From e075f59152890ffd7e3d704afc997dd686c8a781 Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Fri, 23 Mar 2012 15:02:55 -0700 Subject: [PATCH] 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 Cc: Eric Dumazet Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/seq_file.c | 36 ++++++++++++++++++++++++++---------- 1 file changed, 26 insertions(+), 10 deletions(-) diff --git a/fs/seq_file.c b/fs/seq_file.c index 55c293f..46cfb06 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -13,6 +13,22 @@ #include #include + +/* + * 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); -- 2.7.4