From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758223AbZBJTQz (ORCPT ); Tue, 10 Feb 2009 14:16:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755910AbZBJTEJ (ORCPT ); Tue, 10 Feb 2009 14:04:09 -0500 Received: from kroah.org ([198.145.64.141]:54086 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755906AbZBJTEH (ORCPT ); Tue, 10 Feb 2009 14:04:07 -0500 Date: Tue, 10 Feb 2009 11:01:01 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , Domenico Andreoli , Willy Tarreau , Rodrigo Rubira Branco , Jake Edge , Eugene Teo , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Eric Biederman , Paul Turner , Alexey Dobriyan , Al Viro Subject: [patch 37/53] seq_file: move traverse so it can be used from seq_read Message-ID: <20090210190101.GL14308@kroah.com> References: <20090210185337.000769713@mini.kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="seq_file-move-traverse-so-it-can-be-used-from-seq_read.patch" In-Reply-To: <20090210185924.GA14308@kroah.com> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.28-stable review patch. If anyone has any objections, please let us know. ------------------ From: Eric Biederman commit 33da8892a2f9e7d4b2d9a35fc80833ba2d2b1aa6 upstream. In 2.6.25 some /proc files were converted to use the seq_file infrastructure. But seq_files do not correctly support pread(), which broke some usersapce applications. To handle pread correctly we can't assume that f_pos is where we left it in seq_read. So move traverse() so that we can eventually use it in seq_read and do thus some day support pread(). Signed-off-by: Eric Biederman Cc: Paul Turner Cc: Alexey Dobriyan Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/seq_file.c | 114 +++++++++++++++++++++++++++++----------------------------- 1 file changed, 57 insertions(+), 57 deletions(-) --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -54,6 +54,63 @@ int seq_open(struct file *file, const st } EXPORT_SYMBOL(seq_open); +static int traverse(struct seq_file *m, loff_t offset) +{ + loff_t pos = 0, index; + int error = 0; + void *p; + + m->version = 0; + index = 0; + m->count = m->from = 0; + if (!offset) { + m->index = index; + return 0; + } + if (!m->buf) { + m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL); + if (!m->buf) + return -ENOMEM; + } + p = m->op->start(m, &index); + while (p) { + error = PTR_ERR(p); + if (IS_ERR(p)) + break; + error = m->op->show(m, p); + if (error < 0) + break; + if (unlikely(error)) { + error = 0; + m->count = 0; + } + if (m->count == m->size) + goto Eoverflow; + if (pos + m->count > offset) { + m->from = offset - pos; + m->count -= m->from; + m->index = index; + break; + } + pos += m->count; + m->count = 0; + if (pos == offset) { + index++; + m->index = index; + break; + } + p = m->op->next(m, p, &index); + } + m->op->stop(m, p); + return error; + +Eoverflow: + m->op->stop(m, p); + kfree(m->buf); + m->buf = kmalloc(m->size <<= 1, GFP_KERNEL); + return !m->buf ? -ENOMEM : -EAGAIN; +} + /** * seq_read - ->read() method for sequential files. * @file: the file to read from @@ -186,63 +243,6 @@ Efault: } EXPORT_SYMBOL(seq_read); -static int traverse(struct seq_file *m, loff_t offset) -{ - loff_t pos = 0, index; - int error = 0; - void *p; - - m->version = 0; - index = 0; - m->count = m->from = 0; - if (!offset) { - m->index = index; - return 0; - } - if (!m->buf) { - m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL); - if (!m->buf) - return -ENOMEM; - } - p = m->op->start(m, &index); - while (p) { - error = PTR_ERR(p); - if (IS_ERR(p)) - break; - error = m->op->show(m, p); - if (error < 0) - break; - if (unlikely(error)) { - error = 0; - m->count = 0; - } - if (m->count == m->size) - goto Eoverflow; - if (pos + m->count > offset) { - m->from = offset - pos; - m->count -= m->from; - m->index = index; - break; - } - pos += m->count; - m->count = 0; - if (pos == offset) { - index++; - m->index = index; - break; - } - p = m->op->next(m, p, &index); - } - m->op->stop(m, p); - return error; - -Eoverflow: - m->op->stop(m, p); - kfree(m->buf); - m->buf = kmalloc(m->size <<= 1, GFP_KERNEL); - return !m->buf ? -ENOMEM : -EAGAIN; -} - /** * seq_lseek - ->llseek() method for sequential files. * @file: the file in question