Re: [PATCH bpf-next 04/14] xsk: introduce AF_XDP buffer allocation API

On 2020-05-08 13:55, Maxim Mikityanskiy wrote:

On 2020-05-07 13:42, Björn Töpel wrote:

quoted

From: Björn Töpel <redacted>

In order to simplify AF_XDP zero-copy enablement for NIC driver
developers, a new AF_XDP buffer allocation API is added. The
implementation is based on a single core (single producer/consumer)
buffer pool for the AF_XDP UMEM.

A buffer is allocated using the xsk_buff_alloc() function, and
returned using xsk_buff_free(). If a buffer is disassociated with the
pool, e.g. when a buffer is passed to an AF_XDP socket, a buffer is
said to be released. Currently, the release function is only used by
the AF_XDP internals and not visible to the driver.

Drivers using this API should register the XDP memory model with the
new MEM_TYPE_XSK_BUFF_POOL type.

The API is defined in net/xdp_sock_drv.h.

The buffer type is struct xdp_buff, and follows the lifetime of
regular xdp_buffs, i.e.  the lifetime of an xdp_buff is restricted to
a NAPI context. In other words, the API is not replacing xdp_frames.

In addition to introducing the API and implementations, the AF_XDP
core is migrated to use the new APIs.

rfc->v1: Fixed build errors/warnings for m68k and riscv. (kbuild test
          robot)
          Added headroom/chunk size getter. (Maxim/Björn)

Signed-off-by: Maxim Mikityanskiy <redacted>
Signed-off-by: Björn Töpel <redacted>

Björn's signoff should go first (as the original author).

Oh, I didn't know that. I'll fix in the next revision!