Skip to content

Commit

Permalink
enic: bug fix: split TSO fragments larger than 16K into multiple descs
Browse files Browse the repository at this point in the history 
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 <scofeldm@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
  • Loading branch information
Scott Feldman authored and David S. Miller committed Sep 4, 2009
1 parent 4badc38 commit ea0d7d9
Showing 1 changed file with 69 additions and 18 deletions.
87 changes: 69 additions & 18 deletions drivers/net/enic/enic_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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 */
};

Expand Down Expand Up @@ -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]);
Expand Down Expand Up @@ -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),
Expand All @@ -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),
Expand All @@ -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
Expand All @@ -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,
Expand Down Expand Up @@ -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 "
Expand All @@ -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);
Expand Down

0 comments on commit ea0d7d9

Please sign in to comment.