https://github.com/torvalds/linux
Revision 64a146513f8f12ba204b7bf5cb7e9505594ead42 authored by David S. Miller on 06 March 2007, 19:21:05 UTC, committed by David S. Miller on 06 March 2007, 19:21:05 UTC
This reverts two changes:

8488df894d05d6fa41c2bd298c335f944bb0e401
248f06726e866942b3d8ca8f411f9067713b7ff8

A backlog value of N really does mean allow "N + 1" connections
to queue to a listening socket.  This allows one to specify
"0" as the backlog and still get 1 connection.

Noticed by Gerrit Renker and Rick Jones.

Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 187f5f8
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Tip revision: 64a146513f8f12ba204b7bf5cb7e9505594ead42 authored by David S. Miller on 06 March 2007, 19:21:05 UTC
[NET]: Revert incorrect accept queue backlog changes.
Tip revision: 64a1465
dec_and_lock.c
#include <linux/module.h>
#include <linux/spinlock.h>
#include <asm/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)
{
#ifdef CONFIG_SMP
	/* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */
	if (atomic_add_unless(atomic, -1, 1))
		return 0;
#endif
	/* 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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