The caller that orchestrates the state changes is xenwatch_thread
and it takes a mutex. In our processing of Xenbus states we can take
the luxery of going to sleep on a mutex, so lets do that and
also fix this bug:
BUG: sleeping function called from invalid context at /linux/kernel/mutex.c:271
in_atomic(): 1, irqs_disabled(): 0, pid: 32, name: xenwatch
2 locks held by xenwatch/32:
#0: (xenwatch_mutex){......}, at: [<ffffffff813856ab>]
xenwatch_thread+0x4b/0x180
#1: (&(&pdev->dev_lock)->rlock){......}, at: [<ffffffff8138f05b>]
xen_pcibk_disconnect+0x1b/0x80
Pid: 32, comm: xenwatch Not tainted 3.1.0-rc6-00015-g3ce340d #2
Call Trace:
[<ffffffff810892b2>] __might_sleep+0x102/0x130
[<ffffffff8163b90f>] mutex_lock_nested+0x2f/0x50
[<ffffffff81382c1c>] unbind_from_irq+0x2c/0x1b0
[<ffffffff8110da66>] ? free_irq+0x56/0xb0
[<ffffffff81382dbc>] unbind_from_irqhandler+0x1c/0x30
[<ffffffff8138f06b>] xen_pcibk_disconnect+0x2b/0x80
[<ffffffff81390348>] xen_pcibk_frontend_changed+0xe8/0x140
[<ffffffff81387ac2>] xenbus_otherend_changed+0xd2/0x150
[<ffffffff810895c1>] ? get_parent_ip+0x11/0x50
[<ffffffff81387de0>] frontend_changed+0x10/0x20
[<ffffffff81385712>] xenwatch_thread+0xb2/0x180
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
drivers/xen/xen-pciback/pciback.h | 2 +-
drivers/xen/xen-pciback/xenbus.c | 16 +++++-----------
2 files changed, 6 insertions(+), 12 deletions(-)
diff --git a/drivers/xen/xen-pciback/pciback.h
b/drivers/xen/xen-pciback/pciback.h
index a0e131a..c3af628 100644
--- a/drivers/xen/xen-pciback/pciback.h
+++ b/drivers/xen/xen-pciback/pciback.h
@@ -27,7 +27,7 @@ struct pci_dev_entry {
struct xen_pcibk_device {
void *pci_dev_data;
- spinlock_t dev_lock;
+ struct mutex dev_lock;
struct xenbus_device *xdev;
struct xenbus_watch be_watch;
u8 be_watching;
diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
index 978d2c6..c057d67 100644
--- a/drivers/xen/xen-pciback/xenbus.c
+++ b/drivers/xen/xen-pciback/xenbus.c
@@ -44,7 +44,7 @@ static struct xen_pcibk_device *alloc_pdev(struct
xenbus_device *xdev)
pdev->xdev = xdev;
dev_set_drvdata(&xdev->dev, pdev);
- spin_lock_init(&pdev->dev_lock);
+ mutex_init(&pdev->dev_lock);
pdev->sh_info = NULL;
pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
@@ -62,14 +62,13 @@ out:
static void xen_pcibk_disconnect(struct xen_pcibk_device *pdev)
{
- spin_lock(&pdev->dev_lock);
+ mutex_lock(&pdev->dev_lock);
/* Ensure the guest can't trigger our handler before removing devices */
if (pdev->evtchn_irq != INVALID_EVTCHN_IRQ) {
unbind_from_irqhandler(pdev->evtchn_irq, pdev);
pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
}
- spin_unlock(&pdev->dev_lock);
/* If the driver domain started an op, make sure we complete it
* before releasing the shared memory */
@@ -77,13 +76,11 @@ static void xen_pcibk_disconnect(struct xen_pcibk_device
*pdev)
/* Note, the workqueue does not use spinlocks at all.*/
flush_workqueue(xen_pcibk_wq);
- spin_lock(&pdev->dev_lock);
if (pdev->sh_info != NULL) {
xenbus_unmap_ring_vfree(pdev->xdev, pdev->sh_info);
pdev->sh_info = NULL;
}
- spin_unlock(&pdev->dev_lock);
-
+ mutex_unlock(&pdev->dev_lock);
}
static void free_pdev(struct xen_pcibk_device *pdev)
@@ -120,9 +117,8 @@ static int xen_pcibk_do_attach(struct xen_pcibk_device
*pdev, int gnt_ref,
goto out;
}
- spin_lock(&pdev->dev_lock);
+ mutex_lock(&pdev->dev_lock);
pdev->sh_info = vaddr;
- spin_unlock(&pdev->dev_lock);
err = bind_interdomain_evtchn_to_irqhandler(
pdev->xdev->otherend_id, remote_evtchn, xen_pcibk_handle_event,
@@ -132,14 +128,12 @@ static int xen_pcibk_do_attach(struct xen_pcibk_device
*pdev, int gnt_ref,
"Error binding event channel to IRQ");
goto out;
}
-
- spin_lock(&pdev->dev_lock);
pdev->evtchn_irq = err;
- spin_unlock(&pdev->dev_lock);
err = 0;
dev_dbg(&pdev->xdev->dev, "Attached!\n");
out:
+ mutex_unlock(&pdev->dev_lock);
return err;
}
--
1.7.4.1
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