From patchwork Tue Apr 30 01:14:57 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marek Vasut X-Patchwork-Id: 13647919 X-Patchwork-Delegate: kuba@kernel.org Received: from phobos.denx.de (phobos.denx.de [85.214.62.61]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EA0071113 for ; Tue, 30 Apr 2024 01:15:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=85.214.62.61 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714439745; cv=none; b=gI4zJQWz6EStRAIL0atFBlhLDGoAb9bkUfQ9pFeiUylUc4i3/CN8ZdYAyb28wNG7LUfY07023dzcybGkNzUgaqu1DwQybv2J7MXZAr2Qh6x2T/WURLcJpnq8l3Hq5AkX4DN5CCLApk8i3k0n4yyGgKUQF1noMy4dT0QDH4Llc5Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714439745; c=relaxed/simple; bh=tyA/Fdu+Yk0iqk9l6tf/xqs5MBKuZU9Iz0SQumIgvh0=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=KxN2VfEz5aUEcsqMNG/2dbT1rwJKMIcKlsSiWpPSU6bDmJ/yE0T58DSXp7Bx3914ugs4x8XBAlz5p3cQfYBb1IYPlyI6yL20ZVnhmVHq3wsiTrYRApx76ydOp2/jAv8ZtgBEaklPCg0/5vtzWDSsVJNAsBRsYQVn/CCxAJTwb/Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=denx.de; spf=pass smtp.mailfrom=denx.de; dkim=pass (2048-bit key) header.d=denx.de header.i=@denx.de header.b=ezH7qh2/; arc=none smtp.client-ip=85.214.62.61 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=denx.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=denx.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=denx.de header.i=@denx.de header.b="ezH7qh2/" Received: from tr.lan (ip-86-49-120-218.bb.vodafone.cz [86.49.120.218]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: marex@denx.de) by phobos.denx.de (Postfix) with ESMTPSA id 99A6E884EE; Tue, 30 Apr 2024 03:15:40 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=denx.de; s=phobos-20191101; t=1714439741; bh=C2tdQOLxnshoDpoFduDoM28VnzxSbvfHM/++4tsgA0I=; h=From:To:Cc:Subject:Date:From; b=ezH7qh2/GJduAQSiRsXsPYymKTlSJ/BOeLurp+hXfVPZ4KtJH77xCP+IV692Hw4Ca bYahCyt4WNJXwXq0g0q19UbmpVd42RaJsIPiBoYWj7JVFeRZcIwxDL0UicsUHN22Ic bRFbc1zGrUtq1tksoVVPHQJ91A87Z7+hUgRt/E26McWGbPFVNgFNDHT3CEqmguUN63 rkMCs/J4P+r2np5Pg5ySjd7N/+8FB+Oc78IFJKCL6kzO+uDiOn7gCoH6AmVqZmyz8R bvK6Ze+htrK4wPmdfRteMR5TQZfAsGkOB+qEQvKIs2vWTwy16hX2EFIKwKPixPeeBG Kf/K6ngiVmNtQ== From: Marek Vasut To: netdev@vger.kernel.org Cc: Marek Vasut , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Ronald Wahl , Simon Horman Subject: [net,PATCH] net: ks8851: Queue RX packets in IRQ handler instead of disabling BHs Date: Tue, 30 Apr 2024 03:14:57 +0200 Message-ID: <20240430011518.110416-1-marex@denx.de> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Virus-Scanned: clamav-milter 0.103.8 at phobos.denx.de X-Virus-Status: Clean X-Patchwork-Delegate: kuba@kernel.org Currently the driver uses local_bh_disable()/local_bh_enable() in its IRQ handler to avoid triggering net_rx_action() softirq on exit from netif_rx(). The net_rx_action() could trigger this driver .start_xmit callback, which is protected by the same lock as the IRQ handler, so calling the .start_xmit from netif_rx() from the IRQ handler critical section protected by the lock could lead to an attempt to claim the already claimed lock, and a hang. The local_bh_disable()/local_bh_enable() approach works only in case the IRQ handler is protected by a spinlock, but does not work if the IRQ handler is protected by mutex, i.e. this works for KS8851 with Parallel bus interface, but not for KS8851 with SPI bus interface. Remove the BH manipulation and instead of calling netif_rx() inside the IRQ handler code protected by the lock, queue all the received SKBs in the IRQ handler into a queue first, and once the IRQ handler exits the critical section protected by the lock, dequeue all the queued SKBs and push them all into netif_rx(). At this point, it is safe to trigger the net_rx_action() softirq, since the netif_rx() call is outside of the lock that protects the IRQ handler. Fixes: be0384bf599c ("net: ks8851: Handle softirqs at the end of IRQ thread to fix hang") Signed-off-by: Marek Vasut Tested-by: Ronald Wahl --- Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Ronald Wahl Cc: Simon Horman Cc: netdev@vger.kernel.org --- Note: This is basically what Jakub originally suggested in https://patchwork.kernel.org/project/netdevbpf/patch/20240331142353.93792-2-marex@denx.de/#25785606 --- drivers/net/ethernet/micrel/ks8851.h | 1 + drivers/net/ethernet/micrel/ks8851_common.c | 8 ++++---- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/micrel/ks8851.h b/drivers/net/ethernet/micrel/ks8851.h index 31f75b4a67fd7..f311074ea13bc 100644 --- a/drivers/net/ethernet/micrel/ks8851.h +++ b/drivers/net/ethernet/micrel/ks8851.h @@ -399,6 +399,7 @@ struct ks8851_net { struct work_struct rxctrl_work; + struct sk_buff_head rxq; struct sk_buff_head txq; unsigned int queued_len; diff --git a/drivers/net/ethernet/micrel/ks8851_common.c b/drivers/net/ethernet/micrel/ks8851_common.c index d4cdf3d4f5525..f7b48e596631f 100644 --- a/drivers/net/ethernet/micrel/ks8851_common.c +++ b/drivers/net/ethernet/micrel/ks8851_common.c @@ -299,7 +299,7 @@ static void ks8851_rx_pkts(struct ks8851_net *ks) ks8851_dbg_dumpkkt(ks, rxpkt); skb->protocol = eth_type_trans(skb, ks->netdev); - __netif_rx(skb); + skb_queue_tail(&ks->rxq, skb); ks->netdev->stats.rx_packets++; ks->netdev->stats.rx_bytes += rxlen; @@ -330,8 +330,6 @@ static irqreturn_t ks8851_irq(int irq, void *_ks) unsigned long flags; unsigned int status; - local_bh_disable(); - ks8851_lock(ks, &flags); status = ks8851_rdreg16(ks, KS_ISR); @@ -408,7 +406,8 @@ static irqreturn_t ks8851_irq(int irq, void *_ks) if (status & IRQ_LCI) mii_check_link(&ks->mii); - local_bh_enable(); + while (!skb_queue_empty(&ks->rxq)) + netif_rx(skb_dequeue(&ks->rxq)); return IRQ_HANDLED; } @@ -1189,6 +1188,7 @@ int ks8851_probe_common(struct net_device *netdev, struct device *dev, NETIF_MSG_PROBE | NETIF_MSG_LINK); + skb_queue_head_init(&ks->rxq); skb_queue_head_init(&ks->txq); netdev->ethtool_ops = &ks8851_ethtool_ops;