On 07/10/2025 16:01, Adrián Larumbe wrote:
> If we reach the beginning of the LRU AS list, then return an error.
> 
> Reviewed-by: Boris Brezillon <[email protected]>
> Signed-off-by: Adrián Larumbe <[email protected]>

Very much "should never happen", but I guess adding error handling can't
hurt ;)

One minor NIT below, but either way:

Reviewed-by: Steven Price <[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 | 9 ++++++++-
>  4 files changed, 17 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c 
> b/drivers/gpu/drm/panfrost/panfrost_job.c
> index ea3f2878fd15..1b3af5d52081 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -213,7 +213,11 @@ 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;
>  
>               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..a8d821e1bde2 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
> @@ -132,7 +132,12 @@ static int panfrost_perfcnt_enable_locked(struct 
> panfrost_device *pfdev,
>  
>       perfcnt->user = user;

NIT: If we just move this line below the call to panfrost_mmu_as_get()
then we don't need the extra label and the special error handling.

Thanks,
Steve

>  
> -     as = panfrost_mmu_as_get(pfdev, perfcnt->mapping->mmu);
> +     ret = panfrost_mmu_as_get(pfdev, perfcnt->mapping->mmu);
> +     if (ret < 0)
> +             goto err_unsetuser;
> +
> +     as = ret;
> +
>       cfg = GPU_PERFCNT_CFG_AS(as) |
>             GPU_PERFCNT_CFG_MODE(GPU_PERFCNT_CFG_MODE_MANUAL);
>  
> @@ -166,6 +171,8 @@ static int panfrost_perfcnt_enable_locked(struct 
> panfrost_device *pfdev,
>  
>       return 0;
>  
> +err_unsetuser:
> +     perfcnt->user = NULL;
>  err_vunmap:
>       drm_gem_vunmap(&bo->base, &map);
>  err_put_mapping:

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