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Date:   Thu, 9 Sep 2021 06:48:00 +0100
From:   Christoph Hellwig <hch@infradead.org>
To:     Praveen Kumar <kumarpraveen@linux.microsoft.com>
Cc:     linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        axboe@kernel.dk
Subject: Re: [PATCH] blk-mq: export blk_mq_submit_bio symbol
Message-ID: <YTmgEAEx69PR/RMy@infradead.org>
References: <20210909053653.144360-1-kumarpraveen@linux.microsoft.com>
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On Thu, Sep 09, 2021 at 11:06:53AM +0530, Praveen Kumar wrote:
> There are use-cases like replication where need to hook the blk I/O
> operations for devices and perform specific operation and fallback to
> its original I/O operations.
> Prior to v5.9 there was make_request_fn and then blk_mq_submit_bio
> exported apis, which provided infrastructure to drivers to develop these
> features. However in v5.10-rc1 with below commit the API was removed
> from the export list.
> 
> Previous commit: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.10-rc1&id=681cc5e8667e8579a2da8fa4090c48a2d73fc3bb
> 
> This patch exports the blk_mq_submit_bio symbol to provide flexibility
> to the drivers.

Please send your users of this "feature" to this list for inclusion
and we'll help you to massage them into a non-broken version.

And yes, you should have gotten the memo by now that we don't export
anything for out of tree modules.