From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
This is a perfect use for xa_cmpxchg(). Note the use of 0 for GFP
flags; we won't be allocating memory.
Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
---
mm/shmem.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index 50f068f59c82..a7931660897d 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -635,16 +635,13 @@ static void shmem_delete_from_page_cache(struct page *page, void *radswap)
}
/*
- * Remove swap entry from radix tree, free the swap and its page cache.
+ * Remove swap entry from page cache, free the swap and its page cache.
*/
static int shmem_free_swap(struct address_space *mapping,
pgoff_t index, void *radswap)
{
- void *old;
+ void *old = xa_cmpxchg(&mapping->pages, index, radswap, NULL, 0);
- xa_lock_irq(&mapping->pages);
- old = radix_tree_delete_item(&mapping->pages, index, radswap);
- xa_unlock_irq(&mapping->pages);
if (old != radswap)
return -ENOENT;
free_swap_and_cache(radix_to_swp_entry(radswap));
--
2.16.1
