Re: [PATCH v2 14/14] powerpc/pseries/iommu: Rename "direct window" to "dma window"

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 12/09/2020 03:07, Leonardo Bras wrote:
> Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
> 
> A previous change introduced the usage of DDW as a bigger indirect DMA
> mapping when the DDW available size does not map the whole partition.
> 
> As most of the code that manipulates direct mappings was reused for
> indirect mappings, it's necessary to rename all names and debug/info
> messages to reflect that it can be used for both kinds of mapping.
> 
> Also, defines DEFAULT_DMA_WIN as "ibm,dma-window" to document that
> it's the name of the default DMA window.

"ibm,dma-window" is so old so it does not need a macro (which btw would 
be DMA_WIN_PROPNAME to match the other names) :)


> Those changes are not supposed to change how the code works in any
> way, just adjust naming.

I simply have this in my .vimrc for the cases like this one:

===
This should cause no behavioural change.
===


> 
> Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
> ---
>   arch/powerpc/platforms/pseries/iommu.c | 102 +++++++++++++------------
>   1 file changed, 53 insertions(+), 49 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> index c4de23080d1b..56638b7f07fc 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -349,7 +349,7 @@ struct dynamic_dma_window_prop {
>   	__be32	window_shift;	/* ilog2(tce_window_size) */
>   };
>   
> -struct direct_window {
> +struct dma_win {
>   	struct device_node *device;
>   	const struct dynamic_dma_window_prop *prop;
>   	struct list_head list;
> @@ -369,13 +369,14 @@ struct ddw_create_response {
>   	u32 addr_lo;
>   };
>   
> -static LIST_HEAD(direct_window_list);
> +static LIST_HEAD(dma_win_list);
>   /* prevents races between memory on/offline and window creation */
> -static DEFINE_SPINLOCK(direct_window_list_lock);
> +static DEFINE_SPINLOCK(dma_win_list_lock);
>   /* protects initializing window twice for same device */
> -static DEFINE_MUTEX(direct_window_init_mutex);
> +static DEFINE_MUTEX(dma_win_init_mutex);
>   #define DIRECT64_PROPNAME "linux,direct64-ddr-window-info"
>   #define DMA64_PROPNAME "linux,dma64-ddr-window-info"
> +#define DEFAULT_DMA_WIN "ibm,dma-window"
>   
>   static int tce_clearrange_multi_pSeriesLP(unsigned long start_pfn,
>   					unsigned long num_pfn, const void *arg)
> @@ -706,15 +707,18 @@ static void pci_dma_bus_setup_pSeriesLP(struct pci_bus *bus)
>   	pr_debug("pci_dma_bus_setup_pSeriesLP: setting up bus %pOF\n",
>   		 dn);
>   
> -	/* Find nearest ibm,dma-window, walking up the device tree */
> +	/*
> +	 * Find nearest ibm,dma-window (default DMA window), walking up the
> +	 * device tree
> +	 */
>   	for (pdn = dn; pdn != NULL; pdn = pdn->parent) {
> -		dma_window = of_get_property(pdn, "ibm,dma-window", NULL);
> +		dma_window = of_get_property(pdn, DEFAULT_DMA_WIN, NULL);
>   		if (dma_window != NULL)
>   			break;
>   	}
>   
>   	if (dma_window == NULL) {
> -		pr_debug("  no ibm,dma-window property !\n");
> +		pr_debug("  no %s property !\n", DEFAULT_DMA_WIN);
>   		return;
>   	}
>   
> @@ -810,11 +814,11 @@ static void remove_dma_window(struct device_node *np, u32 *ddw_avail,
>   
>   	ret = rtas_call(ddw_avail[DDW_REMOVE_PE_DMA_WIN], 1, 1, NULL, liobn);
>   	if (ret)
> -		pr_warn("%pOF: failed to remove direct window: rtas returned "
> +		pr_warn("%pOF: failed to remove dma window: rtas returned "
>   			"%d to ibm,remove-pe-dma-window(%x) %llx\n",
>   			np, ret, ddw_avail[DDW_REMOVE_PE_DMA_WIN], liobn);
>   	else
> -		pr_debug("%pOF: successfully removed direct window: rtas returned "
> +		pr_debug("%pOF: successfully removed dma window: rtas returned "


s/dma/DMA/ in all user visible strings.



