From 3827e33d371ed2f4024fd42a4409e1b7af8e0938 Mon Sep 17 00:00:00 2001 From: =?utf8?q?J=C3=A9r=C3=B4me=20Pouiller?= Date: Tue, 17 Dec 2019 16:15:37 +0000 Subject: [PATCH] staging: wfx: workaround bug with "iw scan" MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit mac80211 specification does not forbid hw_scan() to call ieee80211_scan_completed(). However, from userspace point of view, not all applications support this behavior. In particular, the code of iw contains a big fat warning: /* * This code has a bug, which requires creating a separate * nl80211 socket to fix: * It is possible for a NL80211_CMD_NEW_SCAN_RESULTS or * NL80211_CMD_SCAN_ABORTED message to be sent by the kernel * before (!) we listen to it, because we only start listening * after we send our scan request. [...] * Alas, the kernel doesn't do that (yet). */ So, we have to avoid to call ieee80211_scan_completed() from hw_scan() (it's a kind of unwritten rule). This patch relocates the hw_scan() process to a work_struct to fix the problem. Signed-off-by: Jérôme Pouiller Link: https://lore.kernel.org/r/20191217161318.31402-52-Jerome.Pouiller@silabs.com Signed-off-by: Greg Kroah-Hartman --- drivers/staging/wfx/scan.c | 47 ++++++++++++++++++++++++-------------- drivers/staging/wfx/scan.h | 1 + drivers/staging/wfx/sta.c | 1 + drivers/staging/wfx/wfx.h | 2 ++ 4 files changed, 34 insertions(+), 17 deletions(-) diff --git a/drivers/staging/wfx/scan.c b/drivers/staging/wfx/scan.c index b73e61e8da46..540009b72240 100644 --- a/drivers/staging/wfx/scan.c +++ b/drivers/staging/wfx/scan.c @@ -71,23 +71,19 @@ static int send_scan_req(struct wfx_vif *wvif, return i - start_idx; } -int wfx_hw_scan(struct ieee80211_hw *hw, struct ieee80211_vif *vif, - struct ieee80211_scan_request *hw_req) +/* + * It is not really necessary to run scan request asynchronously. However, + * there is a bug in "iw scan" when ieee80211_scan_completed() is called before + * wfx_hw_scan() return + */ +void wfx_hw_scan_work(struct work_struct *work) { - struct wfx_dev *wdev = hw->priv; - struct wfx_vif *wvif = (struct wfx_vif *) vif->drv_priv; + struct wfx_vif *wvif = container_of(work, struct wfx_vif, scan_work); + struct ieee80211_scan_request *hw_req = wvif->scan_req; int chan_cur, ret; - WARN_ON(hw_req->req.n_channels > HIF_API_MAX_NB_CHANNELS); - - if (vif->type == NL80211_IFTYPE_AP) - return -EOPNOTSUPP; - - if (wvif->state == WFX_STATE_PRE_STA) - return -EBUSY; - mutex_lock(&wvif->scan_lock); - mutex_lock(&wdev->conf_mutex); + mutex_lock(&wvif->wdev->conf_mutex); update_probe_tmpl(wvif, &hw_req->req); wfx_fwd_probe_req(wvif, true); chan_cur = 0; @@ -96,18 +92,35 @@ int wfx_hw_scan(struct ieee80211_hw *hw, struct ieee80211_vif *vif, if (ret > 0) chan_cur += ret; } while (ret > 0 && chan_cur < hw_req->req.n_channels); - __ieee80211_scan_completed_compat(hw, ret < 0); - mutex_unlock(&wdev->conf_mutex); + mutex_unlock(&wvif->wdev->conf_mutex); mutex_unlock(&wvif->scan_lock); + __ieee80211_scan_completed_compat(wvif->wdev->hw, ret < 0); if (wvif->delayed_unjoin) { wvif->delayed_unjoin = false; - wfx_tx_lock(wdev); + wfx_tx_lock(wvif->wdev); if (!schedule_work(&wvif->unjoin_work)) - wfx_tx_unlock(wdev); + wfx_tx_unlock(wvif->wdev); } else if (wvif->delayed_link_loss) { wvif->delayed_link_loss = false; wfx_cqm_bssloss_sm(wvif, 1, 0, 0); } +} + +int wfx_hw_scan(struct ieee80211_hw *hw, struct ieee80211_vif *vif, + struct ieee80211_scan_request *hw_req) +{ + struct wfx_vif *wvif = (struct wfx_vif *)vif->drv_priv; + + WARN_ON(hw_req->req.n_channels > HIF_API_MAX_NB_CHANNELS); + + if (vif->type == NL80211_IFTYPE_AP) + return -EOPNOTSUPP; + + if (wvif->state == WFX_STATE_PRE_STA) + return -EBUSY; + + wvif->scan_req = hw_req; + schedule_work(&wvif->scan_work); return 0; } diff --git a/drivers/staging/wfx/scan.h b/drivers/staging/wfx/scan.h index 03bc6c7e562d..b547f1927d72 100644 --- a/drivers/staging/wfx/scan.h +++ b/drivers/staging/wfx/scan.h @@ -15,6 +15,7 @@ struct wfx_dev; struct wfx_vif; +void wfx_hw_scan_work(struct work_struct *work); int wfx_hw_scan(struct ieee80211_hw *hw, struct ieee80211_vif *vif, struct ieee80211_scan_request *req); void wfx_scan_complete(struct wfx_vif *wvif, diff --git a/drivers/staging/wfx/sta.c b/drivers/staging/wfx/sta.c index 16f5db873275..4354bb8081c5 100644 --- a/drivers/staging/wfx/sta.c +++ b/drivers/staging/wfx/sta.c @@ -1427,6 +1427,7 @@ int wfx_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif) mutex_init(&wvif->scan_lock); init_completion(&wvif->scan_complete); + INIT_WORK(&wvif->scan_work, wfx_hw_scan_work); mutex_unlock(&wdev->conf_mutex); diff --git a/drivers/staging/wfx/wfx.h b/drivers/staging/wfx/wfx.h index 3356d0cbf7af..b5f763c3fac7 100644 --- a/drivers/staging/wfx/wfx.h +++ b/drivers/staging/wfx/wfx.h @@ -127,7 +127,9 @@ struct wfx_vif { /* avoid some operations in parallel with scan */ struct mutex scan_lock; + struct work_struct scan_work; struct completion scan_complete; + struct ieee80211_scan_request *scan_req; struct completion set_pm_mode_complete; -- 2.45.2