From patchwork Sat Aug 18 13:24:27 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rasmus Villemoes X-Patchwork-Id: 10569553 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 67C1314E1 for ; Sat, 18 Aug 2018 13:25:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 576E32A836 for ; Sat, 18 Aug 2018 13:25:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4B3282A84D; Sat, 18 Aug 2018 13:25:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CEB372A836 for ; Sat, 18 Aug 2018 13:25:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726300AbeHRQc2 (ORCPT ); Sat, 18 Aug 2018 12:32:28 -0400 Received: from mail-ed1-f65.google.com ([209.85.208.65]:39606 "EHLO mail-ed1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726241AbeHRQc1 (ORCPT ); Sat, 18 Aug 2018 12:32:27 -0400 Received: by mail-ed1-f65.google.com with SMTP id h4-v6so5982088edi.6 for ; Sat, 18 Aug 2018 06:24:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rasmusvillemoes.dk; s=google; h=from:to:cc:subject:date:message-id; bh=FV0dNHdRcB4ZhsnEc2fPA731UxnGGox6WwKOreslgto=; b=cSWf8I5iIpCx97/UujKEH5f4Pm0C7XXGUtPWnFGZU9GSyRcVBp2qOKaGIboDU+Sl+w 5ECYG43t986TYdBu/urRth/3/g7/TSTesCmV5AWASVMFPs0tNgZuB3pS7wYbpTrXeoee nE2uxnbQSt4yhH3oxCefGIJk83OnLq+7Pa8Zw= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=FV0dNHdRcB4ZhsnEc2fPA731UxnGGox6WwKOreslgto=; b=a94iZWZMoI0KKcoA2uDiA3O78HywQZ/epFZyXq2OyyplX0h7Tk5WDR9qG4Hn1dPaGY DXroTGF/giZMMQthD8pknn6ctKl5SBvEiRX4QcVcNlbSccvAXdBnEj9yL5i9BKk0sQlV G2iJv0tYtb2XgIbRjG22Po6eQ/SYHBDdVHoDz8pTKO00wJ1qcqwh5003cKyoMCTN/8H1 0DWirEj7kRUmflEP8hYnAPYXkLtkpoNhy2MI6c9LooobZDfsTTnt0TLY+czwGwkshm0P s7GMsRJIygWkuBK/Xawc/C/XkQSfNUN/5x2XAr1PiXfEBhWFWPVcpib+1gUJUt0OXRrR 0SGw== X-Gm-Message-State: AOUpUlEuU4+HJwKDsZAohA23jAMuKnkr0yyDRYvbkvfyzgItEnMkYq8j kmaccewlQLHsgBPCtNPN9i4fxA== X-Google-Smtp-Source: AA+uWPw+UKhHcsh5t3gZC8ty9gStC7DIEPFZMt8/J29uy22Ne6sIfHjTNhfp3IGa4AJ3alXFKM/0QQ== X-Received: by 2002:aa7:c68b:: with SMTP id n11-v6mr47564358edq.122.1534598683408; Sat, 18 Aug 2018 06:24:43 -0700 (PDT) Received: from prevas-ravi.waoo.dk (dhcp-5-186-114-212.cgn.ip.fibianet.dk. [5.186.114.212]) by smtp.gmail.com with ESMTPSA id a11-v6sm2739032edn.95.2018.08.18.06.24.41 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sat, 18 Aug 2018 06:24:42 -0700 (PDT) From: Rasmus Villemoes To: Jonathan Corbet , Alexander Viro Cc: linux-kernel@vger.kernel.org, Rasmus Villemoes , Andreas Dilger , linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, Alexey Dobriyan , linux-nfs@vger.kernel.org, cluster-devel@redhat.com, Michael Ellerman , linuxppc-dev@lists.ozlabs.org, Thierry Reding , Lorenzo Pieralisi Subject: [PATCH v2 1/8] seq_file: introduce seq_open_data helper Date: Sat, 18 Aug 2018 15:24:27 +0200 Message-Id: <20180818132434.9515-1-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 2.16.4 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP There are quite a few callers of seq_open that could be simplified by setting the ->private member via the seq_open call instead of fetching file->private_data afterwards. Signed-off-by: Rasmus Villemoes Reviewed-by: Andy Shevchenko --- v2: - Fix some copy-pastos spotted by Andreas. - Ensure everybody hit by an example patch also gets this cover letter/introducing patch. - Include a few fs/ examples. I've just included a few examples of possible users of this helper, there are many more similar cases. As a bonus, 7/8 fix a potential NULL deref (if one believes that seq_open can actually fail). seq_open_private would have been a better name, but that one is already taken... Documentation/filesystems/seq_file.txt | 9 +++++---- fs/seq_file.c | 16 ++++++++++++---- include/linux/seq_file.h | 1 + 3 files