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[73.185.129.58]) by smtp.gmail.com with ESMTPSA id e17sm6264544iow.30.2022.01.11.11.21.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Jan 2022 11:21:54 -0800 (PST) From: Alex Elder To: davem@davemloft.net, kuba@kernel.org Cc: jponduru@codeaurora.org, avuyyuru@codeaurora.org, bjorn.andersson@linaro.org, agross@kernel.org, cpratapa@codeaurora.org, subashab@codeaurora.org, evgreen@chromium.org, elder@kernel.org, netdev@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net 1/2] net: ipa: fix atomic update in ipa_endpoint_replenish() Date: Tue, 11 Jan 2022 13:21:49 -0600 Message-Id: <20220111192150.379274-2-elder@linaro.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220111192150.379274-1-elder@linaro.org> References: <20220111192150.379274-1-elder@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" In ipa_endpoint_replenish(), if an error occurs when attempting to replenish a receive buffer, we just quit and try again later. In that case we increment the backlog count to reflect that the attempt was unsuccessful. Then, if the add_one flag was true we increment the backlog again. This second increment is not included in the backlog local variable though, and its value determines whether delayed work should be scheduled. This is a bug. Fix this by determining whether 1 or 2 should be added to the backlog before adding it in a atomic_add_return() call. Fixes: 84f9bd12d46db ("soc: qcom: ipa: IPA endpoints") Signed-off-by: Alex Elder Reviewed-by: Matthias Kaehlcke --- drivers/net/ipa/ipa_endpoint.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c index 49d9a077d0375..8b055885cf3cf 100644 --- a/drivers/net/ipa/ipa_endpoint.c +++ b/drivers/net/ipa/ipa_endpoint.c @@ -1080,6 +1080,7 @@ static void ipa_endpoint_replenish(struct ipa_endpoin= t *endpoint, bool add_one) { struct gsi *gsi; u32 backlog; + int delta; =20 if (!endpoint->replenish_enabled) { if (add_one) @@ -1097,10 +1098,8 @@ static void ipa_endpoint_replenish(struct ipa_endpoi= nt *endpoint, bool add_one) =20 try_again_later: /* The last one didn't succeed, so fix the backlog */ - backlog =3D atomic_inc_return(&endpoint->replenish_backlog); - - if (add_one) - atomic_inc(&endpoint->replenish_backlog); + delta =3D add_one ? 2 : 1; + backlog =3D atomic_add_return(delta, &endpoint->replenish_backlog); =20 /* Whenever a receive buffer transaction completes we'll try to * replenish again. It's unlikely, but if we fail to supply even --=20 2.32.0 From nobody Tue Jun 30 18:54:20 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E9D6C4332F for ; Tue, 11 Jan 2022 19:22:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346557AbiAKTWC (ORCPT ); Tue, 11 Jan 2022 14:22:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41548 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244339AbiAKTV5 (ORCPT ); Tue, 11 Jan 2022 14:21:57 -0500 Received: from mail-io1-xd2d.google.com (mail-io1-xd2d.google.com [IPv6:2607:f8b0:4864:20::d2d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 328DBC061751 for ; Tue, 11 Jan 2022 11:21:57 -0800 (PST) Received: by mail-io1-xd2d.google.com with SMTP id v1so223137ioj.10 for ; Tue, 11 Jan 2022 11:21:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=zG6mc9R8T0VuQRaKqR7/UCbKIE1yA2lVDcf9Ztg1BPw=; b=gBRFGEKQyVWTVpOHb0ZBdMzwB0eZcclVsmYYGFXiVzGc7ur6Q/unveTJlSIZDtGNye Bwey6ax7smlPgoxENKvfeUTkXUqsDCnae6KaHOJ+fnmH4iQBKGepbEymAcAWDCi/v2Lv HA1Hxt0IRq3c4TApg664Am2q1WKWazunoH+Io+eaFBgHQZV4tEu0gBC7xAMo3dvVrPvv ftNfkmdZ7MR2hHv6kTugk7ftOl53INz/JHvvnbSUkyNNNswePWt7YZcWirumhuXONycN Cs5ARCOMiIyOmadYZlOWnNPUwTdZ5jqUd6dOgeIgTnRqgiFMxb+yrYTzcswI4y3kuJzo 8j5w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=zG6mc9R8T0VuQRaKqR7/UCbKIE1yA2lVDcf9Ztg1BPw=; b=w3QyIGaCKGb1DBNl7sf8ALk/f13n7xWY1kuql4qC4Bc0DwnL/K9g7QFoEN5ocDPMFc KC//V6kLFvncx7+fvxX24hIX8oAzgH6F7G6kAOykMivkFhDUeRvyASJipiER2Q4SllMt q8G3ZTdtvQ6XhhPoznUU5To4smJXu/N5TFtE3RMl+l9smT18WdgMLKALGz7AIG5CR7uv PcKJuUp1PjnR9AbdmJrmZM1rfwfBfTqMGZUK0CqBpFyTwgiYDpa7+RA4ZkHo0VVGgCKF ieV6qCzuEq3jmtkoKOwsSjF7fXV5SP/51ev1R0wz0lwPtVKCzk/qnxBWPLz0xOVO3Zcj moDw== X-Gm-Message-State: AOAM530cQNrlaA6JhVUFnfyaniaMOxNgWmnlvoZtYeNZqM6vjP774OcM q6S2v6i1cl9TOH9Cs5CT+gglhj/x+aNqGA== X-Google-Smtp-Source: ABdhPJwYaKcnyX6qsqEycE/nqRqkIxKSK9nGRQ6obnUE8Pj9wqslbCcNe1OOivkvsJDA+eENKbC+3Q== X-Received: by 2002:a05:6638:1348:: with SMTP id u8mr3068773jad.278.1641928916610; Tue, 11 Jan 2022 11:21:56 -0800 (PST) Received: from presto.localdomain (c-73-185-129-58.hsd1.mn.comcast.net. [73.185.129.58]) by smtp.gmail.com with ESMTPSA id e17sm6264544iow.30.2022.01.11.11.21.