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authorPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>2006-01-18 20:42:56 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-18 22:20:21 -0500
commit71c8d4c3aad3132765d30b05dce98bb8a9508f02 (patch)
treed9b21742707b5de48511663f2fcd1627fb9a5a86 /arch/um
parente56a78855a4f72fc658bfd21d08939dd6e09fa4c (diff)
[PATCH] uml: fix spinlock recursion and sleep-inside-spinlock in error path
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 <blaisorblade@yahoo.it> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/drivers/net_kern.c15
1 files changed, 13 insertions, 2 deletions
diff --git a/arch/um/drivers/net_kern.c b/arch/um/drivers/net_kern.c
index f3442ce29a21..8ebb2241ad42 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 *dev)
68 return pkt_len; 68 return pkt_len;
69} 69}
70 70
71static void uml_dev_close(void* dev)
72{
73 dev_close( (struct net_device *) dev);
74}
75
71irqreturn_t uml_net_interrupt(int irq, void *dev_id, struct pt_regs *regs) 76irqreturn_t uml_net_interrupt(int irq, void *dev_id, struct pt_regs *regs)
72{ 77{
73 struct net_device *dev = dev_id; 78 struct net_device *dev = dev_id;
@@ -80,15 +85,21 @@ irqreturn_t uml_net_interrupt(int irq, void *dev_id, struct pt_regs *regs)
80 spin_lock(&lp->lock); 85 spin_lock(&lp->lock);
81 while((err = uml_net_rx(dev)) > 0) ; 86 while((err = uml_net_rx(dev)) > 0) ;
82 if(err < 0) { 87 if(err < 0) {
88 DECLARE_WORK(close_work, uml_dev_close, dev);
83 printk(KERN_ERR 89 printk(KERN_ERR
84 "Device '%s' read returned %d, shutting it down\n", 90 "Device '%s' read returned %d, shutting it down\n",
85 dev->name, err); 91 dev->name, err);
86 dev_close(dev); 92 /* dev_close can't be called in interrupt context, and takes
93 * again lp->lock.
94 * And dev_close() can be safely called multiple times on the
95 * same device, since it tests for (dev->flags & IFF_UP). So
96 * there's no harm in delaying the device shutdown. */
97 schedule_work(&close_work);
87 goto out; 98 goto out;
88 } 99 }
89 reactivate_fd(lp->fd, UM_ETH_IRQ); 100 reactivate_fd(lp->fd, UM_ETH_IRQ);
90 101
91 out: 102out:
92 spin_unlock(&lp->lock); 103 spin_unlock(&lp->lock);
93 return(IRQ_HANDLED); 104 return(IRQ_HANDLED);
94} 105}