From patchwork Thu Jun 30 16:35:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Fabio M. De Francesco" X-Patchwork-Id: 12902024 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 63D0CC43334 for ; Thu, 30 Jun 2022 16:35:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235472AbiF3Qfh (ORCPT ); Thu, 30 Jun 2022 12:35:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235389AbiF3Qfg (ORCPT ); Thu, 30 Jun 2022 12:35:36 -0400 Received: from mail-wm1-x331.google.com (mail-wm1-x331.google.com [IPv6:2a00:1450:4864:20::331]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6109F3AA55; Thu, 30 Jun 2022 09:35:35 -0700 (PDT) Received: by mail-wm1-x331.google.com with SMTP id c130-20020a1c3588000000b0039c6fd897b4so2064079wma.4; Thu, 30 Jun 2022 09:35:35 -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:mime-version :content-transfer-encoding; bh=lZIrTmlOnvUkLrFbSOhPtwGibISpt/RODIchaEd1CDY=; b=gvOxH2z87z7QsFkRgTQuNhQyyz+dHV1+8rh1sM7GpDupM74IOa6Ym2zyVx4Y0mEnkA xFy3h+4BLgQAGQb7kHWwxfMcgIUz4Tef84LuOZORClSobvlsqYZZA4JRBDfKNY3iS9A8 W3vDemOPYtYp6bt4LA+muwinmH5c50oo9YbK3ghNa7sz/mzg54ZgVTtrFKX2Cgzw+P3N ELSRjvVF4ivQ1YmTMe+MNMmYKoyNYpV+LtXu6h2BXUafKGQrVOGF0X6LVvrsdTzc/XfD EcDDOVPqA+9w2kvc7GCTWMKYCQjY0KUvF3eMQA1meIaibaLIqLPbyUm6YJoKiAbmsj+a uGnA== 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:mime-version :content-transfer-encoding; bh=lZIrTmlOnvUkLrFbSOhPtwGibISpt/RODIchaEd1CDY=; b=GTEt4q69tWJR2OLe5ZtgtbMVaSXCHk6rFl+Ko7Mg3+tdejbLhNQrZ7yv8of3PJFB0A CRj0NMSrYyMIv1DmTeONmJqx/dc2hDoBsEdpee75d2hd37af4iHnJiMUjeMWfcckq5Ti 1PTnrWm2Vt5xfFsjJOuTpXDNf0rxy/J20CCEq8e8o4TDSlpd5K2JFJ7F1gxs7Cdqcywa pS5vjHKig30sFfm7mYlue0GiTsNsLKeHnlVueUP6YEtZfvgErXKA7AhFJbciQXJgFIDx SpGPD4NzJAy9ZjbTrwVc8L7WrIefPO2dJs7lYYvoMaxbcZWLXilwm+Y6M27vCoNc5CIb acaw== X-Gm-Message-State: AJIora8BaJ8TbUcC2B5jXAMHiQF7qD84IBqucxn25/bqj/KmDHxTyI+A UXuS0uhkwzeGqPuKuZLR8Fk= X-Google-Smtp-Source: AGRyM1sQNe4+WIPmqW10XET/JjOyzodgMYKlJLfdcugPO9fE6FCvfEevPFPhlgS/sBSR469fLSNDFQ== X-Received: by 2002:a1c:4b11:0:b0:3a0:4270:fcfa with SMTP id y17-20020a1c4b11000000b003a04270fcfamr12974836wma.53.1656606933805; Thu, 30 Jun 2022 09:35:33 -0700 (PDT) Received: from localhost.localdomain (host-87-6-98-182.retail.telecomitalia.it. [87.6.98.182]) by smtp.gmail.com with ESMTPSA id u3-20020a05600c210300b003a044fe7fe7sm7112303wml.9.2022.06.30.09.35.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Jun 2022 09:35:32 -0700 (PDT) From: "Fabio M. De Francesco" To: Benjamin LaHaise , Alexander Viro , Eric Biederman , Kees Cook , Dan Williams , Matthew Wilcox , Jan Kara , Jeff Layton , Chuck Lever , Jens Axboe , Pavel Begunkov , Thomas Gleixner , Paul Walmsley , Palmer Dabbelt , Albert Ou , Nathan Chancellor , Nick Desaulniers , Tom Rix , linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, nvdimm@lists.linux.dev, io-uring@vger.kernel.org, linux-riscv@lists.infradead.org, llvm@lists.linux.dev Cc: "Fabio M. De Francesco" , Ira Weiny Subject: [PATCH] fs: Replace kmap{,_atomic}() with kmap_local_page() Date: Thu, 30 Jun 2022 18:35:27 +0200 Message-Id: <20220630163527.9776-1-fmdefrancesco@gmail.com> X-Mailer: git-send-email 2.36.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org The use of kmap() and kmap_atomic() are being deprecated in favor of kmap_local_page(). With kmap_local_page(), the mappings are per thread, CPU local and not globally visible. Furthermore, the mappings can be acquired from any context (including interrupts). Therefore, use kmap_local_page() in exec.c because these mappings are per thread, CPU local, and not globally visible. Tested with xfstests on a QEMU + KVM 32-bits VM booting a kernel with HIGHMEM64GB enabled. Suggested-by: Ira Weiny Signed-off-by: Fabio M. De Francesco Reviewed-by: Ira Weiny --- fs/exec.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 0989fb8472a1..4a2129c0d422 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -583,11 +583,11 @@ static int copy_strings(int argc, struct user_arg_ptr argv, if (kmapped_page) { flush_dcache_page(kmapped_page); - kunmap(kmapped_page); + kunmap_local(kaddr); put_arg_page(kmapped_page); } kmapped_page = page; - kaddr = kmap(kmapped_page); + kaddr = kmap_local_page(kmapped_page); kpos = pos & PAGE_MASK; flush_arg_page(bprm, kpos, kmapped_page); } @@ -601,7 +601,7 @@ static int copy_strings(int argc, struct user_arg_ptr argv, out: if (kmapped_page) { flush_dcache_page(kmapped_page); - kunmap(kmapped_page); + kunmap_local(kaddr); put_arg_page(kmapped_page); } return ret; @@ -883,11 +883,11 @@ int transfer_args_to_stack(struct linux_binprm *bprm, for (index = MAX_ARG_PAGES - 1; index >= stop; index--) { unsigned int offset = index == stop ? bprm->p & ~PAGE_MASK : 0; - char *src = kmap(bprm->page[index]) + offset; + char *src = kmap_local_page(bprm->page[index]) + offset; sp -= PAGE_SIZE - offset; if (copy_to_user((void *) sp, src, PAGE_SIZE - offset) != 0) ret = -EFAULT; - kunmap(bprm->page[index]); + kunmap_local(src); if (ret) goto out; } @@ -1680,13 +1680,13 @@ int remove_arg_zero(struct linux_binprm *bprm) ret = -EFAULT; goto out; } - kaddr = kmap_atomic(page); + kaddr = kmap_local_page(page); for (; offset < PAGE_SIZE && kaddr[offset]; offset++, bprm->p++) ; - kunmap_atomic(kaddr); + kunmap_local(kaddr); put_arg_page(page); } while (offset == PAGE_SIZE);