[PATCH] remove magic number for netdev alignment

["Randy.Dunlap" <rddunlap@xxxxxxxx>]

Hi,
Please apply to 2.6.current.

--
~Randy


// Linux 2.6.3
// remove magic number of '31' for net_device and private alignment;

diffstat:=
 drivers/net/net_init.c    |   13 ++++++++-----
 include/linux/netdevice.h |    7 ++++++-
 2 files changed, 14 insertions(+), 6 deletions(-)


diff -Naurp ./drivers/net/net_init.c~netpriv ./drivers/net/net_init.c
--- ./drivers/net/net_init.c~netpriv    2004-02-17 19:57:14.000000000 -0800
+++ ./drivers/net/net_init.c    2004-03-04 14:15:17.000000000 -0800
@@ -79,8 +79,9 @@ struct net_device *alloc_netdev(int size
 
        /* ensure 32-byte alignment of both the device and private area */
 
-       alloc_size = (sizeof(struct net_device) + 31) & ~31;
-       alloc_size += sizeof_priv + 31;
+       alloc_size = (sizeof(struct net_device) + NETDEV_ALIGN_CONST)
+                       & ~NETDEV_ALIGN_CONST;
+       alloc_size += sizeof_priv + NETDEV_ALIGN_CONST;
 
        p = kmalloc (alloc_size, GFP_KERNEL);
        if (!p) {
@@ -90,7 +91,8 @@ struct net_device *alloc_netdev(int size
 
        memset(p, 0, alloc_size);
 
-       dev = (struct net_device *)(((long)p + 31) & ~31);
+       dev = (struct net_device *)(((long)p + NETDEV_ALIGN_CONST)
+                               & ~NETDEV_ALIGN_CONST);
        dev->padded = (char *)dev - (char *)p;
 
        if (sizeof_priv)
@@ -109,7 +111,7 @@ static struct net_device *init_alloc_dev
        int alloc_size;
 
        /* ensure 32-byte alignment of the private area */
-       alloc_size = sizeof (*dev) + sizeof_priv + 31;
+       alloc_size = sizeof (*dev) + sizeof_priv + NETDEV_ALIGN_CONST;
 
        dev = (struct net_device *) kmalloc (alloc_size, GFP_KERNEL);
        if (dev == NULL)
@@ -121,7 +123,8 @@ static struct net_device *init_alloc_dev
        memset(dev, 0, alloc_size);
 
        if (sizeof_priv)
-               dev->priv = (void *) (((long)(dev + 1) + 31) & ~31);
+               dev->priv = (void *) (((long)(dev + 1) + NETDEV_ALIGN_CONST)
+                               & ~NETDEV_ALIGN_CONST);
 
        return dev;
 }
diff -Naurp ./include/linux/netdevice.h~netpriv ./include/linux/netdevice.h
--- ./include/linux/netdevice.h~netpriv 2004-02-17 19:59:32.000000000 -0800
+++ ./include/linux/netdevice.h 2004-03-04 14:13:42.000000000 -0800
@@ -478,9 +478,14 @@ struct net_device
        int padded;
 };
 
+#define        NETDEV_ALIGN            32
+#define        NETDEV_ALIGN_CONST      (NETDEV_ALIGN - 1)
+
 static inline void *netdev_priv(struct net_device *dev)
 {
-       return (char *)dev + ((sizeof(struct net_device) + 31) & ~31);
+       return (char *)dev + ((sizeof(struct net_device)
+                                       + NETDEV_ALIGN_CONST)
+                               & ~NETDEV_ALIGN_CONST);
 }
 
 #define SET_MODULE_OWNER(dev) do { } while (0)