netdev - [PATCH net-next 07/15] net: airo: Always use JOB_STATS and JOB

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Date:   Tue, 27 Oct 2020 23:54:46 +0100
From:   Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:     netdev@...r.kernel.org
Cc:     Aymen Sghaier <aymen.sghaier@....com>,
        Daniel Drake <dsd@...too.org>,
        "David S. Miller" <davem@...emloft.net>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        Horia Geantă <horia.geanta@....com>,
        Jakub Kicinski <kuba@...nel.org>, Jon Mason <jdmason@...zu.us>,
        Jouni Malinen <j@...fi>, Kalle Valo <kvalo@...eaurora.org>,
        Leon Romanovsky <leon@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-crypto@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, linux-rdma@...r.kernel.org,
        linux-wireless@...r.kernel.org, Li Yang <leoyang.li@....com>,
        Madalin Bucur <madalin.bucur@....com>,
        Ping-Ke Shih <pkshih@...ltek.com>,
        Rain River <rain.1986.08.12@...il.com>,
        Saeed Mahameed <saeedm@...dia.com>,
        Samuel Chessman <chessman@....org>,
        Ulrich Kunitz <kune@...ne-taler.de>,
        Zhu Yanjun <zyjzyj2000@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [PATCH net-next 07/15] net: airo: Always use JOB_STATS and JOB_EVENT

issuecommand() is using in_atomic() to decide if it is safe to invoke
schedule() while waiting for the command to be accepted.

Usage of in_atomic() for this is only half correct as it can not detect all
condition where it is not allowed to schedule(). Also Linus clearly
requested that code which changes behaviour depending on context should
either be seperated or the context be conveyed in an argument passed by the
caller, which usually knows the context.

Chasing the call chains leading up to issuecommand() is straight forward,
but airo_link() and airo_get_stats() would require to pass the context
through a quite large amount of functions.

As this is ancient hardware, avoid the churn and enforce the invocation of
those functions through the JOB machinery.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc: Kalle Valo <kvalo@...eaurora.org>
Cc: "David S. Miller" <davem@...emloft.net>
Cc: Jakub Kicinski <kuba@...nel.org>
Cc: linux-wireless@...r.kernel.org
Cc: netdev@...r.kernel.org
---
 drivers/net/wireless/cisco/airo.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/drivers/net/wireless/cisco/airo.c b/drivers/net/wireless/cisco/airo.c
index ca423f3b6b3ea..369a6ca44d1ff 100644
--- a/drivers/net/wireless/cisco/airo.c
+++ b/drivers/net/wireless/cisco/airo.c
@@ -2286,12 +2286,8 @@ static struct net_device_stats *airo_get_stats(struct net_device *dev)
 	struct airo_info *local =  dev->ml_priv;
 
 	if (!test_bit(JOB_STATS, &local->jobs)) {
-		/* Get stats out of the card if available */
-		if (down_trylock(&local->sem) != 0) {
-			set_bit(JOB_STATS, &local->jobs);
-			wake_up_interruptible(&local->thr_wait);
-		} else
-			airo_read_stats(dev);
+		set_bit(JOB_STATS, &local->jobs);
+		wake_up_interruptible(&local->thr_wait);
 	}
 
 	return &dev->stats;
@@ -3277,11 +3273,9 @@ static void airo_handle_link(struct airo_info *ai)
 		set_bit(FLAG_UPDATE_UNI, &ai->flags);
 		set_bit(FLAG_UPDATE_MULTI, &ai->flags);
 
-		if (down_trylock(&ai->sem) != 0) {
-			set_bit(JOB_EVENT, &ai->jobs);
-			wake_up_interruptible(&ai->thr_wait);
-		} else
-			airo_send_event(ai->dev);
+		set_bit(JOB_EVENT, &ai->jobs);
+		wake_up_interruptible(&ai->thr_wait);
+
 		netif_carrier_on(ai->dev);
 	} else if (!scan_forceloss) {
 		if (auto_wep && !ai->expires) {
-- 
2.28.0