[PATCH] teach seq_file to discard entries

[safe/jmp/linux-2.6] / fs / seq_file.c

diff --git a/fs/seq_file.c b/fs/seq_file.c
index 8537702..bf2bcfd 100644 (file)
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -25,6 +25,7 @@
  *     into the buffer.  In case of error ->start() and ->next() return
  *     ERR_PTR(error).  In the end of sequence they return %NULL. ->show()
  *     returns 0 in case of success and negative number in case of error.
+ *     Returning SEQ_SKIP means "discard this element and move on".
  */
 int seq_open(struct file *file, const struct seq_operations *op)
 {
@@ -114,8 +115,10 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
                if (!p || IS_ERR(p))
                        break;
                err = m->op->show(m, p);
-               if (err)
+               if (err < 0)
                        break;
+               if (unlikely(err))
+                       m->count = 0;
                if (m->count < m->size)
                        goto Fill;
                m->op->stop(m, p);
@@ -140,9 +143,10 @@ Fill:
                        break;
                }
                err = m->op->show(m, p);
-               if (err || m->count == m->size) {
+               if (m->count == m->size || err) {
                        m->count = offs;
-                       break;
+                       if (likely(err <= 0))
+                               break;
                }
                pos = next;
        }
@@ -199,8 +203,12 @@ static int traverse(struct seq_file *m, loff_t offset)
                if (IS_ERR(p))
                        break;
                error = m->op->show(m, p);
-               if (error)
+               if (error < 0)
                        break;
+               if (unlikely(error)) {
+                       error = 0;
+                       m->count = 0;
+               }
                if (m->count == m->size)
                        goto Eoverflow;
                if (pos + m->count > offset) {