[PATCH 2/2] block: change blk_mq_add_to_batch() third argument type to blk_status_t

[Stefan Hajnoczi]

On Tue, Mar 11, 2025 at 10:42 AM Shin'ichiro Kawasaki
<shinichiro.kawasaki at wdc.com> wrote:
>
> Commit 1f47ed294a2b ("block: cleanup and fix batch completion adding
> conditions") modified the evaluation criteria for the third argument,
> 'ioerror', in the blk_mq_add_to_batch() function. Initially, the
> function had checked if 'ioerror' equals zero. Following the commit, it
> started checking for negative error values, with the presumption that
> such values, for instance -EIO, would be passed in.
>
> However, blk_mq_add_to_batch() callers do not pass negative error
> values. Instead, they pass status codes defined in various ways:
>
> - NVMe PCI and Apple drivers pass NVMe status code
> - virtio_blk driver passes the virtblk request header status byte
> - null_blk driver passes blk_status_t
>
> These codes are either zero or positive, therefore the revised check
> fails to function as intended. Specifically, with the NVMe PCI driver,
> this modification led to the failure of the blktests test case nvme/039.
> In this test scenario, errors are artificially injected to the NVMe
> driver, resulting in positive NVMe status codes passed to
> blk_mq_add_to_batch(), which unexpectedly processes the failed I/O in a
> batch. Hence the failure.
>
> To correct the ioerror check within blk_mq_add_to_batch(), make all
> callers to uniformly pass the argument as blk_status_t. Modify the
> callers to translate their specific status codes into blk_status_t. For
> this translation, export the helper function nvme_error_status(). Adjust
> blk_mq_add_to_batch() to translate blk_status_t back into the error
> number for the appropriate check.
>
> Fixes: 1f47ed294a2b ("block: cleanup and fix batch completion adding conditions")
> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki at wdc.com>
> ---
>  drivers/block/null_blk/main.c | 2 +-
>  drivers/block/virtio_blk.c    | 5 +++--

For virtio_blk:
Reviewed-by: Stefan Hajnoczi <stefanha at redhat.com>