get_user_pages fails for contiguous memory?

From: Hiremath, Vaibhav
Date: Tue Sep 23 2008 - 11:50:14 EST


Hi,

For some reason (unknown to me) the VM_IO and VM_PFNMAP vm_flags are set when I use get_user_pages function, causing it to fail for me. I'm currently using 2.6.22 on an ARM platform.

My Actual test case is something -

I trying run/test a simple use case where, I am allocating buffers in one driver using get_free_pages, map them to user application and pass it to another driver for processing.

I am allocating huge memory in frame buffer driver using get_free_pages at the init time. I would like to use this buffer in resizer driver (scatter gather DMA), which resizes the image depending on user configuration.

If I allocate a memory using malloc or memalign from in user space and pass it to resizer driver it works fine.

Any suggestions/solution how to achieve this would really helpful to me.

Thanks,
Vaibhav Hiremath
Senior Software Engg.
Platform Support Products
Texas Instruments Inc
Ph: +91-80-25099927

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