133 lines
3.5 KiB
Diff
133 lines
3.5 KiB
Diff
From: Felix Fietkau <nbd@nbd.name>
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Date: Mon, 8 Feb 2016 14:33:19 +0100
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Subject: [PATCH] cfg80211: reuse existing page fragments in A-MSDU rx
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This massively reduces data copying and thus improves rx performance
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Signed-off-by: Felix Fietkau <nbd@nbd.name>
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---
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--- a/net/wireless/util.c
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+++ b/net/wireless/util.c
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@@ -644,23 +644,93 @@ int ieee80211_data_from_8023(struct sk_b
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}
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EXPORT_SYMBOL(ieee80211_data_from_8023);
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+static void
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+__frame_add_frag(struct sk_buff *skb, struct page *page,
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+ void *ptr, int len, int size)
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+{
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+ struct skb_shared_info *sh = skb_shinfo(skb);
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+ int page_offset;
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+
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+ atomic_inc(&page->_count);
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+ page_offset = ptr - page_address(page);
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+ skb_add_rx_frag(skb, sh->nr_frags, page, page_offset, len, size);
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+}
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+
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+static void
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+__ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct sk_buff *frame,
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+ int offset, int len)
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+{
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+ struct skb_shared_info *sh = skb_shinfo(skb);
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+ const skb_frag_t *frag = &sh->frags[-1];
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+ struct page *frag_page;
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+ void *frag_ptr;
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+ int frag_len, frag_size;
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+ int head_size = skb->len - skb->data_len;
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+ int cur_len;
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+
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+ frag_page = virt_to_head_page(skb->head);
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+ frag_ptr = skb->data;
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+ frag_size = head_size;
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+
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+ while (offset >= frag_size) {
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+ offset -= frag_size;
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+ frag++;
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+ frag_page = skb_frag_page(frag);
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+ frag_ptr = skb_frag_address(frag);
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+ frag_size = skb_frag_size(frag);
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+ }
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+
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+ frag_ptr += offset;
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+ frag_len = frag_size - offset;
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+
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+ cur_len = min(len, frag_len);
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+
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+ __frame_add_frag(frame, frag_page, frag_ptr, cur_len, frag_size);
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+ len -= cur_len;
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+
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+ while (len > 0) {
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+ frag++;
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+ frag_len = skb_frag_size(frag);
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+ cur_len = min(len, frag_len);
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+ __frame_add_frag(frame, skb_frag_page(frag),
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+ skb_frag_address(frag), cur_len, frag_len);
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+ len -= cur_len;
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+ }
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+}
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+
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static struct sk_buff *
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__ieee80211_amsdu_copy(struct sk_buff *skb, unsigned int hlen,
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- int offset, int len)
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+ int offset, int len, bool reuse_frag)
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{
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struct sk_buff *frame;
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+ int cur_len = len;
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if (skb->len - offset < len)
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return NULL;
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/*
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+ * When reusing framents, copy some data to the head to simplify
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+ * ethernet header handling and speed up protocol header processing
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+ * in the stack later.
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+ */
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+ if (reuse_frag)
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+ cur_len = min_t(int, len, 32);
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+
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+ /*
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* Allocate and reserve two bytes more for payload
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* alignment since sizeof(struct ethhdr) is 14.
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*/
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- frame = dev_alloc_skb(hlen + sizeof(struct ethhdr) + 2 + len);
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+ frame = dev_alloc_skb(hlen + sizeof(struct ethhdr) + 2 + cur_len);
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skb_reserve(frame, hlen + sizeof(struct ethhdr) + 2);
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- skb_copy_bits(skb, offset, skb_put(frame, len), len);
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+ skb_copy_bits(skb, offset, skb_put(frame, cur_len), cur_len);
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+
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+ len -= cur_len;
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+ if (!len)
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+ return frame;
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+
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+ offset += cur_len;
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+ __ieee80211_amsdu_copy_frag(skb, frame, offset, len);
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return frame;
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}
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@@ -676,6 +746,7 @@ void ieee80211_amsdu_to_8023s(struct sk_
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u8 *payload;
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int offset = 0, remaining, err;
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struct ethhdr eth;
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+ bool reuse_frag = skb->head_frag && !skb_has_frag_list(skb);
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bool reuse_skb = false;
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bool last = false;
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@@ -703,12 +774,13 @@ void ieee80211_amsdu_to_8023s(struct sk_
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offset += sizeof(struct ethhdr);
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/* reuse skb for the last subframe */
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last = remaining <= subframe_len + padding;
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- if (!skb_is_nonlinear(skb) && last) {
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+ if (!skb_is_nonlinear(skb) && !reuse_frag && last) {
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skb_pull(skb, offset);
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frame = skb;
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reuse_skb = true;
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} else {
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- frame = __ieee80211_amsdu_copy(skb, hlen, offset, len);
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+ frame = __ieee80211_amsdu_copy(skb, hlen, offset, len,
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+ reuse_frag);
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if (!frame)
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goto purge;
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