diff mbox series

[v4,6/8] drm/ttm: Add a parameter to add extra pages into ttm_tt

Message ID 20220319204229.9846-7-ramalingam.c@intel.com (mailing list archive)
State New, archived
Headers show
Series drm/i915/ttm: Evict and restore of compressed object | expand

Commit Message

Ramalingam C March 19, 2022, 8:42 p.m. UTC
Add a parameter called "extra_pages" for ttm_tt_init, to indicate that
driver needs extra pages in ttm_tt.

v2:
  Used imperative wording [Thomas and Christian]

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
cc: Christian Koenig <christian.koenig@amd.com>
cc: Hellstrom Thomas <thomas.hellstrom@intel.com>
Reviewed-by: Thomas Hellstrom <thomas.hellstrom@linux.intel.com>
Reviewed-by: Christian Konig <christian.koenig@amd.com>
---
 drivers/gpu/drm/drm_gem_vram_helper.c      |  2 +-
 drivers/gpu/drm/i915/gem/i915_gem_ttm.c    |  2 +-
 drivers/gpu/drm/qxl/qxl_ttm.c              |  2 +-
 drivers/gpu/drm/ttm/ttm_agp_backend.c      |  2 +-
 drivers/gpu/drm/ttm/ttm_tt.c               | 12 +++++++-----
 drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c |  2 +-
 include/drm/ttm/ttm_tt.h                   |  4 +++-
 7 files changed, 15 insertions(+), 11 deletions(-)

Comments

Nirmoy Das March 21, 2022, 10:11 a.m. UTC | #1
In the previous version I replied only to the mailing list email so 
probably my email slipped through.

