Messages in this thread | | | Date | Mon, 11 Mar 2024 15:37:22 +0100 | Subject | Re: [PATCH v2] mm/swapfile:__swap_duplicate: drop redundant WRITE_ONCE on swap_map for err cases | From | David Hildenbrand <> |
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On 21.02.24 22:08, Barry Song wrote: > From: Barry Song <v-songbaohua@oppo.com> > > The code is quite hard to read, we are still writing swap_map after > errors happen. Though the written value is as before, > > has_cache = count & SWAP_HAS_CACHE; > count &= ~SWAP_HAS_CACHE; > [snipped] > WRITE_ONCE(p->swap_map[offset], count | has_cache); > > It would be better to entirely drop the WRITE_ONCE for both > performance and readability. > > Signed-off-by: Barry Song <v-songbaohua@oppo.com> > --- > -v2: drop goto according to Andrew, Thanks! > > mm/swapfile.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/swapfile.c b/mm/swapfile.c > index 556ff7347d5f..7cb6d9a2d51d 100644 > --- a/mm/swapfile.c > +++ b/mm/swapfile.c > @@ -3320,7 +3320,8 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage) > } else > err = -ENOENT; /* unused swap entry */ > > - WRITE_ONCE(p->swap_map[offset], count | has_cache); > + if (!err) > + WRITE_ONCE(p->swap_map[offset], count | has_cache); > > unlock_out: > unlock_cluster_or_swap_info(p, ci);
Maybe too late, but LGTM
Reviewed-by: David Hildenbrand <david@redhat.com>
-- Cheers,
David / dhildenb
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