On Fri, Feb 06, 2015 at 02:12:32PM +0000, Mathieu Desnoyers wrote: > ----- Original Message ----- > > From: "Pranith Kumar" <[email protected]> > > To: "Mathieu Desnoyers" <[email protected]> > > Cc: "Huang Ying" <[email protected]>, "LKML" > > <[email protected]>, "Paul McKenney" > > <[email protected]>, "David Howells" <[email protected]> > > Sent: Thursday, February 5, 2015 10:44:07 PM > > Subject: Re: [PATCH] llist: Fix missing memory barrier > > > > Hi Mathieu, > > > > On Thu, Feb 5, 2015 at 10:06 PM, Mathieu Desnoyers > > <[email protected]> wrote: > > > A smp_read_barrier_depends() appears to be missing in llist_del_first(). > > > It should only matter for Alpha in practice. Adding it after the check > > > of entry against NULL allows skipping the barrier in a common case. > > > > We recently decided on using lockless_dereference() instead of > > hard-coding smp_read_barrier_depends()[1]. The advantage is that > > lockless_dereference() clearly shows what loads are being ordered. > > Could you resend the patch using that API? > > Since llist.h has been introduced prior to 3.18, I'm wondering if > it would be worthwhile to submit 2 patches for the purpose of > backporting to stable branches: > > 1) Fix introducing smp_read_barrier_depends() (for master and > stable branches) > 2) Move master from smp_read_barrier_depends() to > lockless_dereference(), > > Thoughts ?
Yes, why? What code needs these new apis? confused, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