Reviewed-by: Nirmoy Das <nirmoy.das@intel.com> for patch 6-7

On 3/19/2022 9:42 PM, Ramalingam C wrote:
> Add a parameter called "extra_pages" for ttm_tt_init, to indicate that
> driver needs extra pages in ttm_tt.
>
> v2:
>    Used imperative wording [Thomas and Christian]
>
> Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
> cc: Christian Koenig <christian.koenig@amd.com>
> cc: Hellstrom Thomas <thomas.hellstrom@intel.com>
> Reviewed-by: Thomas Hellstrom <thomas.hellstrom@linux.intel.com>
> Reviewed-by: Christian Konig <christian.koenig@amd.com>
> ---
>   drivers/gpu/drm/drm_gem_vram_helper.c      |  2 +-
>   drivers/gpu/drm/i915/gem/i915_gem_ttm.c    |  2 +-
>   drivers/gpu/drm/qxl/qxl_ttm.c              |  2 +-
>   drivers/gpu/drm/ttm/ttm_agp_backend.c      |  2 +-
>   drivers/gpu/drm/ttm/ttm_tt.c               | 12 +++++++-----
>   drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c |  2 +-
>   include/drm/ttm/ttm_tt.h                   |  4 +++-
>   7 files changed, 15 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c
> index dc7f938bfff2..123045b58fec 100644
> --- a/drivers/gpu/drm/drm_gem_vram_helper.c
> +++ b/drivers/gpu/drm/drm_gem_vram_helper.c
> @@ -867,7 +867,7 @@ static struct ttm_tt *bo_driver_ttm_tt_create(struct ttm_buffer_object *bo,
>   	if (!tt)
>   		return NULL;
>   
> -	ret = ttm_tt_init(tt, bo, page_flags, ttm_cached);
> +	ret = ttm_tt_init(tt, bo, page_flags, ttm_cached, 0);
>   	if (ret < 0)
>   		goto err_ttm_tt_init;
>   
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> index e4a06fcf741a..3b9f99c765c4 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> @@ -290,7 +290,7 @@ static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
>   		i915_tt->is_shmem = true;
>   	}
>   
> -	ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, caching);
> +	ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, caching, 0);
>   	if (ret)
>   		goto err_free;
>   
> diff --git a/drivers/gpu/drm/qxl/qxl_ttm.c b/drivers/gpu/drm/qxl/qxl_ttm.c
> index b2e33d5ba5d0..52156b54498f 100644
> --- a/drivers/gpu/drm/qxl/qxl_ttm.c
> +++ b/drivers/gpu/drm/qxl/qxl_ttm.c
> @@ -113,7 +113,7 @@ static struct ttm_tt *qxl_ttm_tt_create(struct ttm_buffer_object *bo,
>   	ttm = kzalloc(sizeof(struct ttm_tt), GFP_KERNEL);
>   	if (ttm == NULL)
>   		return NULL;
> -	if (ttm_tt_init(ttm, bo, page_flags, ttm_cached)) {
> +	if (ttm_tt_init(ttm, bo, page_flags, ttm_cached, 0)) {
>   		kfree(ttm);
>   		return NULL;
>   	}
> diff --git a/drivers/gpu/drm/ttm/ttm_agp_backend.c b/drivers/gpu/drm/ttm/ttm_agp_backend.c
> index 6ddc16f0fe2b..d27691f2e451 100644
> --- a/drivers/gpu/drm/ttm/ttm_agp_backend.c
> +++ b/drivers/gpu/drm/ttm/ttm_agp_backend.c
> @@ -134,7 +134,7 @@ struct ttm_tt *ttm_agp_tt_create(struct ttm_buffer_object *bo,
>   	agp_be->mem = NULL;
>   	agp_be->bridge = bridge;
>   
> -	if (ttm_tt_init(&agp_be->ttm, bo, page_flags, ttm_write_combined)) {
> +	if (ttm_tt_init(&agp_be->ttm, bo, page_flags, ttm_write_combined, 0)) {
>   		kfree(agp_be);
>   		return NULL;
>   	}
> diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
> index d234aab800a0..1a66d9fc589a 100644
> --- a/drivers/gpu/drm/ttm/ttm_tt.c
> +++ b/drivers/gpu/drm/ttm/ttm_tt.c
> @@ -134,9 +134,10 @@ void ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm)
>   static void ttm_tt_init_fields(struct ttm_tt *ttm,
>   			       struct ttm_buffer_object *bo,
>   			       uint32_t page_flags,
> -			       enum ttm_caching caching)
> +			       enum ttm_caching caching,
> +			       unsigned long extra_pages)
>   {
> -	ttm->num_pages = PAGE_ALIGN(bo->base.size) >> PAGE_SHIFT;
> +	ttm->num_pages = (PAGE_ALIGN(bo->base.size) >> PAGE_SHIFT) + extra_pages;
>   	ttm->caching = ttm_cached;
>   	ttm->page_flags = page_flags;
>   	ttm->dma_address = NULL;
> @@ -146,9 +147,10 @@ static void ttm_tt_init_fields(struct ttm_tt *ttm,
>   }
>   
>   int ttm_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
> -		uint32_t page_flags, enum ttm_caching caching)
> +		uint32_t page_flags, enum ttm_caching caching,
> +		unsigned long extra_pages)
>   {
> -	ttm_tt_init_fields(ttm, bo, page_flags, caching);
> +	ttm_tt_init_fields(ttm, bo, page_flags, caching, extra_pages);
>   
>   	if (ttm_tt_alloc_page_directory(ttm)) {
>   		pr_err("Failed allocating page table\n");
> @@ -180,7 +182,7 @@ int ttm_sg_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
>   {
>   	int ret;
>   
> -	ttm_tt_init_fields(ttm, bo, page_flags, caching);
> +	ttm_tt_init_fields(ttm, bo, page_flags, caching, 0);
>   
>   	if (page_flags & TTM_TT_FLAG_EXTERNAL)
>   		ret = ttm_sg_tt_alloc_page_directory(ttm);
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
> index b84ecc6d6611..4e3938e62c08 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
> @@ -517,7 +517,7 @@ static struct ttm_tt *vmw_ttm_tt_create(struct ttm_buffer_object *bo,
>   				     ttm_cached);
>   	else
>   		ret = ttm_tt_init(&vmw_be->dma_ttm, bo, page_flags,
> -				  ttm_cached);
> +				  ttm_cached, 0);
>   	if (unlikely(ret != 0))
>   		goto out_no_init;
>   
> diff --git a/include/drm/ttm/ttm_tt.h b/include/drm/ttm/ttm_tt.h
> index f20832139815..17a0310e8aaa 100644
> --- a/include/drm/ttm/ttm_tt.h
> +++ b/include/drm/ttm/ttm_tt.h
> @@ -140,6 +140,7 @@ int ttm_tt_create(struct ttm_buffer_object *bo, bool zero_alloc);
>    * @bo: The buffer object we create the ttm for.
>    * @page_flags: Page flags as identified by TTM_TT_FLAG_XX flags.
>    * @caching: the desired caching state of the pages
> + * @extra_pages: Extra pages needed for the driver.
>    *
>    * Create a struct ttm_tt to back data with system memory pages.
>    * No pages are actually allocated.
> @@ -147,7 +148,8 @@ int ttm_tt_create(struct ttm_buffer_object *bo, bool zero_alloc);
>    * NULL: Out of memory.
>    */
>   int ttm_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
> -		uint32_t page_flags, enum ttm_caching caching);
> +		uint32_t page_flags, enum ttm_caching caching,
> +		unsigned long extra_pages);
>   int ttm_sg_tt_init(struct ttm_tt *ttm_dma, struct ttm_buffer_object *bo,
>   		   uint32_t page_flags, enum ttm_caching caching);
>
Ramalingam C March 21, 2022, 11:06 p.m. UTC | #2
On 2022-03-21 at 11:11:33 +0100, Das, Nirmoy wrote:
> In the previous version I replied only to the mailing list email so probably
> my email slipped through.

Sorry for the miss. Thank so much for the review.

Ram
> 
> Reviewed-by: Nirmoy Das <nirmoy.das@intel.com> for patch 6-7
> 
> On 3/19/2022 9:42 PM, Ramalingam C wrote:
> > Add a parameter called "extra_pages" for ttm_tt_init, to indicate that
> > driver needs extra pages in ttm_tt.
> > 
> > v2:
> >    Used imperative wording [Thomas and Christian]
> > 
> > Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
> > cc: Christian Koenig <christian.koenig@amd.com>
> > cc: Hellstrom Thomas <thomas.hellstrom@intel.com>
> > Reviewed-by: Thomas Hellstrom <thomas.hellstrom@linux.intel.com>
> > Reviewed-by: Christian Konig <christian.koenig@amd.com>
> > ---
> >   drivers/gpu/drm/drm_gem_vram_helper.c      |  2 +-
> >   drivers/gpu/drm/i915/gem/i915_gem_ttm.c    |  2 +-
> >   drivers/gpu/drm/qxl/qxl_ttm.c              |  2 +-
> >   drivers/gpu/drm/ttm/ttm_agp_backend.c      |  2 +-
> >   drivers/gpu/drm/ttm/ttm_tt.c               | 12 +++++++-----
> >   drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c |  2 +-
> >   include/drm/ttm/ttm_tt.h                   |  4 +++-
> >   7 files changed, 15 insertions(+), 11 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c
> > index dc7f938bfff2..123045b58fec 100644
> > --- a/drivers/gpu/drm/drm_gem_vram_helper.c
> > +++ b/drivers/gpu/drm/drm_gem_vram_helper.c
> > @@ -867,7 +867,7 @@ static struct ttm_tt *bo_driver_ttm_tt_create(struct ttm_buffer_object *bo,
> >   	if (!tt)
> >   		return NULL;
> > -	ret = ttm_tt_init(tt, bo, page_flags, ttm_cached);
> > +	ret = ttm_tt_init(tt, bo, page_flags, ttm_cached, 0);
> >   	if (ret < 0)
> >   		goto err_ttm_tt_init;
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> > index e4a06fcf741a..3b9f99c765c4 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> > @@ -290,7 +290,7 @@ static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
> >   		i915_tt->is_shmem = true;
> >   	}
> > -	ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, caching);
> > +	ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, caching, 0);
> >   	if (ret)
> >   		goto err_free;
> > diff --git a/drivers/gpu/drm/qxl/qxl_ttm.c b/drivers/gpu/drm/qxl/qxl_ttm.c
> > index b2e33d5ba5d0..52156b54498f 100644
> > --- a/drivers/gpu/drm/qxl/qxl_ttm.c
> > +++ b/drivers/gpu/drm/qxl/qxl_ttm.c
> > @@ -113,7 +113,7 @@ static struct ttm_tt *qxl_ttm_tt_create(struct ttm_buffer_object *bo,
> >   	ttm = kzalloc(sizeof(struct ttm_tt), GFP_KERNEL);
> >   	if (ttm == NULL)
> >   		return NULL;
> > -	if (ttm_tt_init(ttm, bo, page_flags, ttm_cached)) {
> > +	if (ttm_tt_init(ttm, bo, page_flags, ttm_cached, 0)) {
> >   		kfree(ttm);
> >   		return NULL;
> >   	}
> > diff --git a/drivers/gpu/drm/ttm/ttm_agp_backend.c b/drivers/gpu/drm/ttm/ttm_agp_backend.c
> > index 6ddc16f0fe2b..d27691f2e451 100644
> > --- a/drivers/gpu/drm/ttm/ttm_agp_backend.c
> > +++ b/drivers/gpu/drm/ttm/ttm_agp_backend.c
> > @@ -134,7 +134,7 @@ struct ttm_tt *ttm_agp_tt_create(struct ttm_buffer_object *bo,
> >   	agp_be->mem = NULL;
> >   	agp_be->bridge = bridge;
> > -	if (ttm_tt_init(&agp_be->ttm, bo, page_flags, ttm_write_combined)) {
> > +	if (ttm_tt_init(&agp_be->ttm, bo, page_flags, ttm_write_combined, 0)) {
> >   		kfree(agp_be);
> >   		return NULL;
> >   	}
> > diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
