Re: [BUG 5.14] arm64/mm: dma memory mapping fails (in some cases)
From: Mike Rapoport <rppt@kernel.org>
Date: 2021-09-18 08:37:26
Also in:
linux-mm, lkml
On Sat, Sep 18, 2021 at 07:18:43AM +0200, Christoph Hellwig wrote:
On Sat, Sep 18, 2021 at 12:22:47AM +0300, Mike Rapoport wrote:quoted
I did some digging and it seems that the most "generic" way to check if a page is in RAM is page_is_ram(). It's not 100% bullet proof as it'll give false negatives for architectures that do not register "System RAM", but those are not using dma_map_resource() anyway and, apparently, never would.The downside of page_is_ram is that it looks really expensiv for something done at dma mapping time.
Indeed :( But pfn_valid is plain wrong... I'll keep digging. -- Sincerely yours, Mike. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel