Re: [PATCH v2 1/2] powerpc/nvdimm: Use HCALL error as the return value

[Vaibhav Jain <vaibhav@linux.ibm.com>]

Hi Aneesh,

Thanks for the patch. Minor review comments below:

"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:

> This simplifies the error handling and also enable us to switch to
> H_SCM_QUERY hcall in a later patch on H_OVERLAP error.
>
> We also do some kernel print formatting fixup in this patch.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> ---
>  arch/powerpc/platforms/pseries/papr_scm.c | 26 ++++++++++-------------
>  1 file changed, 11 insertions(+), 15 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
> index a5ac371a3f06..3bef4d298ac6 100644
> --- a/arch/powerpc/platforms/pseries/papr_scm.c
> +++ b/arch/powerpc/platforms/pseries/papr_scm.c
> @@ -66,28 +66,22 @@ static int drc_pmem_bind(struct papr_scm_priv *p)
>  	} while (rc == H_BUSY);
>  
>  	if (rc) {
> -		/* H_OVERLAP needs a separate error path */
> -		if (rc == H_OVERLAP)
> -			return -EBUSY;
> -
>  		dev_err(&p->pdev->dev, "bind err: %lld\n", rc);
> -		return -ENXIO;
> +		return rc;
>  	}
>  
>  	p->bound_addr = saved;
> -
> -	dev_dbg(&p->pdev->dev, "bound drc %x to %pR\n", p->drc_index, &p->res);
> -
> -	return 0;

> +	dev_dbg(&p->pdev->dev, "bound drc 0x%x to %pR\n", p->drc_index, &p->res);
s/0x%x/%#x/
> +	return rc;
rc == 0 always at this point hence 'return 0' should still work.

>  }
>  
> -static int drc_pmem_unbind(struct papr_scm_priv *p)
> +static void drc_pmem_unbind(struct papr_scm_priv *p)
>  {
>  	unsigned long ret[PLPAR_HCALL_BUFSIZE];
>  	uint64_t token = 0;
>  	int64_t rc;
>  
> -	dev_dbg(&p->pdev->dev, "unbind drc %x\n", p->drc_index);
> +	dev_dbg(&p->pdev->dev, "unbind drc 0x%x\n", p->drc_index);
>  
>  	/* NB: unbind has the same retry requirements as drc_pmem_bind() */
>  	do {
> @@ -110,10 +104,10 @@ static int drc_pmem_unbind(struct papr_scm_priv *p)
>  	if (rc)
>  		dev_err(&p->pdev->dev, "unbind error: %lld\n", rc);
>  	else
> -		dev_dbg(&p->pdev->dev, "unbind drc %x complete\n",
> +		dev_dbg(&p->pdev->dev, "unbind drc 0x%x complete\n",
>  			p->drc_index);
>  
> -	return rc == H_SUCCESS ? 0 : -ENXIO;
> +	return;
I would prefer drc_pmem_unbind() to still return error from the
HCALL. The caller can descide if it wants to ignore the error or not.

>  }
>  
>  static int papr_scm_meta_get(struct papr_scm_priv *p,
> @@ -436,14 +430,16 @@ static int papr_scm_probe(struct platform_device *pdev)
>  	rc = drc_pmem_bind(p);
>  
>  	/* If phyp says drc memory still bound then force unbound and retry */
> -	if (rc == -EBUSY) {
> +	if (rc == H_OVERLAP) {
>  		dev_warn(&pdev->dev, "Retrying bind after unbinding\n");
>  		drc_pmem_unbind(p);
>  		rc = drc_pmem_bind(p);
>  	}
>  
> -	if (rc)
> +	if (rc != H_SUCCESS) {
> +		rc = -ENXIO;
>  		goto err;
> +	}
>  
>  	/* setup the resource for the newly bound range */
>  	p->res.start = p->bound_addr;
> -- 
> 2.21.0
>

-- 
Vaibhav Jain <vaibhav@linux.ibm.com>
Linux Technology Center, IBM India Pvt. Ltd.