Messages in this thread | | | Subject | Re: [PATCH v2 9/9] netfilter: Replace smp_read_barrier_depends() with lockless_dereference() | From | Eric Dumazet <> | Date | Fri, 21 Nov 2014 16:05:03 -0800 |
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On Fri, 2014-11-21 at 16:57 -0500, Pranith Kumar wrote:
> Hi Eric, > > Thanks for looking at this patch. > > I've been scratching my head since morning trying to find out what was > so obviously wrong with this patch. Alas, I don't see what you do. > > Could you point it out and show me how incompetent I am, please? > > Thanks!
Well, even it the code is _not_ broken, I don't see any value with this patch.
If I use git blame on current code, line containing smp_read_barrier_depends() exactly points to the relevant commit [1]
After your change, it will point to some cleanup, which makes little sense to me, considering you did not change the smp_wmb() in xt_replace_table().
I, as a netfilter contributor would like to keep current code as is, because it is how I feel safe with it.
We have a proliferation of interfaces, but this does not help to understand the issues and code maintenance.
smp_read_barrier_depends() better documents the read barrier than lockless_dereference().
The point of having a lock or not is irrelevant here.
[1] http://git.kernel.org/cgit/linux/kernel/git/davem/net.git/commit/?id=b416c144f46af1a30ddfa4e4319a8f077381ad63
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