[PATCH v2] drm/msm/dpu: Don't use devm for component devices
Andrzej Hajda
a.hajda at samsung.com
Mon Nov 5 06:54:52 UTC 2018
On 02.11.2018 19:25, Jordan Crouse wrote:
> Devices that are bound as components should not use devm since
> device managed memory is not freed when the component is
> unbound.
>
> In particular this is an issue if the compoent bind fails
> due to an -EPROBE_DEFER. In this case the bind would try again
> later and any devm managed meory allocated during the former
> aborted attempt would be leaked until the device itself was
> destroyed. Therefore, all the memory allocated during a bind
> should be freed during an unbind (or bind error case) and there
> isn't any reason to use devm for resources that have a explicit
> teardown step.
It does not look correct, component framework should properly free devm
resources, ie if devm resource was allocated in bind callback, it should
be released after unbind or failed bind.
See comments inside component_bind[1]. If it does not work it should be
fixed in components.
[1]:
https://elixir.bootlin.com/linux/latest/source/drivers/base/component.c#L464
Regards
Andrzej
>
> This doesn't remove devm for all resources - in particular
> msm_ioremap() still uses devm_ioremap() but thats a more
> generic condition that can easily be addressed as a cleanup
> later and the unbind code already does the requisite devm
> calls to unmap it.
>
> v2: free mp->clk_config on failure
>
> Signed-off-by: Jordan Crouse <jcrouse at codeaurora.org>
> ---
> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 4 ++--
> drivers/gpu/drm/msm/disp/dpu1/dpu_io_util.c | 6 +++---
> drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 10 ++++++----
> drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c | 8 +++++---
> 4 files changed, 16 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index 82c55efb500f..287d4c3e58c3 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -2220,14 +2220,14 @@ struct drm_encoder *dpu_encoder_init(struct drm_device *dev,
> struct dpu_encoder_virt *dpu_enc = NULL;
> int rc = 0;
>
> - dpu_enc = devm_kzalloc(dev->dev, sizeof(*dpu_enc), GFP_KERNEL);
> + dpu_enc = kzalloc(sizeof(*dpu_enc), GFP_KERNEL);
> if (!dpu_enc)
> return ERR_PTR(ENOMEM);
>
> rc = drm_encoder_init(dev, &dpu_enc->base, &dpu_encoder_funcs,
> drm_enc_mode, NULL);
> if (rc) {
> - devm_kfree(dev->dev, dpu_enc);
> + kfree(dpu_enc);
> return ERR_PTR(rc);
> }
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_io_util.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_io_util.c
> index 89ee4b36beff..14fecf00e032 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_io_util.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_io_util.c
> @@ -155,9 +155,7 @@ int msm_dss_parse_clock(struct platform_device *pdev,
> return 0;
> }
>
> - mp->clk_config = devm_kzalloc(&pdev->dev,
> - sizeof(struct dss_clk) * num_clk,
> - GFP_KERNEL);
> + mp->clk_config = kcalloc(num_clk, sizeof(struct dss_clk), GFP_KERNEL);
> if (!mp->clk_config)
> return -ENOMEM;
>
> @@ -201,5 +199,7 @@ int msm_dss_parse_clock(struct platform_device *pdev,
>
> err:
> msm_dss_put_clk(mp->clk_config, num_clk);
> + kfree(mp->clk_config);
> + mp->clk_config = NULL;
> return rc;
> }
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> index 985c855796ae..5ac3c3f3b08d 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> @@ -1086,13 +1086,14 @@ static int dpu_bind(struct device *dev, struct device *master, void *data)
> struct dss_module_power *mp;
> int ret = 0;
>
> - dpu_kms = devm_kzalloc(&pdev->dev, sizeof(*dpu_kms), GFP_KERNEL);
> + dpu_kms = kzalloc(sizeof(*dpu_kms), GFP_KERNEL);
> if (!dpu_kms)
> return -ENOMEM;
>
> mp = &dpu_kms->mp;
> ret = msm_dss_parse_clock(pdev, mp);
> if (ret) {
> + kfree(dpu_kms);
> DPU_ERROR("failed to parse clocks, ret=%d\n", ret);
> return ret;
> }
> @@ -1109,7 +1110,7 @@ static int dpu_bind(struct device *dev, struct device *master, void *data)
> dpu_kms->rpm_enabled = true;
>
> priv->kms = &dpu_kms->base;
> - return ret;
> + return 0;
> }
>
> static void dpu_unbind(struct device *dev, struct device *master, void *data)
> @@ -1120,11 +1121,12 @@ static void dpu_unbind(struct device *dev, struct device *master, void *data)
>
> dpu_power_resource_deinit(pdev, &dpu_kms->phandle);
> msm_dss_put_clk(mp->clk_config, mp->num_clk);
> - devm_kfree(&pdev->dev, mp->clk_config);
> - mp->num_clk = 0;
> + kfree(mp->clk_config);
>
> if (dpu_kms->rpm_enabled)
> pm_runtime_disable(&pdev->dev);
> +
> + kfree(dpu_kms);
> }
>
> static const struct component_ops dpu_ops = {
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
> index 2235ef8129f4..c82347afc967 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
> @@ -161,7 +161,7 @@ static void dpu_mdss_destroy(struct drm_device *dev)
> free_irq(platform_get_irq(pdev, 0), dpu_mdss);
>
> msm_dss_put_clk(mp->clk_config, mp->num_clk);
> - devm_kfree(&pdev->dev, mp->clk_config);
> + kfree(mp->clk_config);
>
> if (dpu_mdss->mmio)
> devm_iounmap(&pdev->dev, dpu_mdss->mmio);
> @@ -169,6 +169,8 @@ static void dpu_mdss_destroy(struct drm_device *dev)
>
> pm_runtime_disable(dev->dev);
> priv->mdss = NULL;
> +
> + kfree(dpu_mdss);
> }
>
> static const struct msm_mdss_funcs mdss_funcs = {
> @@ -186,7 +188,7 @@ int dpu_mdss_init(struct drm_device *dev)
> struct dss_module_power *mp;
> int ret = 0;
>
> - dpu_mdss = devm_kzalloc(dev->dev, sizeof(*dpu_mdss), GFP_KERNEL);
> + dpu_mdss = kzalloc(sizeof(*dpu_mdss), GFP_KERNEL);
> if (!dpu_mdss)
> return -ENOMEM;
>
> @@ -238,8 +240,8 @@ int dpu_mdss_init(struct drm_device *dev)
> _dpu_mdss_irq_domain_fini(dpu_mdss);
> irq_domain_error:
> msm_dss_put_clk(mp->clk_config, mp->num_clk);
> + kfree(mp->clk_config);
> clk_parse_err:
> - devm_kfree(&pdev->dev, mp->clk_config);
> if (dpu_mdss->mmio)
> devm_iounmap(&pdev->dev, dpu_mdss->mmio);
> dpu_mdss->mmio = NULL;
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