On Fri, Nov 14, 2014 at 05:17:05PM +0100, Ard Biesheuvel wrote: > On 14 November 2014 16:43, Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote: > > While working on the cryptd request reordering problem, I noticed > > an anomaly where kernel threads are normally allowed to use simd > > per may_use_simd, but as soon as you disable softirqs, they suddenly > > lose that ability for no good reason. > > > > The problem is that in_interrupt does not distinguish between > > softirq processing and simply having softirqs disabled. This > > patch creates a new helper in_serving_interrupt which makes that > > distinction. It then uses this in all current implementations > > of may_use_simd. > > > > Isn't that a much more widespread problem if in_interrupt() yields > true while no interrupt is being served? Good point. Other users of in_interrupt() are just as likely to really want the in_serving version. However, the safe option is to leave them unchanged until we audit each single one. If it turns out that all users of in_interrupt() decay into in_serving_interrupt() then we could remove in_interrupt(). Cheers, -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
