Re: [2.6 patch] NET_SCH_ATM doesn't need ipcommon.o

From: David Miller
Date: Fri Dec 01 2006 - 00:06:22 EST


From: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Date: Mon, 27 Nov 2006 06:04:37 +0000

> On Mon, Nov 27, 2006 at 01:59:34AM +0100, Adrian Bunk wrote:
> > NET_SCH_ATM doesn't need ipcommon.o
> >
> > Signed-off-by: Adrian Bunk <bunk@xxxxxxxxx>
> >
> > --- linux-2.6.19-rc6-mm1/net/atm/Makefile.old 2006-11-26 08:50:05.000000000 +0100
> > +++ linux-2.6.19-rc6-mm1/net/atm/Makefile 2006-11-26 08:56:29.000000000 +0100
> > @@ -10,7 +10,6 @@
> > atm-$(subst m,y,$(CONFIG_ATM_CLIP)) += ipcommon.o
> > obj-$(CONFIG_ATM_BR2684) += br2684.o
> > atm-$(subst m,y,$(CONFIG_ATM_BR2684)) += ipcommon.o
> > -atm-$(subst m,y,$(CONFIG_NET_SCH_ATM)) += ipcommon.o
>
> Btw, ages ago Dave said there plans to get rid of ipcommon.c (it's just
> a single function). Did anything ever happen towards those plans?

Let's get rid of that crap. I just checked the following into
my net-2.6.20 tree.

commit 5465ae68b5ec11b2820db3f9b4c6fd94f113da44
Author: David S. Miller <davem@xxxxxxxxxxxxxxxxxxxx>
Date: Thu Nov 30 21:05:23 2006 -0800

[ATM]: Kill ipcommon.[ch]

All that remained was skb_migrate() and that was overkill
for what the two call sites were trying to do.

Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>

diff --git a/net/atm/Makefile b/net/atm/Makefile
index 89656d6..cc50bd1 100644
--- a/net/atm/Makefile
+++ b/net/atm/Makefile
@@ -7,10 +7,7 @@ mpoa-objs := mpc.o mpoa_caches.o mpoa_pr

obj-$(CONFIG_ATM) += atm.o
obj-$(CONFIG_ATM_CLIP) += clip.o
-atm-$(subst m,y,$(CONFIG_ATM_CLIP)) += ipcommon.o
obj-$(CONFIG_ATM_BR2684) += br2684.o
-atm-$(subst m,y,$(CONFIG_ATM_BR2684)) += ipcommon.o
-atm-$(subst m,y,$(CONFIG_NET_SCH_ATM)) += ipcommon.o
atm-$(CONFIG_PROC_FS) += proc.o

obj-$(CONFIG_ATM_LANE) += lec.o
diff --git a/net/atm/br2684.c b/net/atm/br2684.c
index b04162f..83a1c1b 100644
--- a/net/atm/br2684.c
+++ b/net/atm/br2684.c
@@ -23,7 +23,6 @@ #include <linux/seq_file.h>
#include <linux/atmbr2684.h>

#include "common.h"
-#include "ipcommon.h"

/*
* Define this to use a version of the code which interacts with the higher
@@ -500,11 +499,12 @@ Note: we do not have explicit unassign,
*/
int err;
struct br2684_vcc *brvcc;
- struct sk_buff_head copy;
struct sk_buff *skb;
+ struct sk_buff_head *rq;
struct br2684_dev *brdev;
struct net_device *net_dev;
struct atm_backend_br2684 be;
+ unsigned long flags;

if (copy_from_user(&be, arg, sizeof be))
return -EFAULT;
@@ -554,12 +554,30 @@ Note: we do not have explicit unassign,
brvcc->old_push = atmvcc->push;
barrier();
atmvcc->push = br2684_push;
- skb_queue_head_init(&copy);
- skb_migrate(&sk_atm(atmvcc)->sk_receive_queue, &copy);
- while ((skb = skb_dequeue(&copy)) != NULL) {
+
+ rq = &sk_atm(atmvcc)->sk_receive_queue;
+
+ spin_lock_irqsave(&rq->lock, flags);
+ if (skb_queue_empty(rq)) {
+ skb = NULL;
+ } else {
+ /* NULL terminate the list. */
+ rq->prev->next = NULL;
+ skb = rq->next;
+ }
+ rq->prev = rq->next = (struct sk_buff *)rq;
+ rq->qlen = 0;
+ spin_unlock_irqrestore(&rq->lock, flags);
+
+ while (skb) {
+ struct sk_buff *next = skb->next;
+
+ skb->next = skb->prev = NULL;
BRPRIV(skb->dev)->stats.rx_bytes -= skb->len;
BRPRIV(skb->dev)->stats.rx_packets--;
br2684_push(atmvcc, skb);
+
+ skb = next;
}
__module_get(THIS_MODULE);
return 0;
diff --git a/net/atm/clip.c b/net/atm/clip.c
index 1c41693..5f8a1d2 100644
--- a/net/atm/clip.c
+++ b/net/atm/clip.c
@@ -38,7 +38,6 @@ #include <asm/atomic.h>

#include "common.h"
#include "resources.h"
-#include "ipcommon.h"
#include <net/atmclip.h>


