[PATCH RFC v2 6/9] xdp: Add a flag for disabling napi_direct of xdp_return_frame in xdp_mem_info
From: Toshiaki Makita <hidden>
Date: 2018-06-10 16:02:37
Subsystem:
networking [general], the rest, xdp (express data path) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Alexei Starovoitov, Daniel Borkmann, David S. Miller, Jesper Dangaard Brouer, John Fastabend
From: Toshiaki Makita <redacted> We need some mechanism to disable napi_direct on calling xdp_return_frame_rx_napi() from some context. When veth gets support of XDP_REDIRECT, it will redirects packets which are redirected from other devices. On redirection veth will reuse xdp_mem_info of the redirection source device to make return_frame work. But in this case .ndo_xdp_xmit() called from veth redirection uses xdp_mem_info which is not guarded by NAPI, because the .ndo_xdp_xmit is not called directly from the rxq which owns the xdp_mem_info. This approach introduces a flag in xdp_mem_info to indicate that napi_direct should be disabled even when _rx_napi variant is used. Signed-off-by: Toshiaki Makita <redacted> --- include/net/xdp.h | 4 ++++ net/core/xdp.c | 6 ++++-- 2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/include/net/xdp.h b/include/net/xdp.h
index 2deea7166a34..ea0c80f6c8ee 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h@@ -41,6 +41,9 @@ enum xdp_mem_type { MEM_TYPE_MAX, }; +/* XDP flags for xdp_mem_info */ +#define XDP_MEM_RF_NO_DIRECT BIT(0) /* don't use napi_direct */ + /* XDP flags for ndo_xdp_xmit */ #define XDP_XMIT_FLUSH (1U << 0) /* doorbell signal consumer */ #define XDP_XMIT_FLAGS_MASK XDP_XMIT_FLUSH
@@ -48,6 +51,7 @@ enum xdp_mem_type { struct xdp_mem_info { u32 type; /* enum xdp_mem_type, but known size type */ u32 id; + u32 flags; }; struct page_pool;
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 9d1f22072d5d..e94f146360b2 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c@@ -327,10 +327,12 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */ xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); page = virt_to_head_page(data); - if (xa) + if (xa) { + napi_direct &= !(mem->flags & XDP_MEM_RF_NO_DIRECT); page_pool_put_page(xa->page_pool, page, napi_direct); - else + } else { put_page(page); + } rcu_read_unlock(); break; case MEM_TYPE_PAGE_SHARED:
--
2.14.3