Re: [PATCH] synchronize_irq needs a barrier
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: 2007-10-19 06:23:19
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On Fri, Oct 19, 2007 at 02:26:54PM +1000, Benjamin Herrenschmidt wrote:
I think a simple smp_mb(); here after foo = 1; is enough, which means basically just having an smp_mp(); inside napi_synchronize(), before the test_bit(). Or do I miss something ?
Yes I think you're right. In this case we do have barriers everywhere else so this should work. Although if you want napi_synchronize to have the property that when it returns all NAPI processing effects are visible then you'd need another smp_mb() after the loop. Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} [off-list ref] Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt