Re: [PATCH v2 2/4] drm/v3d: alloc and init job in one shot

[Melissa Wen <mwen@igalia.com>]

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On 09/30, Iago Toral wrote:
> On Wed, 2021-09-29 at 10:43 +0100, Melissa Wen wrote:
> > Move job memory allocation to v3d_job_init function. This aim to
> > facilitate
> > error handling in job initialization, since cleanup steps are similar
> > for all
> > (struct v3d_job)-based types of job involved in a command submission.
> > To
> > generalize v3d_job_init(), this change takes into account that all
> > job structs
> > have the first element a struct v3d_job (bin, render, tfu, csd) or it
> > is a
> > v3d_job itself (clean_job) for pointer casting.
> > 
> > Suggested-by: Iago Toral <itoral@igalia.com>
> > Signed-off-by: Melissa Wen <mwen@igalia.com>
> > ---
> >  drivers/gpu/drm/v3d/v3d_gem.c | 115 +++++++++++++-------------------
> > --
> >  1 file changed, 42 insertions(+), 73 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/v3d/v3d_gem.c
> > b/drivers/gpu/drm/v3d/v3d_gem.c
> > index e60fbc28ef29..9cfa6f8d4357 100644
> > --- a/drivers/gpu/drm/v3d/v3d_gem.c
> > +++ b/drivers/gpu/drm/v3d/v3d_gem.c
> > @@ -392,6 +392,9 @@ v3d_render_job_free(struct kref *ref)
> >  
> >  void v3d_job_cleanup(struct v3d_job *job)
> >  {
> > +	if (!job)
> > +		return;
> > +
> >  	drm_sched_job_cleanup(&job->base);
> >  	v3d_job_put(job);
> >  }
> > @@ -450,12 +453,20 @@ v3d_job_add_deps(struct drm_file *file_priv,
> > struct v3d_job *job,
> >  
> >  static int
> >  v3d_job_init(struct v3d_dev *v3d, struct drm_file *file_priv,
> > -	     struct v3d_job *job, void (*free)(struct kref *ref),
> > +	     void **container, size_t size, void (*free)(struct kref
> > *ref),
> >  	     u32 in_sync, enum v3d_queue queue)
> >  {
> >  	struct v3d_file_priv *v3d_priv = file_priv->driver_priv;
> > +	struct v3d_job *job;
> >  	int ret;
> >  
> > +	*container = kcalloc(1, size, GFP_KERNEL);
> > +	if (!*container) {
> > +		DRM_ERROR("Cannot allocate memory for v3d job.");
> > +		return -ENOMEM;
> > +	}
> > +
> > +	job = *container;
> >  	job->v3d = v3d;
> >  	job->free = free;
> >  
> 
> Right below this hunk we have an early return that doesn't jump to
> fail:
> 
>         ret = pm_runtime_get_sync(v3d->drm.dev);
>         if (ret < 0)
>                 return ret;
> 
> 
> so we should kfree(*container) and set it to NULL there, right?
oh, yes. I missed it on porting downstream to upstream.
> 
> > @@ -479,6 +490,9 @@ v3d_job_init(struct v3d_dev *v3d, struct drm_file
> > *file_priv,
> >  	drm_sched_job_cleanup(&job->base);
> >  fail:
> >  	pm_runtime_put_autosuspend(v3d->drm.dev);
> > +	kfree(*container);
> > +	*container = NULL;
> > +
> >  	return ret;
> >  }
> > 
> 
> (...)
> 
> > @@ -806,29 +789,15 @@ v3d_submit_csd_ioctl(struct drm_device *dev,
> > void *data,
> >  		return -EINVAL;
> >  	}
> >  
> > -	job = kcalloc(1, sizeof(*job), GFP_KERNEL);
> > -	if (!job)
> > -		return -ENOMEM;
> > -
> > -	ret = v3d_job_init(v3d, file_priv, &job->base,
> > +	ret = v3d_job_init(v3d, file_priv, (void *)&job, sizeof(*job),
> >  			   v3d_job_free, args->in_sync, V3D_CSD);
> > -	if (ret) {
> > -		kfree(job);
> > -		return ret;
> > -	}
> > -
> > -	clean_job = kcalloc(1, sizeof(*clean_job), GFP_KERNEL);
> > -	if (!clean_job) {
> > -		v3d_job_cleanup(&job->base);
> > -		return -ENOMEM;
> > -	}
> > +	if (ret)
> > +		goto fail;
> > 
> 
> For this to work we need to explicitly initialize clean_job to NULL. 
> Notice that the same applies to the bin and clean jobs in the CL ioctl,
> but in that case we're already initializing them to NULL.
yes, thanks for pointing it out.

Melissa
> 
> > -	ret = v3d_job_init(v3d, file_priv, clean_job, v3d_job_free, 0,
> > V3D_CACHE_CLEAN);
> > -	if (ret) {
> > -		v3d_job_cleanup(&job->base);
> > -		kfree(clean_job);
> > -		return ret;
> > -	}
> > +	ret = v3d_job_init(v3d, file_priv, (void *)&clean_job,
> > sizeof(*clean_job),
> > +			   v3d_job_free, 0, V3D_CACHE_CLEAN);
> > +	if (ret)
> > +		goto fail;
> >  
> >  	job->args = *args;
> >  
> > @@ -877,7 +846,7 @@ v3d_submit_csd_ioctl(struct drm_device *dev, void
> > *data,
> >  	drm_gem_unlock_reservations(clean_job->bo, clean_job->bo_count,
> >  				    &acquire_ctx);
> >  fail:
> > -	v3d_job_cleanup(&job->base);
> > +	v3d_job_cleanup((void *)job);
> >  	v3d_job_cleanup(clean_job);
> >  
> >  	return ret;
> 

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