From ea0d7d9181b0831f1b570b02fa02a15f25520c12 Mon Sep 17 00:00:00 2001 From: Scott Feldman Date: Thu, 3 Sep 2009 17:02:03 +0000 Subject: [PATCH] enic: bug fix: split TSO fragments larger than 16K into multiple descs enic WQ desc supports a maximum 16K buf size, so split any send fragments larger than 16K into several descs. Signed-off-by: Scott Feldman Signed-off-by: David S. Miller --- drivers/net/enic/enic_main.c | 87 ++++++++++++++++++++++++++++-------- 1 file changed, 69 insertions(+), 18 deletions(-) diff --git a/drivers/net/enic/enic_main.c b/drivers/net/enic/enic_main.c index 58cae6e6a59c..bc5cb225ddac 100644 --- a/drivers/net/enic/enic_main.c +++ b/drivers/net/enic/enic_main.c @@ -44,10 +44,15 @@ #include "enic.h" #define ENIC_NOTIFY_TIMER_PERIOD (2 * HZ) +#define WQ_ENET_MAX_DESC_LEN (1 << WQ_ENET_LEN_BITS) +#define MAX_TSO (1 << 16) +#define ENIC_DESC_MAX_SPLITS (MAX_TSO / WQ_ENET_MAX_DESC_LEN + 1) + +#define PCI_DEVICE_ID_CISCO_VIC_ENET 0x0043 /* ethernet vnic */ /* Supported devices */ static struct pci_device_id enic_id_table[] = { - { PCI_VDEVICE(CISCO, 0x0043) }, + { PCI_VDEVICE(CISCO, PCI_DEVICE_ID_CISCO_VIC_ENET) }, { 0, } /* end of table */ }; @@ -310,7 +315,8 @@ static int enic_wq_service(struct vnic_dev *vdev, struct cq_desc *cq_desc, opaque); if (netif_queue_stopped(enic->netdev) && - vnic_wq_desc_avail(&enic->wq[q_number]) >= MAX_SKB_FRAGS + 1) + vnic_wq_desc_avail(&enic->wq[q_number]) >= + (MAX_SKB_FRAGS + ENIC_DESC_MAX_SPLITS)) netif_wake_queue(enic->netdev); spin_unlock(&enic->wq_lock[q_number]); @@ -525,7 +531,11 @@ static inline void enic_queue_wq_skb_vlan(struct enic *enic, unsigned int len_left = skb->len - head_len; int eop = (len_left == 0); - /* Queue the main skb fragment */ + /* Queue the main skb fragment. The fragments are no larger + * than max MTU(9000)+ETH_HDR_LEN(14) bytes, which is less + * than WQ_ENET_MAX_DESC_LEN length. So only one descriptor + * per fragment is queued. + */ enic_queue_wq_desc(wq, skb, pci_map_single(enic->pdev, skb->data, head_len, PCI_DMA_TODEVICE), @@ -547,7 +557,11 @@ static inline void enic_queue_wq_skb_csum_l4(struct enic *enic, unsigned int csum_offset = hdr_len + skb->csum_offset; int eop = (len_left == 0); - /* Queue the main skb fragment */ + /* Queue the main skb fragment. The fragments are no larger + * than max MTU(9000)+ETH_HDR_LEN(14) bytes, which is less + * than WQ_ENET_MAX_DESC_LEN length. So only one descriptor + * per fragment is queued. + */ enic_queue_wq_desc_csum_l4(wq, skb, pci_map_single(enic->pdev, skb->data, head_len, PCI_DMA_TODEVICE), @@ -565,10 +579,14 @@ static inline void enic_queue_wq_skb_tso(struct enic *enic, struct vnic_wq *wq, struct sk_buff *skb, unsigned int mss, int vlan_tag_insert, unsigned int vlan_tag) { - unsigned int head_len = skb_headlen(skb); - unsigned int len_left = skb->len - head_len; + unsigned int frag_len_left = skb_headlen(skb); + unsigned int len_left = skb->len - frag_len_left; unsigned int hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb); int eop = (len_left == 0); + unsigned int len; + dma_addr_t dma_addr; + unsigned int offset = 0; + skb_frag_t *frag; /* Preload TCP csum field with IP pseudo hdr calculated * with IP length set to zero. HW will later add in length @@ -584,17 +602,49 @@ static inline void enic_queue_wq_skb_tso(struct enic *enic, &ipv6_hdr(skb)->daddr, 0, IPPROTO_TCP, 0); } - /* Queue the main skb fragment */ - enic_queue_wq_desc_tso(wq, skb, - pci_map_single(enic->pdev, skb->data, - head_len, PCI_DMA_TODEVICE), - head_len, - mss, hdr_len, - vlan_tag_insert, vlan_tag, - eop); + /* Queue WQ_ENET_MAX_DESC_LEN length descriptors + * for the main skb fragment + */ + while (frag_len_left) { + len = min(frag_len_left, (unsigned int)WQ_ENET_MAX_DESC_LEN); + dma_addr = pci_map_single(enic->pdev, skb->data + offset, + len, PCI_DMA_TODEVICE); + enic_queue_wq_desc_tso(wq, skb, + dma_addr, + len, + mss, hdr_len, + vlan_tag_insert, vlan_tag, + eop && (len == frag_len_left)); + frag_len_left -= len; + offset += len; + } - if (!eop) - enic_queue_wq_skb_cont(enic, wq, skb, len_left); + if (eop) + return; + + /* Queue WQ_ENET_MAX_DESC_LEN length descriptors + * for additional data fragments + */ + for (frag = skb_shinfo(skb)->frags; len_left; frag++) { + len_left -= frag->size; + frag_len_left = frag->size; + offset = frag->page_offset; + + while (frag_len_left) { + len = min(frag_len_left, + (unsigned int)WQ_ENET_MAX_DESC_LEN); + dma_addr = pci_map_page(enic->pdev, frag->page, + offset, len, + PCI_DMA_TODEVICE); + enic_queue_wq_desc_cont(wq, skb, + dma_addr, + len, + (len_left == 0) && + (len == frag_len_left)); /* EOP? */ + frag_len_left -= len; + offset += len; + } + } } static inline void enic_queue_wq_skb(struct enic *enic, @@ -648,7 +698,8 @@ static netdev_tx_t enic_hard_start_xmit(struct sk_buff *skb, spin_lock_irqsave(&enic->wq_lock[0], flags); - if (vnic_wq_desc_avail(wq) < skb_shinfo(skb)->nr_frags + 1) { + if (vnic_wq_desc_avail(wq) < + skb_shinfo(skb)->nr_frags + ENIC_DESC_MAX_SPLITS) { netif_stop_queue(netdev); /* This is a hard error, log it */ printk(KERN_ERR PFX "%s: BUG! Tx ring full when " @@ -659,7 +710,7 @@ static netdev_tx_t enic_hard_start_xmit(struct sk_buff *skb, enic_queue_wq_skb(enic, wq, skb); - if (vnic_wq_desc_avail(wq) < MAX_SKB_FRAGS + 1) + if (vnic_wq_desc_avail(wq) < MAX_SKB_FRAGS + ENIC_DESC_MAX_SPLITS) netif_stop_queue(netdev); spin_unlock_irqrestore(&enic->wq_lock[0], flags); -- 2.20.1