[Intel-gfx] [PATCH v2: 1/3] drm/i915: Add a function to mmap framebuffer obj
Das, Nirmoy
nirmoy.das at linux.intel.com
Thu Mar 23 08:00:50 UTC 2023
On 3/20/2023 3:02 PM, Andrzej Hajda wrote:
> On 20.03.2023 11:09, Nirmoy Das wrote:
>> Implement i915_gem_fb_mmap() to enable fb_ops.fb_mmap()
>> callback for i915's framebuffer objects.
>>
>> v2: add a comment why i915_gem_object_get() needed(Andi).
>>
>> Cc: Matthew Auld <matthew.auld at intel.com>
>> Cc: Andi Shyti <andi.shyti at linux.intel.com>
>> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
>> Cc: Jani Nikula <jani.nikula at intel.com>
>> Cc: Imre Deak <imre.deak at intel.com>
>> Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
>> Reviewed-by: Andi Shyti <andi.shyti at linux.intel.com>
>
> Reviewed-by: Andrzej Hajda <andrzej.hajda at intel.com>
Thanks, Andrzej.
Going to resend it without RFC now as there are two r-bs and no one
complained.
Regards,
Nirmoy
>
> Regards
> Andrzej
>
>> ---
>> drivers/gpu/drm/i915/gem/i915_gem_mman.c | 127 +++++++++++++++--------
>> drivers/gpu/drm/i915/gem/i915_gem_mman.h | 2 +-
>> 2 files changed, 83 insertions(+), 46 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
>> b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
>> index d3c1dee16af2..341e952d3510 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
>> @@ -927,53 +927,15 @@ static struct file *mmap_singleton(struct
>> drm_i915_private *i915)
>> return file;
>> }
>> -/*
>> - * This overcomes the limitation in drm_gem_mmap's assignment of a
>> - * drm_gem_object as the vma->vm_private_data. Since we need to
>> - * be able to resolve multiple mmap offsets which could be tied
>> - * to a single gem object.
>> - */
>> -int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma)
>> +static int
>> +i915_gem_object_mmap(struct drm_i915_gem_object *obj,
>> + struct i915_mmap_offset *mmo,
>> + struct vm_area_struct *vma)
>> {
>> - struct drm_vma_offset_node *node;
>> - struct drm_file *priv = filp->private_data;
>> - struct drm_device *dev = priv->minor->dev;
>> - struct drm_i915_gem_object *obj = NULL;
>> - struct i915_mmap_offset *mmo = NULL;
>> + struct drm_i915_private *i915 = to_i915(obj->base.dev);
>> + struct drm_device *dev = &i915->drm;
>> struct file *anon;
>> - if (drm_dev_is_unplugged(dev))
>> - return -ENODEV;
>> -
>> - rcu_read_lock();
>> - drm_vma_offset_lock_lookup(dev->vma_offset_manager);
>> - node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,
>> - vma->vm_pgoff,
>> - vma_pages(vma));
>> - if (node && drm_vma_node_is_allowed(node, priv)) {
>> - /*
>> - * Skip 0-refcnted objects as it is in the process of being
>> - * destroyed and will be invalid when the vma manager lock
>> - * is released.
>> - */
>> - if (!node->driver_private) {
>> - mmo = container_of(node, struct i915_mmap_offset,
>> vma_node);
>> - obj = i915_gem_object_get_rcu(mmo->obj);
>> -
>> - GEM_BUG_ON(obj && obj->ops->mmap_ops);
>> - } else {
>> - obj = i915_gem_object_get_rcu
>> - (container_of(node, struct drm_i915_gem_object,
>> - base.vma_node));
>> -
>> - GEM_BUG_ON(obj && !obj->ops->mmap_ops);
>> - }
>> - }
>> - drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
>> - rcu_read_unlock();
>> - if (!obj)
>> - return node ? -EACCES : -EINVAL;
>> -
>> if (i915_gem_object_is_readonly(obj)) {
>> if (vma->vm_flags & VM_WRITE) {
>> i915_gem_object_put(obj);
>> @@ -1005,7 +967,7 @@ int i915_gem_mmap(struct file *filp, struct
>> vm_area_struct *vma)
>> if (obj->ops->mmap_ops) {
>> vma->vm_page_prot =
>> pgprot_decrypted(vm_get_page_prot(vma->vm_flags));
>> vma->vm_ops = obj->ops->mmap_ops;
>> - vma->vm_private_data = node->driver_private;
>> + vma->vm_private_data = obj->base.vma_node.driver_private;
>> return 0;
>> }
>> @@ -1043,6 +1005,81 @@ int i915_gem_mmap(struct file *filp, struct
>> vm_area_struct *vma)
>> return 0;
>> }
>> +/*
>> + * This overcomes the limitation in drm_gem_mmap's assignment of a
>> + * drm_gem_object as the vma->vm_private_data. Since we need to
>> + * be able to resolve multiple mmap offsets which could be tied
>> + * to a single gem object.
