Re: [PATCH 1/5] null_blk: remove the bio based I/O path

[Hannes Reinecke <hare@suse.de>]

On 2/20/24 06:32, Christoph Hellwig wrote:
> The bio based I/O path complicates null_blk and also make various
> data structures, including the per-command one way bigger than
> required for the main request based interface.   As the bio-based
> path is mostly used by stacking drivers and simple memory based
> drivers, and brd is a good example driver for the latter there is
> no need to have a bio based path in null_blk.  Remove the path
> to simplify the driver and make future block layer API changes
> simpler by not having to deal with the complex two API setup in
> null_blk.
> 
> Note that the queue_mode field in struct nullb_device is kept as
> that is simpler than having two different places to check the
> value and fully open coding the debugfs helpers as the existing
> ones won't work without a named struct member.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> Tested-by: Damien Le Moal <dlemoal@kernel.org>
> ---
>   drivers/block/null_blk/main.c     | 365 ++++++------------------------
>   drivers/block/null_blk/null_blk.h |  17 --
>   drivers/block/null_blk/trace.h    |   5 +-
>   drivers/block/null_blk/zoned.c    |  10 +-
>   4 files changed, 69 insertions(+), 328 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
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