Re: [PATCH 16/19] ataflop: use a separate gendisk for each media format

From: Hannes Reinecke
Date: Fri Sep 04 2020 - 06:29:28 EST


On 9/3/20 10:01 AM, Christoph Hellwig wrote:
The Atari floppy driver usually autodetects the media when used with the
ormal /dev/fd? devices, which also are the only nodes created by udev.
But it also supports various aliases that force a given media format.
That is currently supported using the blk_register_region framework
which finds the floppy gendisk even for a 'mismatched' dev_t. The
problem with this (besides the code complexity) is that it creates
multiple struct block_device instances for the whole device of a
single gendisk, which can lead to interesting issues in code not
aware of that fact.

To fix this just create a separate gendisk for each of the aliases
if they are accessed.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/block/ataflop.c | 135 +++++++++++++++++++++++++---------------
1 file changed, 86 insertions(+), 49 deletions(-)

Reviewed-by: Hannes Reinecke <hare@xxxxxxx>

Cheers,

Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
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