On 9/23/2019 9:03 PM, Eric Wong wrote: > This macro is popular within the Linux kernel for supporting > intrusive data structures such as linked lists, red-black trees, > and chained hash tables while allowing the compiler to do > type checking. > > I intend to use this to remove the limitation of "hashmap_entry" > being location-dependent and to allow more compile-time type > checking. nit: I don't know why the first-person singular language caused me to stumble during this message. Perhaps the following rewrite would convey the same information: Later patches will use container_of() to remove the limitation of "hashmap_entry" being location-dependent. This will complete the transition to compile-time type checking for the hashmap API. > This macro already exists in our source as "list_entry" in > list.h and making "list_entry" an alias to "container_of" > as the Linux kernel has done is a possibility. If it is the same code, then I would prefer you do this conversion now so we can see that equivalence in the patch AND we know that existing code will test it. Thanks, -Stolee > > Signed-off-by: Eric Wong <e@xxxxxxxxx> > --- > git-compat-util.h | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/git-compat-util.h b/git-compat-util.h > index 83be89de0a..4cc2c8283a 100644 > --- a/git-compat-util.h > +++ b/git-compat-util.h > @@ -1312,4 +1312,14 @@ void unleak_memory(const void *ptr, size_t len); > */ > #include "banned.h" > > +/* > + * container_of - Get the address of an object containing a field. > + * > + * @ptr: pointer to the field. > + * @type: type of the object. > + * @member: name of the field within the object. > + */ > +#define container_of(ptr, type, member) \ > + ((type *) ((char *)(ptr) - offsetof(type, member))) > + > #endif >
