mm/page-writeback.c: write_cache_pages(): deduplicate identical checks

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@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Link: http://lkml.kernel.org/r/20200218221716.1648-1-mfo@canonical.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 2caf780..ab5a3ce 100644 (file)
--- 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;