DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4D0DB2075B
Message-ID: <1542660730.185366.62.camel@acm.org>
Subject: Re: [PATCH v1 1/4] xprtrdma: Remove support for FMR memory
 registration
From:   Bart Van Assche <bvanassche@acm.org>
To:     Leon Romanovsky <leon@kernel.org>
Cc:     Chuck Lever <chuck.lever@oracle.com>, linux-rdma@vger.kernel.org,
        linux-nfs@vger.kernel.org, oulijun@huawei.com,
        zhongjiang@huawei.com, venkata.s.dhanalakota@intel.com
Date:   Mon, 19 Nov 2018 12:52:10 -0800
In-Reply-To: <20181119190913.GC21715@mtr-leonro.mtl.com>
References: <20181119153707.10832.42881.stgit@manet.1015granger.net>
         <20181119154551.10832.5498.stgit@manet.1015granger.net>
         <1542644197.185366.50.camel@acm.org>
         <20181119190913.GC21715@mtr-leonro.mtl.com>
Content-Type: text/plain; charset="UTF-7"
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-nfs-owner@vger.kernel.org
Precedence: bulk

On Mon, 2018-11-19 at 21:09 +-0200, Leon Romanovsky wrote:
+AD4 The more accurate question is +ACI-how many customers ... use latest,
+AD4 upstream kernel?+ACI

Hi Leon,

If this would not be clear: I am in favor of removing kernel drivers that
are no longer in use. Recently I supported a proposal to remove the SCSI
OSD driver from the kernel tree because that driver
probably has not been
used by anyone in the past five years.

But I think that kernel drivers that are still in use should stay in the
kernel tree, no matter which version is in use. Since the Linux kernel ABI
is backwards compatible, with every Linux distro it is possible to replace
the Linux kernel that was provided by the Linux distributor with a more
recent upstream kernel. I think it would be a very unpleasant surprise for
people who use one of the RDMA adapters that only support FMR if they would
test a more recent kernel and if they would notice that its driver has been
removed.

Bart.