On Sun, Jan 21, 2024 at 07:06:03PM +0100, Lukas Wunner wrote: > On Sun, Jan 14, 2024 at 05:19:57PM +0000, Jonathan Cameron wrote: > > v1: Thanks to Andy for reviewing the RFC. > > Add check for if (!IS_ERR_OR_NULL(_T)) to allow the compiler to optimize > > cases where it knows the passed in parameter is NULL or an error pointer. > > Heads-up: Using IS_ERR_OR_NULL() in DEFINE_FREE() macros bloats > the code with additional IS_ERR() checks and NULL pointer checks. > > See the detailed explanation in this patch which adds a DEFINE_FREE() > macro for x509_free_certificate(): > > https://lore.kernel.org/all/70ecd3904a70d2b92f8f1e04365a2b9ce66fac25.1705857475.git.lukas@xxxxxxxxx/ > > I'm wondering if a solution might be to stop returning IS_ERR() > from "constructors" such as x509_cert_parse() and instead assign > the created "object" (x509_certificate) to a call-by-reference > pointer and return an integer. If the returned integer is not 0, > inhibit "destruction" of the "object" with no_free_ptr(). Another idea would be to use a call-by-reference pointer and check the pointer instead of the return code. E.g.: DEFINE_FREE(x509_free_certificate, struct x509_certificate *, if (_T) x509_free_certificate(_T)) ... struct x509_certificate __free(x509_free_certificate) = NULL; int ret; ret = x509_cert_parse(&cert, buf, len); if (!cert) return ret;
