[PATCH] mac80211: add ieee80211_hw flag for QoS NDP support

Commit 7b6ddeaf27ec ("mac80211: use QoS NDP for AP probing") adds an
argument qos_ok to ieee80211_nullfunc_get to support QoS NDP. Despite
the claim in the commit log "Change all the drivers to *not* allow
QoS NDP for now, even though it looks like most of them should be OK
with that", this commit enables QoS NDP in response to beacons (see
change to mlme.c:ieee80211_send_nullfunc), causing ath9k_htc to lose
IP connectivity. See:
https://patchwork.kernel.org/patch/10241109/
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=891060

This patch replaces the argument qos_ok of ieee80211_nullfunc_get
with an ieee80211_hw flag that drivers can use to declare support for
QoS NDP, allowing consistent behaviour between mlme.c and drivers.

Signed-off-by: Ben Caradoc-Davies <redacted>
---
 drivers/net/wireless/ath/ath9k/channel.c |  2 +-
 drivers/net/wireless/st/cw1200/sta.c     |  4 ++--
 drivers/net/wireless/ti/wl1251/main.c    |  2 +-
 drivers/net/wireless/ti/wlcore/cmd.c     |  5 ++---
 include/net/mac80211.h                   | 12 +++++-------
 net/mac80211/mlme.c                      |  2 +-
 net/mac80211/tx.c                        |  5 ++---
 7 files changed, 14 insertions(+), 18 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/channel.c b/drivers/net/wireless/ath/ath9k/channel.c
index 1b05b5d7a038..dfb26f03c1a2 100644
--- a/drivers/net/wireless/ath/ath9k/channel.c
+++ b/drivers/net/wireless/ath/ath9k/channel.c

@@ -1113,7 +1113,7 @@ ath_chanctx_send_vif_ps_frame(struct ath_softc *sc, struct ath_vif *avp,
 		if (!avp->assoc)
 			return false;
 
-		skb = ieee80211_nullfunc_get(sc->hw, vif, false);
+		skb = ieee80211_nullfunc_get(sc->hw, vif);
 		if (!skb)
 			return false;
 

diff --git a/drivers/net/wireless/st/cw1200/sta.c b/drivers/net/wireless/st/cw1200/sta.c
index 38678e9a0562..03687a80d6e9 100644
--- a/drivers/net/wireless/st/cw1200/sta.c
+++ b/drivers/net/wireless/st/cw1200/sta.c

@@ -198,7 +198,7 @@ void __cw1200_cqm_bssloss_sm(struct cw1200_common *priv,
 
 		priv->bss_loss_state++;
 
-		skb = ieee80211_nullfunc_get(priv->hw, priv->vif, false);
+		skb = ieee80211_nullfunc_get(priv->hw, priv->vif);
 		WARN_ON(!skb);
 		if (skb)
 			cw1200_tx(priv->hw, NULL, skb);

@@ -2265,7 +2265,7 @@ static int cw1200_upload_null(struct cw1200_common *priv)
 		.rate = 0xFF,
 	};
 
-	frame.skb = ieee80211_nullfunc_get(priv->hw, priv->vif, false);
+	frame.skb = ieee80211_nullfunc_get(priv->hw, priv->vif);
 	if (!frame.skb)
 		return -ENOMEM;
 

diff --git a/drivers/net/wireless/ti/wl1251/main.c b/drivers/net/wireless/ti/wl1251/main.c
index 037defd10b91..99a6889a6540 100644
--- a/drivers/net/wireless/ti/wl1251/main.c
+++ b/drivers/net/wireless/ti/wl1251/main.c

@@ -566,7 +566,7 @@ static int wl1251_build_null_data(struct wl1251 *wl)
 		size = sizeof(struct wl12xx_null_data_template);
 		ptr = NULL;
 	} else {
-		skb = ieee80211_nullfunc_get(wl->hw, wl->vif, false);
+		skb = ieee80211_nullfunc_get(wl->hw, wl->vif);
 		if (!skb)
 			goto out;
 		size = skb->len;

diff --git a/drivers/net/wireless/ti/wlcore/cmd.c b/drivers/net/wireless/ti/wlcore/cmd.c
index 761cf8573a80..2bfc12fdc929 100644
--- a/drivers/net/wireless/ti/wlcore/cmd.c
+++ b/drivers/net/wireless/ti/wlcore/cmd.c

@@ -1069,8 +1069,7 @@ int wl12xx_cmd_build_null_data(struct wl1271 *wl, struct wl12xx_vif *wlvif)
 		ptr = NULL;
 	} else {
 		skb = ieee80211_nullfunc_get(wl->hw,
-					     wl12xx_wlvif_to_vif(wlvif),
-					     false);
+					     wl12xx_wlvif_to_vif(wlvif));
 		if (!skb)
 			goto out;
 		size = skb->len;

@@ -1097,7 +1096,7 @@ int wl12xx_cmd_build_klv_null_data(struct wl1271 *wl,
 	struct sk_buff *skb = NULL;
 	int ret = -ENOMEM;
 
