Re: [PATCH v2 1/3] seqlock: add raw_seqcount_try_begin

From: Peter Zijlstra
Date: Fri Nov 22 2024 - 06:19:54 EST


On Fri, Nov 22, 2024 at 12:10:29PM +0100, David Hildenbrand wrote:

> In gup_fast(), we simply do
>
> seq = raw_read_seqcount(&current->mm->write_protect_seq);
> if (seq & 1)
> return 0;
>
> Should we be using that there as well?
>
> if (!raw_seqcount_try_begin(&current->mm->write_protect_seqs, seq))
> return 0;

Might as well. A quick grep doesn't find me another instance of this
pattern, but does find me something 'funny' in net/netfilter/x_tables.c.
Let's pretend I didn't see that for now ... *sigh*

Want me to stick a patch like this on, or do you want to do that later,
when the dust has settled?