>> + */
>> +int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma)
>> +{
>> + struct drm_vma_offset_node *node;
>> + struct drm_file *priv = filp->private_data;
>> + struct drm_device *dev = priv->minor->dev;
>> + struct drm_i915_gem_object *obj = NULL;
>> + struct i915_mmap_offset *mmo = NULL;
>> +
>> + if (drm_dev_is_unplugged(dev))
>> + return -ENODEV;
>> +
>> + rcu_read_lock();
>> + drm_vma_offset_lock_lookup(dev->vma_offset_manager);
>> + node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,
>> + vma->vm_pgoff,
>> + vma_pages(vma));
>> + if (node && drm_vma_node_is_allowed(node, priv)) {
>> + /*
>> + * Skip 0-refcnted objects as it is in the process of being
>> + * destroyed and will be invalid when the vma manager lock
>> + * is released.
>> + */
>> + if (!node->driver_private) {
>> + mmo = container_of(node, struct i915_mmap_offset,
>> vma_node);
>> + obj = i915_gem_object_get_rcu(mmo->obj);
>> +
>> + GEM_BUG_ON(obj && obj->ops->mmap_ops);
>> + } else {
>> + obj = i915_gem_object_get_rcu
>> + (container_of(node, struct drm_i915_gem_object,
>> + base.vma_node));
>> +
>> + GEM_BUG_ON(obj && !obj->ops->mmap_ops);
>> + }
>> + }
>> + drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
>> + rcu_read_unlock();
>> + if (!obj)
>> + return node ? -EACCES : -EINVAL;
>> +
>> + return i915_gem_object_mmap(obj, mmo, vma);
>> +}
>> +
>> +int i915_gem_fb_mmap(struct drm_i915_gem_object *obj, struct
>> vm_area_struct *vma)
>> +{
>> + struct drm_i915_private *i915 = to_i915(obj->base.dev);
>> + struct drm_device *dev = &i915->drm;
>> + struct i915_mmap_offset *mmo = NULL;
>> + enum i915_mmap_type mmap_type;
>> + struct i915_ggtt *ggtt = to_gt(i915)->ggtt;
>> +
>> + if (drm_dev_is_unplugged(dev))
>> + return -ENODEV;
>> +
>> + mmap_type = i915_ggtt_has_aperture(ggtt) ? I915_MMAP_TYPE_GTT :
>> I915_MMAP_TYPE_WC;
>> + mmo = mmap_offset_attach(obj, mmap_type, NULL);
>> + if (!mmo)
>> + return -ENODEV;
>> +
>> + /*
>> + * When we install vm_ops for mmap we are too late for
>> + * the vm_ops->open() which increases the ref_count of
>> + * this obj and then it gets decreased by the vm_ops->close().
>> + * To balance this increase the obj ref_count here.
>> + */
>> + obj = i915_gem_object_get(mmo->obj);
>> + return i915_gem_object_mmap(obj, mmo, vma);
>> +}
>> +
>> #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
>> #include "selftests/i915_gem_mman.c"
>> #endif
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.h
>> b/drivers/gpu/drm/i915/gem/i915_gem_mman.h
>> index 1fa91b3033b3..196417fd0f5c 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.h
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.h
>> @@ -29,5 +29,5 @@ void i915_gem_object_release_mmap_gtt(struct
>> drm_i915_gem_object *obj);
>> void i915_gem_object_runtime_pm_release_mmap_offset(struct
>> drm_i915_gem_object *obj);
>> void i915_gem_object_release_mmap_offset(struct drm_i915_gem_object
>> *obj);
>> -
>> +int i915_gem_fb_mmap(struct drm_i915_gem_object *obj, struct
>> vm_area_struct *vma);
>> #endif
>
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