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Jan 2022 11:21:56 -0800 (PST) From: Alex Elder To: davem@davemloft.net, kuba@kernel.org Cc: jponduru@codeaurora.org, avuyyuru@codeaurora.org, bjorn.andersson@linaro.org, agross@kernel.org, cpratapa@codeaurora.org, subashab@codeaurora.org, evgreen@chromium.org, elder@kernel.org, netdev@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net 2/2] net: ipa: prevent concurrent replenish Date: Tue, 11 Jan 2022 13:21:50 -0600 Message-Id: <20220111192150.379274-3-elder@linaro.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220111192150.379274-1-elder@linaro.org> References: <20220111192150.379274-1-elder@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" We have seen cases where an endpoint RX completion interrupt arrives while replenishing for the endpoint is underway. This causes another instance of replenishing to begin as part of completing the receive transaction. If this occurs it can lead to transaction corruption. Use a new atomic variable to ensure only replenish instance for an endpoint executes at a time. Fixes: 84f9bd12d46db ("soc: qcom: ipa: IPA endpoints") Signed-off-by: Alex Elder --- drivers/net/ipa/ipa_endpoint.c | 13 +++++++++++++ drivers/net/ipa/ipa_endpoint.h | 2 ++ 2 files changed, 15 insertions(+) diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c index 8b055885cf3cf..a1019f5fe1748 100644 --- a/drivers/net/ipa/ipa_endpoint.c +++ b/drivers/net/ipa/ipa_endpoint.c @@ -1088,15 +1088,27 @@ static void ipa_endpoint_replenish(struct ipa_endpo= int *endpoint, bool add_one) return; } =20 + /* If already active, just update the backlog */ + if (atomic_xchg(&endpoint->replenish_active, 1)) { + if (add_one) + atomic_inc(&endpoint->replenish_backlog); + return; + } + while (atomic_dec_not_zero(&endpoint->replenish_backlog)) if (ipa_endpoint_replenish_one(endpoint)) goto try_again_later; + + atomic_set(&endpoint->replenish_active, 0); + if (add_one) atomic_inc(&endpoint->replenish_backlog); =20 return; =20 try_again_later: + atomic_set(&endpoint->replenish_active, 0); + /* The last one didn't succeed, so fix the backlog */ delta =3D add_one ? 2 : 1; backlog =3D atomic_add_return(delta, &endpoint->replenish_backlog); @@ -1691,6 +1703,7 @@ static void ipa_endpoint_setup_one(struct ipa_endpoin= t *endpoint) * backlog is the same as the maximum outstanding TREs. */ endpoint->replenish_enabled =3D false; + atomic_set(&endpoint->replenish_active, 0); atomic_set(&endpoint->replenish_saved, gsi_channel_tre_max(gsi, endpoint->channel_id)); atomic_set(&endpoint->replenish_backlog, 0); diff --git a/drivers/net/ipa/ipa_endpoint.h b/drivers/net/ipa/ipa_endpoint.h index 0a859d10312dc..200f093214997 100644 --- a/drivers/net/ipa/ipa_endpoint.h +++ b/drivers/net/ipa/ipa_endpoint.h @@ -53,6 +53,7 @@ enum ipa_endpoint_name { * @netdev: Network device pointer, if endpoint uses one * @replenish_enabled: Whether receive buffer replenishing is enabled * @replenish_ready: Number of replenish transactions without doorbell + * @replenish_active: 1 when replenishing is active, 0 otherwise * @replenish_saved: Replenish requests held while disabled * @replenish_backlog: Number of buffers needed to fill hardware queue * @replenish_work: Work item used for repeated replenish failures @@ -74,6 +75,7 @@ struct ipa_endpoint { /* Receive buffer replenishing for RX endpoints */ bool replenish_enabled; u32 replenish_ready; + atomic_t replenish_active; atomic_t replenish_saved; atomic_t replenish_backlog; struct delayed_work replenish_work; /* global wq */ --=20 2.32.0