@@ -469,8 +468,9 @@ static struct net_device_stats *clip_get
static int clip_mkip(struct atm_vcc *vcc, int timeout)
{
struct clip_vcc *clip_vcc;
- struct sk_buff_head copy;
struct sk_buff *skb;
+ struct sk_buff_head *rq;
+ unsigned long flags;

if (!vcc->push)
return -EBADFD;
@@ -490,10 +490,26 @@ static int clip_mkip(struct atm_vcc *vcc
clip_vcc->old_pop = vcc->pop;
vcc->push = clip_push;
vcc->pop = clip_pop;
- skb_queue_head_init(&copy);
- skb_migrate(&sk_atm(vcc)->sk_receive_queue, &copy);
+
+ rq = &sk_atm(vcc)->sk_receive_queue;
+
+ spin_lock_irqsave(&rq->lock, flags);
+ if (skb_queue_empty(rq)) {
+ skb = NULL;
+ } else {
+ /* NULL terminate the list. */
+ rq->prev->next = NULL;
+ skb = rq->next;
+ }
+ rq->prev = rq->next = (struct sk_buff *)rq;
+ rq->qlen = 0;
+ spin_unlock_irqrestore(&rq->lock, flags);
+
/* re-process everything received between connection setup and MKIP */
- while ((skb = skb_dequeue(&copy)) != NULL)
+ while (skb) {
+ struct sk_buff *next = skb->next;
+
+ skb->next = skb->prev = NULL;
if (!clip_devs) {
atm_return(vcc, skb->truesize);
kfree_skb(skb);
@@ -506,6 +522,9 @@ static int clip_mkip(struct atm_vcc *vcc
PRIV(skb->dev)->stats.rx_bytes -= len;
kfree_skb(skb);
}
+
+ skb = next;
+ }
return 0;
}

diff --git a/net/atm/ipcommon.c b/net/atm/ipcommon.c
deleted file mode 100644
index 1d3de42..0000000
--- a/net/atm/ipcommon.c
+++ /dev/null
@@ -1,63 +0,0 @@
-/* net/atm/ipcommon.c - Common items for all ways of doing IP over ATM */
-
-/* Written 1996-2000 by Werner Almesberger, EPFL LRC/ICA */
-
-
-#include <linux/module.h>
-#include <linux/string.h>
-#include <linux/skbuff.h>
-#include <linux/netdevice.h>
-#include <linux/in.h>
-#include <linux/atmdev.h>
-#include <linux/atmclip.h>
-
-#include "common.h"
-#include "ipcommon.h"
-
-
-#if 0
-#define DPRINTK(format,args...) printk(KERN_DEBUG format,##args)
-#else
-#define DPRINTK(format,args...)
-#endif
-
-
-/*
- * skb_migrate appends the list at "from" to "to", emptying "from" in the
- * process. skb_migrate is atomic with respect to all other skb operations on
- * "from" and "to". Note that it locks both lists at the same time, so to deal
- * with the lock ordering, the locks are taken in address order.
- *
- * This function should live in skbuff.c or skbuff.h.
- */
-
-
-void skb_migrate(struct sk_buff_head *from, struct sk_buff_head *to)
-{
- unsigned long flags;
- struct sk_buff *skb_from = (struct sk_buff *) from;
- struct sk_buff *skb_to = (struct sk_buff *) to;
- struct sk_buff *prev;
-
- if ((unsigned long) from < (unsigned long) to) {
- spin_lock_irqsave(&from->lock, flags);
- spin_lock_nested(&to->lock, SINGLE_DEPTH_NESTING);
- } else {
- spin_lock_irqsave(&to->lock, flags);
- spin_lock_nested(&from->lock, SINGLE_DEPTH_NESTING);
- }
- prev = from->prev;
- from->next->prev = to->prev;
- prev->next = skb_to;
- to->prev->next = from->next;
- to->prev = from->prev;
- to->qlen += from->qlen;
- spin_unlock(&to->lock);
- from->prev = skb_from;
- from->next = skb_from;
- from->qlen = 0;
- spin_unlock_irqrestore(&from->lock, flags);
-}
-
-
-EXPORT_SYMBOL(skb_migrate);
diff --git a/net/atm/ipcommon.h b/net/atm/ipcommon.h
deleted file mode 100644
index d72165f..0000000
--- a/net/atm/ipcommon.h
+++ /dev/null
@@ -1,22 +0,0 @@
-/* net/atm/ipcommon.h - Common items for all ways of doing IP over ATM */
-
-/* Written 1996-2000 by Werner Almesberger, EPFL LRC/ICA */
-
-
-#ifndef NET_ATM_IPCOMMON_H
-#define NET_ATM_IPCOMMON_H
-
-
-#include <linux/string.h>
-#include <linux/skbuff.h>
-#include <linux/netdevice.h>
-#include <linux/atmdev.h>
-
-/*
- * Appends all skbs from "from" to "to". The operation is atomic with respect
- * to all other skb operations on "from" or "to".
- */
-
-void skb_migrate(struct sk_buff_head *from,struct sk_buff_head *to);
-
-#endif
-
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