Re: [PATCH] block: fix bogus EFAULT error from SG_IO ioctl

[Jeff Moyer <jmoyer@redhat.com>]

Paolo Bonzini <pbonzini@redhat.com> writes:

> Whenever blk_fill_sghdr_rq fails, its errno code is ignored and changed to
> EFAULT.  This can cause very confusing errors:
>
>   $ sg_persist -k /dev/sda
>   persistent reservation in: pass through os error: Bad address
>
> The fix is trivial, just propagate the return value from
> blk_fill_sghdr_rq.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Acked-by: Jeff Moyer <jmoyer@redhat.com>

> ---
>  block/scsi_ioctl.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
> index 55b6f15dac90..dda653ce7b24 100644
> --- a/block/scsi_ioctl.c
> +++ b/block/scsi_ioctl.c
> @@ -326,8 +326,8 @@ static int sg_io(struct request_queue *q, struct gendisk *bd_disk,
>  			goto out_put_request;
>  	}
>  
> -	ret = -EFAULT;
> -	if (blk_fill_sghdr_rq(q, rq, hdr, mode))
> +	ret = blk_fill_sghdr_rq(q, rq, hdr, mode);
> +	if (ret < 0)
>  		goto out_free_cdb;
>  
>  	ret = 0;