Messages in this thread | | | Date | Thu, 8 Dec 2005 18:01:54 -0500 | From | Dmitry Torokhov <> | Subject | Re: Driver bind/unbind and __devinit |
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On 12/8/05, Greg KH <gregkh@suse.de> wrote: > On Thu, Dec 08, 2005 at 05:22:12PM -0500, Dmitry Torokhov wrote: > > On 12/8/05, Greg KH <gregkh@suse.de> wrote: > > > On Thu, Dec 08, 2005 at 04:14:58PM -0500, Dmitry Torokhov wrote: > > > > Hi, > > > > > > > > Many drivers have their probe routines declared as __devinit which is > > > > a no-op unless CONFIG_HOTPLUG is set. However driver's bind/unbind > > > > attributes are created unconditionally, as fas as I can see. Would not > > > > it cause an oops if someone tries to use these attributes with > > > > CONFIG_HOTPLUG=N? Am I missing something? > > > > > > You are missing the CONFIG_HOTPLUG checks around the functions that add > > > and check the device ids from these sysfs files. If CONFIG_HOTPLUG is > > > not enabled, those files do not do anything. > > > > > > > I am slow today... I don't see any dependencies on CONFIG_HOTPLUG in > > drivers/base... Or you talking about one particular subsystem that > > handles this correctly? > > Ugh, very sorry about that, I was thinking of the USB and PCI new_id > stuff. You are right. > > Yes, bind happening after the __init data section is thrown away, if > CONFIG_HOTPLUG is not enabled would be a bad thing. But unbind can > stay. I'll go make up a patch for that. >
Unbind may invoke ->remove code which is __devexit[_p] and may be also discarded if !MODULE && !HOTPLUG.
> > > > Also, unbind implementation does not seem safe - we check the driver > > > > before taking device's semaphore so we risk unbinding wrong driver (in > > > > the unlikely event that we manage to unbind and bind another driver in > > > > another thread). > > > > > > Do you have a suggestion as to how to fix this? > > > > > > > I think we could take the semaphore before checking driver and then > > use __device_release_driver(). But we'd need to make it global or move > > bind/unbind code into drivers/base/dd.c > > I don't have a problem moving the code if it makes it easier. Have a > patch? :) >
Just handwaving for now ;)
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