[PATCH v2 09/14] powerpc/pseries/iommu: Add ddw_property_create() and refactor enable_ddw()

Alexey Kardashevskiy aik at ozlabs.ru
Tue Sep 29 13:56:47 AEST 2020



On 12/09/2020 03:07, Leonardo Bras wrote:
> Cc: linuxppc-dev at lists.ozlabs.org, linux-kernel at vger.kernel.org,
> 
> Code used to create a ddw property that was previously scattered in
> enable_ddw() is now gathered in ddw_property_create(), which deals with
> allocation and filling the property, letting it ready for
> of_property_add(), which now occurs in sequence.
> 
> This created an opportunity to reorganize the second part of enable_ddw():
> 
> Without this patch enable_ddw() does, in order:
> kzalloc() property & members, create_ddw(), fill ddwprop inside property,
> ddw_list_new_entry(), do tce_setrange_multi_pSeriesLP_walk in all memory,
> of_add_property(), and list_add().
> 
> With this patch enable_ddw() does, in order:
> create_ddw(), ddw_property_create(), of_add_property(),
> ddw_list_new_entry(), do tce_setrange_multi_pSeriesLP_walk in all memory,
> and list_add().
> 
> This change requires of_remove_property() in case anything fails after
> of_add_property(), but we get to do tce_setrange_multi_pSeriesLP_walk
> in all memory, which looks the most expensive operation, only if
> everything else succeeds.
> 
> Signed-off-by: Leonardo Bras <leobras.c at gmail.com>
> ---
>   arch/powerpc/platforms/pseries/iommu.c | 106 +++++++++++++++----------
>   1 file changed, 63 insertions(+), 43 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> index bba8584a8f9d..510ccb0521af 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -177,7 +177,7 @@ static int tce_build_pSeriesLP(unsigned long liobn, long tcenum, long tceshift,
>   		if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) {
>   			ret = (int)rc;
>   			tce_free_pSeriesLP(liobn, tcenum_start, tceshift,
> -			                   (npages_start - (npages + 1)));
> +					   (npages_start - (npages + 1)));

Unrelated spaces change, the existing code does not seem incorrect (tabs 
first, then spaces).


>   			break;
>   		}
>   
> @@ -215,7 +215,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
>   	if ((npages == 1) || !firmware_has_feature(FW_FEATURE_PUT_TCE_IND)) {
>   		return tce_build_pSeriesLP(tbl->it_index, tcenum,
>   					   tceshift, npages, uaddr,
> -		                           direction, attrs);
> +					   direction, attrs);


And here.

>   	}
>   
>   	local_irq_save(flags);	/* to protect tcep and the page behind it */
> @@ -269,7 +269,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
>   	if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) {
>   		ret = (int)rc;
>   		tce_freemulti_pSeriesLP(tbl, tcenum_start,
> -		                        (npages_start - (npages + limit)));
> +					(npages_start - (npages + limit)));

And here.

