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

[Chris Snook <csnook@redhat.com>]

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.

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