[PATCH v4 12/23] iommufd/driver: Add iommufd_hw_queue_depend/undepend() helpers

[Nicolin Chen]

On Thu, May 15, 2025 at 01:12:54PM -0300, Jason Gunthorpe wrote:
> On Thu, May 08, 2025 at 08:02:33PM -0700, Nicolin Chen wrote:
> 
> > +/*
> > + * Helpers for IOMMU driver to build/destroy a dependency between two sibling
> > + * structures created by one of the allocators above
> > + */
> > +#define iommufd_hw_queue_depend(dependent, depended, member)                   \
> > +	({                                                                     \
> > +		static_assert(__same_type(struct iommufd_hw_queue,             \
> > +					  dependent->member));                 \
> > +		static_assert(offsetof(typeof(*dependent), member.obj) == 0);  \
> > +		static_assert(__same_type(struct iommufd_hw_queue,             \
> > +					  depended->member));                  \
> > +		static_assert(offsetof(typeof(*depended), member.obj) == 0);   \
> > +		_iommufd_object_depend(&dependent->member.obj,                 \
> > +				       &depended->member.obj);                 \
> > +	})
> 
> This doesn't need the offsetof == 0 checks, it isn't an allocator. And
> you want to check that the two structs have the same type:
> 
> static_assert(__same_type(struct iommufd_hw_queue, dependent->member));
> static_assert(__same_type(typeof(*dependent), *dependend));

Ack. I also added ictx comparison:

+#define iommufd_hw_queue_depend(dependent, depended, member)                   \
+       ({                                                                     \
+               int ret = -EINVAL;                                             \
+                                                                              \
+               static_assert(__same_type(struct iommufd_hw_queue,             \
+                                         dependent->member));                 \
+               static_assert(__same_type(typeof(*dependent), *depended));     \
+               if (!WARN_ON_ONCE(dependent->member.ictx !=                    \
+                                 depended->member.ictx))                      \
+                       ret = _iommufd_object_depend(&dependent->member.obj,   \
+                                                    &depended->member.obj);   \
+               ret;                                                           \
+       })
+
+#define iommufd_hw_queue_undepend(dependent, depended, member)                 \
+       ({                                                                     \
+               static_assert(__same_type(struct iommufd_hw_queue,             \
+                                         dependent->member));                 \
+               static_assert(__same_type(typeof(*dependent), *depended));     \
+               WARN_ON_ONCE(dependent->member.ictx != depended->member.ictx); \
+               _iommufd_object_undepend(&dependent->member.obj,               \
+                                        &depended->member.obj);               \
+       })

Thanks
Nicolin