> > index d234aab800a0..1a66d9fc589a 100644
> > --- a/drivers/gpu/drm/ttm/ttm_tt.c
> > +++ b/drivers/gpu/drm/ttm/ttm_tt.c
> > @@ -134,9 +134,10 @@ void ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm)
> >   static void ttm_tt_init_fields(struct ttm_tt *ttm,
> >   			       struct ttm_buffer_object *bo,
> >   			       uint32_t page_flags,
> > -			       enum ttm_caching caching)
> > +			       enum ttm_caching caching,
> > +			       unsigned long extra_pages)
> >   {
> > -	ttm->num_pages = PAGE_ALIGN(bo->base.size) >> PAGE_SHIFT;
> > +	ttm->num_pages = (PAGE_ALIGN(bo->base.size) >> PAGE_SHIFT) + extra_pages;
> >   	ttm->caching = ttm_cached;
> >   	ttm->page_flags = page_flags;
> >   	ttm->dma_address = NULL;
> > @@ -146,9 +147,10 @@ static void ttm_tt_init_fields(struct ttm_tt *ttm,
> >   }
> >   int ttm_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
> > -		uint32_t page_flags, enum ttm_caching caching)
> > +		uint32_t page_flags, enum ttm_caching caching,
> > +		unsigned long extra_pages)
> >   {
> > -	ttm_tt_init_fields(ttm, bo, page_flags, caching);
> > +	ttm_tt_init_fields(ttm, bo, page_flags, caching, extra_pages);
> >   	if (ttm_tt_alloc_page_directory(ttm)) {
> >   		pr_err("Failed allocating page table\n");
> > @@ -180,7 +182,7 @@ int ttm_sg_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
> >   {
> >   	int ret;
> > -	ttm_tt_init_fields(ttm, bo, page_flags, caching);
> > +	ttm_tt_init_fields(ttm, bo, page_flags, caching, 0);
> >   	if (page_flags & TTM_TT_FLAG_EXTERNAL)
> >   		ret = ttm_sg_tt_alloc_page_directory(ttm);
> > diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
> > index b84ecc6d6611..4e3938e62c08 100644
> > --- a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
> > +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
> > @@ -517,7 +517,7 @@ static struct ttm_tt *vmw_ttm_tt_create(struct ttm_buffer_object *bo,
> >   				     ttm_cached);
> >   	else
> >   		ret = ttm_tt_init(&vmw_be->dma_ttm, bo, page_flags,
> > -				  ttm_cached);
> > +				  ttm_cached, 0);
> >   	if (unlikely(ret != 0))
> >   		goto out_no_init;
> > diff --git a/include/drm/ttm/ttm_tt.h b/include/drm/ttm/ttm_tt.h
> > index f20832139815..17a0310e8aaa 100644
> > --- a/include/drm/ttm/ttm_tt.h
> > +++ b/include/drm/ttm/ttm_tt.h
> > @@ -140,6 +140,7 @@ int ttm_tt_create(struct ttm_buffer_object *bo, bool zero_alloc);
> >    * @bo: The buffer object we create the ttm for.
> >    * @page_flags: Page flags as identified by TTM_TT_FLAG_XX flags.
> >    * @caching: the desired caching state of the pages
> > + * @extra_pages: Extra pages needed for the driver.
> >    *
> >    * Create a struct ttm_tt to back data with system memory pages.
> >    * No pages are actually allocated.
> > @@ -147,7 +148,8 @@ int ttm_tt_create(struct ttm_buffer_object *bo, bool zero_alloc);
> >    * NULL: Out of memory.
> >    */
> >   int ttm_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
> > -		uint32_t page_flags, enum ttm_caching caching);
> > +		uint32_t page_flags, enum ttm_caching caching,
> > +		unsigned long extra_pages);
> >   int ttm_sg_tt_init(struct ttm_tt *ttm_dma, struct ttm_buffer_object *bo,
> >   		   uint32_t page_flags, enum ttm_caching caching);
diff mbox series

