From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B24F5C77B7C for ; Mon, 24 Apr 2023 08:50:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231336AbjDXIu0 (ORCPT ); Mon, 24 Apr 2023 04:50:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38802 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229507AbjDXIuY (ORCPT ); Mon, 24 Apr 2023 04:50:24 -0400 Received: from out30-97.freemail.mail.aliyun.com (out30-97.freemail.mail.aliyun.com [115.124.30.97]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3778FA8; Mon, 24 Apr 2023 01:50:22 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R151e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045170;MF=xuanzhuo@linux.alibaba.com;NM=1;PH=DS;RN=16;SR=0;TI=SMTPD_---0VgrC-uE_1682326217; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0VgrC-uE_1682326217) by smtp.aliyun-inc.com; Mon, 24 Apr 2023 16:50:18 +0800 Message-ID: <1682326210.6946251-1-xuanzhuo@linux.alibaba.com> Subject: Re: [PATCH bpf-next] xsk: Use pool->dma_pages to check for DMA Date: Mon, 24 Apr 2023 16:50:10 +0800 From: Xuan Zhuo To: Kal Conley Cc: Kal Conley , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Magnus Karlsson , Maciej Fijalkowski , Jonathan Lemon , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend References: <20230423180157.93559-1-kal.conley@dectris.com> In-Reply-To: <20230423180157.93559-1-kal.conley@dectris.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 23 Apr 2023 20:01:56 +0200, Kal Conley wrote: > Compare pool->dma_pages instead of pool->dma_pages_cnt to check for an > active DMA mapping. pool->dma_pages needs to be read anyway to access > the map so this compiles to more efficient code. > > Signed-off-by: Kal Conley > Acked-by: Magnus Karlsson Reviewed-by: Xuan Zhuo > --- > include/net/xsk_buff_pool.h | 2 +- > net/xdp/xsk_buff_pool.c | 7 ++++--- > 2 files changed, 5 insertions(+), 4 deletions(-) > > diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h > index d318c769b445..a8d7b8a3688a 100644 > --- a/include/net/xsk_buff_pool.h > +++ b/include/net/xsk_buff_pool.h > @@ -180,7 +180,7 @@ static inline bool xp_desc_crosses_non_contig_pg(struct xsk_buff_pool *pool, > if (likely(!cross_pg)) > return false; > > - return pool->dma_pages_cnt && > + return pool->dma_pages && > !(pool->dma_pages[addr >> PAGE_SHIFT] & XSK_NEXT_PG_CONTIG_MASK); > } > > diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c > index b2df1e0f8153..26f6d304451e 100644 > --- a/net/xdp/xsk_buff_pool.c > +++ b/net/xdp/xsk_buff_pool.c > @@ -350,7 +350,7 @@ void xp_dma_unmap(struct xsk_buff_pool *pool, unsigned long attrs) > { > struct xsk_dma_map *dma_map; > > - if (pool->dma_pages_cnt == 0) > + if (!pool->dma_pages) > return; > > dma_map = xp_find_dma_map(pool); > @@ -364,6 +364,7 @@ void xp_dma_unmap(struct xsk_buff_pool *pool, unsigned long attrs) > > __xp_dma_unmap(dma_map, attrs); > kvfree(pool->dma_pages); > + pool->dma_pages = NULL; > pool->dma_pages_cnt = 0; > pool->dev = NULL; > } > @@ -503,7 +504,7 @@ static struct xdp_buff_xsk *__xp_alloc(struct xsk_buff_pool *pool) > if (pool->unaligned) { > xskb = pool->free_heads[--pool->free_heads_cnt]; > xp_init_xskb_addr(xskb, pool, addr); > - if (pool->dma_pages_cnt) > + if (pool->dma_pages) > xp_init_xskb_dma(xskb, pool, pool->dma_pages, addr); > } else { > xskb = &pool->heads[xp_aligned_extract_idx(pool, addr)]; > @@ -569,7 +570,7 @@ static u32 xp_alloc_new_from_fq(struct xsk_buff_pool *pool, struct xdp_buff **xd > if (pool->unaligned) { > xskb = pool->free_heads[--pool->free_heads_cnt]; > xp_init_xskb_addr(xskb, pool, addr); > - if (pool->dma_pages_cnt) > + if (pool->dma_pages) > xp_init_xskb_dma(xskb, pool, pool->dma_pages, addr); > } else { > xskb = &pool->heads[xp_aligned_extract_idx(pool, addr)]; > -- > 2.39.2 >