Re: [PATCH] nvme-pci: add missing condition check for existence of mapped data

[Keith Busch]

On Wed, Jul 24, 2024 at 01:31:14PM +0300, Leon Romanovsky wrote:
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 102a9fb0c65f..cdc0b25091e9 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -863,7 +863,8 @@ static blk_status_t nvme_prep_rq(struct nvme_dev *dev, struct request *req)
>  	nvme_start_request(req);
>  	return BLK_STS_OK;
>  out_unmap_data:
> -	nvme_unmap_data(dev, req);
> +	if (blk_rq_nr_phys_segments(req))
> +		nvme_unmap_data(dev, req);

This is already applied, but it is kind of strange. We get here only if
metadata mapping fails. Is there actually a command that has metadata
without data?