Hello, I have a question regarding the right design of an USB character driver:
at open(), the device descriptor is allocated from the heap. Inside the descriptor is the mutex to protect against user space race conditions. The pointer to the device descriptor is stored in file->private_data. at release(), the mutex is aquired. Then, the whole descriptor is freed... I have a problem with this design: what happens if another process who has access to the file descriptor does a read() or something similar? The process will have to wait for release of the mutex, which will never happens. I have seen this sort of design in usb_skeleton.c and some other drivers. Is there something in user or kernel space which protects the driver against this race? Is this safe? I have not found an explanation in "Linux device drivers". best regards Wolfgang _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
