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Date: Wed, 2 Mar 2016 17:08:00 -0800
Message-ID: <CA+yUs=xdYodxX8g+uiw+r+V1wSfDukXGP7X7mBUGwDK=c-pP-Q@mail.gmail.com>
Subject: allocate an official device major number for virtio device?
From: Jin Qian <jinqian@android.com>
To: linux-kernel@vger.kernel.org
Cc: jsharkey@google.com, digit@google.com,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>, pprabhu@google.com,
        Yu Ning <yu.ning@intel.com>
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Hi -

Can we allocate an official device major number for virtio devices?
Currently it's using 240-254 (LOCAL/EXPERIMENTAL USE). The reason we
ask for this is because userspace will need to treat virtio block
devices differently and need a way to detect such device. For example,
it checks major number to detect scsi and mmc device.

https://android-review.googlesource.com/#/c/195240

With dynamic major numbers 240-254, we might treat other devices as
virtio block device incorrectly.

Also open for suggestions on what's the correct way to handle this.

Thanks in advance!
jin