[PATCH] drm/etnaviv: Implement mmap as GEM object function
Thomas Zimmermann
tzimmermann at suse.de
Thu Jun 24 10:47:08 UTC 2021
Hi
Am 24.06.21 um 11:11 schrieb Lucas Stach:
> Am Donnerstag, dem 24.06.2021 um 10:58 +0200 schrieb Thomas Zimmermann:
>> Moving the driver-specific mmap code into a GEM object function allows
>> for using DRM helpers for various mmap callbacks.
>>
>> The respective etnaviv functions are being removed. The file_operations
>> structure fops is now being created by the helper macro
>> DEFINE_DRM_GEM_FOPS().
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
>> ---
>> drivers/gpu/drm/etnaviv/etnaviv_drv.c | 14 ++------------
>> drivers/gpu/drm/etnaviv/etnaviv_drv.h | 3 ---
>> drivers/gpu/drm/etnaviv/etnaviv_gem.c | 18 +++++-------------
>> drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c | 13 -------------
>> 4 files changed, 7 insertions(+), 41 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
>> index f0a07278ad04..7dcc6392792d 100644
>> --- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c
>> +++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
>> @@ -468,17 +468,7 @@ static const struct drm_ioctl_desc etnaviv_ioctls[] = {
>> ETNA_IOCTL(PM_QUERY_SIG, pm_query_sig, DRM_RENDER_ALLOW),
>> };
>>
>> -static const struct file_operations fops = {
>> - .owner = THIS_MODULE,
>> - .open = drm_open,
>> - .release = drm_release,
>> - .unlocked_ioctl = drm_ioctl,
>> - .compat_ioctl = drm_compat_ioctl,
>> - .poll = drm_poll,
>> - .read = drm_read,
>> - .llseek = no_llseek,
>> - .mmap = etnaviv_gem_mmap,
>> -};
>> +DEFINE_DRM_GEM_FOPS(fops);
>>
>> static const struct drm_driver etnaviv_drm_driver = {
>> .driver_features = DRIVER_GEM | DRIVER_RENDER,
>> @@ -487,7 +477,7 @@ static const struct drm_driver etnaviv_drm_driver = {
>> .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
>> .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
>> .gem_prime_import_sg_table = etnaviv_gem_prime_import_sg_table,
>> - .gem_prime_mmap = etnaviv_gem_prime_mmap,
>> + .gem_prime_mmap = drm_gem_prime_mmap,
>> #ifdef CONFIG_DEBUG_FS
>> .debugfs_init = etnaviv_debugfs_init,
>> #endif
>> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.h b/drivers/gpu/drm/etnaviv/etnaviv_drv.h
>> index 003288ebd896..049ae87de9be 100644
>> --- a/drivers/gpu/drm/etnaviv/etnaviv_drv.h
>> +++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.h
>> @@ -47,12 +47,9 @@ struct etnaviv_drm_private {
>> int etnaviv_ioctl_gem_submit(struct drm_device *dev, void *data,
>> struct drm_file *file);
>>
>> -int etnaviv_gem_mmap(struct file *filp, struct vm_area_struct *vma);
>> int etnaviv_gem_mmap_offset(struct drm_gem_object *obj, u64 *offset);
>> struct sg_table *etnaviv_gem_prime_get_sg_table(struct drm_gem_object *obj);
>> int etnaviv_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
>> -int etnaviv_gem_prime_mmap(struct drm_gem_object *obj,
>> - struct vm_area_struct *vma);
>> struct drm_gem_object *etnaviv_gem_prime_import_sg_table(struct drm_device *dev,
>> struct dma_buf_attachment *attach, struct sg_table *sg);
>> int etnaviv_gem_prime_pin(struct drm_gem_object *obj);
>> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
>> index b8fa6ed3dd73..8f1b5af47dd6 100644
>> --- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
>> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
>> @@ -130,8 +130,7 @@ static int etnaviv_gem_mmap_obj(struct etnaviv_gem_object *etnaviv_obj,
>> {
>> pgprot_t vm_page_prot;
>>
>> - vma->vm_flags &= ~VM_PFNMAP;
>> - vma->vm_flags |= VM_MIXEDMAP;
>> + vma->vm_flags |= VM_IO | VM_MIXEDMAP | VM_DONTEXPAND | VM_DONTDUMP;
>
> I don't fully understand why this change is needed and the commit log
> is silent about it. Excuse my ignorance, but can you please explain the
> reasoning behind this change?
