Messages in this thread | | | Date | Wed, 10 Nov 1999 12:05:13 +0100 | From | Marcel Lanz <> | Subject | Re: [question/comment/help] pseudo function-call from kernel to a user-process |
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"Richard B. Johnson" wrote: snip snap > Instead, if you are copying something that can change, so you need a > spin-lock, do: > > spin_lock_irqsave(&lock_flag, flags); > memcpy(tmp_buf, volatile_buf, len); > spin_unlock(&lock_flag, flags); > > copy_to_user(user_buf, tmp_buf, len); > > Stuff that can't possibly change during the operation, requires no > spin-locks at all. In your code snippet retained above, everything is > a constant. It needs no lock. > > Cheers, thank you very much. I didn't saw that. I am new on kernel-programming. Now I see that it is all task-local, so I haven't to protect anything.
greetings marcel -- Marcel Lanz <marcel.lanz@ds9.ch>
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