Hi Maxime, On Wed, 20 Aug 2025 11:40:30 +0200 Luca Ceresoli <luca.ceres...@bootlin.com> wrote:
> Hi Maxime, > > On Tue, 19 Aug 2025 18:01:37 +0200 > Luca Ceresoli <luca.ceres...@bootlin.com> wrote: > > > Hi Maxime, > > > > On Tue, 19 Aug 2025 15:47:06 +0200 > > Maxime Ripard <mrip...@kernel.org> wrote: > > > > > > +/** > > > > + * drm_for_each_bridge_in_chain_scoped - iterate over all bridges > > > > attached > > > > + * to an encoder > > > > + * @encoder: the encoder to iterate bridges on > > > > + * @bridge: a bridge pointer updated to point to the current bridge at > > > > each > > > > + * iteration > > > > + * > > > > + * Iterate over all bridges present in the bridge chain attached to > > > > @encoder. > > > > + * > > > > + * Automatically gets/puts the bridge reference while iterating, and > > > > puts > > > > + * the reference even if returning or breaking in the middle of the > > > > loop. > > > > + */ > > > > +#define drm_for_each_bridge_in_chain_scoped(encoder, bridge) > > > > \ > > > > + for (struct drm_bridge *bridge __free(drm_bridge_put) = > > > > \ > > > > + drm_bridge_chain_get_first_bridge(encoder); > > > > \ > > > > > > So my understanding is that the initial value of bridge would be cleaned > > > up with drm_bridge_put... > > > > > > > + bridge; > > > > \ > > > > + bridge = drm_bridge_get_next_bridge_and_put(bridge)) > > > > > > ... but also when iterating? > > > > > > So if we have more than 0 values, we put two references? > > > > No, this is not the case. The __free action is executed only when > > exiting the entire for loop, not a single iteration. > > > > This is consistent with the fact that the loop variable is persistent > > across iterations. > > PS: here's the C language spec reference: > > > 6.8.5.3 The for statement > > The statement > > for ( clause-1 ; expression-2 ; expression-3 ) statement > > behaves as follows: > > [...] > > If clause-1 is a declaration, the scope of any identifiers it declares > > is the remainder of the declaration and the entire loop > > https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf > https://rgambord.github.io/c99-doc/sections/6/8/5/3/index.html I think my replies have proven the correctness of the bridge cleanup in this patch. Based on my arguments, do you agree this patch is correct? If it is, I think most of the remainder of this series is trivial to review, and it would be a good step forward for dynamic bridge lifetime implementation. Otherwise, don't hesitate to let me know your concerns. Best regards, Luca -- Luca Ceresoli, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