-	skb = ieee80211_nullfunc_get(wl->hw, vif, false);
+	skb = ieee80211_nullfunc_get(wl->hw, vif);
 	if (!skb)
 		goto out;
 

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index c96511fa9198..985f32c76ba9 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h

@@ -2063,6 +2063,9 @@ struct ieee80211_txq {
  * @IEEE80211_HW_SUPPORTS_TDLS_BUFFER_STA: Hardware supports buffer STA on
  *	TDLS links.
  *
+ * @IEEE80211_HW_SUPPORTS_QOS_NDP: The driver (or firmware) supports QoS NDP
+ *	for AP probing.
+ *
  * @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing arrays
  */
 enum ieee80211_hw_flags {

@@ -2106,6 +2109,7 @@ enum ieee80211_hw_flags {
 	IEEE80211_HW_REPORTS_LOW_ACK,
 	IEEE80211_HW_SUPPORTS_TX_FRAG,
 	IEEE80211_HW_SUPPORTS_TDLS_BUFFER_STA,
+	IEEE80211_HW_SUPPORTS_QOS_NDP,
 
 	/* keep last, obviously */
 	NUM_IEEE80211_HW_FLAGS

@@ -4478,24 +4482,18 @@ struct sk_buff *ieee80211_pspoll_get(struct ieee80211_hw *hw,
  * ieee80211_nullfunc_get - retrieve a nullfunc template
  * @hw: pointer obtained from ieee80211_alloc_hw().
  * @vif: &struct ieee80211_vif pointer from the add_interface callback.
- * @qos_ok: QoS NDP is acceptable to the caller, this should be set
- *	if at all possible
  *
  * Creates a Nullfunc template which can, for example, uploaded to
  * hardware. The template must be updated after association so that correct
  * BSSID and address is used.
  *
- * If @qos_ndp is set and the association is to an AP with QoS/WMM, the
- * returned packet will be QoS NDP.
- *
  * Note: Caller (or hardware) is responsible for setting the
  * &IEEE80211_FCTL_PM bit as well as Duration and Sequence Control fields.
  *
  * Return: The nullfunc template. %NULL on error.
  */
 struct sk_buff *ieee80211_nullfunc_get(struct ieee80211_hw *hw,
-				       struct ieee80211_vif *vif,
-				       bool qos_ok);
+				       struct ieee80211_vif *vif);
 
 /**
  * ieee80211_probereq_get - retrieve a Probe Request template

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 39b660b9a908..cc55ff8ae979 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c

@@ -896,7 +896,7 @@ void ieee80211_send_nullfunc(struct ieee80211_local *local,
 	struct ieee80211_hdr_3addr *nullfunc;
 	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
 
-	skb = ieee80211_nullfunc_get(&local->hw, &sdata->vif, true);
+	skb = ieee80211_nullfunc_get(&local->hw, &sdata->vif);
 	if (!skb)
 		return;
 

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 69722504e3e1..885285dd247b 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c

@@ -4448,8 +4448,7 @@ struct sk_buff *ieee80211_pspoll_get(struct ieee80211_hw *hw,
 EXPORT_SYMBOL(ieee80211_pspoll_get);
 
 struct sk_buff *ieee80211_nullfunc_get(struct ieee80211_hw *hw,
-				       struct ieee80211_vif *vif,
-				       bool qos_ok)
+				       struct ieee80211_vif *vif)
 {
 	struct ieee80211_hdr_3addr *nullfunc;
 	struct ieee80211_sub_if_data *sdata;

@@ -4465,7 +4464,7 @@ struct sk_buff *ieee80211_nullfunc_get(struct ieee80211_hw *hw,
 	ifmgd = &sdata->u.mgd;
 	local = sdata->local;
 
-	if (qos_ok) {
+	if (ieee80211_hw_check(hw, SUPPORTS_QOS_NDP)) {
 		struct sta_info *sta;
 
 		rcu_read_lock();

-- 
Ben Caradoc-Davies <ben@transient.nz>
Director
Transient Software Limited <https://transient.nz/>
New Zealand

Note that this patch supersedes 
<https://patchwork.kernel.org/patch/10241109/>.

Kind regards,

-- 
Ben Caradoc-Davies [off-list ref]
Director
Transient Software Limited <https://transient.nz/>
New Zealand

Hi Ben,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on v4.16-rc4]
[cannot apply to next-20180316]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Ben-Caradoc-Davies/mac80211-add-ieee80211_hw-flag-for-QoS-NDP-support/20180319-052448
config: i386-randconfig-x013-201811 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All error/warnings (new ones prefixed by >>):

   In file included from include/linux/kernel.h:10:0,
                    from include/linux/list.h:9,
                    from include/linux/wait.h:7,
                    from include/linux/wait_bit.h:8,
                    from include/linux/fs.h:6,
                    from include/linux/debugfs.h:15,
                    from net/mac80211/debugfs.c:11:
   net/mac80211/debugfs.c: In function 'hwflags_read':

quoted

include/linux/compiler.h:339:38: error: call to '__compiletime_assert_234' declared with attribute error: BUILD_BUG_ON failed: ARRAY_SIZE(hw_flag_names) != NUM_IEEE80211_HW_FLAGS

