Messages in this thread | | | Date | Thu, 15 May 2008 09:59:01 -0400 | Subject | Re: How to avoid data copies in a driver ? | From | (Lennart Sorensen) |
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On Thu, May 15, 2008 at 09:44:37AM +0200, Francis Moreau wrote: > So I would need to map this pointer into the kernel space, then fill it, take > care of cache coherency, unmap the kernel pointer. > > Do you have any example of that in the kernel tree ?
I was asking if that would work. Does the to_user and from_user work on a pointer from user space if that pointer points at a memory mapped file?
> BTW, data are received in interrupt context. Is it safe to put them in mapped > memory (can I have page fault ?) in this context ?
Oh I thought you just wanted user space to be able to ask for a chunk of data. I wouldn't want to write to a file in an interrupt handler. Compared to the disk I/O a memory copy sounds rather insignificant to the overall process.
-- Len Sorensen
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