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Commit 6836b9bd authored by jamal's avatar jamal Committed by David S. Miller
Browse files

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: default avatarJamal Hadi Salim <hadi@cyberus.ca>
Acked-by: default avatarEric Dumazet <eric.dumazet@gmail.com>

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e06d41d0

net/xfrm/xfrm_state.c

+5 −5
Original line number Diff line number Diff line
@@ -1462,12 +1462,12 @@ EXPORT_SYMBOL(xfrm_find_acq_byseq); 
u32 xfrm_get_acqseq(void)

{

	u32 res;

	static u32 acqseq;

	static DEFINE_SPINLOCK(acqseq_lock);

	static atomic_t acqseq;



	do {

		res = atomic_inc_return(&acqseq);

	} while (!res);



	spin_lock_bh(&acqseq_lock);

	res = (++acqseq ? : ++acqseq);

	spin_unlock_bh(&acqseq_lock);

	return res;

}

EXPORT_SYMBOL(xfrm_get_acqseq);