[ Upstream commit b769777d92 ]
Instead of using a bare atomic, use the refcount_t type, which despite
being a structure that contains only an atomic, has an API that checks
for underflows and other hazards. This doesn't change the size of the
extent_buffer structure.
This removes the need to do things like this:
WARN_ON(atomic_read(&eb->refs) == 0);
if (atomic_dec_and_test(&eb->refs)) {
(...)
}
And do just:
if (refcount_dec_and_test(&eb->refs)) {
(...)
}
Since refcount_dec_and_test() already triggers a warning when we decrement
a ref count that has a value of 0 (or below zero).
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: ad580dfa38 ("btrfs: fix subpage deadlock in try_release_subpage_extent_buffer()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
98f97e2616