kernel/include/net/xdp.h, branch linux-4.16.y

xdp/qede: setup xdp_rxq_info and intro xdp_rxq_info_is_reg

2018-01-05T23:21:21Z

The driver code qede_free_fp_array() depend on kfree() can be called with a NULL pointer. This stems from the qede_alloc_fp_array() function which either (kz)alloc memory for fp->txq or fp->rxq. This also simplifies error handling code in case of memory allocation failures, but xdp_rxq_info_unreg need to know the difference. Introduce xdp_rxq_info_is_reg() to handle if a memory allocation fails and detect this is the failure path by seeing that xdp_rxq_info was not registred yet, which first happens after successful alloaction in qede_init_fp(). Driver hook points for xdp_rxq_info: * reg : qede_init_fp * unreg: qede_free_fp_array Tested on actual hardware with samples/bpf program. V2: Driver have no proper error path for failed XDP RX-queue info reg, as qede_init_fp() is a void function. Cc: everest-linux-l2@cavium.com Cc: Ariel Elior Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Alexei Starovoitov

xdp: base API for new XDP rx-queue info concept

2018-01-05T23:21:20Z

This patch only introduce the core data structures and API functions. All XDP enabled drivers must use the API before this info can used. There is a need for XDP to know more about the RX-queue a given XDP frames have arrived on. For both the XDP bpf-prog and kernel side. Instead of extending xdp_buff each time new info is needed, the patch creates a separate read-mostly struct xdp_rxq_info, that contains this info. We stress this data/cache-line is for read-only info. This is NOT for dynamic per packet info, use the data_meta for such use-cases. The performance advantage is this info can be setup at RX-ring init time, instead of updating N-members in xdp_buff. A possible (driver level) micro optimization is that xdp_buff->rxq assignment could be done once per XDP/NAPI loop. The extra pointer deref only happens for program needing access to this info (thus, no slowdown to existing use-cases). Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Alexei Starovoitov