[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>

3 files changed, 49 insertions, 2 deletions

diff --git a/drivers/net/wireless/hermes.c b/drivers/net/wireless/hermes.c
index eba0d9d2b7c5..579480dad374 100644
--- a/drivers/net/wireless/hermes.c
+++ b/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);
 
diff --git a/drivers/net/wireless/hermes.h b/drivers/net/wireless/hermes.h
index ad28e3294360..a6bd472d75d4 100644
--- a/drivers/net/wireless/hermes.h
+++ b/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,
diff --git a/drivers/net/wireless/orinoco.c b/drivers/net/wireless/orinoco.c
index 70a3477a2061..488ab06fb79f 100644
--- a/drivers/net/wireless/orinoco.c
+++ b/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",