[PATCH] sky2: fragmented receive for large MTU
Use hardware support for chained receive to break up large frames
into multiple pages. This avoids having to do a mult-page allocation
that can fail on a busy system due to fragmented memory.
For normal size MTU, this code behaves the same.
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index c83d726..7b19db5 100644
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -56,13 +56,12 @@
/*
* The Yukon II chipset takes 64 bit command blocks (called list elements)
* that are organized into three (receive, transmit, status) different rings
- * similar to Tigon3. A transmit can require several elements;
- * a receive requires one (or two if using 64 bit dma).
+ * similar to Tigon3.
*/
-#define RX_LE_SIZE 512
+#define RX_LE_SIZE 1024
#define RX_LE_BYTES (RX_LE_SIZE*sizeof(struct sky2_rx_le))
-#define RX_MAX_PENDING (RX_LE_SIZE/2 - 2)
+#define RX_MAX_PENDING (RX_LE_SIZE/6 - 2)
#define RX_DEF_PENDING RX_MAX_PENDING
#define RX_SKB_ALIGN 8
#define RX_BUF_WRITE 16
@@ -74,7 +73,6 @@
#define STATUS_RING_SIZE 2048 /* 2 ports * (TX + 2*RX) */
#define STATUS_LE_BYTES (STATUS_RING_SIZE*sizeof(struct sky2_status_le))
-#define ETH_JUMBO_MTU 9000
#define TX_WATCHDOG (5 * HZ)
#define NAPI_WEIGHT 64
#define PHY_RETRIES 1000
@@ -90,7 +88,7 @@
module_param(debug, int, 0);
MODULE_PARM_DESC(debug, "Debug level (0=none,...,16=all)");
-static int copybreak __read_mostly = 256;
+static int copybreak __read_mostly = 128;
module_param(copybreak, int, 0);
MODULE_PARM_DESC(copybreak, "Receive copy threshold");
@@ -803,12 +801,12 @@
return sizeof(a) > sizeof(u32) ? (a >> 16) >> 16 : 0;
}
-/* Build description to hardware about buffer */
-static void sky2_rx_add(struct sky2_port *sky2, dma_addr_t map)
+/* Build description to hardware for one receive segment */
+static void sky2_rx_add(struct sky2_port *sky2, u8 op,
+ dma_addr_t map, unsigned len)
{
struct sky2_rx_le *le;
u32 hi = high32(map);
- u16 len = sky2->rx_bufsize;
if (sky2->rx_addr64 != hi) {
le = sky2_next_rx(sky2);
@@ -820,9 +818,52 @@
le = sky2_next_rx(sky2);
le->addr = cpu_to_le32((u32) map);
le->length = cpu_to_le16(len);
- le->opcode = OP_PACKET | HW_OWNER;
+ le->opcode = op | HW_OWNER;
}
+/* Build description to hardware for one possibly fragmented skb */
+static void sky2_rx_submit(struct sky2_port *sky2,
+ const struct rx_ring_info *re)
+{
+ int i;
+
+ sky2_rx_add(sky2, OP_PACKET, re->data_addr, sky2->rx_data_size);
+
+ for (i = 0; i < skb_shinfo(re->skb)->nr_frags; i++)
+ sky2_rx_add(sky2, OP_BUFFER, re->frag_addr[i], PAGE_SIZE);
+}
+
+
+static void sky2_rx_map_skb(struct pci_dev *pdev, struct rx_ring_info *re,
+ unsigned size)
+{
+ struct sk_buff *skb = re->skb;
+ int i;
+
+ re->data_addr = pci_map_single(pdev, skb->data, size, PCI_DMA_FROMDEVICE);
+ pci_unmap_len_set(re, data_size, size);
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+ re->frag_addr[i] = pci_map_page(pdev,
+ skb_shinfo(skb)->frags[i].page,
+ skb_shinfo(skb)->frags[i].page_offset,
+ skb_shinfo(skb)->frags[i].size,
+ PCI_DMA_FROMDEVICE);
+}
+
+static void sky2_rx_unmap_skb(struct pci_dev *pdev, struct rx_ring_info *re)
+{
+ struct sk_buff *skb = re->skb;
+ int i;
+
+ pci_unmap_single(pdev, re->data_addr, pci_unmap_len(re, data_size),
+ PCI_DMA_FROMDEVICE);
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+ pci_unmap_page(pdev, re->frag_addr[i],
+ skb_shinfo(skb)->frags[i].size,
+ PCI_DMA_FROMDEVICE);
+}
/* Tell chip where to start receive checksum.
