Hi Thomas, > > The rte_pktmbuf_detach() function should decrease refcnt on a direct > > buffer. > > > > Signed-off-by: Hiroyuki Mikita <h.mikita89 at gmail.com> > > --- > > v2: > > * introduced a new function rte_pktmbuf_detach2() which decrease refcnt. > > As you have noticed, "whenever the indirect buffer is detached, > the reference counter on the direct buffer is decremented." > So the current behaviour of rte_pktmbuf_detach() is buggy. > Why not fix it without renaming? > If you consider this behavioral bug is part of the API, we > can fix it in a new function unattach and deprecate detach. > But Konstantin, why do you want to keep a restore function? > What is the need?
I think it might be a useful functionality in some situations: some users can attach/detach to external memory buffers (no mbufs) and similar functionality is required. Let say right now examples/vhost/main.c has its own pktmbuf_detach_zcp() which is doing pretty much the same - restore original values, after detaching mbuf from external (virtio) memory buffer. Would be good if we'll use a standard API function here. Konstantin > > Please explicit the function name for the detach operation in > doc/guides/prog_guide/mbuf_lib.rst (whatever detach2 or unattach). > > > * marked rte_pktmbuf_detach() as deprecated. > > * added comments about refcnt to rte_pktmbuf_attach() and > > rte_pktmbuf_detach(). > > * checked refcnt when detaching in unit tests. > > * added this issue to release notes.