Sure, sorry for being brief.
I worked on cleaning up the deprecated gem_prime_* callbacks in struct
drm_driver. These are supposed to be GEM object functions. The only
obsolete gem prime callback in drm_driver is gem_prime_mmap.
Currently drivers
implement mmap in via callbacks in struct file_operations.mmap, struct
drm_driver.gem_prime_mmap and struct drm_gem_object_funcs.mmap (and
sometimes an additional mmap for fbdev emulation). That's way too much
duplication. The correct place to implement mmap is in struct
drm_gem_object_funcs.
I'm consolidating DRM mmap code in struct drm_gem_object_funcs.mmap.
There's even a fixme comment about this. [1] With the cleaned up mmap,
DRM drivers can switch to DRM helpers and macros for all other instances
of mmap.
And only a
handful of drivers if left to convert. For these final drivers (e.g.,
etnaviv) I replace the driver code with the generic helpers and move the
specific flags and setup into the GEM object's mmap function.
Once finished, all DRM drivers will implement gem_prime_mmap with
drm_gem_prime_mmap().
The core code can be further simplified from there and this will allow
to remove gem_prime_mmap and the occasional fbdev mmap.
Best regards
Thomas
[1]
https://elixir.bootlin.com/linux/latest/source/include/drm/drm_drv.h#L388
>
> Regards,
> Lucas
>
>>
>> vm_page_prot = vm_get_page_prot(vma->vm_flags);
>>
>> @@ -154,19 +153,11 @@ static int etnaviv_gem_mmap_obj(struct etnaviv_gem_object *etnaviv_obj,
>> return 0;
>> }
>>
>> -int etnaviv_gem_mmap(struct file *filp, struct vm_area_struct *vma)
>> +static int etnaviv_gem_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
>> {
>> - struct etnaviv_gem_object *obj;
>> - int ret;
>> -
>> - ret = drm_gem_mmap(filp, vma);
>> - if (ret) {
>> - DBG("mmap failed: %d", ret);
>> - return ret;
>> - }
>> + struct etnaviv_gem_object *etnaviv_obj = to_etnaviv_bo(obj);
>>
>> - obj = to_etnaviv_bo(vma->vm_private_data);
>> - return obj->ops->mmap(obj, vma);
>> + return etnaviv_obj->ops->mmap(etnaviv_obj, vma);
>> }
>>
>> static vm_fault_t etnaviv_gem_fault(struct vm_fault *vmf)
>> @@ -567,6 +558,7 @@ static const struct drm_gem_object_funcs etnaviv_gem_object_funcs = {
>> .unpin = etnaviv_gem_prime_unpin,
>> .get_sg_table = etnaviv_gem_prime_get_sg_table,
>> .vmap = etnaviv_gem_prime_vmap,
>> + .mmap = etnaviv_gem_mmap,
>> .vm_ops = &vm_ops,
>> };
>>
>> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
>> index d741b1d735f7..6d8bed9c739d 100644
>> --- a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
>> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
>> @@ -34,19 +34,6 @@ int etnaviv_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>> return 0;
>> }
>>
>> -int etnaviv_gem_prime_mmap(struct drm_gem_object *obj,
>> - struct vm_area_struct *vma)
>> -{
>> - struct etnaviv_gem_object *etnaviv_obj = to_etnaviv_bo(obj);
>> - int ret;
>> -
>> - ret = drm_gem_mmap_obj(obj, obj->size, vma);
>> - if (ret < 0)
>> - return ret;
>> -
>> - return etnaviv_obj->ops->mmap(etnaviv_obj, vma);
>> -}
>> -
>> int etnaviv_gem_prime_pin(struct drm_gem_object *obj)
>> {
>> if (!obj->import_attach) {
>
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer
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