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| author | Oleg Nesterov <oleg@redhat.com> | 2013-07-03 15:08:19 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-07-03 16:08:02 -0700 |
| commit | 5fe9d8ca21cc1517258fe448639392d5d542eec6 (patch) | |
| tree | f1f5e8778d000c4bfaf7b44493186b48a6a5c7e3 /fs/coredump.c | |
| parent | bc03c691aa86948af4e272ebdcdd4203018210f3 (diff) | |
| download | linux-stable-5fe9d8ca21cc1517258fe448639392d5d542eec6.tar.gz linux-stable-5fe9d8ca21cc1517258fe448639392d5d542eec6.tar.bz2 linux-stable-5fe9d8ca21cc1517258fe448639392d5d542eec6.zip | |
coredump: cn_vprintf() has no reason to call vsnprintf() twice
cn_vprintf() looks really overcomplicated and sub-optimal. We do not need
vsnprintf(NULL) to calculate the size we need, we can simply try to print
into the current buffer and expand/retry only if necessary.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Colin Walters <walters@verbum.org>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Lennart Poettering <mzxreary@0pointer.de>
Cc: Lucas De Marchi <lucas.de.marchi@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/coredump.c')
| -rw-r--r-- | fs/coredump.c | 30 |
1 files changed, 12 insertions, 18 deletions
diff --git a/fs/coredump.c b/fs/coredump.c index c10a43aae220..2b1d1f54e630 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -71,26 +71,20 @@ static int expand_corename(struct core_name *cn) static int cn_vprintf(struct core_name *cn, const char *fmt, va_list arg) { - char *cur; - int need; - int ret; - - need = vsnprintf(NULL, 0, fmt, arg); - if (likely(need < cn->size - cn->used - 1)) - goto out_printf; - - ret = expand_corename(cn); - if (ret) - goto expand_fail; + int free, need; + +again: + free = cn->size - cn->used; + need = vsnprintf(cn->corename + cn->used, free, fmt, arg); + if (need < free) { + cn->used += need; + return 0; + } -out_printf: - cur = cn->corename + cn->used; - vsnprintf(cur, need + 1, fmt, arg); - cn->used += need; - return 0; + if (!expand_corename(cn)) + goto again; -expand_fail: - return ret; + return -ENOMEM; } static int cn_printf(struct core_name *cn, const char *fmt, ...) |