From patchwork Mon Dec 7 18:02:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 339975 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.0 required=3.0 tests=BAYES_00, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A67FEC0018C for ; Mon, 7 Dec 2020 18:03:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D030238E8 for ; Mon, 7 Dec 2020 18:03:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726265AbgLGSDI (ORCPT ); Mon, 7 Dec 2020 13:03:08 -0500 Received: from mail.kernel.org ([198.145.29.99]:52698 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726243AbgLGSDI (ORCPT ); Mon, 7 Dec 2020 13:03:08 -0500 From: Ard Biesheuvel Authentication-Results: mail.kernel.org; dkim=permerror (bad message/signature format) To: linux-efi@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, Ard Biesheuvel , Samer El-Haj-Mahmoud Subject: [PATCH 1/2] efi: capsule: use atomic kmap for transient sglist mappings Date: Mon, 7 Dec 2020 19:02:16 +0100 Message-Id: <20201207180216.3349-3-ardb@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201207180216.3349-1-ardb@kernel.org> References: <20201207180216.3349-1-ardb@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org Don't use the heavy-weight kmap() API to create short-lived mappings of the scatter-gather list entries that are released as soon as the entries are written. Instead, use kmap_atomic(), which is more suited to this purpose. Signed-off-by: Ard Biesheuvel --- drivers/firmware/efi/capsule.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/efi/capsule.c b/drivers/firmware/efi/capsule.c index 598b7800d14e..43f6fe7bfe80 100644 --- a/drivers/firmware/efi/capsule.c +++ b/drivers/firmware/efi/capsule.c @@ -244,7 +244,7 @@ int efi_capsule_update(efi_capsule_header_t *capsule, phys_addr_t *pages) for (i = 0; i < sg_count; i++) { efi_capsule_block_desc_t *sglist; - sglist = kmap(sg_pages[i]); + sglist = kmap_atomic(sg_pages[i]); for (j = 0; j < SGLIST_PER_PAGE && count > 0; j++) { u64 sz = min_t(u64, imagesize, @@ -265,7 +265,7 @@ int efi_capsule_update(efi_capsule_header_t *capsule, phys_addr_t *pages) else sglist[j].data = page_to_phys(sg_pages[i + 1]); - kunmap(sg_pages[i]); + kunmap_atomic(sglist); } mutex_lock(&capsule_mutex);