* Actually has two checksums, but set both same to avoid possible byte
@@ -886,9 +927,7 @@
struct rx_ring_info *re = sky2->rx_ring + i;
if (re->skb) {
- pci_unmap_single(sky2->hw->pdev,
- re->mapaddr, sky2->rx_bufsize,
- PCI_DMA_FROMDEVICE);
+ sky2_rx_unmap_skb(sky2->hw->pdev, re);
kfree_skb(re->skb);
re->skb = NULL;
}
@@ -969,38 +1008,57 @@
#endif
/*
+ * Allocate an skb for receiving. If the MTU is large enough
+ * make the skb non-linear with a fragment list of pages.
+ *
* It appears the hardware has a bug in the FIFO logic that
* cause it to hang if the FIFO gets overrun and the receive buffer
* is not 64 byte aligned. The buffer returned from netdev_alloc_skb is
* aligned except if slab debugging is enabled.
*/
-static inline struct sk_buff *sky2_alloc_skb(struct net_device *dev,
- unsigned int length,
- gfp_t gfp_mask)
+static struct sk_buff *sky2_rx_alloc(struct sky2_port *sky2)
{
struct sk_buff *skb;
+ unsigned long p;
+ int i;
- skb = __netdev_alloc_skb(dev, length + RX_SKB_ALIGN, gfp_mask);
- if (likely(skb)) {
- unsigned long p = (unsigned long) skb->data;
- skb_reserve(skb, ALIGN(p, RX_SKB_ALIGN) - p);
+ skb = netdev_alloc_skb(sky2->netdev, sky2->rx_data_size + RX_SKB_ALIGN);
+ if (!skb)
+ goto nomem;
+
+ p = (unsigned long) skb->data;
+ skb_reserve(skb, ALIGN(p, RX_SKB_ALIGN) - p);
+
+ for (i = 0; i < sky2->rx_nfrags; i++) {
+ struct page *page = alloc_page(GFP_ATOMIC);
+
+ if (!page)
+ goto free_partial;
+ skb_fill_page_desc(skb, i, page, 0, PAGE_SIZE);
}
return skb;
+free_partial:
+ kfree_skb(skb);
+nomem:
+ return NULL;
}
/*
* Allocate and setup receiver buffer pool.
- * In case of 64 bit dma, there are 2X as many list elements
- * available as ring entries
- * and need to reserve one list element so we don't wrap around.
+ * Normal case this ends up creating one list element for skb
+ * in the receive ring. Worst case if using large MTU and each
+ * allocation falls on a different 64 bit region, that results
+ * in 6 list elements per ring entry.
+ * One element is used for checksum enable/disable, and one
+ * extra to avoid wrap.
*/
static int sky2_rx_start(struct sky2_port *sky2)
{
struct sky2_hw *hw = sky2->hw;
+ struct rx_ring_info *re;
unsigned rxq = rxqaddr[sky2->port];
- int i;
- unsigned thresh;
+ unsigned i, size, space, thresh;
sky2->rx_put = sky2->rx_next = 0;
sky2_qset(hw, rxq);
@@ -1013,27 +1071,56 @@
sky2_prefetch_init(hw, rxq, sky2->rx_le_map, RX_LE_SIZE - 1);
rx_set_checksum(sky2);
- for (i = 0; i < sky2->rx_pending; i++) {
- struct rx_ring_info *re = sky2->rx_ring + i;
- re->skb = sky2_alloc_skb(sky2->netdev, sky2->rx_bufsize,
- GFP_KERNEL);
+ /* Space needed for frame data + headers rounded up */
+ size = ALIGN(sky2->netdev->mtu + ETH_HLEN + VLAN_HLEN, 8)
+ + 8;
+
+ /* Stopping point for hardware truncation */
+ thresh = (size - 8) / sizeof(u32);
+
+ /* Account for overhead of skb - to avoid order > 0 allocation */
+ space = SKB_DATA_ALIGN(size) + NET_SKB_PAD
+ + sizeof(struct skb_shared_info);
+
+ sky2->rx_nfrags = space >> PAGE_SHIFT;
+ BUG_ON(sky2->rx_nfrags > ARRAY_SIZE(re->frag_addr));
+
+ if (sky2->rx_nfrags != 0) {
+ /* Compute residue after pages */
+ space = sky2->rx_nfrags << PAGE_SHIFT;
+
+ if (space < size)
+ size -= space;
+ else
+ size = 0;
+
+ /* Optimize to handle small packets and headers */
+ if (size < copybreak)
+ size = copybreak;
+ if (size < ETH_HLEN)
+ size = ETH_HLEN;
+ }
+ sky2->rx_data_size = size;
+
+ /* Fill Rx ring */
+ for (i = 0; i < sky2->rx_pending; i++) {
+ re = sky2->rx_ring + i;
+
+ re->skb = sky2_rx_alloc(sky2);
if (!re->skb)
goto nomem;
- re->mapaddr = pci_map_single(hw->pdev, re->skb->data,
- sky2->rx_bufsize, PCI_DMA_FROMDEVICE);
- sky2_rx_add(sky2, re->mapaddr);
+ sky2_rx_map_skb(hw->pdev, re, sky2->rx_data_size);
+ sky2_rx_submit(sky2, re);
}
-
/*
* The receiver hangs if it receives frames larger than the
* packet buffer. As a workaround, truncate oversize frames, but
* the register is limited to 9 bits, so if you do frames > 2052
* you better get the MTU right!
