Re: [PATCH] drm/meson: switch to a managed drm device

[Anastasia Belova <abelova@xxxxxxxxxxxxx>]

Hi,

30/08/24 11:29, neil.armstrong@xxxxxxxxxx пишет:
> On 30/08/2024 10:23, Anastasia Belova wrote:
> > Hi,
> >
> > 29/08/24 15:14, Neil Armstrong пишет:
> > > Hi,
> > >
> > > On 28/08/2024 13:04, Anastasia Belova wrote:
> > > > Switch to a managed drm device to cleanup some error handling
> > > > and make future work easier.
> > > >
> > > > Fix dereference of NULL in meson_drv_bind_master by removing
> > > > drm_dev_put(drm) before meson_encoder_*_remove where drm
> > > > dereferenced.
> > >
> > > Please send the fix separately with a Fixes tag.
> >
> > This fix can't be separated from the patch. drm_dev_put may be
> > removed only while switching to a managed drm. Otherwise
> > a check could be added before calling meson_encoder_*_remove.
> > But it would become redundant after switching to a managed drm.
> >
> > I may send the second version of this patch with Fixes tag, so all
> > changes could be applied to older versions.
>
> Reading the currenrt code, component_unbind_all(dev, drm) is called
> after drm_dev_put(drm), which is quite wrong aswell.
>
> So perhaps we should keep the kref on drm  until component_unbind_all()
> is called in the first case, no ?

Right, but with a managed drm we don't need to release kref ourselves.

The comment for commit is not complete. Information about dereference
of NULL in component_unbind_all may be added in the second version, as
well as Fixes tag.

Anastasia Belova

> Neil
>
> > Thanks,
> > Anastasia Belova
> >
> > > Thanks,
> > > Neil
> > >
> > > > Co-developed by Linux Verification Center (linuxtesting.org).
> > > >
> > > > Signed-off-by: Anastasia Belova <abelova@xxxxxxxxxxxxx>
> > > > ---
> > > >   drivers/gpu/drm/meson/meson_crtc.c         | 10 +--
> > > >   drivers/gpu/drm/meson/meson_drv.c          | 71 
> > > > ++++++++++------------
> > > >   drivers/gpu/drm/meson/meson_drv.h          |  2 +-
> > > >   drivers/gpu/drm/meson/meson_encoder_cvbs.c |  8 +--
> > > >   drivers/gpu/drm/meson/meson_overlay.c      |  8 +--
> > > >   drivers/gpu/drm/meson/meson_plane.c        | 10 +--
> > > >   6 files changed, 51 insertions(+), 58 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/meson/meson_crtc.c 
> > > > b/drivers/gpu/drm/meson/meson_crtc.c
> > > > index d70616da8ce2..e1c0bf3baeea 100644
> > > > --- a/drivers/gpu/drm/meson/meson_crtc.c
> > > > +++ b/drivers/gpu/drm/meson/meson_crtc.c
> > > > @@ -662,13 +662,13 @@ void meson_crtc_irq(struct meson_drm *priv)
> > > >         drm_crtc_handle_vblank(priv->crtc);
> > > >   -    spin_lock_irqsave(&priv->drm->event_lock, flags);
> > > > +    spin_lock_irqsave(&priv->drm.event_lock, flags);
> > > >       if (meson_crtc->event) {
> > > >           drm_crtc_send_vblank_event(priv->crtc, meson_crtc->event);
> > > >           drm_crtc_vblank_put(priv->crtc);
> > > >           meson_crtc->event = NULL;
> > > >       }
> > > > - spin_unlock_irqrestore(&priv->drm->event_lock, flags);
> > > > +    spin_unlock_irqrestore(&priv->drm.event_lock, flags);
> > > >   }
> > > >     int meson_crtc_create(struct meson_drm *priv)
> > > > @@ -677,18 +677,18 @@ int meson_crtc_create(struct meson_drm *priv)
> > > >       struct drm_crtc *crtc;
> > > >       int ret;
> > > >   -    meson_crtc = devm_kzalloc(priv->drm->dev, sizeof(*meson_crtc),
> > > > +    meson_crtc = devm_kzalloc(priv->drm.dev, sizeof(*meson_crtc),
> > > >                     GFP_KERNEL);
> > > >       if (!meson_crtc)
> > > >           return -ENOMEM;
> > > >         meson_crtc->priv = priv;
> > > >       crtc = &meson_crtc->base;
> > > > -    ret = drm_crtc_init_with_planes(priv->drm, crtc,
> > > > +    ret = drm_crtc_init_with_planes(&priv->drm, crtc,
> > > >                       priv->primary_plane, NULL,
> > > >                       &meson_crtc_funcs, "meson_crtc");
> > > >       if (ret) {
> > > > -        dev_err(priv->drm->dev, "Failed to init CRTC\n");
> > > > +        dev_err(priv->drm.dev, "Failed to init CRTC\n");
> > > >           return ret;
> > > >       }
> > > >   diff --git a/drivers/gpu/drm/meson/meson_drv.c 
> > > > b/drivers/gpu/drm/meson/meson_drv.c
> > > > index 4bd0baa2a4f5..2e7c2e7c7b82 100644
> > > > --- a/drivers/gpu/drm/meson/meson_drv.c
> > > > +++ b/drivers/gpu/drm/meson/meson_drv.c
> > > > @@ -182,7 +182,6 @@ static int meson_drv_bind_master(struct device 
> > > > *dev, bool has_components)
> > > >       struct platform_device *pdev = to_platform_device(dev);
> > > >       const struct meson_drm_match_data *match;
> > > >       struct meson_drm *priv;
> > > > -    struct drm_device *drm;
> > > >       struct resource *res;
> > > >       void __iomem *regs;
> > > >       int ret, i;
> > > > @@ -197,17 +196,13 @@ static int meson_drv_bind_master(struct 
> > > > device *dev, bool has_components)
> > > >       if (!match)
> > > >           return -ENODEV;
> > > >   -    drm = drm_dev_alloc(&meson_driver, dev);
> > > > -    if (IS_ERR(drm))
> > > > -        return PTR_ERR(drm);
> > > > +    priv = devm_drm_dev_alloc(dev, &meson_driver,
> > > > +                 struct meson_drm, drm);
> > > >   -    priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > > > -    if (!priv) {
> > > > -        ret = -ENOMEM;
> > > > -        goto free_drm;
> > > > -    }
> > > > -    drm->dev_private = priv;
> > > > -    priv->drm = drm;
> > > > +    if (IS_ERR(priv))
> > > > +        return PTR_ERR(priv);
> > > > +
> > > > +    priv->drm.dev_private = priv;
> > > >       priv->dev = dev;
> > > >       priv->compat = match->compat;
> > > >       priv->afbcd.ops = match->afbcd_ops;
> > > > @@ -215,7 +210,7 @@ static int meson_drv_bind_master(struct device 
> > > > *dev, bool has_components)
> > > >       regs = devm_platform_ioremap_resource_byname(pdev, "vpu");
> > > >       if (IS_ERR(regs)) {
> > > >           ret = PTR_ERR(regs);
> > > > -        goto free_drm;
> > > > +        goto remove_encoders;
> > > >       }
> > > >         priv->io_base = regs;
> > > > @@ -223,13 +218,13 @@ static int meson_drv_bind_master(struct 
> > > > device *dev, bool has_components)
> > > >       res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "hhi");
> > > >       if (!res) {
> > > >           ret = -EINVAL;
> > > > -        goto free_drm;
> > > > +        goto remove_encoders;
> > > >       }
> > > >       /* Simply ioremap since it may be a shared register zone */
> > > >       regs = devm_ioremap(dev, res->start, resource_size(res));
> > > >       if (!regs) {
> > > >           ret = -EADDRNOTAVAIL;
> > > > -        goto free_drm;
> > > > +        goto remove_encoders;
> > > >       }
> > > >         priv->hhi = devm_regmap_init_mmio(dev, regs,
> > > > @@ -237,18 +232,18 @@ static int meson_drv_bind_master(struct 
