mm: change to return bool for isolate_lru_page()

The isolate_lru_page() can only return 0 or -EBUSY, and most users did not
care about the negative error of isolate_lru_page(), except one user in
add_page_for_migration().  So we can convert the isolate_lru_page() to
return a boolean value, which can help to make the code more clear when
checking the return value of isolate_lru_page().

Also convert all users' logic of checking the isolation state.

No functional changes intended.

Link: https://lkml.kernel.org/r/3074c1ab628d9dbf139b33f248a8bc253a3f95f0.1676424378.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 3 insertions, 9 deletions

diff --git a/mm/folio-compat.c b/mm/folio-compat.c
index 540373cf904e..cabcd1de9ecb 100644
--- a/mm/folio-compat.c
+++ b/mm/folio-compat.c
@@ -113,17 +113,11 @@ struct page *grab_cache_page_write_begin(struct address_space *mapping,
 }
 EXPORT_SYMBOL(grab_cache_page_write_begin);
 
-int isolate_lru_page(struct page *page)
+bool isolate_lru_page(struct page *page)
 {
-	bool ret;
-
 	if (WARN_RATELIMIT(PageTail(page), "trying to isolate tail page"))
-		return -EBUSY;
-	ret = folio_isolate_lru((struct folio *)page);
-	if (ret)
-		return 0;
-
-	return -EBUSY;
+		return false;
+	return folio_isolate_lru((struct folio *)page);
 }
 
 void putback_lru_page(struct page *page)