[PATCH 04/12] mm: alloc_contig_freed_pages() added

On Thu, 31 Mar 2011 17:58:03 +0200, Dave Hansen [off-list ref]  
wrote:

On Thu, 2011-03-31 at 15:16 +0200, Marek Szyprowski wrote:

quoted

+unsigned long alloc_contig_freed_pages(unsigned long start, unsigned  
long end,
+                                      gfp_t flag)
+{
+       unsigned long pfn = start, count;
+       struct page *page;
+       struct zone *zone;
+       int order;
+
+       VM_BUG_ON(!pfn_valid(start));

This seems kinda mean.  Could we return an error?  I understand that
this is largely going to be an early-boot thing, but surely trying to
punt on crappy input beats a full-on BUG().

Actually, I would have to check but I think that the usage of this function
(in this patchset) is that the caller expects the function to succeed.  It  
is
quite a low-level function so before running it a lot of preparation is  
needed
and the caller must make sure that several conditions are met.  I don't  
really
see advantage of returning a value rather then BUG()ing.

Also, CMA does not call this function at boot time.

-- 
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.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michal "mina86" Nazarewicz    (o o)
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