On 15/10/2025 01:09, Adrián Larumbe wrote:
> If we reach the beginning of the LRU AS list, then return an error.
> 
> Reviewed-by: Steven Price <[email protected]>
> Reviewed-by: Boris Brezillon <[email protected]>
> Signed-off-by: Adrián Larumbe <[email protected]>
> ---
>  drivers/gpu/drm/panfrost/panfrost_job.c     | 6 +++++-
>  drivers/gpu/drm/panfrost/panfrost_mmu.c     | 5 +++--
>  drivers/gpu/drm/panfrost/panfrost_mmu.h     | 2 +-
>  drivers/gpu/drm/panfrost/panfrost_perfcnt.c | 8 ++++++--
>  4 files changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c 
> b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 0722f297d142..d53e9db945ad 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -217,7 +217,11 @@ static int panfrost_job_hw_submit(struct panfrost_job 
> *job, int js)
>               goto err_hwsubmit;
>       }
>  
> -     cfg = panfrost_mmu_as_get(pfdev, job->mmu);
> +     ret = panfrost_mmu_as_get(pfdev, job->mmu);
> +     if (ret < 0)
> +             goto err_hwsubmit;
> +
> +     cfg = ret;
>  
>       panfrost_devfreq_record_busy(&pfdev->pfdevfreq);
>  
> diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c 
> b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> index 1d696eeea2fa..cf272b167feb 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> @@ -258,7 +258,7 @@ static int panfrost_mmu_cfg_init(struct panfrost_mmu *mmu,
>       }
>  }
>  
> -u32 panfrost_mmu_as_get(struct panfrost_device *pfdev, struct panfrost_mmu 
> *mmu)
> +int panfrost_mmu_as_get(struct panfrost_device *pfdev, struct panfrost_mmu 
> *mmu)
>  {
>       int as;
>  
> @@ -300,7 +300,8 @@ u32 panfrost_mmu_as_get(struct panfrost_device *pfdev, 
> struct panfrost_mmu *mmu)
>                       if (!atomic_read(&lru_mmu->as_count))
>                               break;
>               }
> -             WARN_ON(&lru_mmu->list == &pfdev->as_lru_list);
> +             if (WARN_ON(&lru_mmu->list == &pfdev->as_lru_list))
> +                     return -EBUSY;

I was about to apply this series, but sparse told me that this is
broken. We're holding the as_lock here, so we need to drop that before
returning.

Thanks,

Steve

>  
>               list_del_init(&lru_mmu->list);
>               as = lru_mmu->as;
> diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.h 
> b/drivers/gpu/drm/panfrost/panfrost_mmu.h
> index 022a9a74a114..e6e6966a0cca 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_mmu.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.h
> @@ -16,7 +16,7 @@ void panfrost_mmu_fini(struct panfrost_device *pfdev);
>  void panfrost_mmu_reset(struct panfrost_device *pfdev);
>  void panfrost_mmu_suspend_irq(struct panfrost_device *pfdev);
>  
> -u32 panfrost_mmu_as_get(struct panfrost_device *pfdev, struct panfrost_mmu 
> *mmu);
> +int panfrost_mmu_as_get(struct panfrost_device *pfdev, struct panfrost_mmu 
> *mmu);
>  void panfrost_mmu_as_put(struct panfrost_device *pfdev, struct panfrost_mmu 
> *mmu);
>  
>  struct panfrost_mmu *panfrost_mmu_ctx_get(struct panfrost_mmu *mmu);
> diff --git a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c 
> b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
> index 718eb44b40f8..7020c0192e18 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
> @@ -130,9 +130,11 @@ static int panfrost_perfcnt_enable_locked(struct 
> panfrost_device *pfdev,
>               goto err_vunmap;
>       }
>  
> -     perfcnt->user = user;
> +     ret = panfrost_mmu_as_get(pfdev, perfcnt->mapping->mmu);
> +     if (ret < 0)
> +             goto err_vunmap;
>  
> -     as = panfrost_mmu_as_get(pfdev, perfcnt->mapping->mmu);
> +     as = ret;
>       cfg = GPU_PERFCNT_CFG_AS(as) |
>             GPU_PERFCNT_CFG_MODE(GPU_PERFCNT_CFG_MODE_MANUAL);
>  
> @@ -164,6 +166,8 @@ static int panfrost_perfcnt_enable_locked(struct 
> panfrost_device *pfdev,
>       /* The BO ref is retained by the mapping. */
>       drm_gem_object_put(&bo->base);
>  
> +     perfcnt->user = user;
> +
>       return 0;
>  
>  err_vunmap:

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