[PATCH v7 0/2] DRM-SHMEM fixes

[PATCH v7 0/2] DRM-SHMEM fixes

[Dmitry Osipenko]

This series fixes two minor problems in the DRM-SHMEM helper.

Changelog:

v7: - Factored out DRM-SHMEM fixes from [1] since I'll be working on
      the dma-buf locking in a separate patchset now.

[1] https://lore.kernel.org/all/20220526235040.678984-1-dmitry.osipenko@collabora.com/

Dmitry Osipenko (2):
  drm/shmem-helper: Add missing vunmap on error
  drm/shmem-helper: Correct doc-comment of drm_gem_shmem_get_sg_table()

 drivers/gpu/drm/drm_gem_shmem_helper.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

-- 
2.36.1

[PATCH v7 1/2] drm/shmem-helper: Add missing vunmap on error

[Dmitry Osipenko]

The vmapping of dma-buf may succeed, but DRM SHMEM rejects the IOMEM
mapping, and thus, drm_gem_shmem_vmap_locked() should unvmap the IOMEM
before erroring out.

Cc: stable@vger.kernel.org
Fixes: 49a3f51dfeee ("drm/gem: Use struct dma_buf_map in GEM vmap ops and convert GEM backends")
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 drivers/gpu/drm/drm_gem_shmem_helper.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 8ad0e02991ca..904fc893c905 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -302,6 +302,7 @@ static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem,
 		ret = dma_buf_vmap(obj->import_attach->dmabuf, map);
 		if (!ret) {
 			if (WARN_ON(map->is_iomem)) {
+				dma_buf_vunmap(obj->import_attach->dmabuf, map);
 				ret = -EIO;
 				goto err_put_pages;
 			}
-- 
2.36.1

[PATCH v7 2/2] drm/shmem-helper: Correct doc-comment of drm_gem_shmem_get_sg_table()

[Dmitry Osipenko]

drm_gem_shmem_get_sg_table() never returns NULL on error, but a ERR_PTR.
Correct the doc comment which says that it returns NULL on error.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 drivers/gpu/drm/drm_gem_shmem_helper.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 904fc893c905..0b526657fbea 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -663,7 +663,8 @@ EXPORT_SYMBOL(drm_gem_shmem_print_info);
  * drm_gem_shmem_get_pages_sgt() instead.
  *
  * Returns:
- * A pointer to the scatter/gather table of pinned pages or NULL on failure.
+ * A pointer to the scatter/gather table of pinned pages or an ERR_PTR()-encoded
+ * error code on failure.
  */
 struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_shmem_object *shmem)
 {
@@ -689,7 +690,8 @@ EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table);
  * drm_gem_shmem_get_sg_table() should not be directly called by drivers.
  *
  * Returns:
- * A pointer to the scatter/gather table of pinned pages or errno on failure.
+ * A pointer to the scatter/gather table of pinned pages or an ERR_PTR()-encoded
+ * error code on failure.
  */
 struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_shmem_object *shmem)
 {
-- 
2.36.1

Re: [PATCH v7 2/2] drm/shmem-helper: Correct doc-comment of drm_gem_shmem_get_sg_table()

[Daniel Vetter]

On Thu, Jun 30, 2022 at 11:00:58PM +0300, Dmitry Osipenko wrote:
> drm_gem_shmem_get_sg_table() never returns NULL on error, but a ERR_PTR.
> Correct the doc comment which says that it returns NULL on error.
> 
> Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
> ---
>  drivers/gpu/drm/drm_gem_shmem_helper.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
> index 904fc893c905..0b526657fbea 100644
> --- a/drivers/gpu/drm/drm_gem_shmem_helper.c
> +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
> @@ -663,7 +663,8 @@ EXPORT_SYMBOL(drm_gem_shmem_print_info);
>   * drm_gem_shmem_get_pages_sgt() instead.
>   *
>   * Returns:
> - * A pointer to the scatter/gather table of pinned pages or NULL on failure.
> + * A pointer to the scatter/gather table of pinned pages or an ERR_PTR()-encoded
> + * error code on failure.

There was a conflict here because another patch adjusted this already, but
I fixed it up and merged this to drm-misc-next.

Thanks, Daniel

>   */
>  struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_shmem_object *shmem)
>  {
> @@ -689,7 +690,8 @@ EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table);
>   * drm_gem_shmem_get_sg_table() should not be directly called by drivers.
>   *
>   * Returns:
> - * A pointer to the scatter/gather table of pinned pages or errno on failure.
> + * A pointer to the scatter/gather table of pinned pages or an ERR_PTR()-encoded
> + * error code on failure.
>   */
>  struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_shmem_object *shmem)
>  {
> -- 
> 2.36.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH v7 1/2] drm/shmem-helper: Add missing vunmap on error

[Daniel Vetter]

On Thu, Jun 30, 2022 at 11:00:57PM +0300, Dmitry Osipenko wrote:
> The vmapping of dma-buf may succeed, but DRM SHMEM rejects the IOMEM
> mapping, and thus, drm_gem_shmem_vmap_locked() should unvmap the IOMEM
> before erroring out.
> 
> Cc: stable@vger.kernel.org
> Fixes: 49a3f51dfeee ("drm/gem: Use struct dma_buf_map in GEM vmap ops and convert GEM backends")
> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>

Pushed to drm-misc-next-fixes, thanks for your patch.
-Daniel

> ---
>  drivers/gpu/drm/drm_gem_shmem_helper.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
> index 8ad0e02991ca..904fc893c905 100644
> --- a/drivers/gpu/drm/drm_gem_shmem_helper.c
> +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
> @@ -302,6 +302,7 @@ static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem,
>  		ret = dma_buf_vmap(obj->import_attach->dmabuf, map);
>  		if (!ret) {
>  			if (WARN_ON(map->is_iomem)) {
> +				dma_buf_vunmap(obj->import_attach->dmabuf, map);
>  				ret = -EIO;
>  				goto err_put_pages;
>  			}
> -- 
> 2.36.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch