Re: [PATCH v5 08/11] powerpc/pseries/iommu: Update remove_dma_window() to accept property name

From: Frederic Barrat <fbarrat@linux.ibm.com>
To: Leonardo Bras <leobras.c@gmail.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Alexey Kardashevskiy <aik@ozlabs.ru>,
	David Gibson <david@gibson.dropbear.id.au>,
	kernel test robot <lkp@intel.com>,
	Nicolin Chen <nicoleotsuka@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 08/11] powerpc/pseries/iommu: Update remove_dma_window() to accept property name
Date: Tue, 20 Jul 2021 19:51:23 +0200	[thread overview]
Message-ID: <8dbd08fb-375c-9f21-f8ab-bec163b157bf@linux.ibm.com> (raw)
In-Reply-To: <20210716082755.428187-9-leobras.c@gmail.com>

On 16/07/2021 10:27, 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.
> 
> Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
>   arch/powerpc/platforms/pseries/iommu.c | 21 +++++++++++----------
>   1 file changed, 11 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> index 108c3dcca686..17c6f4706e76 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -830,31 +830,32 @@ static void remove_dma_window(struct device_node *np, u32 *ddw_avail,
>   			np, ret, ddw_avail[DDW_REMOVE_PE_DMA_WIN], 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)
>   {

Why switch to returning an int? None of the callers check it.

   Fred

>   	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;
> -
> -	win = of_find_property(np, DIRECT64_PROPNAME, NULL);
> -	if (!win)
> -		return;
> +		return 0;
>   
>   	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)
> @@ -907,7 +908,7 @@ 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;
>   		}
>   
> @@ -1382,7 +1383,7 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   	kfree(win64);
>   
>   out_remove_win:
> -	remove_ddw(pdn, true);
> +	remove_ddw(pdn, true, DIRECT64_PROPNAME);
>   
>   out_failed:
>   	if (default_win_removed)
> @@ -1547,7 +1548,7 @@ 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);
> 