Re: [PATCH 12/21] drm/i915/gtt: Introduce kmap|kunmap for dma page

[Michel Thierry <michel.thierry@intel.com>]

On 6/11/2015 6:50 PM, Mika Kuoppala wrote:
> As there is flushing involved when we have done the cpu
> write, make functions for mapping for cpu space. Make macros
> to map any type of paging structure.
>
> v2: Make it clear tha flushing kunmap is only for ppgtt (Ville)
> v3: Flushing fixed (Ville, Michel). Removed superfluous semicolon
>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>

Reviewed-by: Michel Thierry <michel.thierry@intel.com>

> Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
> ---
>   drivers/gpu/drm/i915/i915_gem_gtt.c | 77 +++++++++++++++++++------------------
>   1 file changed, 40 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 60796b7..3ac8671 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -330,15 +330,16 @@ static void cleanup_page_dma(struct drm_device *dev, struct i915_page_dma *p)
>   	memset(p, 0, sizeof(*p));
>   }
>
> -static void fill_page_dma(struct drm_device *dev, struct i915_page_dma *p,
> -			  const uint64_t val)
> +static void *kmap_page_dma(struct i915_page_dma *p)
>   {
> -	int i;
> -	uint64_t * const vaddr = kmap_atomic(p->page);
> -
> -	for (i = 0; i < 512; i++)
> -		vaddr[i] = val;
> +	return kmap_atomic(p->page);
> +}
>
> +/* We use the flushing unmap only with ppgtt structures:
> + * page directories, page tables and scratch pages.
> + */
> +static void kunmap_page_dma(struct drm_device *dev, void *vaddr)
> +{
>   	/* There are only few exceptions for gen >=6. chv and bxt.
>   	 * And we are not sure about the latter so play safe for now.
>   	 */
> @@ -348,6 +349,21 @@ static void fill_page_dma(struct drm_device *dev, struct i915_page_dma *p,
>   	kunmap_atomic(vaddr);
>   }
>
> +#define kmap_px(px) kmap_page_dma(&(px)->base)
> +#define kunmap_px(ppgtt, vaddr) kunmap_page_dma((ppgtt)->base.dev, (vaddr))
> +
> +static void fill_page_dma(struct drm_device *dev, struct i915_page_dma *p,
> +			  const uint64_t val)
> +{
> +	int i;
> +	uint64_t * const vaddr = kmap_page_dma(p);
> +
> +	for (i = 0; i < 512; i++)
> +		vaddr[i] = val;
> +
> +	kunmap_page_dma(dev, vaddr);
> +}
> +
>   static void fill_page_dma_32(struct drm_device *dev, struct i915_page_dma *p,
>   			     const uint32_t val32)
>   {
> @@ -503,7 +519,6 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
>   	while (num_entries) {
>   		struct i915_page_directory *pd;
>   		struct i915_page_table *pt;
> -		struct page *page_table;
>
>   		if (WARN_ON(!ppgtt->pdp.page_directory[pdpe]))
>   			continue;
> @@ -518,22 +533,18 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
>   		if (WARN_ON(!pt->base.page))
>   			continue;
>
> -		page_table = pt->base.page;
> -
>   		last_pte = pte + num_entries;
>   		if (last_pte > GEN8_PTES)
>   			last_pte = GEN8_PTES;
>
> -		pt_vaddr = kmap_atomic(page_table);
> +		pt_vaddr = kmap_px(pt);
>
>   		for (i = pte; i < last_pte; i++) {
>   			pt_vaddr[i] = scratch_pte;
>   			num_entries--;
>   		}
>
> -		if (!HAS_LLC(ppgtt->base.dev))
> -			drm_clflush_virt_range(pt_vaddr, PAGE_SIZE);
> -		kunmap_atomic(pt_vaddr);
> +		kunmap_px(ppgtt, pt);
>
>   		pte = 0;
>   		if (++pde == I915_PDES) {
> @@ -565,18 +576,14 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm,
>   		if (pt_vaddr == NULL) {
>   			struct i915_page_directory *pd = ppgtt->pdp.page_directory[pdpe];
>   			struct i915_page_table *pt = pd->page_table[pde];
> -			struct page *page_table = pt->base.page;
> -
> -			pt_vaddr = kmap_atomic(page_table);
> +			pt_vaddr = kmap_px(pt);
