[PATCH stable-4.14] driver core: Fix bus_type.match() error handling in __driver_attach()

["Isaac J. Manjarres" <isaacmanjarres@google.com>]

commit 27c0d217340e47ec995557f61423ef415afba987 upstream.

When a driver registers with a bus, it will attempt to match with every
device on the bus through the __driver_attach() function. Currently, if
the bus_type.match() function encounters an error that is not
-EPROBE_DEFER, __driver_attach() will return a negative error code, which
causes the driver registration logic to stop trying to match with the
remaining devices on the bus.

This behavior is not correct; a failure while matching a driver to a
device does not mean that the driver won't be able to match and bind
with other devices on the bus. Update the logic in __driver_attach()
to reflect this.

Fixes: 656b8035b0ee ("ARM: 8524/1: driver cohandle -EPROBE_DEFER from bus_type.match()")
Cc: stable@vger.kernel.org
Cc: Saravana Kannan <saravanak@google.com>
Signed-off-by: Isaac J. Manjarres <isaacmanjarres@google.com>
---
 drivers/base/dd.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index a7bcbb99e820..0f006cad2be7 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -785,8 +785,12 @@ static int __driver_attach(struct device *dev, void *data)
 		 */
 		return 0;
 	} else if (ret < 0) {
-		dev_dbg(dev, "Bus failed to match device: %d", ret);
-		return ret;
+		dev_dbg(dev, "Bus failed to match device: %d\n", ret);
+		/*
+		 * Driver could not match with device, but may match with
+		 * another device on the bus.
+		 */
+		return 0;
 	} /* ret > 0 means positive match */
 
 	if (dev->parent)	/* Needed for USB */
-- 
2.39.0.314.g84b9a713c41-goog