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| author | KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> | 2012-03-23 15:02:55 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-03-23 16:58:42 -0700 |
| commit | e075f59152890ffd7e3d704afc997dd686c8a781 (patch) | |
| tree | 94dbf5eda32d7dea9821ca308c4317e75756f7bd /fs/seq_file.c | |
| parent | 1b26c9b334044cff6d1d2698f2be41bc7d9a0864 (diff) | |
| download | lwn-e075f59152890ffd7e3d704afc997dd686c8a781.tar.gz lwn-e075f59152890ffd7e3d704afc997dd686c8a781.zip | |
seq_file: add seq_set_overflow(), seq_overflow()
It is undocumented but a seq_file's overflow state is indicated by
m->count == m->size. Add seq_set_overflow() and seq_overflow() to
set/check overflow status explicitly.
Based on an idea from Eric Dumazet.
[akpm@linux-foundation.org: tweak code comment]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Eric Dumazet <eric.dumazet@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>
Diffstat (limited to 'fs/seq_file.c')
| -rw-r--r-- | fs/seq_file.c | 36 |
1 files changed, 26 insertions, 10 deletions
diff --git a/fs/seq_file.c b/fs/seq_file.c index 55c293f7024d..46cfb067fc3a 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -13,6 +13,22 @@ #include <asm/uaccess.h> #include <asm/page.h> + +/* + * seq_files have a buffer which can may overflow. When this happens a larger + * buffer is reallocated and all the data will be printed again. + * The overflow state is true when m->count == m->size. + */ +static bool seq_overflow(struct seq_file *m) +{ + return m->count == m->size; +} + +static void seq_set_overflow(struct seq_file *m) +{ + m->count = m->size; +} + /** * seq_open - initialize sequential file * @file: file we initialize @@ -92,7 +108,7 @@ static int traverse(struct seq_file *m, loff_t offset) error = 0; m->count = 0; } - if (m->count == m->size) + if (seq_overflow(m)) goto Eoverflow; if (pos + m->count > offset) { m->from = offset - pos; @@ -234,7 +250,7 @@ Fill: break; } err = m->op->show(m, p); - if (m->count == m->size || err) { + if (seq_overflow(m) || err) { m->count = offs; if (likely(err <= 0)) break; @@ -361,7 +377,7 @@ int seq_escape(struct seq_file *m, const char *s, const char *esc) *p++ = '0' + (c & 07); continue; } - m->count = m->size; + seq_set_overflow(m); return -1; } m->count = p - m->buf; @@ -383,7 +399,7 @@ int seq_printf(struct seq_file *m, const char *f, ...) return 0; } } - m->count = m->size; + seq_set_overflow(m); return -1; } EXPORT_SYMBOL(seq_printf); @@ -512,7 +528,7 @@ int seq_bitmap(struct seq_file *m, const unsigned long *bits, return 0; } } - m->count = m->size; + seq_set_overflow(m); return -1; } EXPORT_SYMBOL(seq_bitmap); @@ -528,7 +544,7 @@ int seq_bitmap_list(struct seq_file *m, const unsigned long *bits, return 0; } } - m->count = m->size; + seq_set_overflow(m); return -1; } EXPORT_SYMBOL(seq_bitmap_list); @@ -639,7 +655,7 @@ int seq_puts(struct seq_file *m, const char *s) m->count += len; return 0; } - m->count = m->size; + seq_set_overflow(m); return -1; } EXPORT_SYMBOL(seq_puts); @@ -673,7 +689,7 @@ int seq_put_decimal_ull(struct seq_file *m, char delimiter, m->count += len; return 0; overflow: - m->count = m->size; + seq_set_overflow(m); return -1; } EXPORT_SYMBOL(seq_put_decimal_ull); @@ -683,7 +699,7 @@ int seq_put_decimal_ll(struct seq_file *m, char delimiter, { if (num < 0) { if (m->count + 3 >= m->size) { - m->count = m->size; + seq_set_overflow(m); return -1; } if (delimiter) @@ -711,7 +727,7 @@ int seq_write(struct seq_file *seq, const void *data, size_t len) seq->count += len; return 0; } - seq->count = seq->size; + seq_set_overflow(seq); return -1; } EXPORT_SYMBOL(seq_write); |