From: ebiederm@xmission.com (Eric W. Biederman)
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Paul Turner <pjt@google.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] seq_file: Move traverse so it can be used from seq_read
Date: Tue, 27 Jan 2009 13:48:56 -0800 [thread overview]
Message-ID: <m1mydcbet3.fsf_-_@fess.ebiederm.org> (raw)
In-Reply-To: <m1r62obev3.fsf@fess.ebiederm.org> (Eric W. Biederman's message of "Tue\, 27 Jan 2009 13\:47\:44 -0800")
To handle pread correctly we can't assume that f_pos is
where we left it in seq_read. So modify traverse
so we can use it in seq_read.
Signed-off-by: Eric Biederman <ebiederm@xmission.com>
---
fs/seq_file.c | 114 ++++++++++++++++++++++++++++----------------------------
1 files changed, 57 insertions(+), 57 deletions(-)
diff --git a/fs/seq_file.c b/fs/seq_file.c
index b569ff1..2716c12 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -54,6 +54,63 @@ int seq_open(struct file *file, const struct seq_operations *op)
}
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
--
1.5.6.3
next prev parent reply other threads:[~2009-01-27 21:48 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-17 7:51 Migration of kernel interfaces to seq_files breaks pread() consumers Paul Turner
2009-01-25 2:19 ` Andrew Morton
2009-01-25 3:40 ` Paul Turner
2009-01-25 12:08 ` Alexey Dobriyan
2009-01-27 21:47 ` Eric W. Biederman
2009-01-27 21:48 ` Eric W. Biederman [this message]
2009-01-27 21:49 ` [PATCH 2/2] seq_file: Properly cope with pread Eric W. Biederman
2009-01-30 1:26 ` Migration of kernel interfaces to seq_files breaks pread() consumers Paul Turner
2009-01-30 3:01 ` Eric W. Biederman
2009-01-30 6:09 ` Paul Turner
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