On 02/04/2013 04:10 PM, Marc Kleine-Budde wrote:

On 02/04/2013 02:59 PM, Roger Quadros wrote:

quoted

On 02/04/2013 03:24 PM, Sascha Hauer wrote:

quoted

From: Marc Kleine-Budde <mkl@pengutronix.de>

In patch "5d3c28b usb: otg: add device tree support to otg library"
devm_usb_get_phy_by_phandle() was added. It uses try_module_get() to lock the
phy driver in memory. The corresponding module_put() is missing in that patch.

This patch adds try_module_get() to usb_get_phy() and usb_get_phy_dev().
Further the missing module_put() is added to usb_put_phy().

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/usb/otg/otg.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/otg/otg.c b/drivers/usb/otg/otg.c
index e181439..2bd03d2 100644
--- a/drivers/usb/otg/otg.c
+++ b/drivers/usb/otg/otg.c

@@ -130,7 +130,7 @@ struct usb_phy *usb_get_phy(enum usb_phy_type type)
 	spin_lock_irqsave(&phy_lock, flags);
 
 	phy = __usb_find_phy(&phy_list, type);
-	if (IS_ERR(phy)) {
+	if (IS_ERR(phy) || !try_module_get(phy->dev->driver->owner)) {
 		pr_err("unable to find transceiver of type %s\n",
 			usb_phy_type_string(type));
 		goto err0;

There are 2 problems with this.

- If phy was found but try_module_get failed you are not returning error code.

Correct - but....

quoted

- If phy was found and try_module_get fails we would want to use deferred probing,
since this case is possible if the phy module is not yet loaded and alive but can be in
the future.

...this should not happen, as the phy list is protected by the
spin_lock. If a phy driver module has added a the phy to the
infrastructure, but has been rmmod'ed without removing the phy. The phy
driver is broken anyway.

Yes, you are right.

cheers,
-roger