*/
- thresh = (sky2->rx_bufsize - 8) / sizeof(u32);
if (thresh > 0x1ff)
sky2_write32(hw, SK_REG(sky2->port, RX_GMF_CTRL_T), RX_TRUNC_OFF);
else {
@@ -1041,7 +1128,6 @@
sky2_write32(hw, SK_REG(sky2->port, RX_GMF_CTRL_T), RX_TRUNC_ON);
}
-
/* Tell chip about available buffers */
sky2_write16(hw, Y2_QADDR(rxq, PREF_UNIT_PUT_IDX), sky2->rx_put);
return 0;
@@ -1743,15 +1829,6 @@
}
}
-
-/* Want receive buffer size to be multiple of 64 bits
- * and incl room for vlan and truncation
- */
-static inline unsigned sky2_buf_size(int mtu)
-{
- return ALIGN(mtu + ETH_HLEN + VLAN_HLEN, 8) + 8;
-}
-
static int sky2_change_mtu(struct net_device *dev, int new_mtu)
{
struct sky2_port *sky2 = netdev_priv(dev);
@@ -1786,7 +1863,7 @@
sky2_rx_clean(sky2);
dev->mtu = new_mtu;
- sky2->rx_bufsize = sky2_buf_size(new_mtu);
+
mode = DATA_BLIND_VAL(DATA_BLIND_DEF) |
GM_SMOD_VLAN_ENA | IPG_DATA_VAL(IPG_DATA_DEF);
@@ -1812,9 +1889,93 @@
return err;
}
+/* For small just reuse existing skb for next receive */
+static struct sk_buff *receive_copy(struct sky2_port *sky2,
+ const struct rx_ring_info *re,
+ unsigned length)
+{
+ struct sk_buff *skb;
+
+ skb = netdev_alloc_skb(sky2->netdev, length + 2);
+ if (likely(skb)) {
+ skb_reserve(skb, 2);
+ pci_dma_sync_single_for_cpu(sky2->hw->pdev, re->data_addr,
+ length, PCI_DMA_FROMDEVICE);
+ memcpy(skb->data, re->skb->data, length);
+ skb->ip_summed = re->skb->ip_summed;
+ skb->csum = re->skb->csum;
+ pci_dma_sync_single_for_device(sky2->hw->pdev, re->data_addr,
+ length, PCI_DMA_FROMDEVICE);
+ re->skb->ip_summed = CHECKSUM_NONE;
+ __skb_put(skb, length);
+ }
+ return skb;
+}
+
+/* Adjust length of skb with fragments to match received data */
+static void skb_put_frags(struct sk_buff *skb, unsigned int hdr_space,
+ unsigned int length)
+{
+ int i, num_frags;
+ unsigned int size;
+
+ /* put header into skb */
+ size = min(length, hdr_space);
+ skb->tail += size;
+ skb->len += size;
+ length -= size;
+
+ num_frags = skb_shinfo(skb)->nr_frags;
+ for (i = 0; i < num_frags; i++) {
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+ if (length == 0) {
+ /* don't need this page */
+ __free_page(frag->page);
+ --skb_shinfo(skb)->nr_frags;
+ } else {
+ size = min(length, (unsigned) PAGE_SIZE);
+
+ frag->size = size;
+ skb->data_len += size;
+ skb->truesize += size;
+ skb->len += size;
+ length -= size;
+ }
+ }
+}
+
+/* Normal packet - take skb from ring element and put in a new one */
+static struct sk_buff *receive_new(struct sky2_port *sky2,
+ struct rx_ring_info *re,
+ unsigned int length)
+{
+ struct sk_buff *skb, *nskb;
+ unsigned hdr_space = sky2->rx_data_size;
+
+ pr_debug(PFX "receive new length=%d\n", length);
+
+ /* Don't be tricky about reusing pages (yet) */
+ nskb = sky2_rx_alloc(sky2);
+ if (unlikely(!nskb))
+ return NULL;
+
+ skb = re->skb;
+ sky2_rx_unmap_skb(sky2->hw->pdev, re);
+
+ prefetch(skb->data);
+ re->skb = nskb;
+ sky2_rx_map_skb(sky2->hw->pdev, re, hdr_space);
+
+ if (skb_shinfo(skb)->nr_frags)
+ skb_put_frags(skb, hdr_space, length);
+ else
+ skb_put(skb, hdr_space);
+ return skb;
+}
+
/*
* Receive one packet.
