2006-12-08 10:28:18

by Peter Zijlstra

[permalink] [raw]
Subject: [PATCH] uml:


fixup the work on stack and exit scope trouble by placing the work_struct in
the uml_net_private data.

Signed-off-by: Peter Zijlstra <[email protected]>
---
arch/um/drivers/net_kern.c | 15 +++++++++------
arch/um/include/net_kern.h | 2 ++
2 files changed, 11 insertions(+), 6 deletions(-)

Index: linux-2.6-git/arch/um/drivers/net_kern.c
===================================================================
--- linux-2.6-git.orig/arch/um/drivers/net_kern.c 2006-12-08 10:32:56.000000000 +0100
+++ linux-2.6-git/arch/um/drivers/net_kern.c 2006-12-08 11:14:28.000000000 +0100
@@ -72,9 +72,11 @@ static int uml_net_rx(struct net_device
return pkt_len;
}

-static void uml_dev_close(void* dev)
+static void uml_dev_close(struct work_struct *work)
{
- dev_close( (struct net_device *) dev);
+ struct uml_net_private *lp =
+ container_of(work, struct uml_net_private, work);
+ dev_close(lp->dev);
}

irqreturn_t uml_net_interrupt(int irq, void *dev_id)
@@ -89,7 +91,6 @@ irqreturn_t uml_net_interrupt(int irq, v
spin_lock(&lp->lock);
while((err = uml_net_rx(dev)) > 0) ;
if(err < 0) {
- DECLARE_WORK(close_work, uml_dev_close, dev);
printk(KERN_ERR
"Device '%s' read returned %d, shutting it down\n",
dev->name, err);
@@ -97,9 +98,10 @@ irqreturn_t uml_net_interrupt(int irq, v
* again lp->lock.
* And dev_close() can be safely called multiple times on the
* same device, since it tests for (dev->flags & IFF_UP). So
- * there's no harm in delaying the device shutdown. */
- schedule_work(&close_work);
-#error this is not permitted - close_work will go out of scope
+ * there's no harm in delaying the device shutdown.
+ * Furthermore, the workqueue will not re-enqueue an already
+ * enqueued work item. */
+ schedule_work(&lp->work);
goto out;
}
reactivate_fd(lp->fd, UM_ETH_IRQ);
@@ -366,6 +368,7 @@ static int eth_configure(int n, void *in
/* This points to the transport private data. It's still clear, but we
* must memset it to 0 *now*. Let's help the drivers. */
memset(lp, 0, size);
+ INIT_WORK(&lp->work, uml_dev_close);

/* sysfs register */
if (!driver_registered) {
Index: linux-2.6-git/arch/um/include/net_kern.h
===================================================================
--- linux-2.6-git.orig/arch/um/include/net_kern.h 2006-12-08 10:55:25.000000000 +0100
+++ linux-2.6-git/arch/um/include/net_kern.h 2006-12-08 11:00:26.000000000 +0100
@@ -11,6 +11,7 @@
#include <linux/skbuff.h>
#include <linux/socket.h>
#include <linux/list.h>
+#include <linux/workqueue.h>

struct uml_net {
struct list_head list;
@@ -26,6 +27,7 @@ struct uml_net_private {
struct net_device *dev;
struct timer_list tl;
struct net_device_stats stats;
+ struct work_struct work;
int fd;
unsigned char mac[ETH_ALEN];
unsigned short (*protocol)(struct sk_buff *);



2006-12-08 16:40:43

by Jeff Dike

[permalink] [raw]
Subject: Re: [PATCH] uml:

On Fri, Dec 08, 2006 at 11:20:34AM +0100, Peter Zijlstra wrote:
>
> fixup the work on stack and exit scope trouble by placing the work_struct in
> the uml_net_private data.
>
> Signed-off-by: Peter Zijlstra <[email protected]>

Acked-by: Jeff Dike <[email protected]>

--
Work email - jdike at linux dot intel dot com

2006-12-08 10:52:51

by Peter Zijlstra

[permalink] [raw]
Subject: Re: [PATCH] uml: fix net_kern workqueue abuse

Garh, it seems I forgot to finish the subject.

