Messages in this thread | | | From | "Ramesh Sudini" <> | Subject | Re: Copy_to_user and copy_from_user | Date | Mon, 09 Aug 2004 13:26:45 +0000 |
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Then, how do I make sure that all the data I wanted to be copied is infact copied?? What are the scenarios where copy_to/from_user could fail and how can I avoid it.
Thanks -Ramesh
> >No you cannot call it until all data has been copied. copy_{to,from}_user >fails when a fault happens during the copy process. So you simply cannot >try again... It will fault again. >Well, not 100% true. An other running thread (same mm with the process >which copies data) can "fix" the faulty adress space. Bad thread.... > >Ramesh Sudini wrote: >>Hi, >> >>If copy_from_user returns non zero value, then I do not see any driver(for >>example PPP) try to copy the remaining data. It treats it as an error >>scenario. >> >>Why is this? Shouldnt it have a while loop and attempt to copy_from_user >>till all the data is copied?? >> >>I am writing a driver and trying to understand what needs to be done in >>case it returns a non-zero value? I have huge amount of data to be copied >>from user space Ex: 3000byte messages. >> >>Can somebody suggest me what is the best I could do...(Please cc me >>personally with your response) >> >>Thanks >>Ramesh >>
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