>   			"%d to ibm,remove-pe-dma-window(%x) %llx\n",
>   			np, ret, ddw_avail[DDW_REMOVE_PE_DMA_WIN], liobn);
>   }
> @@ -842,7 +846,7 @@ static int remove_ddw(struct device_node *np, bool remove_prop, const char *win_
>   
>   	ret = of_remove_property(np, win);
>   	if (ret)
> -		pr_warn("%pOF: failed to remove direct window property: %d\n",
> +		pr_warn("%pOF: failed to remove dma window property: %d\n",
>   			np, ret);
>   	return 0;
>   }
> @@ -886,34 +890,34 @@ static phys_addr_t ddw_memory_hotplug_max(void)
>   
>   static bool find_existing_ddw(struct device_node *pdn, u64 *dma_addr, bool *direct_mapping)
>   {
> -	struct direct_window *window;
> -	const struct dynamic_dma_window_prop *direct64;
> +	struct dma_win *window;
> +	const struct dynamic_dma_window_prop *dma64;
>   	unsigned long window_size;
>   	bool found = false;
>   
> -	spin_lock(&direct_window_list_lock);
> +	spin_lock(&dma_win_list_lock);
>   	/* check if we already created a window and dupe that config if so */
> -	list_for_each_entry(window, &direct_window_list, list) {
> +	list_for_each_entry(window, &dma_win_list, list) {
>   		if (window->device == pdn) {
> -			direct64 = window->prop;
> -			*dma_addr = be64_to_cpu(direct64->dma_base);
> +			dma64 = window->prop;
> +			*dma_addr = be64_to_cpu(dma64->dma_base);
>   
> -			window_size = (1UL << be32_to_cpu(direct64->window_shift));
> +			window_size = (1UL << be32_to_cpu(dma64->window_shift));
>   			*direct_mapping = (window_size >= ddw_memory_hotplug_max());
>   
>   			found = true;
>   			break;
>   		}
>   	}
> -	spin_unlock(&direct_window_list_lock);
> +	spin_unlock(&dma_win_list_lock);
>   
>   	return found;
>   }
>   
> -static struct direct_window *ddw_list_new_entry(struct device_node *pdn,
> -						const struct dynamic_dma_window_prop *dma64)
> +static struct dma_win *ddw_list_new_entry(struct device_node *pdn,
> +					  const struct dynamic_dma_window_prop *dma64)
>   {
> -	struct direct_window *window;
> +	struct dma_win *window;
>   
>   	window = kzalloc(sizeof(*window), GFP_KERNEL);
>   	if (!window)
> @@ -929,7 +933,7 @@ static void find_existing_ddw_windows_named(const char *name)
>   {
>   	int len;
>   	struct device_node *pdn;
> -	struct direct_window *window;
> +	struct dma_win *window;
>   	const struct dynamic_dma_window_prop *dma64;
>   
>   	for_each_node_with_property(pdn, name) {
> @@ -943,9 +947,9 @@ static void find_existing_ddw_windows_named(const char *name)
>   		if (!window)
>   			break;
>   
> -		spin_lock(&direct_window_list_lock);
> -		list_add(&window->list, &direct_window_list);
> -		spin_unlock(&direct_window_list_lock);
> +		spin_lock(&dma_win_list_lock);
> +		list_add(&window->list, &dma_win_list);
> +		spin_unlock(&dma_win_list_lock);
>   	}
>   }
>   
> @@ -1179,7 +1183,7 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   	u64 max_addr, win_addr;
>   	struct device_node *dn;
>   	u32 ddw_avail[DDW_APPLICABLE_SIZE];
> -	struct direct_window *window;
> +	struct dma_win *window;
>   	const char *win_name;
>   	struct property *win64 = NULL;
>   	struct failed_ddw_pdn *fpdn;
> @@ -1187,10 +1191,10 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   	struct pci_dn *pci = PCI_DN(pdn);
>   	struct iommu_table *tbl = pci->table_group->tables[0];
>   
> -	mutex_lock(&direct_window_init_mutex);
> +	mutex_lock(&dma_win_init_mutex);
>   
>   	if (find_existing_ddw(pdn, &dev->dev.archdata.dma_offset, &direct_mapping)) {
> -		mutex_unlock(&direct_window_init_mutex);
> +		mutex_unlock(&dma_win_init_mutex);
>   		return direct_mapping;
>   	}
>   
> @@ -1241,7 +1245,7 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   		struct property *default_win;
>   		int reset_win_ext;
>   
> -		default_win = of_find_property(pdn, "ibm,dma-window", NULL);
> +		default_win = of_find_property(pdn, DEFAULT_DMA_WIN, NULL);
>   		if (!default_win)
>   			goto out_failed;
>   
> @@ -1272,8 +1276,8 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   	} else if ((query.page_size & 1) && PAGE_SHIFT >= 12) {
>   		page_shift = 12; /* 4kB */
>   	} else {
> -		dev_dbg(&dev->dev, "no supported direct page size in mask %x",
> -			  query.page_size);
> +		dev_dbg(&dev->dev, "no supported page size in mask %x",
