PATCH: Better fixup for the orinoco driver

Alan Cox
2005-10-15T18:12:11Z

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.

Patch v current -mm so before the bogus skb->len/skb=skb_padto change
went in.

Signed-off-by: Alan Cox <alan@redhat.com>

diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.14-rc2-mm1/drivers/net/wireless/hermes.c linux-2.6.14-rc2-mm1/drivers/net/wireless/hermes.c
--- linux.vanilla-2.6.14-rc2-mm1/drivers/net/wireless/hermes.c 2005-09-22 15:21:45.000000000 +0100
+++ linux-2.6.14-rc2-mm1/drivers/net/wireless/hermes.c 2005-10-13 13:18:46.000000000 +0100
@@ -451,6 +451,43 @@
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
@@ -538,6 +575,7 @@

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 -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.14-rc2-mm1/drivers/net/wireless/hermes.h linux-2.6.14-rc2-mm1/drivers/net/wireless/hermes.h
--- linux.vanilla-2.6.14-rc2-mm1/drivers/net/wireless/hermes.h 2005-09-22 15:21:45.000000000 +0100
+++ linux-2.6.14-rc2-mm1/drivers/net/wireless/hermes.h 2005-10-13 13:08:48.000000000 +0100
@@ -377,6 +377,8 @@
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 -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.14-rc2-mm1/drivers/net/wireless/orinoco.c linux-2.6.14-rc2-mm1/drivers/net/wireless/orinoco.c
--- linux.vanilla-2.6.14-rc2-mm1/drivers/net/wireless/orinoco.c 2005-09-22 15:22:54.000000000 +0100
+++ linux-2.6.14-rc2-mm1/drivers/net/wireless/orinoco.c 2005-10-13 13:17:19.000000000 +0100
@@ -502,8 +502,7 @@
}

/* Length of the packet body */
- /* FIXME: what if the skb is smaller than this? */
- len = max_t(int,skb->len - ETH_HLEN, ETH_ZLEN - ETH_HLEN);
+ len = max_t(int,skb->len, ETH_ZLEN) - ETH_HLEN;

eh = (struct ethhdr *)skb->data;

@@ -549,14 +548,21 @@
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",