seq_file: move traverse so it can be used from seq_read

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 <ebiederm@xmission.com>
Cc: Paul Turner <pjt@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 57 insertions, 57 deletions

diff --git a/fs/seq_file.c b/fs/seq_file.c
index b569ff1c4dc8..2716c12eacf5 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