User mode and kernel mode communication, ioctrl and copy_ from_ User, what scenarios are used

CSDN Q & A 2022-02-13 08:13:34 阅读数:930

user mode kernel mode communication

I think when the user mode is called to the kernel mode , sometimes , stay ioctrl After the function is called to the kernel , Will use copy_from_user Used to copy parameters . sometimes , Not applicable copy_from_user, Just put the parameters in ioctrl The last pointer passes . That's why , I was wrong ? If you're right , What scenarios to use copy_from_user, When not to use it ?

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