From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 91E9AC982D2 for ; Thu, 17 Sep 2026 06:48:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:content-type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=xhy1oPI87yyvqHmm/cTWCpICGutbjIXVcLaiKDJSziQ=; b=Mc41v1M4PH8mX1pJVvXDINJ6bd leBIuk3ynfdWi/rYeKfl9/fE0URwEC+dwfIWY5mk9BqFaBb2nvY73htSBTNq2NwfwHfEcxRohiETO wPdhB6Hy0nZtxGLZtrHLFuzUkGuBmPTX4WUm1+RGMkrNks/F4halBsduR8aEhP7N3UeWwj594ufuM lGxiiy0agJA4PLjBAWISwNxTGoUnFvHhO8mmMvq040wts2YGqSQKJQFZ1eoDOMiLqH5ExFG6vc6u5 /Kbrh7FNdpzVXd0kWMroobb72sMvvTy3jk+LrvfHkmyZds55vNBjEwBo8x1nMsZWrGORglhdglRHn KXseVILQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x75vR-0000000AhNj-1Tyi; Thu, 17 Sep 2026 06:48:53 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x75vP-0000000AhKW-1zoZ for ath11k@lists.infradead.org; Thu, 17 Sep 2026 06:48:52 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1789627730; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xhy1oPI87yyvqHmm/cTWCpICGutbjIXVcLaiKDJSziQ=; b=JV7rxaU2O0l3XmBzmbGwRBOzI9rSOHoj0fzjuGCEziDh+TNaHlbhYp1igMJkNWm/tf2ciP /D5zhcN2PUys3i43EiF1e17IcmxZSXkwWbMldPHg+1c+PYDoAqOjNkIhKHQHmFjkkCYPQa 1e5QJKghkjkxwI3Dlol0tWYk6HZSSjw= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-155-FId06UmSPnGcBkT7AMkqSw-1; Thu, 17 Sep 2026 02:48:48 -0400 X-MC-Unique: FId06UmSPnGcBkT7AMkqSw-1 X-Mimecast-MFC-AGG-ID: FId06UmSPnGcBkT7AMkqSw_1789627727 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B9D34180A98A; Thu, 17 Sep 2026 06:48:47 +0000 (UTC) Received: from fedora.redhat.corp (headnet05.pony-001.prod.iad2.dc.redhat.com [10.2.32.117]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 072893003EED; Thu, 17 Sep 2026 06:48:45 +0000 (UTC) From: Jose Ignacio Tornos Martinez To: jjohnson@kernel.org Cc: ath11k@lists.infradead.org, ath12k@lists.infradead.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, Jose Ignacio Tornos Martinez Subject: [PATCH v7 3/4] wifi: ath11k: implement custom wake_tx_queue with flow control Date: Thu, 17 Sep 2026 08:48:24 +0200 Message-ID: <20260917064825.12747-4-jtornosm@redhat.com> In-Reply-To: <20260917064825.12747-1-jtornosm@redhat.com> References: <20260917064825.12747-1-jtornosm@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-Mimecast-MFC-PROC-ID: omrKE_j3wJ8GowPjzhpz7m3XwJSVDj3oy9xk8Ar4u4s_1789627727 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260916_234851_594256_C8720406 X-CRM114-Status: GOOD ( 17.05 ) X-BeenThere: ath11k@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "ath11k" Errors-To: ath11k-bounces+ath11k=archiver.kernel.org@lists.infradead.org Under heavy traffic, ath11k experiences frequent -ENOMEM errors ("failed to transmit frame -12") when the hardware TCL ring fills up. This issue is more commonly observed in VMs with PCIe passthrough but also occurs on bare metal systems. It is particularly problematic on devices with a single shared TCL ring where all traffic classes compete for the same 512 descriptor slots. Implement a custom wake_tx_queue operation that: 1. Checks hardware ring space before dequeuing packets from mac80211 2. Uses per-ring locking (wake_tx_lock with spin_lock_bh) to serialize concurrent wake_tx_queue calls targeting the same ring and to ensure bottom halves are disabled as required by ieee80211_tx_dequeue() 3. Syncs with hardware state to get accurate free slot count 4. Resolves the target TCL ring using get_ring_selector(txq->ac), which selects the ring based on the access category 5. Returns early during firmware crash in the same way as other tx paths This approach follows the pattern used in the iwlwifi driver, adapted for ath11k's hardware ring architecture. This eliminates -ENOMEM errors and improves throughput by optimizing resource usage and preventing unnecessary packet drops. Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41 Signed-off-by: Jose Ignacio Tornos Martinez --- v7: Address comments from Jeff Johnson: - Add the defensive pattern _bh in both spinlocks v6: https://lore.kernel.org/all/20260811172435.616200-4-jtornosm@redhat.com/ drivers/net/wireless/ath/ath11k/dp.c | 1 + drivers/net/wireless/ath/ath11k/dp.h | 2 ++ drivers/net/wireless/ath/ath11k/mac.c | 49 ++++++++++++++++++++++++++- 3 files changed, 51 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/ath/ath11k/dp.c b/drivers/net/wireless/ath/ath11k/dp.c index f389b97acbdd..2e5978ec2b05 100644 --- a/drivers/net/wireless/ath/ath11k/dp.c +++ b/drivers/net/wireless/ath/ath11k/dp.c @@ -1087,6 +1087,7 @@ int ath11k_dp_alloc(struct ath11k_base *ab) for (i = 0; i < ab->hw_params.hal_params->num_tx_rings; i++) { idr_init(&dp->tx_ring[i].txbuf_idr); spin_lock_init(&dp->tx_ring[i].tx_idr_lock); + spin_lock_init(&dp->tx_ring[i].wake_tx_lock); dp->tx_ring[i].tcl_data_ring_id = i; dp->tx_ring[i].tx_status_head = 0; diff --git a/drivers/net/wireless/ath/ath11k/dp.h b/drivers/net/wireless/ath/ath11k/dp.h index 84f66839f0c6..6d99501aa269 100644 --- a/drivers/net/wireless/ath/ath11k/dp.h +++ b/drivers/net/wireless/ath/ath11k/dp.h @@ -87,6 +87,8 @@ struct dp_tx_ring { struct idr txbuf_idr; /* Protects txbuf_idr and num_pending */ spinlock_t tx_idr_lock; + /* Serializes wake_tx_queue operations for this ring */ + spinlock_t wake_tx_lock; struct hal_wbm_release_ring *tx_status; int tx_status_head; int tx_status_tail; diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c index 2d55cdc4d165..da006ae5ea79 100644 --- a/drivers/net/wireless/ath/ath11k/mac.c +++ b/drivers/net/wireless/ath/ath11k/mac.c @@ -10065,9 +10065,56 @@ static int ath11k_mac_op_sta_state(struct ieee80211_hw *hw, return ret; } +static void ath11k_mac_op_wake_tx_queue(struct ieee80211_hw *hw, + struct ieee80211_txq *txq) +{ + struct ieee80211_tx_control control = { + .sta = txq->sta, + }; + struct ath11k *ar = hw->priv; + struct dp_tx_ring *tx_ring; + struct hal_srng *tcl_ring; + struct sk_buff *skb; + u32 ring_selector; + int num_free; + u8 ring_id; + + ring_selector = ar->ab->hw_params.hw_ops->get_ring_selector(txq->ac); + ring_id = ring_selector % ar->ab->hw_params.hal_params->num_tx_rings; + tx_ring = &ar->ab->dp.tx_ring[ring_id]; + tcl_ring = &ar->ab->hal.srng_list[tx_ring->tcl_data_ring.ring_id]; + + while (1) { + if (unlikely(test_bit(ATH11K_FLAG_CRASH_FLUSH, + &ar->ab->dev_flags))) + break; + + spin_lock_bh(&tx_ring->wake_tx_lock); + + spin_lock_bh(&tcl_ring->lock); + num_free = ath11k_hal_srng_src_num_free(ar->ab, tcl_ring, true); + spin_unlock_bh(&tcl_ring->lock); + + if (num_free == 0) { + spin_unlock_bh(&tx_ring->wake_tx_lock); + break; + } + + skb = ieee80211_tx_dequeue(hw, txq); + if (!skb) { + spin_unlock_bh(&tx_ring->wake_tx_lock); + break; + } + + ath11k_mac_op_tx(hw, &control, skb); + + spin_unlock_bh(&tx_ring->wake_tx_lock); + } +} + static const struct ieee80211_ops ath11k_ops = { .tx = ath11k_mac_op_tx, - .wake_tx_queue = ieee80211_handle_wake_tx_queue, + .wake_tx_queue = ath11k_mac_op_wake_tx_queue, .start = ath11k_mac_op_start, .stop = ath11k_mac_op_stop, .reconfig_complete = ath11k_mac_op_reconfig_complete, -- 2.54.0