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Commit 5fe9d8ca authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
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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: default avatarOleg 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: default avatarNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent bc03c691

fs/coredump.c

+12 −18
Original line number Diff line number Diff line
@@ -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;

	int free, need;



	ret = expand_corename(cn);

	if (ret)

		goto expand_fail;



out_printf:

	cur = cn->corename + cn->used;

	vsnprintf(cur, need + 1, fmt, arg);

again:

	free = cn->size - cn->used;

	need = vsnprintf(cn->corename + cn->used, free, fmt, arg);

	if (need < free) {

		cn->used += need;

		return 0;

	}



expand_fail:

	return ret;

	if (!expand_corename(cn))

		goto again;



	return -ENOMEM;

}



static int cn_printf(struct core_name *cn, const char *fmt, ...)