Re: [PATCH] i2c: dev: Fix bus callback return values

From: Wolfram Sang
Date: Thu Mar 09 2023 - 16:11:36 EST


On Thu, Mar 09, 2023 at 08:45:46AM +0100, Geert Uytterhoeven wrote:
> The i2cdev_{at,de}tach_adapter() callbacks are used for two purposes:
> 1. As notifier callbacks, when (un)registering I2C adapters created or
> destroyed after i2c_dev_init(),
> 2. As bus iterator callbacks, for registering already existing
> adapters from i2c_dev_init(), and for cleanup.
>
> Unfortunately both use cases expect different return values: the former
> expects NOTIFY_* return codes, while the latter expects zero or error
> codes, and aborts in case of error.
>
> Hence in case 2, as soon as i2cdev_{at,de}tach_adapter() returns
> (non-zero) NOTIFY_OK, the bus iterator aborts. This causes (a) only the
> first already existing adapter to be registered, leading to missing
> /dev/i2c-* entries, and (b) a failure to unregister all but the first
> I2C adapter during cleanup.
>
> Fix this by introducing separate callbacks for the bus iterator,
> wrapping the notifier functions, and always returning succes.
> Any errors inside these callback functions are unlikely to happen, and
> are fatal anyway.
>
> Fixes: cddf70d0bce71c2a ("i2c: dev: fix notifier return values")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>

Applied to for-current, thanks!

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