Return-path: Received: from nbd.name ([46.4.11.11]:60830 "EHLO nbd.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751762AbcBHNep (ORCPT ); Mon, 8 Feb 2016 08:34:45 -0500 From: Felix Fietkau To: linux-wireless@vger.kernel.org Cc: johannes@sipsolutions.net Subject: [PATCH] cfg80211: reuse existing page fragments in A-MSDU rx Date: Mon, 8 Feb 2016 14:34:42 +0100 Message-Id: <1454938482-81027-1-git-send-email-nbd@openwrt.org> (sfid-20160208_143449_162815_D5CFBE8E) Sender: linux-wireless-owner@vger.kernel.org List-ID: This massively reduces data copying and thus improves rx performance Signed-off-by: Felix Fietkau --- net/wireless/util.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 77 insertions(+), 5 deletions(-) diff --git a/net/wireless/util.c b/net/wireless/util.c index 9880c89..c7f6820 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -644,23 +644,93 @@ int ieee80211_data_from_8023(struct sk_buff *skb, const u8 *addr, } EXPORT_SYMBOL(ieee80211_data_from_8023); +static void +__frame_add_frag(struct sk_buff *skb, struct page *page, + void *ptr, int len, int size) +{ + struct skb_shared_info *sh = skb_shinfo(skb); + int page_offset; + + atomic_inc(&page->_count); + page_offset = ptr - page_address(page); + skb_add_rx_frag(skb, sh->nr_frags, page, page_offset, len, size); +} + +static void +__ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct sk_buff *frame, + int offset, int len) +{ + struct skb_shared_info *sh = skb_shinfo(skb); + const skb_frag_t *frag = &sh->frags[-1]; + struct page *frag_page; + void *frag_ptr; + int frag_len, frag_size; + int head_size = skb->len - skb->data_len; + int cur_len; + + frag_page = virt_to_head_page(skb->head); + frag_ptr = skb->data; + frag_size = head_size; + + while (offset >= frag_size) { + offset -= frag_size; + frag++; + frag_page = skb_frag_page(frag); + frag_ptr = skb_frag_address(frag); + frag_size = skb_frag_size(frag); + } + + frag_ptr += offset; + frag_len = frag_size - offset; + + cur_len = min(len, frag_len); + + __frame_add_frag(frame, frag_page, frag_ptr, cur_len, frag_size); + len -= cur_len; + + while (len > 0) { + frag++; + frag_len = skb_frag_size(frag); + cur_len = min(len, frag_len); + __frame_add_frag(frame, skb_frag_page(frag), + skb_frag_address(frag), cur_len, frag_len); + len -= cur_len; + } +} + static struct sk_buff * __ieee80211_amsdu_copy(struct sk_buff *skb, unsigned int hlen, - int offset, int len) + int offset, int len, bool reuse_frag) { struct sk_buff *frame; + int cur_len = len; if (skb->len - offset < len) return NULL; /* + * When reusing framents, copy some data to the head to simplify + * ethernet header handling and speed up protocol header processing + * in the stack later. + */ + if (reuse_frag) + cur_len = min_t(int, len, 32); + + /* * Allocate and reserve two bytes more for payload * alignment since sizeof(struct ethhdr) is 14. */ - frame = dev_alloc_skb(hlen + sizeof(struct ethhdr) + 2 + len); + frame = dev_alloc_skb(hlen + sizeof(struct ethhdr) + 2 + cur_len); skb_reserve(frame, hlen + sizeof(struct ethhdr) + 2); - skb_copy_bits(skb, offset, skb_put(frame, len), len); + skb_copy_bits(skb, offset, skb_put(frame, cur_len), cur_len); + + len -= cur_len; + if (!len) + return frame; + + offset += cur_len; + __ieee80211_amsdu_copy_frag(skb, frame, offset, len); return frame; } @@ -676,6 +746,7 @@ void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list, u8 *payload; int offset = 0, remaining, err; struct ethhdr eth; + bool reuse_frag = skb->head_frag && !skb_has_frag_list(skb); bool reuse_skb = false; bool last = false; @@ -703,12 +774,13 @@ void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list, offset += sizeof(struct ethhdr); /* reuse skb for the last subframe */ last = remaining <= subframe_len + padding; - if (!skb_is_nonlinear(skb) && last) { + if (!skb_is_nonlinear(skb) && !reuse_frag && last) { skb_pull(skb, offset); frame = skb; reuse_skb = true; } else { - frame = __ieee80211_amsdu_copy(skb, hlen, offset, len); + frame = __ieee80211_amsdu_copy(skb, hlen, offset, len, + reuse_frag); if (!frame) goto purge; -- 2.2.2