[dpdk-dev] [PATCH v2 02/15] crypto: add total raw buffer length

[Akhil Goyal]

> > Hi Konstantin
> >
> > On 9/21/2021 12:58 AM, Akhil Goyal wrote:
> > >>> From: Gagandeep Singh <g.singh at nxp.com>
> > >>>
> > >>> The current crypto raw data vectors is extended to support
> > >>> rte_security usecases, where we need total data length to know
> > >>> how much additional memory space is available in buffer other
> > >>> than data length so that driver/HW can write expanded size
> > >>> data after encryption.
> > >>>
> > >>> Signed-off-by: Gagandeep Singh <g.singh at nxp.com>
> > >>> Acked-by: Akhil Goyal <gakhil at marvell.com>
> > >>> ---
> > >>>   lib/cryptodev/rte_crypto_sym.h | 6 ++++++
> > >>>   1 file changed, 6 insertions(+)
> > >>>
> > >>> diff --git a/lib/cryptodev/rte_crypto_sym.h
> > >> b/lib/cryptodev/rte_crypto_sym.h
> > >>> index dcc0bd5933..e5cef1fb72 100644
> > >>> --- a/lib/cryptodev/rte_crypto_sym.h
> > >>> +++ b/lib/cryptodev/rte_crypto_sym.h
> > >>> @@ -37,6 +37,8 @@ struct rte_crypto_vec {
> > >>>   	rte_iova_t iova;
> > >>>   	/** length of the data buffer */
> > >>>   	uint32_t len;
> > >>> +	/** total buffer length*/
> > >>> +	uint32_t tot_len;
> > >>>   };
> > >>>
> > >>>   /**
> > >>> @@ -980,12 +982,14 @@ rte_crypto_mbuf_to_vec(const struct
> rte_mbuf
> > >> *mb, uint32_t ofs, uint32_t len,
> > >>>   	seglen = mb->data_len - ofs;
> > >>>   	if (len <= seglen) {
> > >>>   		vec[0].len = len;
> > >>> +		vec[0].tot_len = mb->buf_len;
> > >> That doesn't look right.
> > >> We should take into a count mbuf headroom and input offset.
> > >> Something like:
> > >> vec[0].tot_len = mb->buf_len - rte_pktmbuf_headroom(m) - ofs;
> > >> Same in other places below.
> > >>
> > > I believe the packet can expand into headroom based on the protocol
> support.
> > Yes, total length is representing the total buffer length available. The
> > security protocol shall take care of the headroom and offsets.
> 
> Hmm, and how it will now how many bytes are in head-room, and how
> many are in tail-room?
> We either need to provide values for both, or assume that only tail-room is
> available for the driver.
I believe it should be starting point where output can be written till the end of buffer.
There should not be any headroom and tailroom for raw buffers.
It should be mbuf->buf_len - ofs.