On 4/22/25 14:56, Mina Almasry wrote:
On Tue, Apr 22, 2025 at 1:43 AM Pavel Begunkov <asml.silence@xxxxxxxxx> wrote:
On 4/18/25 00:15, Mina Almasry wrote:
Currently net_iovs support only pp ref counts, and do not support a
page ref equivalent.
Makes me wonder why it's needed. In theory, nobody should ever be
taking page references without going through struct ubuf_info
handling first, all in kernel users of these pages should always
be paired with ubuf_info, as it's user memory, it's not stable,
and without ubuf_info the user is allowed to overwrite it.
The concern about the stability of the from-userspace data is already
called out in the MSG_ZEROCOPY documentation that we're piggybacking
devmem TX onto:
Sure, I didn't object that. There is no problem as long as the
ubuf_info semantics is followed, which by extension mean that
any ref manipulation should already be gated on ubuf_info, and
there should be no need in changing generic paths.
--
Pavel Begunkov
