On 12/4/2014 4:22 PM, Thierry Reding wrote:
From: Thierry Reding <treding@xxxxxxxxxx>
Commit 1290a958d48e ("usb: phy: propagate __of_usb_find_phy()'s error on
failure") broke platforms that rely on deferred probing to order probing
of PHY and host controller drivers. The reason is that the commit simply
propagates errors from __of_usb_find_phy(), which returns -ENODEV if no
PHY has been registered yet for a given device tree node. The only case
in which -EPROBE_DEFER would now be returned is if try_module_get() did
fail, which does not make sense.
The correct thing to do is to return -EPROBE_DEFER if a PHY hasn't been
registered yet. The only condition under which it makes sense to return
-ENODEV is if the device tree node representing the PHY has been
disabled (via the status property) because in that case the PHY will
never be registered.
This patch addresses the problem by making __of_usb_find_phy() return an
appropriate error code while keeping in line with the above-mentioned
commit to propagate error codes rather than overwriting them. At the
same time the check for a valid PHY is decoupled from the check for the
try_module_get() call and a separate error code is returned if the
latter fails.
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
---
drivers/usb/phy/phy.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/phy/phy.c b/drivers/usb/phy/phy.c
index b4066a001ba0..2f9735b35338 100644
--- a/drivers/usb/phy/phy.c
+++ b/drivers/usb/phy/phy.c
[...]
@@ -190,10 +193,13 @@ struct usb_phy *devm_usb_get_phy_by_phandle(struct device *dev,
spin_lock_irqsave(&phy_lock, flags);
phy = __of_usb_find_phy(node);
- if (IS_ERR(phy) || !try_module_get(phy->dev->driver->owner)) {
- if (!IS_ERR(phy))
- phy = ERR_PTR(-EPROBE_DEFER);
+ if (IS_ERR(phy)) {
+ devres_free(ptr);
+ goto err1;
+ }
+ if (!try_module_get(phy->dev->driver->owner)) {
+ phy = ERR_PTR(-ENODEV);
devres_free(ptr);
goto err1;
}
I think devres_free() should now be called in one place, under the new
'err2' label.
That'd make things very confusing, though. devres_free() should only be
called on error, whereas both err1 and err0 are shared with the success
case as well. If we were to do what you suggest we'd end up with
something like this:
[...]
That's pretty spaghetti-like.
Oh, sorry, I wasn't looking attentively enough. :-/
Thierry
WBR, Sergei
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