Patch

diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c
index dc7f938bfff2..123045b58fec 100644
--- a/drivers/gpu/drm/drm_gem_vram_helper.c
+++ b/drivers/gpu/drm/drm_gem_vram_helper.c
@@ -867,7 +867,7 @@  static struct ttm_tt *bo_driver_ttm_tt_create(struct ttm_buffer_object *bo,
 	if (!tt)
 		return NULL;
 
-	ret = ttm_tt_init(tt, bo, page_flags, ttm_cached);
+	ret = ttm_tt_init(tt, bo, page_flags, ttm_cached, 0);
 	if (ret < 0)
 		goto err_ttm_tt_init;
 
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index e4a06fcf741a..3b9f99c765c4 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -290,7 +290,7 @@  static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
 		i915_tt->is_shmem = true;
 	}
 
-	ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, caching);
+	ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, caching, 0);
 	if (ret)
 		goto err_free;
 
diff --git a/drivers/gpu/drm/qxl/qxl_ttm.c b/drivers/gpu/drm/qxl/qxl_ttm.c
index b2e33d5ba5d0..52156b54498f 100644
--- a/drivers/gpu/drm/qxl/qxl_ttm.c
+++ b/drivers/gpu/drm/qxl/qxl_ttm.c
@@ -113,7 +113,7 @@  static struct ttm_tt *qxl_ttm_tt_create(struct ttm_buffer_object *bo,
 	ttm = kzalloc(sizeof(struct ttm_tt), GFP_KERNEL);
 	if (ttm == NULL)
 		return NULL;
-	if (ttm_tt_init(ttm, bo, page_flags, ttm_cached)) {
+	if (ttm_tt_init(ttm, bo, page_flags, ttm_cached, 0)) {
 		kfree(ttm);
 		return NULL;
 	}
diff --git a/drivers/gpu/drm/ttm/ttm_agp_backend.c b/drivers/gpu/drm/ttm/ttm_agp_backend.c
index 6ddc16f0fe2b..d27691f2e451 100644
--- a/drivers/gpu/drm/ttm/ttm_agp_backend.c
+++ b/drivers/gpu/drm/ttm/ttm_agp_backend.c
@@ -134,7 +134,7 @@  struct ttm_tt *ttm_agp_tt_create(struct ttm_buffer_object *bo,
 	agp_be->mem = NULL;
 	agp_be->bridge = bridge;
 
