ps_timeout(struct wfx_vif *wvif, bool *enable_ps)
>  			return 30;
>  	}
>  	if (enable_ps)
> -		*enable_ps = wvif->vif->bss_conf.ps;
> -	if (wvif->vif->bss_conf.assoc && wvif->vif->bss_conf.ps)
> +		*enable_ps = wvif_to_vif(wvif)->bss_conf.ps;
> +	if (wvif_to_vif(wvif)->bss_conf.assoc && wvif_to_vif(wvif)->bss_conf.ps)
>  		return conf->dynamic_ps_timeout;
>  	else
>  		return -1;
> @@ -189,7 +189,7 @@ int wfx_update_pm(struct wfx_vif *wvif)
>  	int ps_timeout;
>  	bool ps;
>
> -	if (!wvif->vif->bss_conf.assoc)
> +	if (!wvif_to_vif(wvif)->bss_conf.assoc)
>  		return 0;
>  	ps_timeout = wfx_get_ps_timeout(wvif, &ps);
>  	if (!ps)
> @@ -215,7 +215,7 @@ int wfx_conf_tx(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
>  	mutex_lock(&wdev->conf_mutex);
>  	assign_bit(queue, &wvif->uapsd_mask, params->uapsd);
>  	wfx_hif_set_edca_queue_params(wvif, queue, params);
> -	if (wvif->vif->type == NL80211_IFTYPE_STATION && old_uapsd != wvif->uapsd_mask) {
> +	if (wvif_to_vif(wvif)->type == NL80211_IFTYPE_STATION && old_uapsd != wvif->uapsd_mask) {
>  		wfx_hif_set_uapsd_info(wvif, wvif->uapsd_mask);
>  		wfx_update_pm(wvif);
>  	}
> @@ -242,20 +242,20 @@ void wfx_event_report_rssi(struct wfx_vif *wvif, u8 raw_rcpi_rssi)
>  	int cqm_evt;
>
>  	rcpi_rssi = raw_rcpi_rssi / 2 - 110;
> -	if (rcpi_rssi <= wvif->vif->bss_conf.cqm_rssi_thold)
> +	if (rcpi_rssi <= wvif_to_vif(wvif)->bss_conf.cqm_rssi_thold)
>  		cqm_evt = NL80211_CQM_RSSI_THRESHOLD_EVENT_LOW;
>  	else
>  		cqm_evt = NL80211_CQM_RSSI_THRESHOLD_EVENT_HIGH;
> -	ieee80211_cqm_rssi_notify(wvif->vif, cqm_evt, rcpi_rssi, GFP_KERNEL);
> +	ieee80211_cqm_rssi_notify(wvif_to_vif(wvif), cqm_evt, rcpi_rssi, GFP_KERNEL);
>  }
>
>  static void wfx_beacon_loss_work(struct work_struct *work)
>  {
>  	struct wfx_vif *wvif = container_of(to_delayed_work(work), struct wfx_vif,
>  					    beacon_loss_work);
> -	struct ieee80211_bss_conf *bss_conf = &wvif->vif->bss_conf;
> +	struct ieee80211_bss_conf *bss_conf = &wvif_to_vif(wvif)->bss_conf;
>
> -	ieee80211_beacon_loss(wvif->vif);
> +	ieee80211_beacon_loss(wvif_to_vif(wvif));
>  	schedule_delayed_work(to_delayed_work(work), msecs_to_jiffies(bss_conf->beacon_int));
>  }
>
> @@ -323,13 +323,13 @@ static int wfx_upload_ap_templates(struct wfx_vif *wvif)
>  {
>  	struct sk_buff *skb;
>
> -	skb = ieee80211_beacon_get(wvif->wdev->hw, wvif->vif);
> +	skb = ieee80211_beacon_get(wvif->wdev->hw, wvif_to_vif(wvif));
>  	if (!skb)
>  		return -ENOMEM;
>  	wfx_hif_set_template_frame(wvif, skb, HIF_TMPLT_BCN, API_RATE_INDEX_B_1MBPS);
>  	dev_kfree_skb(skb);
>
> -	skb = ieee80211_proberesp_get(wvif->wdev->hw, wvif->vif);
> +	skb = ieee80211_proberesp_get(wvif->wdev->hw, wvif_to_vif(wvif));
>  	if (!skb)
>  		return -ENOMEM;
>  	wfx_hif_set_template_frame(wvif, skb, HIF_TMPLT_PRBRES, API_RATE_INDEX_B_1MBPS);
> @@ -339,7 +339,7 @@ static int wfx_upload_ap_templates(struct wfx_vif *wvif)
>
>  static void wfx_set_mfp_ap(struct wfx_vif *wvif)
>  {
> -	struct sk_buff *skb = ieee80211_beacon_get(wvif->wdev->hw, wvif->vif);
> +	struct sk_buff *skb = ieee80211_beacon_get(wvif->wdev->hw, wvif_to_vif(wvif));
