On Tue, Feb 18, 2020 at 07:17:16PM -0300, Mauricio Faria de Oliveira wrote:
> There used to be a 'retry' label in between the two (identical) checks
> when first introduced in commit f446daaea9d4 ("mm: implement writeback
> livelock avoidance using page tagging"), and later modified/updated in
> commit 6e6938b6d313 ("writeback: introduce .tagged_writepages for the
> WB_SYNC_NONE sync stage").
>
> The label has been removed in commit 64081362e8ff ("mm/page-writeback.c:
> fix range_cyclic writeback vs writepages deadlock"), and the (identical)
> checks are now present / performed immediately one after another.
>
> So, remove/deduplicate the latter check, moving tag_pages_for_writeback()
> into the former check before the 'tag' variable assignment, so it's clear
> that it's not used in this (similarly-named) function call but only later
> in pagevec_lookup_range_tag().
>
> Signed-off-by: Mauricio Faria de Oliveira <mfo@xxxxxxxxxxxxx>
Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx>
> ---
>
> v2: add the missing braces to the conditional statement
> with more than a single statement.. doh; and to the
> else branch (w/a single statement, per coding style.)
>
> mm/page-writeback.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 2caf780a42e7..ab5a3cee8ad3 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -2182,12 +2182,12 @@ int write_cache_pages(struct address_space *mapping,
> if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
> range_whole = 1;
> }
> - if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
> + if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) {
> + tag_pages_for_writeback(mapping, index, end);
> tag = PAGECACHE_TAG_TOWRITE;
> - else
> + } else {
> tag = PAGECACHE_TAG_DIRTY;
> - if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
> - tag_pages_for_writeback(mapping, index, end);
> + }
> done_index = index;
> while (!done && (index <= end)) {
> int i;
> --
> 2.20.1
>
