linux-kernel - Re: [PATCH 1/2] mm/cma: remove unsupported gfp_mask parameter from cma

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20180712071536.GA15506@lst.de>
Date:   Thu, 12 Jul 2018 09:15:36 +0200
From:   Christoph Hellwig <hch@....de>
To:     Joonsoo Kim <js1304@...il.com>
Cc:     Michal Hocko <mhocko@...nel.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Linux Memory Management List <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-arm-kernel@...ts.infradead.org,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        iommu@...ts.linux-foundation.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michal Nazarewicz <mina86@...a86.com>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Christoph Hellwig <hch@....de>,
        Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Paul Mackerras <paulus@...abs.org>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Chris Zankel <chris@...kel.net>,
        Martin Schwidefsky <schwidefsky@...ibm.com>,
        Joerg Roedel <joro@...tes.org>,
        Sumit Semwal <sumit.semwal@...aro.org>,
        Robin Murphy <robin.murphy@....com>,
        Laura Abbott <labbott@...hat.com>,
        linaro-mm-sig@...ts.linaro.org
Subject: Re: [PATCH 1/2] mm/cma: remove unsupported gfp_mask parameter from
        cma_alloc()

On Thu, Jul 12, 2018 at 11:48:47AM +0900, Joonsoo Kim wrote:
> One of existing user is general DMA layer and it takes gfp flags that is
> provided by user. I don't check all the DMA allocation sites but how do
> you convince that none of them try to use anything other
> than GFP_KERNEL [|__GFP_NOWARN]?

They use a few others things still like __GFP_COMP, __GPF_DMA or
GFP_HUGEPAGE.  But all these are bogus as we have various implementations
that can't respect them.  I plan to get rid of the gfp_t argument
in the dma_map_ops alloc method in a few merge windows because of that,
but it needs further implementation consolidation first.