     _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
                                         ^
   include/linux/compiler.h:319:4: note: in definition of macro '__compiletime_assert'
       prefix ## suffix();    \
       ^~~~~~
   include/linux/compiler.h:339:2: note: in expansion of macro '_compiletime_assert'
     _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
     ^~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:45:37: note: in expansion of macro 'compiletime_assert'
    #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
                                        ^~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:69:2: note: in expansion of macro 'BUILD_BUG_ON_MSG'
     BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
     ^~~~~~~~~~~~~~~~

quoted

net/mac80211/debugfs.c:234:2: note: in expansion of macro 'BUILD_BUG_ON'

     BUILD_BUG_ON(ARRAY_SIZE(hw_flag_names) != NUM_IEEE80211_HW_FLAGS);
     ^~~~~~~~~~~~
--
   In file included from include/linux/kernel.h:10:0,
                    from include/linux/list.h:9,
                    from include/linux/wait.h:7,
                    from include/linux/wait_bit.h:8,
                    from include/linux/fs.h:6,
                    from include/linux/debugfs.h:15,
                    from net//mac80211/debugfs.c:11:
   net//mac80211/debugfs.c: In function 'hwflags_read':

quoted

include/linux/compiler.h:339:38: error: call to '__compiletime_assert_234' declared with attribute error: BUILD_BUG_ON failed: ARRAY_SIZE(hw_flag_names) != NUM_IEEE80211_HW_FLAGS

     _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
                                         ^
   include/linux/compiler.h:319:4: note: in definition of macro '__compiletime_assert'
       prefix ## suffix();    \
       ^~~~~~
   include/linux/compiler.h:339:2: note: in expansion of macro '_compiletime_assert'
     _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
     ^~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:45:37: note: in expansion of macro 'compiletime_assert'
    #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
                                        ^~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:69:2: note: in expansion of macro 'BUILD_BUG_ON_MSG'
     BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
     ^~~~~~~~~~~~~~~~
   net//mac80211/debugfs.c:234:2: note: in expansion of macro 'BUILD_BUG_ON'
     BUILD_BUG_ON(ARRAY_SIZE(hw_flag_names) != NUM_IEEE80211_HW_FLAGS);
     ^~~~~~~~~~~~

vim +/__compiletime_assert_234 +339 include/linux/compiler.h

9a8ab1c3 Daniel Santos 2013-02-21  325  
9a8ab1c3 Daniel Santos 2013-02-21  326  #define _compiletime_assert(condition, msg, prefix, suffix) \
9a8ab1c3 Daniel Santos 2013-02-21  327  	__compiletime_assert(condition, msg, prefix, suffix)
9a8ab1c3 Daniel Santos 2013-02-21  328  
9a8ab1c3 Daniel Santos 2013-02-21  329  /**
9a8ab1c3 Daniel Santos 2013-02-21  330   * compiletime_assert - break build and emit msg if condition is false
9a8ab1c3 Daniel Santos 2013-02-21  331   * @condition: a compile-time constant condition to check
9a8ab1c3 Daniel Santos 2013-02-21  332   * @msg:       a message to emit if condition is false
9a8ab1c3 Daniel Santos 2013-02-21  333   *
9a8ab1c3 Daniel Santos 2013-02-21  334   * In tradition of POSIX assert, this macro will break the build if the
9a8ab1c3 Daniel Santos 2013-02-21  335   * supplied condition is *false*, emitting the supplied error message if the
9a8ab1c3 Daniel Santos 2013-02-21  336   * compiler has support to do so.
9a8ab1c3 Daniel Santos 2013-02-21  337   */
9a8ab1c3 Daniel Santos 2013-02-21  338  #define compiletime_assert(condition, msg) \
9a8ab1c3 Daniel Santos 2013-02-21 @339  	_compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
9a8ab1c3 Daniel Santos 2013-02-21  340  

:::::: The code at line 339 was first introduced by commit
:::::: 9a8ab1c39970a4938a72d94e6fd13be88a797590 bug.h, compiler.h: introduce compiletime_assert & BUILD_BUG_ON_MSG

:::::: TO: Daniel Santos [off-list ref]
:::::: CC: Linus Torvalds [off-list ref]

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

On 19/03/18 11:12, kbuild test robot wrote:

    net/mac80211/debugfs.c: In function 'hwflags_read':

quoted

quoted

include/linux/compiler.h:339:38: error: call to '__compiletime_assert_234' declared with attribute error: BUILD_BUG_ON failed: ARRAY_SIZE(hw_flag_names) != NUM_IEEE80211_HW_FLAGS

Please reject this patch. I will submit a revised patch that adds the 
new flag to hw_flag_names in net/mac80211/debugfs.c.

Kind regards,

-- 
Ben Caradoc-Davies [off-list ref]
Director
Transient Software Limited <https://transient.nz/>
New Zealand