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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 D1BC5C4742C for ; Tue, 10 Nov 2020 04:05:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7AEF620721 for ; Tue, 10 Nov 2020 04:05:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="pyxnm4NC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732770AbgKJDyh (ORCPT ); Mon, 9 Nov 2020 22:54:37 -0500 Received: from mail.kernel.org ([198.145.29.99]:55506 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732752AbgKJDyg (ORCPT ); Mon, 9 Nov 2020 22:54:36 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8022E20731; Tue, 10 Nov 2020 03:54:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604980475; bh=OidxuqgApJGSfeLbGgjwnebB6KwQH162UtIBtQlTeno=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pyxnm4NCAP1gfEPzlsO6fuBk6KpGW/hQOtBq7kXmQ7vaCGMJnLgDV50ZTdBdaVS/e dSlmLyI9c0DnUaNFKGnElm+HD/iNcH6TrCFfQ+1ayceAwTIh9QZ4e/DGd2PvGGfNqs F9iFFAycBetucHL/HRkZ45AzTDdvpVrQmp5/sb0M= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Christoph Hellwig , Greg Kroah-Hartman , Linus Torvalds , Sasha Levin , linux-fsdevel@vger.kernel.org Subject: [PATCH AUTOSEL 5.9 53/55] seq_file: add seq_read_iter Date: Mon, 9 Nov 2020 22:53:16 -0500 Message-Id: <20201110035318.423757-53-sashal@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20201110035318.423757-1-sashal@kernel.org> References: <20201110035318.423757-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Christoph Hellwig [ Upstream commit d4d50710a8b46082224376ef119a4dbb75b25c56 ] iov_iter based variant for reading a seq_file. seq_read is reimplemented on top of the iter variant. Signed-off-by: Christoph Hellwig Tested-by: Greg Kroah-Hartman Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- fs/seq_file.c | 45 ++++++++++++++++++++++++++++------------ include/linux/seq_file.h | 1 + 2 files changed, 33 insertions(+), 13 deletions(-) diff --git a/fs/seq_file.c b/fs/seq_file.c index 31219c1db17de..3b20e21604e74 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include @@ -146,7 +147,28 @@ 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; + struct iovec iov = { .iov_base = buf, .iov_len = size}; + struct kiocb kiocb; + struct iov_iter iter; + ssize_t ret; + + init_sync_kiocb(&kiocb, file); + iov_iter_init(&iter, READ, &iov, 1, size); + + kiocb.ki_pos = *ppos; + ret = seq_read_iter(&kiocb, &iter); + *ppos = kiocb.ki_pos; + return ret; +} +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 +180,14 @@ 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 +196,7 @@ 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 +209,11 @@ 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 +274,7 @@ 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 +283,7 @@ 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 +295,7 @@ 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 813614d4b71fb..b83b3ae3c877f 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); -- 2.27.0