[PATCH] Better fixup for the orinoco driver

The latest kernel added a pretty ugly fix for the orinoco etherleak bug
which contains bogus skb->len checks already done by the caller and causes
copies of all odd sized frames (which are quite common)

While the skb->len check should be ripped out the other fix is harder to do
properly so I'm proposing for this the -mm tree only until next 2.6.x so
that it gets tested.

Instead of copying buffers around blindly this code implements a padding
aware version of the hermes buffer writing function which does padding as
the buffer is loaded and thus more cleanly and without bogus 1.5K copies.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

drivers/net/wireless/hermes.c

@@ -444,6 +444,43 @@ int hermes_bap_pwrite(hermes_t *hw, int bap, const void *buf, unsigned len,
 	return err;
 }
 
+/* Write a block of data to the chip's buffer with padding if
+ * neccessary, via the BAP. Synchronization/serialization is the
+ * caller's problem. len must be even.
+ *
+ * Returns: < 0 on internal failure (errno), 0 on success, > 0 on error from firmware
+ */
+int hermes_bap_pwrite_pad(hermes_t *hw, int bap, const void *buf, unsigned data_len, unsigned len,
+		      u16 id, u16 offset)
+{
+	int dreg = bap ? HERMES_DATA1 : HERMES_DATA0;
+	int err = 0;
+
+	if (len < 0 || len % 2 || data_len > len)
+		return -EINVAL;
+
+	err = hermes_bap_seek(hw, bap, id, offset);
+	if (err)
+		goto out;
+
+	/* Transfer all the complete words of data */
+	hermes_write_words(hw, dreg, buf, data_len/2);
+	/* If there is an odd byte left over pad and transfer it */
+	if (data_len & 1) {
+		u8 end[2];
+		end[1] = 0;
+		end[0] = ((unsigned char *)buf)[data_len - 1];
+		hermes_write_words(hw, dreg, end, 1);
+		data_len ++;
+	}
+	/* Now send zeros for the padding */
+	if (data_len < len)
+		hermes_clear_words(hw, dreg, (len - data_len) / 2);
+	/* Complete */
+ out:
+	return err;
+}
+
 /* Read a Length-Type-Value record from the card.
  *
  * If length is NULL, we ignore the length read from the card, and
@@ -531,6 +568,7 @@ EXPORT_SYMBOL(hermes_allocate);
 
 EXPORT_SYMBOL(hermes_bap_pread);
 EXPORT_SYMBOL(hermes_bap_pwrite);
+EXPORT_SYMBOL(hermes_bap_pwrite_pad);
 EXPORT_SYMBOL(hermes_read_ltv);
 EXPORT_SYMBOL(hermes_write_ltv);
 

drivers/net/wireless/hermes.h

@@ -376,6 +376,8 @@ int hermes_bap_pread(hermes_t *hw, int bap, void *buf, unsigned len,
 		       u16 id, u16 offset);
 int hermes_bap_pwrite(hermes_t *hw, int bap, const void *buf, unsigned len,
 			u16 id, u16 offset);
+int hermes_bap_pwrite_pad(hermes_t *hw, int bap, const void *buf,
+			unsigned data_len, unsigned len, u16 id, u16 offset);
 int hermes_read_ltv(hermes_t *hw, int bap, u16 rid, unsigned buflen,
 		    u16 *length, void *buf);
 int hermes_write_ltv(hermes_t *hw, int bap, u16 rid,

drivers/net/wireless/orinoco.c

@@ -542,14 +542,21 @@ static int orinoco_xmit(struct sk_buff *skb, struct net_device *dev)
 			stats->tx_errors++;
 			goto fail;
 		}
+		/* Actual xfer length - allow for padding */
+		len = ALIGN(data_len, 2);
+		if (len < ETH_ZLEN - ETH_HLEN)
+			len = ETH_ZLEN - ETH_HLEN;
 	} else { /* IEEE 802.3 frame */
 		data_len = len + ETH_HLEN;
 		data_off = HERMES_802_3_OFFSET;
 		p = skb->data;
+		/* Actual xfer length - round up for odd length packets */
+		len = ALIGN(data_len, 2);
+		if (len < ETH_ZLEN)
+			len = ETH_ZLEN;
 	}
 
-	/* Round up for odd length packets */
-	err = hermes_bap_pwrite(hw, USER_BAP, p, ALIGN(data_len, 2),
+	err = hermes_bap_pwrite_pad(hw, USER_BAP, p, data_len, len,
 				txfid, data_off);
 	if (err) {
 		printk(KERN_ERR "%s: Error %d writing packet to BAP\n",