> -----Original Message-----
> From: lng-odp [mailto:[email protected]] On Behalf Of
> Verma, Shally
> Sent: Wednesday, March 01, 2017 10:38 AM
> To: Francois Ozog <[email protected]>
> Cc: [email protected]
> Subject: Re: [lng-odp] Generic handle in ODP
>
> HI Francois
>
> What you said is correct and in such case API should only have
> odp_packet_t as an its type signature and access memory as per
> implementation policy.
>
> I am talking about use case where an API can input data both as a plain
> buffer (which is a contiguous memory) *OR* as a packet (which is variable,
> scattered/non-scattered segmented memory). So when API sees that input
> data is from buffer pool, can simply use address returned by
> odp_buf_addr as memory pointer and do direct read/write (as its not
> segmented and contiguous memory) and when it sees chunk is from packet
> pool , then access data according to its base hw implementation.
>
> I am taking here a simple memcpy() pseudo example to explain case . Say,
> if I want to enable memcpy from both packet and buffer memory, then there
> are 2 ways of doing it:
>
> 1. Add two separate APIs , say memcpy_from_buffer(odp_buffer_t
> buf,size_t len, void *dst) and memcpy_from_packet(odp_packet_t packet,
> size_t len, void *) OR
>
> 2. Or, make one API say memcpy(odp_handle_t handle, odp_pool_t pool,
> size_t len, void *dst)
>
> {
>
> if (pool type== odp_buffer_t ) then
>
> addr=odp_buffer_addr((odp_buffer_t)handle);
>
> else
>
> addr=odp_packet_data((odp_packet_t)handle);
>
>
>
> memcpy(dst,addr,len);
>
> }
>
> Hope this could explain intended use case to an extent.
>
> Thanks
> Shally
As Maxim mentioned, odp_event_t is the single type (that is passed through
queues). An event can be buffer, packet, timeout, crypto/ipsec completion, etc.
Application needs to check event type and convert it to correct sub-type (e.g.
packet) to access the data/metadata.
Application needs to be careful to handle buffers vs. packets correctly.
Buffers are simple, always contiguous memory blocks - whereas packets may be
fragmented. The example above would break if a packet segment boundary is hit
between addr[0]...addr[len-1]. There are a bunch of packet_copy functions which
handle segmentation correctly.
if (odp_event_type(ev) == ODP_EVENT_PACKET) {
pkt = odp_packet_from_event(ev);
odp_packet_copy_to_mem(pkt, 0, len, dst);
} else if (odp_event_type(ev) == ODP_EVENT_BUFFER) {
buf = odp_buffer_from_event(ev);
addr = odp_buffer_addr(buf);
memcpy(dst, addr, len);
} else {
// BAD EVENT TYPE. NO DATA TO COPY.
}
-Petri
