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Date: Fri, 8 Oct 2010 16:57:40 -0700
From: "Duyck, Alexander H" <alexander.h.duyck@...el.com>
To: David Miller <davem@...emloft.net>
CC: "Kirsher, Jeffrey T" <jeffrey.t.kirsher@...el.com>,
"Brandeburg, Jesse" <jesse.brandeburg@...el.com>,
"Allan, Bruce W" <bruce.w.allan@...el.com>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [RFC] ixgbe: v3 normalize frag_list usage
Dave,
Below is the new and improved version of the RSC chaining approach. Basically
I am holding off on merging the SKB into the frame until the SKB has data in
order to make it take a more standard approach.
Let me know if this will work with the new pointer structure.
Thanks,
Alex
---
This change drops the RSC queue approach and instead creates a normalized
frag_list skb but the tail is kept active and regularly merged into the
host SKB every time it is completed. In order to identify the tail skb
as a tail we set the head pointer in the RSC CB block of the skb. To locate
the head we just need to check to see if skb->prev is set and make sure to
clean up the pointer before we pass it up to the stack.
Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com>
---
drivers/net/ixgbe/ixgbe.h | 3 +
drivers/net/ixgbe/ixgbe_main.c | 96 +++++++++++++++++++++++-----------------
2 files changed, 58 insertions(+), 41 deletions(-)
diff --git a/drivers/net/ixgbe/ixgbe.h b/drivers/net/ixgbe/ixgbe.h
index a62d19c..397f9e1 100644
--- a/drivers/net/ixgbe/ixgbe.h
+++ b/drivers/net/ixgbe/ixgbe.h
@@ -469,8 +469,9 @@ enum ixbge_state_t {
};
struct ixgbe_rsc_cb {
+ struct sk_buff *head;
dma_addr_t dma;
- u16 skb_cnt;
+ u16 append_cnt;
bool delay_unmap;
};
#define IXGBE_RSC_CB(skb) ((struct ixgbe_rsc_cb *)(skb)->cb)
diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c
index 8edce66..104a833 100644
--- a/drivers/net/ixgbe/ixgbe_main.c
+++ b/drivers/net/ixgbe/ixgbe_main.c
@@ -1251,34 +1251,51 @@ static inline u16 ixgbe_get_hlen(union ixgbe_adv_rx_desc *rx_desc)
}
/**
- * ixgbe_transform_rsc_queue - change rsc queue into a full packet
- * @skb: pointer to the last skb in the rsc queue
+ * ixgbe_merge_active_tail - merge active tail into frag_list skb
+ * @tail: pointer to active tail in frag_list
*
- * This function changes a queue full of hw rsc buffers into a completed
- * packet. It uses the ->prev pointers to find the first packet and then
- * turns it into the frag list owner.
+ * This function merges the length and data of an active tail into the
+ * skb containing the frag_list. It resets the tail's pointer to the head,
+ * but it leaves the heads pointer to tail intact.
**/
-static inline struct sk_buff *ixgbe_transform_rsc_queue(struct sk_buff *skb)
+static inline struct sk_buff *ixgbe_merge_active_tail(struct sk_buff *tail)
{
- unsigned int frag_list_size = 0;
- unsigned int skb_cnt = 1;
+ struct sk_buff *head = IXGBE_RSC_CB(tail)->head;
- while (skb->prev) {
- struct sk_buff *prev = skb->prev;
- frag_list_size += skb->len;
- skb->prev = NULL;
- skb = prev;
- skb_cnt++;
- }
+ if (!head)
+ return tail;
+
+ IXGBE_RSC_CB(tail)->head = NULL;
+
+ if (head->prev)
+ head->prev->next = tail;
+ else
+ skb_shinfo(head)->frag_list = tail;
+
+ head->len += tail->len;
+ head->data_len += tail->len;
+ head->truesize += tail->len;
- skb_shinfo(skb)->frag_list = skb->next;
- skb->next = NULL;
- skb->len += frag_list_size;
- skb->data_len += frag_list_size;
- skb->truesize += frag_list_size;
- IXGBE_RSC_CB(skb)->skb_cnt = skb_cnt;
+ head->prev = tail;
+ IXGBE_RSC_CB(head)->append_cnt++;
- return skb;
+ return head;
+}
+
+/**
+ * ixgbe_close_active_frag_list - cleanup pointers on a frag_list skb
+ * @head: pointer to head of an active frag list
+ *
+ * This function will clear the frag_tail_tracker pointer on an active
+ * frag_list and returns true if the pointer was actually set
+ **/
+static inline bool ixgbe_close_active_frag_list(struct sk_buff *head)
+{
+ if (head->prev) {
+ head->prev = NULL;
+ return true;
+ }
+ return false;
}
static inline bool ixgbe_get_rsc_state(union ixgbe_adv_rx_desc *rx_desc)
@@ -1397,6 +1414,8 @@ static void ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
next_buffer = &rx_ring->rx_buffer_info[i];
}
+ skb = ixgbe_merge_active_tail(skb);
+
if (!(staterr & IXGBE_RXD_STAT_EOP)) {
if (ring_is_ps_enabled(rx_ring)) {
rx_buffer_info->skb = next_buffer->skb;
@@ -1404,15 +1423,13 @@ static void ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
next_buffer->skb = skb;
next_buffer->dma = 0;
} else {
- skb->next = next_buffer->skb;
- skb->next->prev = skb;
+ IXGBE_RSC_CB(next_buffer->skb)->head = skb;
}
rx_ring->rx_stats.non_eop_descs++;
goto next_desc;
}
- if (skb->prev) {
- skb = ixgbe_transform_rsc_queue(skb);
+ if (ixgbe_close_active_frag_list(skb)) {
/* if we got here without RSC the packet is invalid */
if (!pkt_is_rsc) {
__pskb_trim(skb, 0);
@@ -1437,7 +1454,7 @@ static void ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
skb_shinfo(skb)->nr_frags;
else
rx_ring->rx_stats.rsc_count +=
- IXGBE_RSC_CB(skb)->skb_cnt;
+ IXGBE_RSC_CB(skb)->append_cnt;
rx_ring->rx_stats.rsc_flush++;
}
@@ -3907,19 +3924,18 @@ static void ixgbe_clean_rx_ring(struct ixgbe_ring *rx_ring)
if (rx_buffer_info->skb) {
struct sk_buff *skb = rx_buffer_info->skb;
rx_buffer_info->skb = NULL;
- do {
- struct sk_buff *this = skb;
- if (IXGBE_RSC_CB(this)->delay_unmap) {
- dma_unmap_single(dev,
- IXGBE_RSC_CB(this)->dma,
- rx_ring->rx_buf_len,
- DMA_FROM_DEVICE);
- IXGBE_RSC_CB(this)->dma = 0;
- IXGBE_RSC_CB(skb)->delay_unmap = false;
- }
- skb = skb->prev;
- dev_kfree_skb(this);
- } while (skb);
+ /* We need to clean up RSC frag lists */
+ skb = ixgbe_merge_active_tail(skb);
+ ixgbe_close_active_frag_list(skb);
+ if (IXGBE_RSC_CB(skb)->delay_unmap) {
+ dma_unmap_single(dev,
+ IXGBE_RSC_CB(skb)->dma,
+ rx_ring->rx_buf_len,
+ DMA_FROM_DEVICE);
+ IXGBE_RSC_CB(skb)->dma = 0;
+ IXGBE_RSC_CB(skb)->delay_unmap = false;
+ }
+ dev_kfree_skb(skb);
}
if (!rx_buffer_info->page)
continue;
--
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