changed, 18 insertions(+), 8 deletions(-) diff --git a/Documentation/filesystems/seq_file.txt b/Documentation/filesystems/seq_file.txt index 9de4303201e1..68571b8275d8 100644 --- a/Documentation/filesystems/seq_file.txt +++ b/Documentation/filesystems/seq_file.txt @@ -234,10 +234,11 @@ Here, the call to seq_open() takes the seq_operations structure we created before, and gets set up to iterate through the virtual file. On a successful open, seq_open() stores the struct seq_file pointer in -file->private_data. If you have an application where the same iterator can -be used for more than one file, you can store an arbitrary pointer in the -private field of the seq_file structure; that value can then be retrieved -by the iterator functions. +file->private_data. If you have an application where the same iterator +can be used for more than one file, you can store an arbitrary pointer +in the private field of the seq_file structure; that value can then be +retrieved by the iterator functions. Using the wrapper seq_open_data() +allows you to set the initial value for that field. There is also a wrapper function to seq_open() called seq_open_private(). It kmallocs a zero filled block of memory and stores a pointer to it in the diff --git a/fs/seq_file.c b/fs/seq_file.c index 4cc090b50cc5..c8c86660f6db 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -33,11 +33,12 @@ static void *seq_buf_alloc(unsigned long size) } /** - * seq_open - initialize sequential file + * seq_open_data - initialize sequential file * @file: file we initialize * @op: method table describing the sequence + * @data: initial value for ->private field * - * seq_open() sets @file, associating it with a sequence described + * seq_open_data() sets @file, associating it with a sequence described * by @op. @op->start() sets the iterator up and returns the first * element of sequence. @op->stop() shuts it down. @op->next() * returns the next element of sequence. @op->show() prints element @@ -45,10 +46,10 @@ static void *seq_buf_alloc(unsigned long size) * ERR_PTR(error). In the end of sequence they return %NULL. ->show() * returns 0 in case of success and negative number in case of error. * Returning SEQ_SKIP means "discard this element and move on". - * Note: seq_open() will allocate a struct seq_file and store its + * Note: seq_open_data() will allocate a struct seq_file and store its * pointer in @file->private_data. This pointer should not be modified. */ -int seq_open(struct file *file, const struct seq_operations *op) +int seq_open_data(struct file *file, const struct seq_operations *op, void *data) { struct seq_file *p; @@ -62,6 +63,7 @@ int seq_open(struct file *file, const struct seq_operations *op) mutex_init(&p->lock); p->op = op; + p->private = data; // No refcounting: the lifetime of 'p' is constrained // to the lifetime of the file. @@ -86,6 +88,12 @@ int seq_open(struct file *file, const struct seq_operations *op) file->f_mode &= ~FMODE_PWRITE; return 0; } +EXPORT_SYMBOL(seq_open_data); + +int seq_open(struct file *file, const struct seq_operations *op) +{ + return seq_open_data(file, op, NULL); +} EXPORT_SYMBOL(seq_open); static int traverse(struct seq_file *m, loff_t offset) diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h index a121982af0f5..1142e39bfad2 100644 --- a/include/linux/seq_file.h +++ b/include/linux/seq_file.h @@ -107,6 +107,7 @@ void seq_pad(struct seq_file *m, char c); char *mangle_path(char *s, const char *p, const char *esc); int seq_open(struct file *, const struct seq_operations *); +int seq_open_data(struct file *, const struct seq_operations *, void *); ssize_t seq_read(struct file *, char __user *, size_t, loff_t *); loff_t seq_lseek(struct file *, loff_t, int); int seq_release(struct inode *, struct file *); From patchwork Sat Aug 18 13:24:31 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rasmus Villemoes X-Patchwork-Id: 10569547 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 88D75139B for ; Sat, 18 Aug 2018 13:25:13 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 777842A836 for ; Sat, 18 Aug 2018 13:25:13 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6B4662A84D; Sat, 18 Aug 2018 13:25:13 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2208E2A836 for ; Sat, 18 Aug 2018 13:25:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726189AbeHRQcx (ORCPT ); Sat, 18 Aug 2018 12:32:53 -0400 Received: from mail-ed1-f67.google.com ([209.85.208.67]:45620 "EHLO mail-ed1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726443AbeHRQcb (ORCPT ); Sat, 18 Aug 2018 12:32:31 -0400 Received: by mail-ed1-f67.google.com with SMTP id s16-v6so5972470edq.12 for ; Sat, 18 Aug 2018 06:24:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rasmusvillemoes.dk; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=zk17HYVnUW58q1BR+6HYl6kqaH3L5J58mMwPolfdUbw=; b=KMM1Qe5vTRLN7KXhwDFKuGMbnvZcq8zfuoD3P7a00qb5GPO9kRJXvu7ZcumJgECqMi FWGHFCBN6hdMO4IE5uO3MzdbCs36Jc0gSe4yOOATvonVl5jIYxwxogOYIvwYajrrk1y3 VR99P99AWsRR5GUBnNS9IjluXyFZRe8Awbm1Q= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=zk17HYVnUW58q1BR+6HYl6kqaH3L5J58mMwPolfdUbw=; b=qOQeZj3hZRVPkIEXUUzgOlqwIigZHCDnI2Ghdb8RZ9jn3MJZbTqV3IREqkqq1i3wNA xZ8QTjSdw+RwZyyMVX8pRMH7zvXiWLCOEwoTeJ2uU7arr9OpRroQEnBgYgbtBEg4nh6E FqvxMfaYb6L7bVa+r+8FU5rDeY/G02dipe7ZbnVTngriB3cxdq2BEhLD87mFN9pWYQmN DA7P/xIAaAF3lSexaOSyIB/x12A2RhRJUgzkGruGVnjwm0Efk9RkMI4donkII+KDtOdD vK77yj56r0Wq5+vZvFecd5KStnGz1Dtt/9LeFVSJRW9rRChwk9p2abT5tUGEABYgvsAg X6zA== X-Gm-Message-State: AOUpUlGVC36MLdQ/VCntdnZoa25Zaix9KJi+HzKP+Jzz7egrTO56tIOH 2KxT9rXQBy+pqcxjqbYehhh/enG+4Lr1IA== X-Google-Smtp-Source: AA+uWPxhrYDWnSfRi8u/2HjN9SurCTN4ESCd2SzEtbEfGZQw2TQwz8JPqoRglpGUxIzOj3kD8Npxzg== X-Received: by 2002:a50:c181:: with SMTP id m1-v6mr3842455edf.199.1534598687404; Sat, 18 Aug 2018 06:24:47 -0700 (PDT) Received: from prevas-ravi.waoo.dk (dhcp-5-186-114-212.cgn.ip.fibianet.dk. [5.186.114.212]) by smtp.gmail.com with ESMTPSA id a11-v6sm2739032edn.95.2018.08.18.06.24.46 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sat, 18 Aug 2018 06:24:46 -0700 (PDT) From: Rasmus Villemoes To: linux-nfs@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Rasmus Villemoes Subject: [PATCH v2 5/8] nfsd: use seq_open_data() in exports_net_open() Date: Sat, 18 Aug 2018 15:24:31 +0200 Message-Id: <20180818132434.9515-5-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20180818132434.9515-1-linux@rasmusvillemoes.dk> References: <20180818132434.9515-1-linux@rasmusvillemoes.dk> Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Using the seq_open_data() helper, exports_net_open() essentially becomes a oneliner. Signed-off-by: Rasmus Villemoes --- Depends on 1/8 introducing seq_open_data. fs/nfsd/nfsctl.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index d107b4426f7e..483a849b9ce1 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -135,17 +135,9 @@ static const struct file_operations transaction_ops = { static int exports_net_open(struct net *net, struct file *file) { - int err; - struct seq_file *seq; struct nfsd_net *nn = net_generic(net, nfsd_net_id); - err = seq_open(file, &nfs_exports_op); - if (err) - return err; - - seq = file->private_data; - seq->private = nn->svc_export_cache; - return 0; + return seq_open_data(file, &nfs_exports_op, nn->svc_export_cache); } static int exports_proc_open(struct inode *inode, struct file *file)