dax: Remove optimisation from dax_lock_mapping_entry

Skipping some of the revalidation after we sleep can lead to returning a mapping which has already been freed. Just drop this optimisation. Reported-by: Dan Williams <[email protected]> Fixes: 9f32d22 ("dax: Convert dax_lock_mapping_entry to XArray") Signed-off-by: Matthew Wilcox <[email protected]>
ambv · Nov 16, 2018 · 6d7cd8c · 6d7cd8c
1 parent 5404a7f
commit 6d7cd8c
Showing 1 changed file with 2 additions and 5 deletions.
diff --git a/fs/dax.c b/fs/dax.c
@@ -383,11 +383,8 @@ bool dax_lock_mapping_entry(struct page *page)
 		entry = xas_load(&xas);
 		if (dax_is_locked(entry)) {
 			entry = get_unlocked_entry(&xas);
-			/* Did the page move while we slept? */
-			if (dax_to_pfn(entry) != page_to_pfn(page)) {
-				xas_unlock_irq(&xas);
-				continue;
-			}
+			xas_unlock_irq(&xas);
+			continue;
 		}
 		dax_lock_entry(&xas, entry);
 		xas_unlock_irq(&xas);