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 <dan.j.williams@intel.com>
Fixes: 9f32d221301c ("dax: Convert dax_lock_mapping_entry to XArray")
Signed-off-by: Matthew Wilcox <willy@infradead.org>
diff --git a/fs/dax.c b/fs/dax.c
index 616e36e..529ac9d 100644
--- 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);