Revision 565ce8f32ac4a233b474f401e1d3e7e1de0a31fd authored by Nikolay Aleksandrov on 27 June 2016, 16:34:42 UTC, committed by David S. Miller on 29 June 2016, 09:33:35 UTC
I made a dumb off-by-one mistake when I added the vlan stats counter
dumping code. The increment should happen before the check, not after
otherwise we miss one entry when we continue dumping.

Fixes: a60c090361ea ("bridge: netlink: export per-vlan stats")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent a3d2e9f
Raw File
dec_and_lock.c
#include <linux/export.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>

/*
 * This is an implementation of the notion of "decrement a
 * reference count, and return locked if it decremented to zero".
 *
 * NOTE NOTE NOTE! This is _not_ equivalent to
 *
 *	if (atomic_dec_and_test(&atomic)) {
 *		spin_lock(&lock);
 *		return 1;
 *	}
 *	return 0;
 *
 * because the spin-lock and the decrement must be
 * "atomic".
 */
int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
{
	/* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */
	if (atomic_add_unless(atomic, -1, 1))
		return 0;

	/* Otherwise do it the slow way */
	spin_lock(lock);
	if (atomic_dec_and_test(atomic))
		return 1;
	spin_unlock(lock);
	return 0;
}

EXPORT_SYMBOL(_atomic_dec_and_lock);
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