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 X-Spam-Level: X-Spam-Status: No, score=-11.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=unavailable 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 C1CEAC43470 for ; Wed, 31 Mar 2021 21:08:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 954B86109F for ; Wed, 31 Mar 2021 21:08:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230071AbhCaVIR (ORCPT ); Wed, 31 Mar 2021 17:08:17 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:34586 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229890AbhCaVIJ (ORCPT ); Wed, 31 Mar 2021 17:08:09 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: shreeya) with ESMTPSA id 626441F461A9 From: Shreeya Patel To: tytso@mit.edu, adilger.kernel@dilger.ca, jaegeuk@kernel.org, chao@kernel.org, krisman@collabora.com, ebiggers@google.com, drosen@google.com, ebiggers@kernel.org, yuchao0@huawei.com Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, kernel@collabora.com, andre.almeida@collabora.com Subject: [PATCH v6 0/4] Make UTF-8 encoding loadable Date: Thu, 1 Apr 2021 02:37:47 +0530 Message-Id: <20210331210751.281645-1-shreeya.patel@collabora.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org utf8data.h_shipped has a large database table which is an auto-generated decodification trie for the unicode normalization functions and it is not necessary to carry this large table in the kernel. Goal is to make UTF-8 encoding loadable by converting it into a module and adding a layer between the filesystems and the utf8 module which will load the module whenever any filesystem that needs unicode is mounted. Currently only UTF-8 encoding is supported but if any other encodings are supported in future then the layer file would be responsible for loading the desired encoding module. 1st patch in the series resolves the warning reported by kernel test robot by using strscpy instead of strncpy. Unicode is the subsystem and utf8 is a charachter encoding for the subsystem, hence 2nd and 3rd patches in the series are renaming functions and file name to unicode for better understanding the difference between UTF-8 module and unicode layer. Last patch in the series adds the layer and utf8 module and also uses static calls which gives performance benefit when compared to indirect calls using function pointers. --- Changes in v6 - Add spinlock to protect utf8mod and avoid NULL pointer dereference. - Change the static call function names for being consistent with kernel coding style. - Merge the unicode_load_module function with unicode_load as it is not really needed to have a separate function. - Use try_then_module_get instead of module_get to avoid loading the module even when it is already loaded. - Improve the commit message. Changes in v5 - Remove patch which adds NULL check in ext4/super.c and f2fs/super.c before calling unicode_unload(). - Rename global variables and default static call functions for better understanding - Make only config UNICODE_UTF8 visible and config UNICODE to be always enabled provided UNICODE_UTF8 is enabled. - Improve the documentation for Kconfig - Improve the commit message. Changes in v4 - Return error from the static calls instead of doing nothing and succeeding even without loading the module. - Remove the complete usage of utf8_ops and use static calls at all places. - Restore the static calls to default values when module is unloaded. - Decrement the reference of module after calling the unload function. - Remove spinlock as there will be no race conditions after removing utf8_ops. Changes in v3 - Add a patch which checks if utf8 is loaded before calling utf8_unload() in ext4 and f2fs filesystems - Return error if strscpy() returns value < 0 - Correct the conditions to prevent NULL pointer dereference while accessing functions via utf8_ops variable. - Add spinlock to avoid race conditions. - Use static_call() for preventing speculative execution attacks. Changes in v2 - Remove the duplicate file from the last patch. - Make the wrapper functions inline. - Remove msleep and use try_module_get() and module_put() for ensuring that module is loaded correctly and also doesn't get unloaded while in use. - Resolve the warning reported by kernel test robot. - Resolve all the checkpatch.pl warnings. Shreeya Patel (4): fs: unicode: Use strscpy() instead of strncpy() fs: unicode: Rename function names from utf8 to unicode fs: unicode: Rename utf8-core file to unicode-core fs: unicode: Add utf8 module and a unicode layer fs/ext4/hash.c | 2 +- fs/ext4/namei.c | 12 +- fs/ext4/super.c | 6 +- fs/f2fs/dir.c | 12 +- fs/f2fs/super.c | 6 +- fs/libfs.c | 6 +- fs/unicode/Kconfig | 17 ++- fs/unicode/Makefile | 5 +- fs/unicode/unicode-core.c | 152 +++++++++++++++++++++ fs/unicode/{utf8-core.c => unicode-utf8.c} | 98 ++++++++----- fs/unicode/utf8-selftest.c | 8 +- include/linux/unicode.h | 100 +++++++++++--- 12 files changed, 344 insertions(+), 80 deletions(-) create mode 100644 fs/unicode/unicode-core.c rename fs/unicode/{utf8-core.c => unicode-utf8.c} (57%) -- 2.30.2