> > > > device *dev, bool has_components)
> > > >       if (IS_ERR(priv->hhi)) {
> > > >           dev_err(&pdev->dev, "Couldn't create the HHI regmap\n");
> > > >           ret = PTR_ERR(priv->hhi);
> > > > -        goto free_drm;
> > > > +        goto remove_encoders;
> > > >       }
> > > >         priv->canvas = meson_canvas_get(dev);
> > > >       if (IS_ERR(priv->canvas)) {
> > > >           ret = PTR_ERR(priv->canvas);
> > > > -        goto free_drm;
> > > > +        goto remove_encoders;
> > > >       }
> > > >         ret = meson_canvas_alloc(priv->canvas, &priv->canvas_id_osd1);
> > > >       if (ret)
> > > > -        goto free_drm;
> > > > +        goto remove_encoders;
> > > >       ret = meson_canvas_alloc(priv->canvas, &priv->canvas_id_vd1_0);
> > > >       if (ret)
> > > >           goto free_canvas_osd1;
> > > > @@ -261,7 +256,7 @@ static int meson_drv_bind_master(struct device 
> > > > *dev, bool has_components)
> > > >         priv->vsync_irq = platform_get_irq(pdev, 0);
> > > >   -    ret = drm_vblank_init(drm, 1);
> > > > +    ret = drm_vblank_init(&priv->drm, 1);
> > > >       if (ret)
> > > >           goto free_canvas_vd1_2;
> > > >   @@ -284,10 +279,10 @@ static int meson_drv_bind_master(struct 
> > > > device *dev, bool has_components)
> > > >       ret = drmm_mode_config_init(drm);
> > > >       if (ret)
> > > >           goto free_canvas_vd1_2;
> > > > -    drm->mode_config.max_width = 3840;
> > > > -    drm->mode_config.max_height = 2160;
> > > > -    drm->mode_config.funcs = &meson_mode_config_funcs;
> > > > -    drm->mode_config.helper_private    = &meson_mode_config_helpers;
> > > > +    priv->drm.mode_config.max_width = 3840;
> > > > +    priv->drm.mode_config.max_height = 2160;
> > > > +    priv->drm.mode_config.funcs = &meson_mode_config_funcs;
> > > > +    priv->drm.mode_config.helper_private = 
> > > > &meson_mode_config_helpers;
> > > >         /* Hardware Initialization */
> > > >   @@ -308,9 +303,9 @@ static int meson_drv_bind_master(struct 
> > > > device *dev, bool has_components)
> > > >           goto exit_afbcd;
> > > >         if (has_components) {
> > > > -        ret = component_bind_all(dev, drm);
> > > > +        ret = component_bind_all(dev, &priv->drm);
> > > >           if (ret) {
> > > > -            dev_err(drm->dev, "Couldn't bind all components\n");
> > > > +            dev_err(priv->drm.dev, "Couldn't bind all components\n");
> > > >               /* Do not try to unbind */
> > > >               has_components = false;
> > > >               goto exit_afbcd;
> > > > @@ -339,26 +334,26 @@ static int meson_drv_bind_master(struct 
> > > > device *dev, bool has_components)
> > > >       if (ret)
> > > >           goto exit_afbcd;
> > > >   -    ret = request_irq(priv->vsync_irq, meson_irq, 0, 
> > > > drm->driver->name, drm);
> > > > +    ret = request_irq(priv->vsync_irq, meson_irq, 0, 
> > > > priv->drm.driver->name, &priv->drm);
> > > >       if (ret)
> > > >           goto exit_afbcd;
> > > >   -    drm_mode_config_reset(drm);
> > > > +    drm_mode_config_reset(&priv->drm);
> > > >   -    drm_kms_helper_poll_init(drm);
> > > > +    drm_kms_helper_poll_init(&priv->drm);
> > > >         platform_set_drvdata(pdev, priv);
> > > >   -    ret = drm_dev_register(drm, 0);
> > > > +    ret = drm_dev_register(&priv->drm, 0);