> +			query.page_size);
>   		goto out_failed;
>   	}
>   
> @@ -1331,7 +1335,7 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   		ret = walk_system_ram_range(0, memblock_end_of_DRAM() >> PAGE_SHIFT,
>   					    win64->value, tce_setrange_multi_pSeriesLP_walk);
>   		if (ret) {
> -			dev_info(&dev->dev, "failed to map direct window for %pOF: %d\n",
> +			dev_info(&dev->dev, "failed to map DMA window for %pOF: %d\n",
>   				 dn, ret);
>   			goto out_list_del;
>   		}
> @@ -1354,9 +1358,9 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   		set_iommu_table_base(&dev->dev, tbl);
>   	}
>   
> -	spin_lock(&direct_window_list_lock);
> -	list_add(&window->list, &direct_window_list);
> -	spin_unlock(&direct_window_list_lock);
> +	spin_lock(&dma_win_list_lock);
> +	list_add(&window->list, &dma_win_list);
> +	spin_unlock(&dma_win_list_lock);
>   
>   	dev->dev.archdata.dma_offset = win_addr;
>   	goto out_unlock;
> @@ -1387,7 +1391,7 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   	list_add(&fpdn->list, &failed_ddw_pdn_list);
>   
>   out_unlock:
> -	mutex_unlock(&direct_window_init_mutex);
> +	mutex_unlock(&dma_win_init_mutex);
>   	return win64 && direct_mapping;
>   }
>   
> @@ -1411,7 +1415,7 @@ static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
>   
>   	for (pdn = dn; pdn && PCI_DN(pdn) && !PCI_DN(pdn)->table_group;
>   	     pdn = pdn->parent) {
> -		dma_window = of_get_property(pdn, "ibm,dma-window", NULL);
> +		dma_window = of_get_property(pdn, DEFAULT_DMA_WIN, NULL);
>   		if (dma_window)
>   			break;
>   	}
> @@ -1461,7 +1465,7 @@ static bool iommu_bypass_supported_pSeriesLP(struct pci_dev *pdev, u64 dma_mask)
>   	 */
>   	for (pdn = dn; pdn && PCI_DN(pdn) && !PCI_DN(pdn)->table_group;
>   			pdn = pdn->parent) {
> -		dma_window = of_get_property(pdn, "ibm,dma-window", NULL);
> +		dma_window = of_get_property(pdn, DEFAULT_DMA_WIN, NULL);
>   		if (dma_window)
>   			break;
>   	}
> @@ -1475,29 +1479,29 @@ static bool iommu_bypass_supported_pSeriesLP(struct pci_dev *pdev, u64 dma_mask)
>   static int iommu_mem_notifier(struct notifier_block *nb, unsigned long action,
>   		void *data)
>   {
> -	struct direct_window *window;
> +	struct dma_win *window;
>   	struct memory_notify *arg = data;
>   	int ret = 0;
>   
>   	switch (action) {
>   	case MEM_GOING_ONLINE:
> -		spin_lock(&direct_window_list_lock);
> -		list_for_each_entry(window, &direct_window_list, list) {
> +		spin_lock(&dma_win_list_lock);
> +		list_for_each_entry(window, &dma_win_list, list) {
>   			ret |= tce_setrange_multi_pSeriesLP(arg->start_pfn,
>   					arg->nr_pages, window->prop);
>   			/* XXX log error */
>   		}
> -		spin_unlock(&direct_window_list_lock);
> +		spin_unlock(&dma_win_list_lock);
>   		break;
>   	case MEM_CANCEL_ONLINE:
>   	case MEM_OFFLINE:
> -		spin_lock(&direct_window_list_lock);
> -		list_for_each_entry(window, &direct_window_list, list) {
> +		spin_lock(&dma_win_list_lock);
> +		list_for_each_entry(window, &dma_win_list, list) {
>   			ret |= tce_clearrange_multi_pSeriesLP(arg->start_pfn,
>   					arg->nr_pages, window->prop);
>   			/* XXX log error */
>   		}
> -		spin_unlock(&direct_window_list_lock);
> +		spin_unlock(&dma_win_list_lock);
>   		break;
>   	default:
>   		break;
> @@ -1518,7 +1522,7 @@ static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long acti
>   	struct of_reconfig_data *rd = data;
>   	struct device_node *np = rd->dn;
>   	struct pci_dn *pci = PCI_DN(np);
> -	struct direct_window *window;
> +	struct dma_win *window;
>   
>   	switch (action) {
>   	case OF_RECONFIG_DETACH_NODE:
> @@ -1537,15 +1541,15 @@ static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long acti
>   			iommu_pseries_free_group(pci->table_group,
>   					np->full_name);
>   
> -		spin_lock(&direct_window_list_lock);
> -		list_for_each_entry(window, &direct_window_list, list) {
> +		spin_lock(&dma_win_list_lock);
> +		list_for_each_entry(window, &dma_win_list, list) {
>   			if (window->device == np) {
>   				list_del(&window->list);
>   				kfree(window);
>   				break;
>   			}
>   		}
> -		spin_unlock(&direct_window_list_lock);
> +		spin_unlock(&dma_win_list_lock);
>   		break;
>   	default:
>   		err = NOTIFY_DONE;
> 

-- 
Alexey