From patchwork Tue Dec 19 11:33:56 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stanislaw Gruszka X-Patchwork-Id: 10123103 X-Patchwork-Delegate: kvalo@adurom.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 7A24C6019C for ; Tue, 19 Dec 2017 11:34:19 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7AD47292A7 for ; Tue, 19 Dec 2017 11:34:19 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6FEF4292AD; Tue, 19 Dec 2017 11:34:19 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2AB40292A7 for ; Tue, 19 Dec 2017 11:34:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751578AbdLSLeR (ORCPT ); Tue, 19 Dec 2017 06:34:17 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41598 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751520AbdLSLeR (ORCPT ); Tue, 19 Dec 2017 06:34:17 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 04C56155E4; Tue, 19 Dec 2017 11:34:17 +0000 (UTC) Received: from localhost (unknown [10.43.2.28]) by smtp.corp.redhat.com (Postfix) with ESMTP id 941101837E; Tue, 19 Dec 2017 11:34:16 +0000 (UTC) From: Stanislaw Gruszka To: linux-wireless@vger.kernel.org Cc: Helmut Schaa , Enrico Mioso , Daniel Golle , Felix Fietkau , Stanislaw Gruszka Subject: [PATCH 2/2] rt2x00: do not pause queue unconditionally on error path Date: Tue, 19 Dec 2017 12:33:56 +0100 Message-Id: <1513683236-13402-2-git-send-email-sgruszka@redhat.com> In-Reply-To: <1513683236-13402-1-git-send-email-sgruszka@redhat.com> References: <1513683236-13402-1-git-send-email-sgruszka@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Tue, 19 Dec 2017 11:34:17 +0000 (UTC) Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Pausing queue without checking threshold is racy with txdone path. Moreover we do not need pause queue on any error, but only if queue is full - in case when we send RTS frame ( other cases of almost full queue are already handled in rt2x00queue_write_tx_frame() ). Patch fixes of theoretically possible problem of pausing empty queue. Signed-off-by: Stanislaw Gruszka Tested-by: Enrico Mioso --- drivers/net/wireless/ralink/rt2x00/rt2x00mac.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c b/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c index c8a6f163102f..a971bc7a6b63 100644 --- a/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c +++ b/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c @@ -142,22 +142,28 @@ void rt2x00mac_tx(struct ieee80211_hw *hw, if (!rt2x00dev->ops->hw->set_rts_threshold && (tx_info->control.rates[0].flags & (IEEE80211_TX_RC_USE_RTS_CTS | IEEE80211_TX_RC_USE_CTS_PROTECT))) { - if (rt2x00queue_available(queue) <= 1) - goto exit_fail; + if (rt2x00queue_available(queue) <= 1) { + /* + * Recheck for full queue under lock to avoid race + * conditions with rt2x00lib_txdone(). + */ + spin_lock(&queue->tx_lock); + if (rt2x00queue_threshold(queue)) + rt2x00queue_pause_queue(queue); + spin_unlock(&queue->tx_lock); + + goto exit_free_skb; + } if (rt2x00mac_tx_rts_cts(rt2x00dev, queue, skb)) - goto exit_fail; + goto exit_free_skb; } if (unlikely(rt2x00queue_write_tx_frame(queue, skb, control->sta, false))) - goto exit_fail; + goto exit_free_skb; return; - exit_fail: - spin_lock(&queue->tx_lock); - rt2x00queue_pause_queue(queue); - spin_unlock(&queue->tx_lock); exit_free_skb: ieee80211_free_txskb(hw, skb); }