Robert, Vladimir,
On 5/19/22 07:14, Vladimir Zapolskiy wrote:
> The change simplifies driver's probe and remove functions, no functional
> change is intended.
>
> Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@xxxxxxxxxx>
> ---
> Changes from v1 to v2:
> * rebased on top of media/master
>
> drivers/media/platform/qcom/camss/camss.c | 33 +++++++----------------
> 1 file changed, 10 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/media/platform/qcom/camss/camss.c b/drivers/media/platform/qcom/camss/camss.c
> index 79ad82e233cb..2055233af101 100644
> --- a/drivers/media/platform/qcom/camss/camss.c
> +++ b/drivers/media/platform/qcom/camss/camss.c
> @@ -1529,7 +1529,7 @@ static int camss_probe(struct platform_device *pdev)
> struct camss *camss;
> int num_subdevs, ret;
>
> - camss = kzalloc(sizeof(*camss), GFP_KERNEL);
> + camss = devm_kzalloc(dev, sizeof(*camss), GFP_KERNEL);
In general it is not a good idea to use devm_*alloc. The problem is that if a
device instance is forcibly unbound, then all the memory allocated with devm_
is immediately freed. But if an application still has a file handle to a device
open, then it can still use that memory.
Now in this case the driver is already using devm_kcalloc, so it doesn't matter,
but it is something to keep in mind. In general, hotpluggable devices cannot use
devm_*alloc.
In general, my recommendation is to not use devm_*alloc for this, but since it
is already in use in this driver, it's better to use devm_*alloc consistently.
Or, alternatively, not use it all. That's up to Robert.
This is just as background information.
Regards,
Hans
> if (!camss)
> return -ENOMEM;
>
> @@ -1567,39 +1567,30 @@ static int camss_probe(struct platform_device *pdev)
> camss->csid_num = 4;
> camss->vfe_num = 4;
> } else {
> - ret = -EINVAL;
> - goto err_free;
> + return -EINVAL;
> }
>
> camss->csiphy = devm_kcalloc(dev, camss->csiphy_num,
> sizeof(*camss->csiphy), GFP_KERNEL);
> - if (!camss->csiphy) {
> - ret = -ENOMEM;
> - goto err_free;
> - }
> + if (!camss->csiphy)
> + return -ENOMEM;
>
> camss->csid = devm_kcalloc(dev, camss->csid_num, sizeof(*camss->csid),
> GFP_KERNEL);
> - if (!camss->csid) {
> - ret = -ENOMEM;
> - goto err_free;
> - }
> + if (!camss->csid)
> + return -ENOMEM;
>
> if (camss->version == CAMSS_8x16 ||
> camss->version == CAMSS_8x96) {
> camss->ispif = devm_kcalloc(dev, 1, sizeof(*camss->ispif), GFP_KERNEL);
> - if (!camss->ispif) {
> - ret = -ENOMEM;
> - goto err_free;
> - }
> + if (!camss->ispif)
> + return -ENOMEM;
> }
>
> camss->vfe = devm_kcalloc(dev, camss->vfe_num, sizeof(*camss->vfe),
> GFP_KERNEL);
> - if (!camss->vfe) {
> - ret = -ENOMEM;
> - goto err_free;
> - }
> + if (!camss->vfe)
> + return -ENOMEM;
>
> v4l2_async_nf_init(&camss->notifier);
>
> @@ -1681,8 +1672,6 @@ static int camss_probe(struct platform_device *pdev)
> v4l2_device_unregister(&camss->v4l2_dev);
> err_cleanup:
> v4l2_async_nf_cleanup(&camss->notifier);
> -err_free:
> - kfree(camss);
>
> return ret;
> }
> @@ -1709,8 +1698,6 @@ void camss_delete(struct camss *camss)
> device_link_del(camss->genpd_link[i]);
> dev_pm_domain_detach(camss->genpd[i], true);
> }
> -
> - kfree(camss);
> }
>
> /*
