From e7a121e34c79bca171e5076a4c30a17d9966e88f Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Fri, 16 Nov 2018 15:50:02 -0500 Subject: [PATCH] dax: Avoid losing wakeup in dax_lock_mapping_entry commit 25bbe21bf427a81b8e3ccd480ea0e1d940256156 upstream. After calling get_unlocked_entry(), you have to call put_unlocked_entry() to avoid subsequent waiters losing wakeups. Fixes: c2a7d2a11552 ("filesystem-dax: Introduce dax_lock_mapping_entry()") Cc: stable@vger.kernel.org Signed-off-by: Matthew Wilcox Signed-off-by: Greg Kroah-Hartman --- fs/dax.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/dax.c b/fs/dax.c index 0fb270f0a0ef..b0cd1364c68f 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -217,6 +217,9 @@ static inline void *unlock_slot(struct address_space *mapping, void **slot) return (void *)entry; } +static void put_unlocked_mapping_entry(struct address_space *mapping, + pgoff_t index, void *entry); + /* * Lookup entry in radix tree, wait for it to become unlocked if it is * exceptional entry and return it. The caller must call @@ -256,8 +259,10 @@ static void *__get_unlocked_mapping_entry(struct address_space *mapping, revalidate = wait_fn(); finish_wait(wq, &ewait.wait); xa_lock_irq(&mapping->i_pages); - if (revalidate) + if (revalidate) { + put_unlocked_mapping_entry(mapping, index, entry); return ERR_PTR(-EAGAIN); + } } } -- 2.17.1