- * For small packets or errors, just reuse existing skb.
* For larger packets, get new buffer.
*/
static struct sk_buff *sky2_receive(struct net_device *dev,
@@ -1840,40 +2001,12 @@
if (length > dev->mtu + ETH_HLEN)
goto oversize;
- if (length < copybreak) {
- skb = netdev_alloc_skb(dev, length + 2);
- if (!skb)
- goto resubmit;
-
- skb_reserve(skb, 2);
- pci_dma_sync_single_for_cpu(sky2->hw->pdev, re->mapaddr,
- length, PCI_DMA_FROMDEVICE);
- memcpy(skb->data, re->skb->data, length);
- skb->ip_summed = re->skb->ip_summed;
- skb->csum = re->skb->csum;
- pci_dma_sync_single_for_device(sky2->hw->pdev, re->mapaddr,
- length, PCI_DMA_FROMDEVICE);
- } else {
- struct sk_buff *nskb;
-
- nskb = sky2_alloc_skb(dev, sky2->rx_bufsize, GFP_ATOMIC);
- if (!nskb)
- goto resubmit;
-
- skb = re->skb;
- re->skb = nskb;
- pci_unmap_single(sky2->hw->pdev, re->mapaddr,
- sky2->rx_bufsize, PCI_DMA_FROMDEVICE);
- prefetch(skb->data);
-
- re->mapaddr = pci_map_single(sky2->hw->pdev, nskb->data,
- sky2->rx_bufsize, PCI_DMA_FROMDEVICE);
- }
-
- skb_put(skb, length);
+ if (length < copybreak)
+ skb = receive_copy(sky2, re, length);
+ else
+ skb = receive_new(sky2, re, length);
resubmit:
- re->skb->ip_summed = CHECKSUM_NONE;
- sky2_rx_add(sky2, re->mapaddr);
+ sky2_rx_submit(sky2, re);
return skb;
@@ -3125,7 +3258,6 @@
spin_lock_init(&sky2->phy_lock);
sky2->tx_pending = TX_DEF_PENDING;
sky2->rx_pending = RX_DEF_PENDING;
- sky2->rx_bufsize = sky2_buf_size(ETH_DATA_LEN);
hw->dev[port] = dev;
diff --git a/drivers/net/sky2.h b/drivers/net/sky2.h
index 403486a..f66109a 100644
--- a/drivers/net/sky2.h
+++ b/drivers/net/sky2.h
@@ -4,6 +4,8 @@
#ifndef _SKY2_H
#define _SKY2_H
+#define ETH_JUMBO_MTU 9000 /* Maximum MTU supported */
+
/* PCI device specific config registers */
enum {
PCI_DEV_REG1 = 0x40,
@@ -1779,7 +1781,9 @@
struct rx_ring_info {
struct sk_buff *skb;
- dma_addr_t mapaddr;
+ dma_addr_t data_addr;
+ DECLARE_PCI_UNMAP_ADDR(data_size);
+ dma_addr_t frag_addr[ETH_JUMBO_MTU >> PAGE_SHIFT];
};
struct sky2_port {
@@ -1804,7 +1808,9 @@
u16 rx_next; /* next re to check */
u16 rx_put; /* next le index to use */
u16 rx_pending;
- u16 rx_bufsize;
+ u16 rx_data_size;
+ u16 rx_nfrags;
+
#ifdef SKY2_VLAN_TAG_USED
u16 rx_tag;
struct vlan_group *vlgrp;