Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Thu, 9 Apr 2020 18:50:30 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Minchan Kim <minchan@kernel.org>
Cc:     Christoph Hellwig <hch@lst.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>, x86@kernel.org,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Laura Abbott <labbott@redhat.com>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Nitin Gupta <ngupta@vflare.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Christophe Leroy <christophe.leroy@c-s.fr>,
        linuxppc-dev@lists.ozlabs.org, linux-hyperv@vger.kernel.org,
        dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org,
        linux-arch@vger.kernel.org, linux-mm@kvack.org,
        iommu@lists.linux-foundation.org,
        linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org,
        bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        sergey.senozhatsky@gmail.com
Subject: Re: [PATCH 10/28] mm: only allow page table mappings for built-in
 zsmalloc
Message-ID: <20200409165030.GG20713@hirez.programming.kicks-ass.net>
References: <20200408115926.1467567-1-hch@lst.de>
 <20200408115926.1467567-11-hch@lst.de>
 <20200409160826.GC247701@google.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200409160826.GC247701@google.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, Apr 09, 2020 at 09:08:26AM -0700, Minchan Kim wrote:
> On Wed, Apr 08, 2020 at 01:59:08PM +0200, Christoph Hellwig wrote:
> > This allows to unexport map_vm_area and unmap_kernel_range, which are
> > rather deep internal and should not be available to modules.
> 
> Even though I don't know how many usecase we have using zsmalloc as
> module(I heard only once by dumb reason), it could affect existing
> users. Thus, please include concrete explanation in the patch to
> justify when the complain occurs.

The justification is 'we can unexport functions that have no sane reason
of being exported in the first place'.

The Changelog pretty much says that.