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 DA252ECAAA1 for ; Tue, 6 Sep 2022 09:29:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239099AbiIFJ3S (ORCPT ); Tue, 6 Sep 2022 05:29:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239710AbiIFJ2o (ORCPT ); Tue, 6 Sep 2022 05:28:44 -0400 Received: from mga06.intel.com (mga06b.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 114B56F263 for ; Tue, 6 Sep 2022 02:28:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1662456517; x=1693992517; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=QqmXy2GZLHSohVU0zyxyHogpet/ueg+VsoCb0iGCfBE=; b=LYZqZGnlmUns3OTpnk34/sPBcxVfdHwDIX+2DUFgGejYvurKWhPvNVU8 kd/BxGbte5NnlzmyQa3HdsoVqM8F0LZFdbIa7Ae5jojC0CcazdWtwC/HN EvNCIr13d+aSUFdgZkC6WMtPevsdw0gDYmcWqjiohDEFw+m52+j/gb314 Lc2Eo9i4j/uEyJPEqWww4hgJWw47i0bcPzQNE5Qy2ik5yx1o8bPYljAWy WDUDHQhNaMg7OfjvLuQ+0djb5XiNLZXCoFLh3kqxwagx3jjG8YXv7I0i/ lNhFAu6JOEFQHDYhsllDJa1X8ghBsmpBPotctTMzru3FZ/ZsNQKTe50Da A==; X-IronPort-AV: E=McAfee;i="6500,9779,10461"; a="358264015" X-IronPort-AV: E=Sophos;i="5.93,293,1654585200"; d="scan'208";a="358264015" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Sep 2022 02:28:36 -0700 X-IronPort-AV: E=Sophos;i="5.93,293,1654585200"; d="scan'208";a="644091572" Received: from zhaohaif-mobl1.ccr.corp.intel.com (HELO [10.254.214.249]) ([10.254.214.249]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Sep 2022 02:28:32 -0700 Message-ID: <1d80f56c-bef7-6e5f-0bca-dad35f5e5a8e@linux.intel.com> Date: Tue, 6 Sep 2022 17:28:29 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.13.0 Subject: Re: [PATCH v2 1/2] iova: Remove some magazine pointer NULL checks To: John Garry , robin.murphy@arm.com, joro@8bytes.org, will@kernel.org Cc: iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linuxarm@huawei.com References: <1662369083-238529-1-git-send-email-john.garry@huawei.com> <1662369083-238529-2-git-send-email-john.garry@huawei.com> From: Ethan Zhao In-Reply-To: <1662369083-238529-2-git-send-email-john.garry@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org John, 在 2022/9/5 17:11, John Garry 写道: > Since commit 32e92d9f6f87 ("iommu/iova: Separate out rcache init") it > has not been possible to have NULL CPU rcache "loaded" or "prev" magazine > pointers. As such, the checks in iova_magazine_full(), > iova_magazine_empty(), and iova_magazine_free_pfns() may be dropped. > > Signed-off-by: John Garry > Reviewed-by: Robin Murphy > --- > drivers/iommu/iova.c | 7 ++----- > 1 file changed, 2 insertions(+), 5 deletions(-) > > diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c > index 47d1983dfa2a..580fdf669922 100644 > --- a/drivers/iommu/iova.c > +++ b/drivers/iommu/iova.c > @@ -661,9 +661,6 @@ iova_magazine_free_pfns(struct iova_magazine *mag, struct iova_domain *iovad) > unsigned long flags; > int i; > > - if (!mag) > - return; > - iommu_probe_device ops->probe_finalize(dev); intel_iommu_probe_finalize iommu_setup_dma_ops iommu_dma_init_domain(domain, dma_base, dma_limit, dev) iova_domain_init_rcaches { ... cpu_rcache->loaded = iova_magazine_alloc(GFP_KERNEL); cpu_rcache->prev = iova_magazine_alloc(GFP_KERNEL); if (!cpu_rcache->loaded || !cpu_rcache->prev) { ret = -ENOMEM; goto out_err; Do you mean iova_magazine_alloc() is impossible to fail ? Thanks, Ethan > spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); > > for (i = 0 ; i < mag->size; ++i) { > @@ -683,12 +680,12 @@ iova_magazine_free_pfns(struct iova_magazine *mag, struct iova_domain *iovad) > > static bool iova_magazine_full(struct iova_magazine *mag) > { > - return (mag && mag->size == IOVA_MAG_SIZE); > + return mag->size == IOVA_MAG_SIZE; > } > > static bool iova_magazine_empty(struct iova_magazine *mag) > { > - return (!mag || mag->size == 0); > + return mag->size == 0; > } > > static unsigned long iova_magazine_pop(struct iova_magazine *mag, -- "firm, enduring, strong, and long-lived"