Re: [linux-usb-devel] Re: [OOPS, usbcore, releaseintf] 2.6.0-test10-mm1

[Alan Stern]

On Mon, 8 Dec 2003, Duncan Sands wrote:

> Hi Alan, this is for usbfs, not a normal driver.  Recall that I want to replace
> use of ps->devsem with ps->dev->serialize.

Maybe you shouldn't do that.  Other drivers maintain their own data 
structure separately from the struct usb_device and with its own lock.  
But usbfs may suffer from complications as a result of its unorthodox 
approach to device ownership.

>  Currently ps->dev is set to NULL in
> the devio.c usbfs disconnect method (if some interface is claimed) or in
> inode.c on device disconnect, making it hard to lock with ps->dev->serialize :)
> Thus disconnect should no longer be signalled by setting ps->dev to NULL.

If you would keep the ps->devsem lock, would there be any problem in 
setting ps->dev to NULL to indicate disconnection?

Are they any reasons for not keeping ps->devsem?  Since usbfs generally 
acts as a driver and drivers generally don't have to concern themselves 
with usbdev->serialize (the core handles it for them), shouldn't usbfs 
also be able to ignore ps->dev->serialize?

Alan Stern

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