>  	const int ieoffset = offsetof(struct ieee80211_mgmt, u.beacon.variable);
>  	const u16 *ptr = (u16 *)cfg80211_find_ie(WLAN_EID_RSN, skb->data + ieoffset,
>  						 skb->len - ieoffset);
> @@ -389,7 +389,7 @@ void wfx_stop_ap(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
>  static void wfx_join(struct wfx_vif *wvif)
>  {
>  	int ret;
> -	struct ieee80211_bss_conf *conf = &wvif->vif->bss_conf;
> +	struct ieee80211_bss_conf *conf = &wvif_to_vif(wvif)->bss_conf;
>  	struct cfg80211_bss *bss = NULL;
>  	u8 ssid[IEEE80211_MAX_SSID_LEN];
>  	const u8 *ssid_ie = NULL;
> @@ -420,7 +420,7 @@ static void wfx_join(struct wfx_vif *wvif)
>  	wvif->join_in_progress = true;
>  	ret = wfx_hif_join(wvif, conf, wvif->channel, ssid, ssid_len);
>  	if (ret) {
> -		ieee80211_connection_loss(wvif->vif);
> +		ieee80211_connection_loss(wvif_to_vif(wvif));
>  		wfx_reset(wvif);
>  	} else {
>  		/* Due to beacon filtering it is possible that the AP's beacon is not known for the
> @@ -440,7 +440,7 @@ static void wfx_join_finalize(struct wfx_vif *wvif, struct ieee80211_bss_conf *i
>
>  	rcu_read_lock(); /* protect sta */
>  	if (info->bssid && !info->ibss_joined)
> -		sta = ieee80211_find_sta(wvif->vif, info->bssid);
> +		sta = ieee80211_find_sta(wvif_to_vif(wvif), info->bssid);
>  	if (sta && sta->ht_cap.ht_supported)
>  		ampdu_density = sta->ht_cap.ampdu_density;
>  	if (sta && sta->ht_cap.ht_supported &&
> @@ -565,7 +565,7 @@ static int wfx_update_tim(struct wfx_vif *wvif)
>  	u16 tim_offset, tim_length;
>  	u8 *tim_ptr;
>
> -	skb = ieee80211_beacon_get_tim(wvif->wdev->hw, wvif->vif, &tim_offset, &tim_length);
> +	skb = ieee80211_beacon_get_tim(wvif->wdev->hw, wvif_to_vif(wvif), &tim_offset, &tim_length);
>  	if (!skb)
>  		return -ENOENT;
>  	tim_ptr = skb->data + tim_offset;
> @@ -707,8 +707,6 @@ int wfx_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
>  		return -EOPNOTSUPP;
>  	}
>
> -	/* FIXME: prefer use of container_of() to get vif */
> -	wvif->vif = vif;
>  	wvif->wdev = wdev;
>
>  	wvif->link_id_map = 1; /* link-id 0 is reserved for multicast */
> @@ -767,7 +765,6 @@ void wfx_remove_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
>
>  	cancel_delayed_work_sync(&wvif->beacon_loss_work);
>  	wdev->vif[wvif->id] = NULL;
> -	wvif->vif = NULL;
>
>  	mutex_unlock(&wdev->conf_mutex);
>
> diff --git a/drivers/staging/wfx/wfx.h b/drivers/staging/wfx/wfx.h
> index 6594cc647c2f..78f2a416fe4f 100644
> --- a/drivers/staging/wfx/wfx.h
> +++ b/drivers/staging/wfx/wfx.h
> @@ -25,6 +25,8 @@
>  #define USEC_PER_TXOP 32 /* see struct ieee80211_tx_queue_params */
>  #define USEC_PER_TU 1024
>
> +#define wvif_to_vif(ptr)(container_of((void *)ptr, struct ieee80211_vif, drv_priv))
> +
>  struct wfx_hwbus_ops;
>
>  struct wfx_dev {
> @@ -61,7 +63,6 @@ struct wfx_dev {
>
>  struct wfx_vif {
>  	struct wfx_dev             *wdev;
> -	struct ieee80211_vif       *vif;
>  	struct ieee80211_channel   *channel;
>  	int                        id;
>
> --
> 2.25.1
>
>
>
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