Commit 6836b9bd authored Feb 16, 2010 by jamal Committed by David S. Miller Feb 16, 2010

xfrm: avoid spinlock in get_acqseq() used by xfrm user



Eric's version fixed it for pfkey. This one is for xfrm user.
I thought about amortizing those two get_acqseq()s but it seems
reasonable to have two of these sequence spaces for the two different
interfaces.

cheers,
jamal
commit d5168d5addbc999c94aacda8f28a4a173756a72b
Author: Jamal Hadi Salim <hadi@cyberus.ca>
Date:   Tue Feb 16 06:51:22 2010 -0500

    xfrm: avoid spinlock in get_acqseq() used by xfrm user

    This is in the same spirit as commit 28aecb9d
    by Eric Dumazet.
    Use atomic_inc_return() in get_acqseq() to avoid taking a spinlock

    Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>

Signed-off-by: David S. Miller <davem@davemloft.net>

parent e06d41d0

net/xfrm/xfrm_state.c

+5 −5

Original line number	Original line	Diff line number	Diff line
	@@ -1462,12 +1462,12 @@ EXPORT_SYMBOL(xfrm_find_acq_byseq);
	u32 xfrm_get_acqseq(void)		u32 xfrm_get_acqseq(void)
	{		{
	u32 res;		u32 res;
	static u32 acqseq;		static atomic_t acqseq;
	static DEFINE_SPINLOCK(acqseq_lock);
			do {
			res = atomic_inc_return(&acqseq);
			} while (!res);

	spin_lock_bh(&acqseq_lock);
	res = (++acqseq ? : ++acqseq);
	spin_unlock_bh(&acqseq_lock);
	return res;		return res;
	}		}
	EXPORT_SYMBOL(xfrm_get_acqseq);		EXPORT_SYMBOL(xfrm_get_acqseq);

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