Re: [PATCH v4 6/9] i2c: atr: allow replacing mappings in attach_addr()

Luca Ceresoli
2025-04-30T14:33:59Z

On Mon, 28 Apr 2025 13:25:11 +0300
Cosmin Tanislav <demonsingur@gmail.com> wrote:

> It is possible for aliases to be exhausted while we are still attaching
> children.
>
> Allow replacing mapping on attach by calling
> i2c_atr_replace_mapping_by_addr() if i2c_atr_create_mapping_by_addr()
> fails.
>
> Signed-off-by: Cosmin Tanislav <demonsingur@gmail.com>
> ---
> drivers/i2c/i2c-atr.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/i2c/i2c-atr.c b/drivers/i2c/i2c-atr.c
> index bf7b2ac5e9cf..7214a59ddf15 100644
> --- a/drivers/i2c/i2c-atr.c
> +++ b/drivers/i2c/i2c-atr.c
> @@ -543,6 +543,9 @@ static int i2c_atr_attach_addr(struct i2c_adapter *adapter,
> mutex_lock(&chan->alias_pairs_lock);
>
> c2a = i2c_atr_create_mapping_by_addr(chan, addr);
> + if (!c2a)
> + c2a = i2c_atr_replace_mapping_by_addr(chan, addr);
> +
> if (!c2a) {
> dev_err(atr->dev, "failed to find a free alias\n");
> ret = -EBUSY;

Looks like this should be squashed into patch 5, no? I might be
wrong, but IIUC the change in patch 5 is introducing a "bug" ("It is
possible for aliases to be exhausted while we are still attaching
children") and this patch fixes it.

Ah, nitpick: I wouldn't add that empty line.

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering