Re: get_user_pages ?

[Mark Hounschell <markh@compro.net>]

Nick Piggin wrote:
> Mark Hounschell wrote:
>> For some reason (unknown to me) the VM_IO and even newer VM_PFNMAP
>> vm_flags are set when I use this call causing it to fail for me. I'm
>> currently using 2.6.16.9 on an x86 platform.
> 
> [...]
> 
>> I'm not the author of any of this code so please gentle with me. Nor do
>> I have much of an understanding of the vm system. Any help in how this
>> task should really be accomplished, taken the stated limitations of the
>> pci card in mind, would be greatly appreciated. And any help as to what
>> would just make it work again would also be greatly appreciated. As I
>> stated above this all worked fine until the VM_PFNMAP bit was added to
>> the vm->flags and subsequently checked for in the get_user_pages call.
> 
> remap_pfn_range isn't the best API for someone who needs get_user_pages.
> remap_pfn_range operates on the pfn level only, so underlying addresses
> may not even have a struct page.
> 
> This area is going through some changes lately. If you want something to
> quickly get things working, removing VM_PFNMAP from your vma flags should
> work.
> 

Yes, that actually does work while the task is running but as soon as I
exit the task the machine freezes.

Mark
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