[Q] comedi: vmap of the async->prealloc_buf
H Hartley Sweeten
hartleys at visionengravers.com
Thu Dec 20 23:38:38 UTC 2012
On Thursday, December 20, 2012 3:37 PM, Ian Abbott wrote:
> On 20/12/12 17:09, H Hartley Sweeten wrote:
>> In the comedi core, the asynchronous 'prealloc_buf' is vmap'ed after
>> the page list has been allocated. The code in question looks like this:
>> async->prealloc_buf =
>> #ifdef PAGE_KERNEL_NOCACHE
>> vmap(pages, n_pages, VM_MAP, PAGE_KERNEL_NOCACHE);
>> vmap(pages, n_pages, VM_MAP, PAGE_KERNEL);
>> Is the #ifdef something left over from an older kernel?
>> Isn't PAGE_KERNEL_NOCACHE always defined?
> Unfortunately not; it's arch dependent. Neither ARM nor PowerPC define
> it, for example.
Well that's annoying...
More information about the devel