Re: [PATCH v1] i2c: i2c-core-base: Modify the maximum idr id for i2c adapter

Wolfram Sang
2023-01-09T15:15:29Z

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On Fri, Dec 16, 2022 at 10:07:51AM +0800, Riwen Lu wrote:
> From: Riwen Lu <luriwen@kylinos.cn>
>
> Change the maximum idr ID to INT_MAX for i2c adapter.
> This fix the following adding i2c adapter error while the idr with
> adap->nr has been allocated by other i2c driver, and find a proper ID

How did this happen that another i2c driver could get this? Were you
able to follow the code paths that lead to this situation?

> for it.
> [ 357.620685][ 3] [ T3655] ------------[ cut here ]------------
> [ 357.626544][ 3] [ T3655] couldn't get idr
>
> Signed-off-by: Riwen Lu <luriwen@kylinos.cn>
> ---
> drivers/i2c/i2c-core-base.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index 7539b0740351..c2982861057a 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -1535,11 +1535,12 @@ static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
> int id;
>
> mutex_lock(&core_lock);
> - id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
> + id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, 0, GFP_KERNEL);
> mutex_unlock(&core_lock);
> if (WARN(id < 0, "couldn't get idr"))
> return id == -ENOSPC ? -EBUSY : id;
>
> + adap->nr = id;
> return i2c_register_adapter(adap);
> }
>
> --
> 2.25.1
>

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