diff options
| author | Al Viro <viro@zeniv.linux.org.uk> | 2008-08-24 07:45:33 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2008-08-25 01:18:10 -0400 |
| commit | 4cdfe84b51420c9ac95c7133da2d4c8a191094af (patch) | |
| tree | b15ad9cd9d9db1117be13b5da1b00399ee544c70 /fs/seq_file.c | |
| parent | 59af1584bf33810639cb98d79856021253e2177c (diff) | |
| download | lwn-4cdfe84b51420c9ac95c7133da2d4c8a191094af.tar.gz lwn-4cdfe84b51420c9ac95c7133da2d4c8a191094af.zip | |
[PATCH] deal with the first call of ->show() generating no output
seq_read() has a subtle bug - we want the first loop there to go
until at least one *non-empty* record had fit entirely into buffer.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/seq_file.c')
| -rw-r--r-- | fs/seq_file.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/fs/seq_file.c b/fs/seq_file.c index 5d54205e486b..bd20f7f5a933 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -108,9 +108,9 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) goto Done; } /* we need at least one record in buffer */ + pos = m->index; + p = m->op->start(m, &pos); while (1) { - pos = m->index; - p = m->op->start(m, &pos); err = PTR_ERR(p); if (!p || IS_ERR(p)) break; @@ -119,6 +119,11 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) break; if (unlikely(err)) m->count = 0; + if (unlikely(!m->count)) { + p = m->op->next(m, p, &pos); + m->index = pos; + continue; + } if (m->count < m->size) goto Fill; m->op->stop(m, p); @@ -128,6 +133,8 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) goto Enomem; m->count = 0; m->version = 0; + pos = m->index; + p = m->op->start(m, &pos); } m->op->stop(m, p); m->count = 0; |