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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80E5AC04A68 for ; Wed, 27 Jul 2022 16:50:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240623AbiG0QuK (ORCPT ); Wed, 27 Jul 2022 12:50:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240732AbiG0QtS (ORCPT ); Wed, 27 Jul 2022 12:49:18 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9A1B61719; Wed, 27 Jul 2022 09:32:48 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E9A5A619BF; Wed, 27 Jul 2022 16:32:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F3660C433C1; Wed, 27 Jul 2022 16:32:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658939567; bh=SHk0fwewRjaoZyPCGm84OVVHt3jkU1HAF03YpkNu5AU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l1xdjcfZhlOkm/LPw7vrjN0ionug5F153AuUvAiJtr5odUiHDY8v94EYktRiiFyBn 7otmWWt12OscbeMvMr8jga4HHW7rx81TkTW+aZ4jxTzDKrRke+o4IdECxoFTT6AMSD bQbifsn77pQNBUe6yUOTV0ZJc+JmsLdcdj1SDQXo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Jeffrey Hugo , Dexuan Cui , Michael Kelley , Wei Liu , Carl Vanderlip Subject: [PATCH 5.10 019/105] PCI: hv: Reuse existing IRTE allocation in compose_msi_msg() Date: Wed, 27 Jul 2022 18:10:05 +0200 Message-Id: <20220727161012.867192792@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220727161012.056867467@linuxfoundation.org> References: <20220727161012.056867467@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jeffrey Hugo commit b4b77778ecc5bfbd4e77de1b2fd5c1dd3c655f1f upstream. Currently if compose_msi_msg() is called multiple times, it will free any previous IRTE allocation, and generate a new allocation. While nothing prevents this from occurring, it is extraneous when Linux could just reuse the existing allocation and avoid a bunch of overhead. However, when future IRTE allocations operate on blocks of MSIs instead of a single line, freeing the allocation will impact all of the lines. This could cause an issue where an allocation of N MSIs occurs, then some of the lines are retargeted, and finally the allocation is freed/reallocated. The freeing of the allocation removes all of the configuration for the entire block, which requires all the lines to be retargeted, which might not happen since some lines might already be unmasked/active. Signed-off-by: Jeffrey Hugo Reviewed-by: Dexuan Cui Tested-by: Dexuan Cui Tested-by: Michael Kelley Link: https://lore.kernel.org/r/1652282582-21595-1-git-send-email-quic_jhugo@quicinc.com Signed-off-by: Wei Liu Signed-off-by: Carl Vanderlip Signed-off-by: Greg Kroah-Hartman --- drivers/pci/controller/pci-hyperv.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -1409,6 +1409,15 @@ static void hv_compose_msi_msg(struct ir u32 size; int ret; + /* Reuse the previous allocation */ + if (data->chip_data) { + int_desc = data->chip_data; + msg->address_hi = int_desc->address >> 32; + msg->address_lo = int_desc->address & 0xffffffff; + msg->data = int_desc->data; + return; + } + pdev = msi_desc_to_pci_dev(irq_data_get_msi_desc(data)); dest = irq_data_get_effective_affinity_mask(data); pbus = pdev->bus; @@ -1418,13 +1427,6 @@ static void hv_compose_msi_msg(struct ir if (!hpdev) goto return_null_message; - /* Free any previous message that might have already been composed. */ - if (data->chip_data) { - int_desc = data->chip_data; - data->chip_data = NULL; - hv_int_desc_free(hpdev, int_desc); - } - int_desc = kzalloc(sizeof(*int_desc), GFP_ATOMIC); if (!int_desc) goto drop_reference;