This patchset fix page_pool API and users, such that drivers can use it for DMA-mapping. A number of places exist, where the DMA-mapping would not get released/unmapped, all these are fixed. This occurs e.g. when an xdp_frame gets converted to an SKB. As network stack doesn't have any callback for XDP memory models.
The patchset also address a shutdown race-condition. Today removing a XDP memory model, based on page_pool, is only delayed one RCU grace period. This isn't enough as redirected xdp_frames can still be in-flight on different queues (remote driver TX, cpumap or veth). We stress that when drivers use page_pool for DMA-mapping, then they MUST use one packet per page. This might change in the future, but more work lies ahead, before we can lift this restriction. This patchset change the page_pool API to be more strict, as in-flight page accounting is added. --- Ilias Apalodimas (2): net: page_pool: add helper function to retrieve dma addresses net: page_pool: add helper function to unmap dma addresses Jesper Dangaard Brouer (9): xdp: fix leak of IDA cyclic id if rhashtable_insert_slow fails xdp: page_pool related fix to cpumap veth: use xdp_release_frame for XDP_PASS page_pool: introduce page_pool_free and use in mlx5 mlx5: more strict use of page_pool API xdp: tracking page_pool resources and safe removal xdp: force mem allocator removal and periodic warning xdp: add tracepoints for XDP mem page_pool: add tracepoints for page_pool with details need by XDP drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 12 +- drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 3 - drivers/net/veth.c | 1 include/net/page_pool.h | 69 +++++++++++- include/net/xdp.h | 15 +++ include/net/xdp_priv.h | 23 ++++ include/trace/events/page_pool.h | 87 +++++++++++++++ include/trace/events/xdp.h | 115 ++++++++++++++++++++ kernel/bpf/cpumap.c | 3 + net/core/net-traces.c | 4 + net/core/page_pool.c | 87 +++++++++++++-- net/core/xdp.c | 120 ++++++++++++++++++--- 12 files changed, 494 insertions(+), 45 deletions(-) create mode 100644 include/net/xdp_priv.h create mode 100644 include/trace/events/page_pool.h --