On Fri, 2006-12-08 at 11:20 +0100, Peter Zijlstra wrote:
> fixup the work on stack and exit scope trouble by placing the work_struct in
> the uml_net_private data.
>
> Signed-off-by: Peter Zijlstra <[email protected]>
> ---
> arch/um/drivers/net_kern.c | 15 +++++++++------
> arch/um/include/net_kern.h | 2 ++
> 2 files changed, 11 insertions(+), 6 deletions(-)
>
> Index: linux-2.6-git/arch/um/drivers/net_kern.c
> ===================================================================
> --- linux-2.6-git.orig/arch/um/drivers/net_kern.c 2006-12-08 10:32:56.000000000 +0100
> +++ linux-2.6-git/arch/um/drivers/net_kern.c 2006-12-08 11:14:28.000000000 +0100
> @@ -72,9 +72,11 @@ static int uml_net_rx(struct net_device
> return pkt_len;
> }
>
> -static void uml_dev_close(void* dev)
> +static void uml_dev_close(struct work_struct *work)
> {
> - dev_close( (struct net_device *) dev);
> + struct uml_net_private *lp =
> + container_of(work, struct uml_net_private, work);
> + dev_close(lp->dev);
> }
>
> irqreturn_t uml_net_interrupt(int irq, void *dev_id)
> @@ -89,7 +91,6 @@ irqreturn_t uml_net_interrupt(int irq, v
> spin_lock(&lp->lock);
> while((err = uml_net_rx(dev)) > 0) ;
> if(err < 0) {
> - DECLARE_WORK(close_work, uml_dev_close, dev);
> printk(KERN_ERR
> "Device '%s' read returned %d, shutting it down\n",
> dev->name, err);
> @@ -97,9 +98,10 @@ irqreturn_t uml_net_interrupt(int irq, v
> * again lp->lock.
> * And dev_close() can be safely called multiple times on the
> * same device, since it tests for (dev->flags & IFF_UP). So
> - * there's no harm in delaying the device shutdown. */
> - schedule_work(&close_work);
> -#error this is not permitted - close_work will go out of scope
> + * there's no harm in delaying the device shutdown.
> + * Furthermore, the workqueue will not re-enqueue an already
> + * enqueued work item. */
> + schedule_work(&lp->work);
> goto out;
> }
> reactivate_fd(lp->fd, UM_ETH_IRQ);
> @@ -366,6 +368,7 @@ static int eth_configure(int n, void *in
> /* This points to the transport private data. It's still clear, but we
> * must memset it to 0 *now*. Let's help the drivers. */
> memset(lp, 0, size);
> + INIT_WORK(&lp->work, uml_dev_close);
>
> /* sysfs register */
> if (!driver_registered) {
> Index: linux-2.6-git/arch/um/include/net_kern.h
> ===================================================================
> --- linux-2.6-git.orig/arch/um/include/net_kern.h 2006-12-08 10:55:25.000000000 +0100
> +++ linux-2.6-git/arch/um/include/net_kern.h 2006-12-08 11:00:26.000000000 +0100
> @@ -11,6 +11,7 @@
> #include <linux/skbuff.h>
> #include <linux/socket.h>
> #include <linux/list.h>
> +#include <linux/workqueue.h>
>
> struct uml_net {
> struct list_head list;
> @@ -26,6 +27,7 @@ struct uml_net_private {
> struct net_device *dev;
> struct timer_list tl;
> struct net_device_stats stats;
> + struct work_struct work;
> int fd;
> unsigned char mac[ETH_ALEN];
> unsigned short (*protocol)(struct sk_buff *);
>
>
> -
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