> > > >       if (ret)
> > > >           goto uninstall_irq;
> > > >   -    drm_fbdev_dma_setup(drm, 32);
> > > > +    drm_fbdev_dma_setup(&priv->drm, 32);
> > > >         return 0;
> > > >     uninstall_irq:
> > > > -    free_irq(priv->vsync_irq, drm);
> > > > +    free_irq(priv->vsync_irq, &priv->drm);
> > > >   exit_afbcd:
> > > >       if (priv->afbcd.ops)
> > > >           priv->afbcd.ops->exit(priv);
> > > > @@ -370,15 +365,14 @@ static int meson_drv_bind_master(struct 
> > > > device *dev, bool has_components)
> > > >       meson_canvas_free(priv->canvas, priv->canvas_id_vd1_0);
> > > >   free_canvas_osd1:
> > > >       meson_canvas_free(priv->canvas, priv->canvas_id_osd1);
> > > > -free_drm:
> > > > -    drm_dev_put(drm);
> > > > +remove_encoders:
> > > >         meson_encoder_dsi_remove(priv);
> > > >       meson_encoder_hdmi_remove(priv);
> > > >       meson_encoder_cvbs_remove(priv);
> > > >         if (has_components)
> > > > -        component_unbind_all(dev, drm);
> > > > +        component_unbind_all(dev, &priv->drm);
> > > >         return ret;
> > > >   }
> > > > @@ -391,7 +385,7 @@ static int meson_drv_bind(struct device *dev)
> > > >   static void meson_drv_unbind(struct device *dev)
> > > >   {
> > > >       struct meson_drm *priv = dev_get_drvdata(dev);
> > > > -    struct drm_device *drm = priv->drm;
> > > > +    struct drm_device *drm = &priv->drm;
> > > >         if (priv->canvas) {
> > > >           meson_canvas_free(priv->canvas, priv->canvas_id_osd1);
> > > > @@ -404,7 +398,6 @@ static void meson_drv_unbind(struct device *dev)
> > > >       drm_kms_helper_poll_fini(drm);
> > > >       drm_atomic_helper_shutdown(drm);
> > > >       free_irq(priv->vsync_irq, drm);
> > > > -    drm_dev_put(drm);
> > > >         meson_encoder_dsi_remove(priv);
> > > >       meson_encoder_hdmi_remove(priv);
> > > > @@ -428,7 +421,7 @@ static int __maybe_unused 
> > > > meson_drv_pm_suspend(struct device *dev)
> > > >       if (!priv)
> > > >           return 0;
> > > >   -    return drm_mode_config_helper_suspend(priv->drm);
> > > > +    return drm_mode_config_helper_suspend(&priv->drm);
> > > >   }
> > > >     static int __maybe_unused meson_drv_pm_resume(struct device *dev)
> > > > @@ -445,7 +438,7 @@ static int __maybe_unused 
> > > > meson_drv_pm_resume(struct device *dev)
> > > >       if (priv->afbcd.ops)
> > > >           priv->afbcd.ops->init(priv);
> > > >   -    return drm_mode_config_helper_resume(priv->drm);
> > > > +    return drm_mode_config_helper_resume(&priv->drm);
> > > >   }
> > > >     static void meson_drv_shutdown(struct platform_device *pdev)
> > > > @@ -455,8 +448,8 @@ static void meson_drv_shutdown(struct 
> > > > platform_device *pdev)
> > > >       if (!priv)
> > > >           return;
> > > >   -    drm_kms_helper_poll_fini(priv->drm);
> > > > -    drm_atomic_helper_shutdown(priv->drm);
> > > > +    drm_kms_helper_poll_fini(&priv->drm);
> > > > +    drm_atomic_helper_shutdown(&priv->drm);
> > > >   }
> > > >     /*
> > > > diff --git a/drivers/gpu/drm/meson/meson_drv.h 
> > > > b/drivers/gpu/drm/meson/meson_drv.h
> > > > index 3f9345c14f31..c4c6c810cb20 100644
> > > > --- a/drivers/gpu/drm/meson/meson_drv.h
> > > > +++ b/drivers/gpu/drm/meson/meson_drv.h
> > > > @@ -53,7 +53,7 @@ struct meson_drm {
> > > >       u8 canvas_id_vd1_1;
> > > >       u8 canvas_id_vd1_2;
> > > >   -    struct drm_device *drm;
> > > > +    struct drm_device drm;
> > > >       struct drm_crtc *crtc;
> > > >       struct drm_plane *primary_plane;
> > > >       struct drm_plane *overlay_plane;
> > > > diff --git a/drivers/gpu/drm/meson/meson_encoder_cvbs.c 
> > > > b/drivers/gpu/drm/meson/meson_encoder_cvbs.c
> > > > index d1191de855d9..ddca22c8c1ff 100644
> > > > --- a/drivers/gpu/drm/meson/meson_encoder_cvbs.c
> > > > +++ b/drivers/gpu/drm/meson/meson_encoder_cvbs.c
> > > > @@ -104,7 +104,7 @@ static int meson_encoder_cvbs_get_modes(struct 
> > > > drm_bridge *bridge,
> > > >       for (i = 0; i < MESON_CVBS_MODES_COUNT; ++i) {
> > > >           struct meson_cvbs_mode *meson_mode = &meson_cvbs_modes[i];
> > > >   -        mode = drm_mode_duplicate(priv->drm, &meson_mode->mode);
> > > > +        mode = drm_mode_duplicate(&priv->drm, &meson_mode->mode);
> > > >           if (!mode) {
> > > >               dev_err(priv->dev, "Failed to create a new display 
> > > > mode\n");
> > > >               return 0;
> > > > @@ -221,7 +221,7 @@ static const struct drm_bridge_funcs 
> > > > meson_encoder_cvbs_bridge_funcs = {
> > > >     int meson_encoder_cvbs_probe(struct meson_drm *priv)
> > > >   {
> > > > -    struct drm_device *drm = priv->drm;
> > > > +    struct drm_device *drm = &priv->drm;
> > > >       struct meson_encoder_cvbs *meson_encoder_cvbs;
> > > >       struct drm_connector *connector;
> > > >       struct device_node *remote;
> > > > @@ -256,7 +256,7 @@ int meson_encoder_cvbs_probe(struct meson_drm 
> > > > *priv)
> > > >       meson_encoder_cvbs->priv = priv;
> > > >         /* Encoder */
> > > > -    ret = drm_simple_encoder_init(priv->drm, 
> > > > &meson_encoder_cvbs->encoder,
> > > > +    ret = drm_simple_encoder_init(&priv->drm, 
> > > > &meson_encoder_cvbs->encoder,
> > > >                         DRM_MODE_ENCODER_TVDAC);
> > > >       if (ret)
> > > >           return dev_err_probe(priv->dev, ret,
> > > > @@ -273,7 +273,7 @@ int meson_encoder_cvbs_probe(struct meson_drm 
> > > > *priv)
> > > >       }
> > > >         /* Initialize & attach Bridge Connector */
> > > > -    connector = drm_bridge_connector_init(priv->drm, 
> > > > &meson_encoder_cvbs->encoder);
> > > > +    connector = drm_bridge_connector_init(&priv->drm, 
> > > > &meson_encoder_cvbs->encoder);
> > > >       if (IS_ERR(connector))
> > > >           return dev_err_probe(priv->dev, PTR_ERR(connector),
> > > >                        "Unable to create CVBS bridge connector\n");
> > > > diff --git a/drivers/gpu/drm/meson/meson_overlay.c 
> > > > b/drivers/gpu/drm/meson/meson_overlay.c
> > > > index 7f98de38842b..60ee7f758723 100644
> > > > --- a/drivers/gpu/drm/meson/meson_overlay.c
> > > > +++ b/drivers/gpu/drm/meson/meson_overlay.c
> > > > @@ -484,7 +484,7 @@ static void meson_overlay_atomic_update(struct 
> > > > drm_plane *plane,
> > > >         interlace_mode = new_state->crtc->mode.flags & 
> > > > DRM_MODE_FLAG_INTERLACE;
> > > >   -    spin_lock_irqsave(&priv->drm->event_lock, flags);
> > > > +    spin_lock_irqsave(&priv->drm.event_lock, flags);
> > > >         if ((fb->modifier & DRM_FORMAT_MOD_AMLOGIC_FBC(0, 0)) ==
> > > >                   DRM_FORMAT_MOD_AMLOGIC_FBC(0, 0)) {
> > > > @@ -717,7 +717,7 @@ static void meson_overlay_atomic_update(struct 
> > > > drm_plane *plane,
> > > >         priv->viu.vd1_enabled = true;
