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=-9.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 3DC84C433E1 for ; Wed, 1 Jul 2020 20:24:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1AAA12067D for ; Wed, 1 Jul 2020 20:24:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="YnuYezN4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727072AbgGAUYP (ORCPT ); Wed, 1 Jul 2020 16:24:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49316 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727840AbgGAUXU (ORCPT ); Wed, 1 Jul 2020 16:23:20 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6353EC08C5DD; Wed, 1 Jul 2020 13:23:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=sTsOMUcnMDqLSD97+IRNpD3MR/vvaG/xJH7og4zU1hM=; b=YnuYezN4+MFW2eL7CEutWGvUtV n75quBvQ1ecPh3bwne533P0dXMjdMDx2oiQeEV7l16uxa52mDAq83VnGv3Asy3waP1dTMhcIwSttQ sbzcQp23iXy1OhbWXkgnP7MnuB69eYnzWEMQFGXabfZ6TOBawVfI7hdo9/7YlLGh9PC2Hrlk5k219 9AM87iCxpBmV1NPL8mpN5ulS0ICO5XG/kTu9wd+Gdn0S1Xul2ZnKboAJ50Fv0A/Jg/k3wV4u2qiSg 6XkxIbAXfYGMINtLLEQAIr383NxvchQJqp4M/k5GPtNGsQDhH00JmOwqtompd+cIgDtql/DPlP5Kz ikPHhSRw==; Received: from [2001:4bb8:18c:3b3b:379a:a079:66b5:89c3] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jqjGG-0002Rb-82; Wed, 01 Jul 2020 20:23:16 +0000 From: Christoph Hellwig To: Al Viro , Linus Torvalds Cc: Luis Chamberlain , Matthew Wilcox , Kees Cook , Iurii Zaikin , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 15/23] seq_file: add seq_read_iter Date: Wed, 1 Jul 2020 22:09:43 +0200 Message-Id: <20200701200951.3603160-16-hch@lst.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200701200951.3603160-1-hch@lst.de> References: <20200701200951.3603160-1-hch@lst.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org iov_iter based variant for reading a seq_file. seq_read is reimplemented on top of the iter variant. Signed-off-by: Christoph Hellwig --- fs/seq_file.c | 34 +++++++++++++++++++++------------- include/linux/seq_file.h | 1 + 2 files changed, 22 insertions(+), 13 deletions(-) diff --git a/fs/seq_file.c b/fs/seq_file.c index 4e6239f33c066a..159a3e12cadd30 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include @@ -146,7 +147,17 @@ static int traverse(struct seq_file *m, loff_t offset) */ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) { - struct seq_file *m = file->private_data; + return iter_read(file, buf, size, ppos, seq_read_iter); +} +EXPORT_SYMBOL(seq_read); + +/* + * Ready-made ->f_op->read_iter() + */ +ssize_t seq_read_iter(struct kiocb *iocb, struct iov_iter *iter) +{ + struct seq_file *m = iocb->ki_filp->private_data; + size_t size = iov_iter_count(iter); size_t copied = 0; size_t n; void *p; @@ -158,14 +169,14 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) * if request is to read from zero offset, reset iterator to first * record as it might have been already advanced by previous requests */ - if (*ppos == 0) { + if (iocb->ki_pos == 0) { m->index = 0; m->count = 0; } - /* Don't assume *ppos is where we left it */ - if (unlikely(*ppos != m->read_pos)) { - while ((err = traverse(m, *ppos)) == -EAGAIN) + /* Don't assume ki_pos is where we left it */ + if (unlikely(iocb->ki_pos != m->read_pos)) { + while ((err = traverse(m, iocb->ki_pos)) == -EAGAIN) ; if (err) { /* With prejudice... */ @@ -174,7 +185,7 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) m->count = 0; goto Done; } else { - m->read_pos = *ppos; + m->read_pos = iocb->ki_pos; } } @@ -187,13 +198,11 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) /* if not empty - flush it first */ if (m->count) { n = min(m->count, size); - err = copy_to_user(buf, m->buf + m->from, n); - if (err) + if (copy_to_iter(m->buf + m->from, n, iter) != n) goto Efault; m->count -= n; m->from += n; size -= n; - buf += n; copied += n; if (!size) goto Done; @@ -254,8 +263,7 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) } m->op->stop(m, p); n = min(m->count, size); - err = copy_to_user(buf, m->buf, n); - if (err) + if (copy_to_iter(m->buf, n, iter) != n) goto Efault; copied += n; m->count -= n; @@ -264,7 +272,7 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) if (!copied) copied = err; else { - *ppos += copied; + iocb->ki_pos += copied; m->read_pos += copied; } mutex_unlock(&m->lock); @@ -276,7 +284,7 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) err = -EFAULT; goto Done; } -EXPORT_SYMBOL(seq_read); +EXPORT_SYMBOL(seq_read_iter); /** * seq_lseek - ->llseek() method for sequential files. diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h index 813614d4b71fbc..b83b3ae3c877f3 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 *); ssize_t seq_read(struct file *, char __user *, size_t, loff_t *); +ssize_t seq_read_iter(struct kiocb *iocb, struct iov_iter *iter); loff_t seq_lseek(struct file *, loff_t, int); int seq_release(struct inode *, struct file *); int seq_write(struct seq_file *seq, const void *data, size_t len); -- 2.26.2