From nobody Mon Jun 22 17:41:46 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 483E7C433EF for ; Sat, 19 Mar 2022 07:31:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234023AbiCSHdQ (ORCPT ); Sat, 19 Mar 2022 03:33:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57388 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240305AbiCSHdN (ORCPT ); Sat, 19 Mar 2022 03:33:13 -0400 Received: from mail-pg1-x536.google.com (mail-pg1-x536.google.com [IPv6:2607:f8b0:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F47812FF8B for ; Sat, 19 Mar 2022 00:31:53 -0700 (PDT) Received: by mail-pg1-x536.google.com with SMTP id q19so6621219pgm.6 for ; Sat, 19 Mar 2022 00:31:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id; bh=QzDLV0cCeAb+rv+fxj0RGmela1ApQSWzei1cauVEwFA=; b=LEVXNTeZJJ80nn6qVqrPjCAcSkk/56tEmue/nPO2/9UaeSJgvFWzXfIFRecH5iE4E3 WNUnWW2FcXS6nhGW7Qz0yr19v5QN36AmkPB/xP0YyNJFTL/LNX9OXsZHHzfjtXozSPHu 2rmlM7OOZD0bzRcGj+d0TSmQ9xZAMJyPvXgVmivjyNWZARh1l9uca/IA+QVR6Pr21xMw cr/rVjdkDM0PIP5m4rtUTDFQKYWxfqR5424AiBoIC5fmpk0Vw9KJkP0KIV92HQNhSzqI wfuEjNXXHmFnn1SHyvhh+zHf5Mzw3Yvb7j32ptAEfGJbB64TVCqp0RkQFFpJW9yutlW5 66Ug== 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; bh=QzDLV0cCeAb+rv+fxj0RGmela1ApQSWzei1cauVEwFA=; b=LciCBjkHD2TffFqd++IQfo34h+Y6bKPLGOzYmDLX3GG1rYAdoQMAZ1vBLjJRZLTq9S mVn8/srPLFjB2wf1dZSTBUw1PN9ez4ORRzmGeEZL1E/zpRdG6nRx2RpFTXpZga+O/bEm wRttnt0ef9P88OCTxkUfK02KFAddBuPQhz0qhYRR0G3L+hVApLwIJrZpimVjBY+TnpOQ tuDdlqLQ4ZDeiREMOkcbaJ3blq2v9J1gTPxVC/WZ0x5ISIoKgAG64u7hLcMTeF4SYryB X8lV7Qraw5mLMeSLnvYVz2P3P1v+PYZr1/Dm/v/zOP3LDgOfnQ6sWcwGjLUVwb7qPUar biCg== X-Gm-Message-State: AOAM533cxLWLbyO3S1unOVMdZlioscVBUU5p1gpKXhy71Gb+9cuZSCmH rEujp48rAmEkLdTJScVhdDBgGrk37zNj8g== X-Google-Smtp-Source: ABdhPJzdkru/fjwamVbwAzLqdlW6FlPJy3EfUcUF/R5TE/jyds0+NPhvAtL1tF5jNkXNCDVjjzP/2g== X-Received: by 2002:a05:6a00:24cd:b0:4f7:2340:a6cf with SMTP id d13-20020a056a0024cd00b004f72340a6cfmr13894631pfv.36.1647675112656; Sat, 19 Mar 2022 00:31:52 -0700 (PDT) Received: from ubuntu.huawei.com ([119.3.119.18]) by smtp.googlemail.com with ESMTPSA id s30-20020a056a001c5e00b004f73f27aa40sm11358882pfw.161.2022.03.19.00.31.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 19 Mar 2022 00:31:52 -0700 (PDT) From: Xiaomeng Tong To: christian.koenig@amd.com, ray.huang@amd.com, airlied@linux.ie, daniel@ffwll.ch Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Xiaomeng Tong Subject: [PATCH] ttm: remove check of list iterator against head outside the loop Date: Sat, 19 Mar 2022 15:31:43 +0800 Message-Id: <20220319073143.30184-1-xiam0nd.tong@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" When list_for_each_entry() completes the iteration over the whole list without breaking the loop, the iterator value will be a bogus pointer computed based on the head element. While it is safe to use the pointer to determine if it was computed based on the head element with &pos->member =3D=3D head, using the iterator variable after the loop should be avoided. In preparation to limiting the scope of a list iterator to the list traversal loop, use a dedicated pointer to point to the found element [1]. Link: https://lore.kernel.org/all/YhdfEIwI4EdtHdym@kroah.com/ Signed-off-by: Xiaomeng Tong --- drivers/gpu/drm/ttm/ttm_bo.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index db3dc7ef5382..413b5bbf2414 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -673,36 +673,36 @@ int ttm_mem_evict_first(struct ttm_device *bdev, struct ww_acquire_ctx *ticket) { struct ttm_buffer_object *bo =3D NULL, *busy_bo =3D NULL; + struct ttm_buffer_object *iter; bool locked =3D false; unsigned i; int ret; =20 spin_lock(&bdev->lru_lock); for (i =3D 0; i < TTM_MAX_BO_PRIORITY; ++i) { - list_for_each_entry(bo, &man->lru[i], lru) { + list_for_each_entry(iter, &man->lru[i], lru) { bool busy; =20 - if (!ttm_bo_evict_swapout_allowable(bo, ctx, place, + if (!ttm_bo_evict_swapout_allowable(iter, ctx, place, &locked, &busy)) { if (busy && !busy_bo && ticket !=3D - dma_resv_locking_ctx(bo->base.resv)) - busy_bo =3D bo; + dma_resv_locking_ctx(iter->base.resv)) + busy_bo =3D iter; continue; } =20 - if (!ttm_bo_get_unless_zero(bo)) { + if (!ttm_bo_get_unless_zero(iter)) { if (locked) - dma_resv_unlock(bo->base.resv); + dma_resv_unlock(iter->base.resv); continue; } + + bo =3D iter; break; } =20 - /* If the inner loop terminated early, we have our candidate */ - if (&bo->lru !=3D &man->lru[i]) + if (bo) break; - - bo =3D NULL; } =20 if (!bo) { --=20 2.17.1