4.19-stable review patch. If anyone has any objections, please let me know.
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From: Matthew Wilcox willy@infradead.org
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 willy@infradead.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/dax.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
--- a/fs/dax.c +++ b/fs/dax.c @@ -217,6 +217,9 @@ static inline void *unlock_slot(struct a 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_entr 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); + } } }