-	if (ttm_tt_init(&agp_be->ttm, bo, page_flags, ttm_write_combined)) {
+	if (ttm_tt_init(&agp_be->ttm, bo, page_flags, ttm_write_combined, 0)) {
 		kfree(agp_be);
 		return NULL;
 	}
diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
index d234aab800a0..1a66d9fc589a 100644
--- a/drivers/gpu/drm/ttm/ttm_tt.c
+++ b/drivers/gpu/drm/ttm/ttm_tt.c
@@ -134,9 +134,10 @@  void ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm)
 static void ttm_tt_init_fields(struct ttm_tt *ttm,
 			       struct ttm_buffer_object *bo,
 			       uint32_t page_flags,
-			       enum ttm_caching caching)
+			       enum ttm_caching caching,
+			       unsigned long extra_pages)
 {
-	ttm->num_pages = PAGE_ALIGN(bo->base.size) >> PAGE_SHIFT;
+	ttm->num_pages = (PAGE_ALIGN(bo->base.size) >> PAGE_SHIFT) + extra_pages;
 	ttm->caching = ttm_cached;
 	ttm->page_flags = page_flags;
 	ttm->dma_address = NULL;
@@ -146,9 +147,10 @@  static void ttm_tt_init_fields(struct ttm_tt *ttm,
 }
 
 int ttm_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
-		uint32_t page_flags, enum ttm_caching caching)
+		uint32_t page_flags, enum ttm_caching caching,
+		unsigned long extra_pages)
 {
-	ttm_tt_init_fields(ttm, bo, page_flags, caching);
+	ttm_tt_init_fields(ttm, bo, page_flags, caching, extra_pages);
 
 	if (ttm_tt_alloc_page_directory(ttm)) {
 		pr_err("Failed allocating page table\n");
@@ -180,7 +182,7 @@  int ttm_sg_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
 {
 	int ret;
 
-	ttm_tt_init_fields(ttm, bo, page_flags, caching);
+	ttm_tt_init_fields(ttm, bo, page_flags, caching, 0);
 
 	if (page_flags & TTM_TT_FLAG_EXTERNAL)
 		ret = ttm_sg_tt_alloc_page_directory(ttm);
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
index b84ecc6d6611..4e3938e62c08 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
@@ -517,7 +517,7 @@  static struct ttm_tt *vmw_ttm_tt_create(struct ttm_buffer_object *bo,
 				     ttm_cached);
 	else
 		ret = ttm_tt_init(&vmw_be->dma_ttm, bo, page_flags,
-				  ttm_cached);
+				  ttm_cached, 0);
 	if (unlikely(ret != 0))
 		goto out_no_init;
 
diff --git a/include/drm/ttm/ttm_tt.h b/include/drm/ttm/ttm_tt.h
index f20832139815..17a0310e8aaa 100644
--- a/include/drm/ttm/ttm_tt.h
+++ b/include/drm/ttm/ttm_tt.h
@@ -140,6 +140,7 @@  int ttm_tt_create(struct ttm_buffer_object *bo, bool zero_alloc);
  * @bo: The buffer object we create the ttm for.
  * @page_flags: Page flags as identified by TTM_TT_FLAG_XX flags.
  * @caching: the desired caching state of the pages
+ * @extra_pages: Extra pages needed for the driver.
  *
  * Create a struct ttm_tt to back data with system memory pages.
  * No pages are actually allocated.
@@ -147,7 +148,8 @@  int ttm_tt_create(struct ttm_buffer_object *bo, bool zero_alloc);
  * NULL: Out of memory.
  */
 int ttm_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
-		uint32_t page_flags, enum ttm_caching caching);
+		uint32_t page_flags, enum ttm_caching caching,
+		unsigned long extra_pages);
 int ttm_sg_tt_init(struct ttm_tt *ttm_dma, struct ttm_buffer_object *bo,
 		   uint32_t page_flags, enum ttm_caching caching);