Re: [PATCH] cleanup large frame handling for natsemi.c

[Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>]

Jeff Garzik wrote:

> On Sun, Jun 20, 2004 at 02:14:59PM +0200, Manfred Spraul wrote:
>  
>
> > Jeff, could you apply it? I've stress tested vlan for an hour with 
> > tbench and parallel kernel compiles, not obvious problems.
> >    
> I would if you had actually included a patch ;-)
>
>  
Ups, sorry. Here's the patch.

--
   Manfred

--- 2.6/drivers/net/natsemi.c   2004-06-20 11:24:02.959200463 +0200
+++ build-2.6/drivers/net/natsemi.c     2004-06-20 12:11:31.170607816 +0200
@@ -236,7 +236,14 @@
 #define NATSEMI_REGS_SIZE      (NATSEMI_NREGS * sizeof(u32))
 #define NATSEMI_EEPROM_SIZE    24 /* 12 16-bit values */
 
-#define PKT_BUF_SZ             1536 /* Size of each temporary Rx buffer. */
+/* Buffer sizes:
+ * The nic writes 32-bit values, even if the upper bytes of
+ * a 32-bit value are beyond the end of the buffer.
+ */
+#define NATSEMI_HEADERS                22      /* 2*mac,type,vlan,crc */
+#define NATSEMI_PADDING                64      /* 2 bytes should be sufficient 
*/
+#define NATSEMI_LONGPKT                1518    /* limit for long packets */
+#define NATSEMI_RX_LIMIT       2046    /* maximum supported by hardware */
 
 /* These identify the driver base version and may not be removed. */
 static char version[] __devinitdata =
@@ -1688,7 +1695,7 @@
         */
        np->rx_config = RxMxdma_256 | 0x20;
        /* if receive ring now has bigger buffers than normal, enable jumbo */
-       if (np->rx_buf_sz > PKT_BUF_SZ)
+       if (np->rx_buf_sz > NATSEMI_LONGPKT)
                np->rx_config |= RxAcceptLong;
 
        writel(np->rx_config, ioaddr + RxConfig);
@@ -1870,7 +1877,7 @@
                struct sk_buff *skb;
                int entry = np->dirty_rx % RX_RING_SIZE;
                if (np->rx_skbuff[entry] == NULL) {
-                       unsigned int buflen = np->rx_buf_sz + RX_OFFSET;
+                       unsigned int buflen = np->rx_buf_sz+NATSEMI_PADDING;
                        skb = dev_alloc_skb(buflen);
                        np->rx_skbuff[entry] = skb;
                        if (skb == NULL)
@@ -1909,9 +1916,13 @@
        np->dirty_rx = 0;
        np->cur_rx = RX_RING_SIZE;
        np->oom = 0;
-       np->rx_buf_sz = PKT_BUF_SZ;
-       if (dev->mtu > ETH_DATA_LEN)
-               np->rx_buf_sz += dev->mtu - ETH_DATA_LEN;
+       if (dev->mtu <= ETH_DATA_LEN)
+               np->rx_buf_sz = ETH_DATA_LEN + NATSEMI_HEADERS;
+       else
+               np->rx_buf_sz = dev->mtu + NATSEMI_HEADERS;
+       if (np->rx_buf_sz > NATSEMI_RX_LIMIT)
+               np->rx_buf_sz = NATSEMI_RX_LIMIT;
+
        np->rx_head_desc = &np->rx_ring[0];
 
        /* Please be carefull before changing this loop - at least gcc-2.95.1
@@ -1949,7 +1960,7 @@
 static void drain_ring(struct net_device *dev)
 {
        struct netdev_private *np = dev->priv;
-       unsigned int buflen = np->rx_buf_sz + RX_OFFSET;
+       unsigned int buflen = np->rx_buf_sz;
        int i;
 
        /* Free all the skbuffs in the Rx queue. */
@@ -2154,7 +2165,7 @@
        int entry = np->cur_rx % RX_RING_SIZE;
        int boguscnt = np->dirty_rx + RX_RING_SIZE - np->cur_rx;
        s32 desc_status = le32_to_cpu(np->rx_head_desc->cmd_status);
-       unsigned int buflen = np->rx_buf_sz + RX_OFFSET;
+       unsigned int buflen = np->rx_buf_sz;
 
        /* If the driver owns the next entry it's a new packet. Send it up. */
        while (desc_status < 0) { /* e.g. & DescOwn */
@@ -2881,6 +2892,7 @@
        }
        return 0;
 }
+
 static int netdev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
 {
        struct mii_ioctl_data *data = if_mii(rq);