Messages in this thread | | | Subject | Re: [PATCH 04/12] mm: alloc_contig_freed_pages() added | Date | Thu, 31 Mar 2011 23:09:42 +0200 | From | "Michal Nazarewicz" <> |
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On Thu, 31 Mar 2011 17:58:03 +0200, Dave Hansen <dave@linux.vnet.ibm.com> wrote:
> On Thu, 2011-03-31 at 15:16 +0200, Marek Szyprowski wrote: >> >> +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.
-- Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o ..o | Computer Science, Michal "mina86" Nazarewicz (o o) ooo +-----<email/xmpp: mnazarewicz@google.com>-----ooO--(_)--Ooo--
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