From mboxrd@z Thu Jan 1 00:00:00 1970 From: mina86@mina86.com (Michal Nazarewicz) Date: Thu, 31 Mar 2011 23:09:42 +0200 Subject: [PATCH 04/12] mm: alloc_contig_freed_pages() added In-Reply-To: <1301587083.31087.1032.camel@nimitz> References: <1301577368-16095-1-git-send-email-m.szyprowski@samsung.com> <1301577368-16095-5-git-send-email-m.szyprowski@samsung.com> <1301587083.31087.1032.camel@nimitz> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, 31 Mar 2011 17:58:03 +0200, Dave Hansen 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 +----------ooO--(_)--Ooo--