From 2b43470add8c8ff1e1ee28dffc5c5df97e955d09 Mon Sep 17 00:00:00 2001 From: Björn Töpel Date: Wed, 20 May 2020 21:20:53 +0200 Subject: xsk: Introduce AF_XDP buffer allocation API MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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) v1->v2: Swapped SoBs. (Maxim) v2->v3: Initialize struct xdp_buff member frame_sz. (Björn) Add API to query the DMA address of a frame. (Maxim) Do DMA sync for CPU till the end of the frame to handle possible growth (frame_sz). (Maxim) Signed-off-by: Björn Töpel Signed-off-by: Maxim Mikityanskiy Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200520192103.355233-6-bjorn.topel@gmail.com --- net/core/xdp.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) (limited to 'net/core') diff --git a/net/core/xdp.c b/net/core/xdp.c index 490b8f5fa8ee..f0ce8b195193 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -17,6 +17,7 @@ #include #include /* struct xdp_mem_allocator */ #include +#include #define REG_STATE_NEW 0x0 #define REG_STATE_REGISTERED 0x1 @@ -361,7 +362,7 @@ EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model); * of xdp_frames/pages in those cases. */ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, - unsigned long handle) + unsigned long handle, struct xdp_buff *xdp) { struct xdp_mem_allocator *xa; struct page *page; @@ -390,6 +391,11 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); xa->zc_alloc->free(xa->zc_alloc, handle); rcu_read_unlock(); + break; + case MEM_TYPE_XSK_BUFF_POOL: + /* NB! Only valid from an xdp_buff! */ + xsk_buff_free(xdp); + break; default: /* Not possible, checked in xdp_rxq_info_reg_mem_model() */ break; @@ -398,19 +404,19 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, void xdp_return_frame(struct xdp_frame *xdpf) { - __xdp_return(xdpf->data, &xdpf->mem, false, 0); + __xdp_return(xdpf->data, &xdpf->mem, false, 0, NULL); } EXPORT_SYMBOL_GPL(xdp_return_frame); void xdp_return_frame_rx_napi(struct xdp_frame *xdpf) { - __xdp_return(xdpf->data, &xdpf->mem, true, 0); + __xdp_return(xdpf->data, &xdpf->mem, true, 0, NULL); } EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi); void xdp_return_buff(struct xdp_buff *xdp) { - __xdp_return(xdp->data, &xdp->rxq->mem, true, xdp->handle); + __xdp_return(xdp->data, &xdp->rxq->mem, true, xdp->handle, xdp); } EXPORT_SYMBOL_GPL(xdp_return_buff); -- cgit v1.2.3