linux-kernel - Re: [PATCH v6 08/11] powerpc/pseries/iommu: Update remove_dma

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Message-ID: <50172860-7ceb-184e-6173-2cd728584d81@linux.ibm.com>
Date:   Fri, 27 Aug 2021 18:58:04 +0200
From:   Frederic Barrat <fbarrat@...ux.ibm.com>
To:     Leonardo Bras <leobras.c@...il.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Alexey Kardashevskiy <aik@...abs.ru>,
        David Gibson <david@...son.dropbear.id.au>,
        Nicolin Chen <nicoleotsuka@...il.com>,
        kernel test robot <lkp@...el.com>
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 08/11] powerpc/pseries/iommu: Update
 remove_dma_window() to accept property name



On 17/08/2021 08:39, Leonardo Bras wrote:
> Update remove_dma_window() so it can be used to remove DDW with a given
> property name.
> 
> This enables the creation of new property names for DDW, so we can
> have different usage for it, like indirect mapping.
> 
> Also, add return values to it so we can check if the property was found
> while removing the active DDW. This allows skipping the remaining property
> names while reducing the impact of multiple property names.
> 
> Signed-off-by: Leonardo Bras <leobras.c@...il.com>
> Reviewed-by: Alexey Kardashevskiy <aik@...abs.ru>
> ---


Reviewed-by: Frederic Barrat <fbarrat@...ux.ibm.com>



>   arch/powerpc/platforms/pseries/iommu.c | 18 ++++++++++--------
>   1 file changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> index a47f59a8f107..901f290999d0 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -844,31 +844,33 @@ static void remove_dma_window(struct device_node *np, u32 *ddw_avail,
>   	__remove_dma_window(np, ddw_avail, liobn);
>   }
>   
> -static void remove_ddw(struct device_node *np, bool remove_prop)
> +static int remove_ddw(struct device_node *np, bool remove_prop, const char *win_name)
>   {
>   	struct property *win;
>   	u32 ddw_avail[DDW_APPLICABLE_SIZE];
>   	int ret = 0;
>   
> +	win = of_find_property(np, win_name, NULL);
> +	if (!win)
> +		return -EINVAL;
> +
>   	ret = of_property_read_u32_array(np, "ibm,ddw-applicable",
>   					 &ddw_avail[0], DDW_APPLICABLE_SIZE);
>   	if (ret)
> -		return;
> +		return 0;
>   
> -	win = of_find_property(np, DIRECT64_PROPNAME, NULL);
> -	if (!win)
> -		return;
>   
>   	if (win->length >= sizeof(struct dynamic_dma_window_prop))
>   		remove_dma_window(np, ddw_avail, win);
>   
>   	if (!remove_prop)
> -		return;
> +		return 0;
>   
>   	ret = of_remove_property(np, win);
>   	if (ret)
>   		pr_warn("%pOF: failed to remove direct window property: %d\n",
>   			np, ret);
> +	return 0;
>   }
>   
>   static bool find_existing_ddw(struct device_node *pdn, u64 *dma_addr, int *window_shift)
> @@ -921,7 +923,7 @@ static int find_existing_ddw_windows(void)
>   	for_each_node_with_property(pdn, DIRECT64_PROPNAME) {
>   		direct64 = of_get_property(pdn, DIRECT64_PROPNAME, &len);
>   		if (!direct64 || len < sizeof(*direct64)) {
> -			remove_ddw(pdn, true);
> +			remove_ddw(pdn, true, DIRECT64_PROPNAME);
>   			continue;
>   		}
>   
> @@ -1565,7 +1567,7 @@ static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long acti
>   		 * we have to remove the property when releasing
>   		 * the device node.
>   		 */
> -		remove_ddw(np, false);
> +		remove_ddw(np, false, DIRECT64_PROPNAME);
>   		if (pci && pci->table_group)
>   			iommu_pseries_free_group(pci->table_group,
>   					np->full_name);
>