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>

diff --git a/fs/seq_file.c b/fs/seq_file.c
index b569ff1c4dc81570bec822be5df54069af18a162..2716c12eacf5062501634111ae1544f653342c62 100644 (file)
--- 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