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To:     Bart Van Assche <bvanassche@acm.org>
Cc:     Nick Desaulniers <ndesaulniers@google.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        ooo@electrozaur.com, Nathan Chancellor <natechancellor@gmail.com>,
        "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        linux-scsi@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        hch@infradead.org
Subject: Re: [PATCH] libosd: Remove ignored __weak attribute
From:   "Martin K. Petersen" <martin.petersen@oracle.com>
Organization: Oracle Corporation
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Date:   Sat, 27 Oct 2018 09:28:21 -0400
In-Reply-To: <1540592684.66186.136.camel@acm.org> (Bart Van Assche's message
        of "Fri, 26 Oct 2018 15:24:44 -0700")
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Bart,

> Removing kernel drivers that are not used helps to reduce the workload
> of a maintainer and hence is a rational action. Additionally, if
> anyone would ever complain about removal of a kernel driver, it can be
> brought back by reverting the commit through which it has been
> removed.  Martin, please reply if you see this differently.

We remove crusty old SCSI drivers all the time. The heuristic is based
on lack of user bug reports and absence of commits that are not due to
kernel interface changes or trivial cleanups. So removing stuff is
perfectly normal.

The OSD protocol failed to get traction in the industry, adoption was
very limited. If the code just plugged straight into existing kernel
interfaces it would be easier to justify keeping it around. However, the
OSD support requires bidirectional command support so we carry a bunch
of additional plumbing in both block and SCSI to accommodate it. There
are no other users of these interfaces, so dropping OSD would mean we
could simplify some (hot) code paths. That would be a win in my book.
Consequently, if a patch were to materialize that disentangled and
removed OSD, I'd be inclined to merge it.

But I do think that this is an orthogonal discussion to the innocuous
__weak attribute cleanup.

-- 
Martin K. Petersen	Oracle Linux Engineering