Re: [PATCH 3/4] atl1: Main C file for Attansic L1 driver

Chris Snook
2006-11-20T06:14:13Z

Arnd Bergmann wrote:
> On Sunday 19 November 2006 21:30, Jay Cliburn wrote:
>> This patch contains the main C file for the Attansic L1 gigabit ethernet
>> adapter driver.
>
> Just a few style comments:
>
>> + /* PCI config space info */
>> + hw->vendor_id = pdev->vendor;
>> + hw->device_id = pdev->device;
>> + hw->subsystem_vendor_id = pdev->subsystem_vendor;
>> + hw->subsystem_id = pdev->subsystem_device;
>
> Do you actually need the copies of these fields? I guess you can
> always access the data from pdev.

Probably not. Thanks for pointing this out.

>> + size = sizeof(struct at_buffer) * (tpd_ring->count + rfd_ring->count);
>> + tpd_ring->buffer_info = kmalloc(size, GFP_KERNEL);
>> + if (unlikely(!tpd_ring->buffer_info)) {
>> + printk(KERN_WARNING "%s: kmalloc failed , size = D%d\n",
>> + at_driver_name, size);
>> + return -ENOMEM;
>> + }
>> + rfd_ring->buffer_info =
>> + (struct at_buffer *)(tpd_ring->buffer_info + tpd_ring->count);
>> +
>> + memset(tpd_ring->buffer_info, 0, size);
>
> Use kzalloc or kcalloc here.

Good point. I guess we should check the whole driver over for that.

>> + ring_header->desc =
>> + pci_alloc_consistent(pdev, ring_header->size, &ring_header->dma);
>> + if (unlikely(!ring_header->desc)) {
>> + kfree(tpd_ring->buffer_info);
>> + printk(KERN_WARNING
>> + "%s: pci_alloc_consistent failed, size = D%d\n",
>> + at_driver_name, size);
>> + return -ENOMEM;
>> + }
>
> Your cleanup path gets simpler if you use goto, and only one
> instance of kfree at the end, instead of multiple return statements
> in this function.
>
>
>> + while (!buffer_info->alloced && !next_info->alloced) {
>> + if (NULL != buffer_info->skb) {
>> + buffer_info->alloced = 1;
>> + goto next;
>> + }
>
> Instead of 'if (NULL != buffer_info->skb)', you should write
> 'if (buffer_info->skb)', like you do elsewhere.

Thanks for pointing this out. Seeing as this code is a ripoff of e1000,
hacked up by Attansic, and then heavily reworked by Jay and I, there are
some stylistic differences, but we'll try to make it more consistent.

>> + next:
>> + rfd_next_to_use = next_next;
>> + if (unlikely(++next_next == rfd_ring->count))
>> + next_next = 0;
>
> Labels go to the start of a line.

I blame Attansic.

>> +#ifdef NETIF_F_HW_VLAN_TX
>> + if (adapter->vlgrp && (rrd->pkt_flg & PACKET_FLAG_VLAN_INS)) {
>> + u16 vlan_tag = (rrd->vlan_tag >> 4) |
>> + ((rrd->vlan_tag & 7) << 13) |
>> + ((rrd->vlan_tag & 8) << 9);
>> + vlan_hwaccel_rx(skb, adapter->vlgrp, vlan_tag);
>> + } else
>> +#endif
>
> No need for the #ifdef when submitting the driver for inclusion.
> In this kernel version, NETIF_F_HW_VLAN_TX is always defined.

Thanks. There are a lot of ifdefs that we're not sure are always
defined. Removing those would make this code much easier to review.
More eyes on those ifdefs would be appreciated.

>> +static int at_mii_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
>> +{
>> + struct at_adapter *adapter = netdev_priv(netdev);
>> +/* struct mii_ioctl_data *data = (struct mii_ioctl_data *)&ifr->ifr_data;*/
>> + struct mii_ioctl_data *data = if_mii(ifr);
>> + unsigned long flags;
>> +
>> + switch (cmd) {
>> + case SIOCGMIIPHY:
>> + data->phy_id = 0;
>> + break;
>> + case SIOCGMIIREG:
>> + if (!capable(CAP_NET_ADMIN))
>> + return -EPERM;
>> + spin_lock_irqsave(&adapter->stats_lock, flags);
>> + if (at_read_phy_reg
>> + (&adapter->hw, data->reg_num & 0x1F, &data->val_out)) {
>> + spin_unlock_irqrestore(&adapter->stats_lock, flags);
>> + return -EIO;
>> + }
>> + spin_unlock_irqrestore(&adapter->stats_lock, flags);
>> + break;
>> + case SIOCSMIIREG:
>> + if (!capable(CAP_NET_ADMIN))
>> + return -EPERM;
>> + if (data->reg_num & ~(0x1F))
>> + return -EFAULT;
>> + spin_lock_irqsave(&adapter->stats_lock, flags);
>> + printk(KERN_DEBUG "%s: at_mii_ioctl write %x %x\n",
>> + at_driver_name, data->reg_num,
>> + data->val_in);
>> + if (at_write_phy_reg(&adapter->hw, data->reg_num, data->val_in)) {
>> + spin_unlock_irqrestore(&adapter->stats_lock, flags);
>> + return -EIO;
>> + }
>> + spin_unlock_irqrestore(&adapter->stats_lock, flags);
>> + break;
>> + default:
>> + return -EOPNOTSUPP;
>> + }
>> + return AT_SUCCESS;
>> +}
>> +#endif /* SIOCGMIIPHY */
>
> Any reason why you can't use generic_mii_ioctl?

I decided to mostly leave this code alone, in the hope that we could
just rip out MII support entirely and nobody would mind. What do you think?

-- Chris

>> + err_init_hw:
>> + err_reset:
>> + err_register:
>> + err_sw_init:
>> + err_eeprom:
>> + iounmap(adapter->hw.hw_addr);
>> + err_ioremap:
>> + free_netdev(netdev);
>> + err_alloc_etherdev:
>> + pci_release_regions(pdev);
>> + return err;
>
> It's more common to have a single label with multiple gotos instead
> of multiple labels that all go to one statement.