>   		}
>
>   		pt_vaddr[pte] =
>   			gen8_pte_encode(sg_page_iter_dma_address(&sg_iter),
>   					cache_level, true);
>   		if (++pte == GEN8_PTES) {
> -			if (!HAS_LLC(ppgtt->base.dev))
> -				drm_clflush_virt_range(pt_vaddr, PAGE_SIZE);
> -			kunmap_atomic(pt_vaddr);
> +			kunmap_px(ppgtt, pt_vaddr);
>   			pt_vaddr = NULL;
>   			if (++pde == I915_PDES) {
>   				pdpe++;
> @@ -585,11 +592,9 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm,
>   			pte = 0;
>   		}
>   	}
> -	if (pt_vaddr) {
> -		if (!HAS_LLC(ppgtt->base.dev))
> -			drm_clflush_virt_range(pt_vaddr, PAGE_SIZE);
> -		kunmap_atomic(pt_vaddr);
> -	}
> +
> +	if (pt_vaddr)
> +		kunmap_px(ppgtt, pt_vaddr);
>   }
>
>   static void __gen8_do_map_pt(gen8_pde_t * const pde,
> @@ -869,7 +874,7 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
>   	/* Allocations have completed successfully, so set the bitmaps, and do
>   	 * the mappings. */
>   	gen8_for_each_pdpe(pd, &ppgtt->pdp, start, length, temp, pdpe) {
> -		gen8_pde_t *const page_directory = kmap_atomic(pd->base.page);
> +		gen8_pde_t *const page_directory = kmap_px(pd);
>   		struct i915_page_table *pt;
>   		uint64_t pd_len = gen8_clamp_pd(start, length);
>   		uint64_t pd_start = start;
> @@ -899,10 +904,7 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
>   			 * point we're still relying on insert_entries() */
>   		}
>
> -		if (!HAS_LLC(vm->dev))
> -			drm_clflush_virt_range(page_directory, PAGE_SIZE);
> -
> -		kunmap_atomic(page_directory);
> +		kunmap_px(ppgtt, page_directory);
>
>   		set_bit(pdpe, ppgtt->pdp.used_pdpes);
>   	}
> @@ -991,7 +993,8 @@ static void gen6_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m)
>   				   expected);
>   		seq_printf(m, "\tPDE: %x\n", pd_entry);
>
> -		pt_vaddr = kmap_atomic(ppgtt->pd.page_table[pde]->base.page);
> +		pt_vaddr = kmap_px(ppgtt->pd.page_table[pde]);
> +
>   		for (pte = 0; pte < GEN6_PTES; pte+=4) {
>   			unsigned long va =
>   				(pde * PAGE_SIZE * GEN6_PTES) +
> @@ -1013,7 +1016,7 @@ static void gen6_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m)
>   			}
>   			seq_puts(m, "\n");
>   		}
> -		kunmap_atomic(pt_vaddr);
> +		kunmap_px(ppgtt, pt_vaddr);
>   	}
>   }
>
> @@ -1216,12 +1219,12 @@ static void gen6_ppgtt_clear_range(struct i915_address_space *vm,
>   		if (last_pte > GEN6_PTES)
>   			last_pte = GEN6_PTES;
>
> -		pt_vaddr = kmap_atomic(ppgtt->pd.page_table[act_pt]->base.page);
> +		pt_vaddr = kmap_px(ppgtt->pd.page_table[act_pt]);
>
>   		for (i = first_pte; i < last_pte; i++)
>   			pt_vaddr[i] = scratch_pte;
>
> -		kunmap_atomic(pt_vaddr);
> +		kunmap_px(ppgtt, pt_vaddr);
>
>   		num_entries -= last_pte - first_pte;
>   		first_pte = 0;
> @@ -1245,21 +1248,21 @@ static void gen6_ppgtt_insert_entries(struct i915_address_space *vm,
>   	pt_vaddr = NULL;
>   	for_each_sg_page(pages->sgl, &sg_iter, pages->nents, 0) {
>   		if (pt_vaddr == NULL)
> -			pt_vaddr = kmap_atomic(ppgtt->pd.page_table[act_pt]->base.page);
> +			pt_vaddr = kmap_px(ppgtt->pd.page_table[act_pt]);
>
>   		pt_vaddr[act_pte] =
>   			vm->pte_encode(sg_page_iter_dma_address(&sg_iter),
>   				       cache_level, true, flags);
>
>   		if (++act_pte == GEN6_PTES) {
> -			kunmap_atomic(pt_vaddr);
> +			kunmap_px(ppgtt, pt_vaddr);
>   			pt_vaddr = NULL;
>   			act_pt++;
>   			act_pte = 0;
>   		}
>   	}
>   	if (pt_vaddr)
> -		kunmap_atomic(pt_vaddr);
> +		kunmap_px(ppgtt, pt_vaddr);
>   }
>
>   static void gen6_initialize_pt(struct i915_address_space *vm,
>
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