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: 9f32d22130 ("dax: Convert dax_lock_mapping_entry to XArray")
Signed-off-by: Matthew Wilcox <willy@infradead.org>
This commit is contained in:
Matthew Wilcox 2018-11-06 13:11:57 -05:00
parent 5404a7f1c2
commit 6d7cd8c137

View File

@ -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);