[RESEND PATCH v1] driver core: fix possible missing of device probe

From: Ming Lei
Date: Fri Jan 04 2013 - 22:22:42 EST

Inside bus_add_driver(), one device might be added(device_add()) into
the bus or probed which is triggered by deferred probe
just after completing of driver_attach() and before
'klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers)',
so the device won't be probed by this driver.

This patch moves the below line

'klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers)'

before driver_attach() inside bus_add_driver() to fix the

Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>
- remove memory barrier part of previous commit log because
klist lock of 'bus->p->klist_drivers' is held during both
adding driver into the list and iterating the driver list,
so the new added driver can always be perceived immediately
on other CPUs.
drivers/base/bus.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 181ed26..3b5bddb 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -714,12 +714,12 @@ int bus_add_driver(struct device_driver *drv)
if (error)
goto out_unregister;

+ klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers);
if (drv->bus->p->drivers_autoprobe) {
error = driver_attach(drv);
if (error)
goto out_unregister;
- klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers);
module_add_driver(drv->owner, drv);

error = driver_create_file(drv, &driver_attr_uevent);

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