From nobody Wed Dec 17 10:58:41 2025 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 4CB3EC4167B for ; Mon, 27 Nov 2023 16:01:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234275AbjK0QBj (ORCPT ); Mon, 27 Nov 2023 11:01:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38496 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233859AbjK0QBh (ORCPT ); Mon, 27 Nov 2023 11:01:37 -0500 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B84FBB4 for ; Mon, 27 Nov 2023 08:01:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1701100903; x=1732636903; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=yv7LtoQLd141WmTkO/xz5VJsS/q7Vvm2oGrcJcBIg/8=; b=fSYpJ9WH6pRxgBR9eOgwb1PJOOeNRBab7/BWFnCXQLLKijO97k95EDoN hC5yGfqf/SfXIOMnqN0waUP/o8PyKYe6M4+APhkeEbbNh/kCYY1kOKyWl UfsuJe/DPgB1LLJ1neAIYZKMpRglxIa+Rp0fC1flAfaOx0rPgZBzY3QPU A0pVHHdSNYuasAzcUoLkv9r5y11lg0yrFcxis826X9Vq1/NZR2tz/sN3V ulUgX3lSsHbmEtA9WVYJdszfY6zrcKzqgqo0PHLGy/obw6w+/BPj83zit mwXIUUqcpHeT8AHphRLLLo4N7x9X0ycEpikqMFnV+81W82ycnbdlKbOFo w==; X-IronPort-AV: E=McAfee;i="6600,9927,10907"; a="391609974" X-IronPort-AV: E=Sophos;i="6.04,231,1695711600"; d="scan'208";a="391609974" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Nov 2023 08:01:43 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10907"; a="1099823579" X-IronPort-AV: E=Sophos;i="6.04,231,1695711600"; d="scan'208";a="1099823579" Received: from fdefranc-mobl3.ger.corp.intel.com (HELO fdefranc-mobl3.Hitronhub.home) ([10.213.15.40]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Nov 2023 08:01:40 -0800 From: "Fabio M. De Francesco" To: Seth Jennings , Dan Streetman , Vitaly Wool , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: "Fabio M. De Francesco" , Ira Weiny Subject: [PATCH] mm/zswap: Replace kmap_atomic() with kmap_local_page() Date: Mon, 27 Nov 2023 16:55:21 +0100 Message-ID: <20231127160058.586446-1-fabio.maria.de.francesco@linux.intel.com> X-Mailer: git-send-email 2.42.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" kmap_atomic() has been deprecated in favor of kmap_local_page(). Therefore, replace kmap_atomic() with kmap_local_page() in zswap.c. kmap_atomic() is implemented like a kmap_local_page() which also disables page-faults and preemption (the latter only in !PREEMPT_RT kernels). The kernel virtual addresses returned by these two API are only valid in the context of the callers (i.e., they cannot be handed to other threads). With kmap_local_page() the mappings are per thread and CPU local like in kmap_atomic(); however, they can handle page-faults and can be called from any context (including interrupts). The tasks that call kmap_local_page() can be preempted and, when they are scheduled to run again, the kernel virtual addresses are restored and are still valid. In mm/zswap.c, the blocks of code between the mappings and un-mappings do not depend on the above-mentioned side effects of kmap_atomic(), so that the mere replacements of the old API with the new one is all that is required (i.e., there is no need to explicitly call pagefault_disable() and/or preempt_disable()). Cc: Ira Weiny Signed-off-by: Fabio M. De Francesco Acked-by: Chris Li (Google) Reviewed-by: Nhat Pham --- mm/zswap.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/mm/zswap.c b/mm/zswap.c index 74411dfdad92..699c6ee11222 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -1267,16 +1267,16 @@ bool zswap_store(struct folio *folio) } =20 if (zswap_same_filled_pages_enabled) { - src =3D kmap_atomic(page); + src =3D kmap_local_page(page); if (zswap_is_page_same_filled(src, &value)) { - kunmap_atomic(src); + kunmap_local(src); entry->swpentry =3D swp_entry(type, offset); entry->length =3D 0; entry->value =3D value; atomic_inc(&zswap_same_filled_pages); goto insert_entry; } - kunmap_atomic(src); + kunmap_local(src); } =20 if (!zswap_non_same_filled_pages_enabled) @@ -1422,9 +1422,9 @@ bool zswap_load(struct folio *folio) spin_unlock(&tree->lock); =20 if (!entry->length) { - dst =3D kmap_atomic(page); + dst =3D kmap_local_page(page); zswap_fill_page(dst, entry->value); - kunmap_atomic(dst); + kunmap_local(dst); ret =3D true; goto stats; } --=20 2.42.0