linux-kernel - Re: [PATCH v2] dma-contiguous: define proper name for global cma region

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Message-ID: <20230731112155.GA3662@lst.de>
Date:   Mon, 31 Jul 2023 13:21:55 +0200
From:   Christoph Hellwig <hch@....de>
To:     Pintu Kumar <quic_pintu@...cinc.com>
Cc:     linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
        linux-mm@...ck.org, hch@....de, m.szyprowski@...sung.com,
        robin.murphy@....com, iommu@...ts.linux.dev, pintu.ping@...il.com,
        Sumit Semwal <sumit.semwal@...aro.org>,
        Benjamin Gaignard <benjamin.gaignard@...labora.com>,
        Liam Mark <lmark@...eaurora.org>,
        Laura Abbott <labbott@...hat.com>,
        Brian Starkey <Brian.Starkey@....com>,
        John Stultz <jstultz@...gle.com>,
        Christian König <christian.koenig@....com>,
        linux-media@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linaro-mm-sig@...ts.linaro.org
Subject: Re: [PATCH v2] dma-contiguous: define proper name for global cma
 region

Hi Pintu,

On Sat, Jul 29, 2023 at 08:05:15AM +0530, Pintu Kumar wrote:
> The current global cma region name defined as "reserved"
> which is misleading, creates confusion and too generic.
> 
> Also, the default cma allocation happens from global cma region,
> so, if one has to figure out all allocations happening from
> global cma region, this seems easier.
> 
> Thus, change the name from "reserved" to "global-cma-region".

I agree that reserved is not a very useful name.  Unfortuately the
name of the region leaks to userspace through cma_heap.

So I think we need prep patches to hardcode "reserved" in
add_default_cma_heap first, and then remove the cma_get_name
first.