> > > >   - spin_unlock_irqrestore(&priv->drm->event_lock, flags);
> > > > +    spin_unlock_irqrestore(&priv->drm.event_lock, flags);
> > > >         DRM_DEBUG_DRIVER("\n");
> > > >   }
> > > > @@ -838,7 +838,7 @@ int meson_overlay_create(struct meson_drm *priv)
> > > >         DRM_DEBUG_DRIVER("\n");
> > > >   -    meson_overlay = devm_kzalloc(priv->drm->dev, 
> > > > sizeof(*meson_overlay),
> > > > +    meson_overlay = devm_kzalloc(priv->drm.dev, 
> > > > sizeof(*meson_overlay),
> > > >                      GFP_KERNEL);
> > > >       if (!meson_overlay)
> > > >           return -ENOMEM;
> > > > @@ -846,7 +846,7 @@ int meson_overlay_create(struct meson_drm *priv)
> > > >       meson_overlay->priv = priv;
> > > >       plane = &meson_overlay->base;
> > > >   -    drm_universal_plane_init(priv->drm, plane, 0xFF,
> > > > +    drm_universal_plane_init(&priv->drm, plane, 0xFF,
> > > >                    &meson_overlay_funcs,
> > > >                    supported_drm_formats,
> > > >                    ARRAY_SIZE(supported_drm_formats),
> > > > diff --git a/drivers/gpu/drm/meson/meson_plane.c 
> > > > b/drivers/gpu/drm/meson/meson_plane.c
> > > > index b43ac61201f3..13be94309bf4 100644
> > > > --- a/drivers/gpu/drm/meson/meson_plane.c
> > > > +++ b/drivers/gpu/drm/meson/meson_plane.c
> > > > @@ -157,7 +157,7 @@ static void meson_plane_atomic_update(struct 
> > > > drm_plane *plane,
> > > >        * Update Buffer
> > > >        * Enable Plane
> > > >        */
> > > > -    spin_lock_irqsave(&priv->drm->event_lock, flags);
> > > > +    spin_lock_irqsave(&priv->drm.event_lock, flags);
> > > >         /* Check if AFBC decoder is required for this buffer */
> > > >       if ((meson_vpu_is_compatible(priv, VPU_COMPATIBLE_GXM) ||
> > > > @@ -393,7 +393,7 @@ static void meson_plane_atomic_update(struct 
> > > > drm_plane *plane,
> > > >         priv->viu.osd1_enabled = true;
> > > >   - spin_unlock_irqrestore(&priv->drm->event_lock, flags);
> > > > +    spin_unlock_irqrestore(&priv->drm.event_lock, flags);
> > > >   }
> > > >     static void meson_plane_atomic_disable(struct drm_plane *plane,
> > > > @@ -536,7 +536,7 @@ int meson_plane_create(struct meson_drm *priv)
> > > >       const uint64_t *format_modifiers = format_modifiers_default;
> > > >       int ret;
> > > >   -    meson_plane = devm_kzalloc(priv->drm->dev, 
> > > > sizeof(*meson_plane),
> > > > +    meson_plane = devm_kzalloc(priv->drm.dev, sizeof(*meson_plane),
> > > >                      GFP_KERNEL);
> > > >       if (!meson_plane)
> > > >           return -ENOMEM;
> > > > @@ -549,14 +549,14 @@ int meson_plane_create(struct meson_drm *priv)
> > > >       else if (meson_vpu_is_compatible(priv, VPU_COMPATIBLE_G12A))
> > > >           format_modifiers = format_modifiers_afbc_g12a;
> > > >   -    ret = drm_universal_plane_init(priv->drm, plane, 0xFF,
> > > > +    ret = drm_universal_plane_init(&priv->drm, plane, 0xFF,
> > > >                       &meson_plane_funcs,
> > > >                       supported_drm_formats,
> > > >                       ARRAY_SIZE(supported_drm_formats),
> > > >                       format_modifiers,
> > > >                       DRM_PLANE_TYPE_PRIMARY, "meson_primary_plane");
> > > >       if (ret) {
> > > > -        devm_kfree(priv->drm->dev, meson_plane);
> > > > +        devm_kfree(priv->drm.dev, meson_plane);
> > > >           return ret;
> > > >       }