Re: [PATCH net] dpll: Prevent duplicate registrations

[Vadim Fedorenko <vadim.fedorenko@linux.dev>]

On 21/01/2026 13:00, Ivan Vecera wrote:
> Modify the internal registration helpers dpll_xa_ref_{dpll,pin}_add()
> to reject duplicate registration attempts.
> 
> Previously, if a caller attempted to register the same pin multiple
> times (with the same ops, priv, and cookie) on the same device, the core
> silently increments the reference count and return success. This behavior
> is incorrect because if the caller makes these duplicate registrations
> then for the first one dpll_pin_registration is allocated and for others
> the associated dpll_pin_ref.refcount is incremented. During the first
> unregistration the associated dpll_pin_registration is freed and for
> others WARN is fired.
> 
> Fix this by updating the logic to return `-EEXIST` if a matching
> registration is found to enforce a strict "register once" policy.
> 
> Fixes: 9431063ad323 ("dpll: core: Add DPLL framework base functions")
> Signed-off-by: Ivan Vecera <ivecera@redhat.com>
> ---
>   drivers/dpll/dpll_core.c | 12 ++++--------
>   1 file changed, 4 insertions(+), 8 deletions(-)

Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>