[PATCH v1] driver core: Fix bus_type.match() error handling in __driver_attach()

[Isaac J. Manjarres]

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@xxxxxxxxxxxxxxx
Cc: Saravana Kannan <saravanak@xxxxxxxxxx>
Signed-off-by: Isaac J. Manjarres <isaacmanjarres@xxxxxxxxxx>
---
 drivers/base/dd.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

This problem was not reported anywhere, but rather it was something that
I noticed while looking at this function.

--Isaac

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index ec69b43f926a..6669daf1f31f 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -1162,7 +1162,11 @@ static int __driver_attach(struct device *dev, void *data)
 		return 0;
 	} else if (ret < 0) {
 		dev_dbg(dev, "Bus failed to match device: %d\n", ret);
-		return ret;
+		/*
+		 * Driver could not match with device, but may match with
+		 * another device on the bus.
+		 */
+		return 0;
 	} /* ret > 0 means positive match */
 
 	if (driver_allows_async_probing(drv)) {
-- 
2.37.3.968.ga6b4b080e4-goog