linux-kernel - Re: [PATCH v4 1/5] platform/chrome: cros_ec: fix error handling in cros_ec

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Date:   Tue, 15 Feb 2022 21:44:05 -0800
From:   Prashant Malani <pmalani@...omium.org>
To:     Tzung-Bi Shih <tzungbi@...gle.com>
Cc:     bleung@...omium.org, groeck@...omium.org,
        chrome-platform@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 1/5] platform/chrome: cros_ec: fix error handling in cros_ec_register()

On Tue, Feb 15, 2022 at 8:36 PM Tzung-Bi Shih <tzungbi@...gle.com> wrote:
>
> Fix cros_ec_register() to unregister platform devices if
> blocking_notifier_chain_register() fails.
>
> Also use the single exit path to handle the platform device
> unregistration.
>
> Fixes: 42cd0ab476e2 ("platform/chrome: cros_ec: Query EC protocol version if EC transitions between RO/RW")
> Signed-off-by: Tzung-Bi Shih <tzungbi@...gle.com>
Reviewed-by: Prashant Malani <pmalani@...omium.org>

> ---
> Changes from v3:
> (https://patchwork.kernel.org/project/chrome-platform/patch/20220209095703.517608-2-tzungbi@google.com/)
> - Simplify by initializing the variables at the beginning.
>
> Changes from v2:
> (https://patchwork.kernel.org/project/chrome-platform/patch/20220209045035.380615-2-tzungbi@google.com/)
> - Fix grammar error in commit message.
> - Change the code that don't rely on zeroed memory.
> - Remove unnecessary `if` checks before calling platform_device_unregister().
>
> Changes from v1:
> (https://lore.kernel.org/lkml/20220125101527.1812887-1-tzungbi@google.com/T/#u)
> - Use imperative mood in commit message.
> - Use IS_ERR_OR_NULL() in 1st patch.
>
>  drivers/platform/chrome/cros_ec.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
> index fc5aa1525d13..ff2a24b0c611 100644
> --- a/drivers/platform/chrome/cros_ec.c
> +++ b/drivers/platform/chrome/cros_ec.c
> @@ -189,6 +189,8 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
>         ec_dev->max_request = sizeof(struct ec_params_hello);
>         ec_dev->max_response = sizeof(struct ec_response_get_protocol_info);
>         ec_dev->max_passthru = 0;
> +       ec_dev->ec = NULL;
> +       ec_dev->pd = NULL;
>
>         ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
>         if (!ec_dev->din)
> @@ -245,18 +247,16 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
>                 if (IS_ERR(ec_dev->pd)) {
>                         dev_err(ec_dev->dev,
>                                 "Failed to create CrOS PD platform device\n");
> -                       platform_device_unregister(ec_dev->ec);
> -                       return PTR_ERR(ec_dev->pd);
> +                       err = PTR_ERR(ec_dev->pd);
> +                       goto exit;
>                 }
>         }
>
>         if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
>                 err = devm_of_platform_populate(dev);
>                 if (err) {
> -                       platform_device_unregister(ec_dev->pd);
> -                       platform_device_unregister(ec_dev->ec);
>                         dev_err(dev, "Failed to register sub-devices\n");
> -                       return err;
> +                       goto exit;
>                 }
>         }
>
> @@ -278,7 +278,7 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
>                 err = blocking_notifier_chain_register(&ec_dev->event_notifier,
>                                                       &ec_dev->notifier_ready);
>                 if (err)
> -                       return err;
> +                       goto exit;
>         }
>
>         dev_info(dev, "Chrome EC device registered\n");
> @@ -291,6 +291,10 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
>                 cros_ec_irq_thread(0, ec_dev);
>
>         return 0;
> +exit:
> +       platform_device_unregister(ec_dev->ec);
> +       platform_device_unregister(ec_dev->pd);
> +       return err;
>  }
>  EXPORT_SYMBOL(cros_ec_register);
>
> --
> 2.35.1.265.g69c8d7142f-goog
>