Dan Williams said the following on 2008-9-6 1:06: > On Fri, 2008-09-05 at 08:50 -0400, John W. Linville wrote: >> On Fri, Sep 05, 2008 at 11:27:39AM +0800, Wang Chen wrote: >>> We have some reasons to kill netdev->priv: >>> 1. netdev->priv is equal to netdev_priv(). >>> 2. netdev_priv() wraps the calculation of netdev->priv's offset, obviously >>> netdev_priv() is more flexible than netdev->priv. >>> But we cann't kill netdev->priv, because so many drivers reference to it >>> directly. >>> >>> OK, becasue Dave S. Miller said, "every direct netdev->priv usage is a bug", >>> and I want to kill netdev->priv later, I decided to convert all the direct >>> reference of netdev->priv first. >>> >>> Different to readonly reference of netdev->priv, in this driver, netdev->priv >>> was changed. I use netdev->ml_priv to replace netdev->priv. >>> >>> Signed-off-by: Wang Chen <wangchen@xxxxxxxxxxxxxx> >> Thank you for your patch. However, I do not understand why you didn't >> simply replace netdev->priv with netdev_priv()? Can you explain? > > Yeah, that would have been my first choice too... > 1. Why I don't use netdev_priv() to replace netdev->priv here? Because, here > @@ -2665,7 +2666,7 @@ static struct net_device *init_wifidev(struct airo_info *ai, > struct net_device *dev = alloc_netdev(0, "wifi%d", wifi_setup); > if (!dev) > return NULL; > - dev->priv = ethdev->priv; > + dev->ml_priv = ethdev->ml_priv; > @@ -2766,7 +2767,7 @@ static struct net_device *_init_airo_card( unsigned short irq, int port, > return NULL; > } > > - ai = dev->priv; > + ai = dev->ml_priv = netdev_priv(dev); netdev->priv was changed here, but it shouldn't, the memory was allocated when alloc_netdev and netdev->priv should always pointed to that memory. 2. Why I use netdev->ml_priv here to replace netdev->priv? In this driver, netdev->priv are shared by multi wifidevs, that means wifidevs need mid-layer private data, which are all same as their parent netdev. This usage is same as Dave's commit "syncppp: Fix crashes." -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
