From: Paolo 'Blaisorblade' Giarrusso <[EMAIL PROTECTED]>
In this error path, when the interface has had a problem, we call dev_close(),
which is disallowed for two reasons:
*) takes again the UML internal spinlock, inside the ->stop method of this
device
*) can be called in process context only, while we're in interrupt context.
I've also thought that calling dev_close() may be a wrong policy to follow, but
it's not up to me to decide that.
However, we may end up with multiple dev_close() queued on the same device.
But the initial test for (dev->flags & IFF_UP) makes this harmless, though -
and dev_close() is supposed to care about races with itself. So there's no harm
in delaying the shutdown, IMHO.
Something to mark the interface as "going to shutdown" would be appreciated, but
dev_deactivate has the same problems as dev_close(), so we can't use it either.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <[EMAIL PROTECTED]>
---
arch/um/drivers/net_kern.c | 15 +++++++++++++--
1 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/arch/um/drivers/net_kern.c b/arch/um/drivers/net_kern.c
index 98350bb..178f68b 100644
--- a/arch/um/drivers/net_kern.c
+++ b/arch/um/drivers/net_kern.c
@@ -68,6 +68,11 @@ static int uml_net_rx(struct net_device
return pkt_len;
}
+static void uml_dev_close(void* dev)
+{
+ dev_close( (struct net_device *) dev);
+}
+
irqreturn_t uml_net_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
struct net_device *dev = dev_id;
@@ -80,15 +85,21 @@ 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);
- dev_close(dev);
+ /* dev_close can't be called in interrupt context, and takes
+ * 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);
goto out;
}
reactivate_fd(lp->fd, UM_ETH_IRQ);
- out:
+out:
spin_unlock(&lp->lock);
return(IRQ_HANDLED);
}
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