>   		return ret;
>   	}
>   
> @@ -1121,6 +1121,35 @@ static void reset_dma_window(struct pci_dev *dev, struct device_node *par_dn)
>   			 ret);
>   }
>   
> +static struct property *ddw_property_create(const char *propname, u32 liobn, u64 dma_addr,
> +					    u32 page_shift, u32 window_shift)
> +{
> +	struct dynamic_dma_window_prop *ddwprop;
> +	struct property *win64;
> +
> +	win64 = kzalloc(sizeof(*win64), GFP_KERNEL);
> +	if (!win64)
> +		return NULL;
> +
> +	win64->name = kstrdup(propname, GFP_KERNEL);
> +	ddwprop = kzalloc(sizeof(*ddwprop), GFP_KERNEL);
> +	win64->value = ddwprop;
> +	win64->length = sizeof(*ddwprop);
> +	if (!win64->name || !win64->value) {
> +		kfree(win64);
> +		kfree(win64->name);
> +		kfree(win64->value);
> +		return NULL;
> +	}
> +
> +	ddwprop->liobn = cpu_to_be32(liobn);
> +	ddwprop->dma_base = cpu_to_be64(dma_addr);
> +	ddwprop->tce_shift = cpu_to_be32(page_shift);
> +	ddwprop->window_shift = cpu_to_be32(window_shift);
> +
> +	return win64;
> +}
> +
>   /*
>    * If the PE supports dynamic dma windows, and there is space for a table
>    * that can map all pages in a linear offset, then setup such a table,
> @@ -1138,12 +1167,11 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   	struct ddw_query_response query;
>   	struct ddw_create_response create;
>   	int page_shift;
> -	u64 max_addr;
> +	u64 max_addr, win_addr;
>   	struct device_node *dn;
>   	u32 ddw_avail[DDW_APPLICABLE_SIZE];
>   	struct direct_window *window;
> -	struct property *win64;
> -	struct dynamic_dma_window_prop *ddwprop;
> +	struct property *win64 = NULL;
>   	struct failed_ddw_pdn *fpdn;
>   	bool default_win_removed = false;
>   
> @@ -1245,72 +1273,64 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   		goto out_failed;
>   	}
>   	len = order_base_2(max_addr);
> -	win64 = kzalloc(sizeof(struct property), GFP_KERNEL);
> -	if (!win64) {
> -		dev_info(&dev->dev,
> -			"couldn't allocate property for 64bit dma window\n");
> -		goto out_failed;
> -	}
> -	win64->name = kstrdup(DIRECT64_PROPNAME, GFP_KERNEL);
> -	win64->value = ddwprop = kmalloc(sizeof(*ddwprop), GFP_KERNEL);
> -	win64->length = sizeof(*ddwprop);
> -	if (!win64->name || !win64->value) {
> -		dev_info(&dev->dev,
> -			"couldn't allocate property name and value\n");
> -		goto out_free_prop;
> -	}
>   
>   	ret = create_ddw(dev, ddw_avail, &create, page_shift, len);
>   	if (ret != 0)
> -		goto out_free_prop;
> -
> -	ddwprop->liobn = cpu_to_be32(create.liobn);
> -	ddwprop->dma_base = cpu_to_be64(((u64)create.addr_hi << 32) |
> -			create.addr_lo);
> -	ddwprop->tce_shift = cpu_to_be32(page_shift);
> -	ddwprop->window_shift = cpu_to_be32(len);
> +		goto out_failed;
>   
>   	dev_dbg(&dev->dev, "created tce table LIOBN 0x%x for %pOF\n",
> -		  create.liobn, dn);
> +		create.liobn, dn);


Unrelated. If you think the spaces/tabs thing needs to be fixed, make it 
a separate patch and do all these changes there at once.


>   
> -	window = ddw_list_new_entry(pdn, ddwprop);
> +	win_addr = ((u64)create.addr_hi << 32) | create.addr_lo;
> +	win64 = ddw_property_create(DIRECT64_PROPNAME, create.liobn, win_addr,
> +				    page_shift, len);
> +	if (!win64) {
> +		dev_info(&dev->dev,
> +			 "couldn't allocate property, property name, or value\n");
> +		goto out_win_del;
> +	}
> +
> +	ret = of_add_property(pdn, win64);
> +	if (ret) {
> +		dev_err(&dev->dev, "unable to add dma window property for %pOF: %d",
> +			pdn, ret);
> +		goto out_prop_free;
> +	}
> +
> +	window = ddw_list_new_entry(pdn, win64->value);
>   	if (!window)
> -		goto out_clear_window;
> +		goto out_prop_del;
>   
>   	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",
>   			 dn, ret);
> -		goto out_free_window;
> -	}
> -
> -	ret = of_add_property(pdn, win64);
> -	if (ret) {
> -		dev_err(&dev->dev, "unable to add dma window property for %pOF: %d",
> -			 pdn, ret);
> -		goto out_free_window;
> +		goto out_list_del;
>   	}
>   
>   	spin_lock(&direct_window_list_lock);
>   	list_add(&window->list, &direct_window_list);
>   	spin_unlock(&direct_window_list_lock);
>   
> -	dev->dev.archdata.dma_offset = be64_to_cpu(ddwprop->dma_base);
> +	dev->dev.archdata.dma_offset = win_addr;
>   	goto out_unlock;
>   
> -out_free_window:
> +out_list_del:
>   	kfree(window);
>   
> -out_clear_window:
> -	remove_ddw(pdn, true);
> +out_prop_del:
> +	of_remove_property(pdn, win64);
>   
> -out_free_prop:
> +out_prop_free:


Really? :) s/out_prop_del/out_del_prop/ may be? The less unrelated 
changes the better.


>   	kfree(win64->name);
>   	kfree(win64->value);
>   	kfree(win64);
>   	win64 = NULL;
>   
> +out_win_del:
> +	remove_ddw(pdn, true);
> +
>   out_failed:
>   	if (default_win_removed)
>   		reset_dma_window(dev, pdn);
> 

-- 
Alexey


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