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authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-09-16 14:43:14 -0400
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-09-21 18:18:16 -0400
commitb1766b62890e3bba1a778a20ef8bf9348d6096c2 (patch)
tree88655f8ba5d96d8086358c5ebd76680ef1f1ea08 /drivers
parent402c5e15b44070461dcc2f41536c16d0cfbca9c3 (diff)
xen/pciback: Use mutexes when working with Xenbus state transitions.
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@oracle.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/xen/xen-pciback/pciback.h2
-rw-r--r--drivers/xen/xen-pciback/xenbus.c22
2 files changed, 10 insertions, 14 deletions
diff --git a/drivers/xen/xen-pciback/pciback.h b/drivers/xen/xen-pciback/pciback.h
index d095acdc0e65..e9b4011c5f9a 100644
--- a/drivers/xen/xen-pciback/pciback.h
+++ b/drivers/xen/xen-pciback/pciback.h
@@ -29,7 +29,7 @@ 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 522f2daa96cc..474d52ec3374 100644
--- a/drivers/xen/xen-pciback/xenbus.c
+++ b/drivers/xen/xen-pciback/xenbus.c
@@ -43,7 +43,7 @@ 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;
@@ -61,14 +61,12 @@ 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 */
@@ -76,13 +74,11 @@ 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)
@@ -119,9 +115,7 @@ static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,
goto out;
}
- spin_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,
@@ -131,10 +125,7 @@ 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");
@@ -149,6 +140,7 @@ static int xen_pcibk_attach(struct xen_pcibk_device *pdev)
char *magic = NULL;
+ mutex_lock(&pdev->dev_lock);
/* Make sure we only do this setup once */
if (xenbus_read_driver_state(pdev->xdev->nodename) !=
XenbusStateInitialised)
@@ -193,6 +185,7 @@ static int xen_pcibk_attach(struct xen_pcibk_device *pdev)
dev_dbg(&pdev->xdev->dev, "Connected? %d\n", err);
out:
+ mutex_unlock(&pdev->dev_lock);
kfree(magic);
@@ -368,6 +361,7 @@ static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");
+ mutex_lock(&pdev->dev_lock);
/* Make sure we only reconfigure once */
if (xenbus_read_driver_state(pdev->xdev->nodename) !=
XenbusStateReconfiguring)
@@ -505,6 +499,7 @@ static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
}
out:
+ mutex_unlock(&pdev->dev_lock);
return 0;
}
@@ -561,6 +556,7 @@ static int xen_pcibk_setup_backend(struct xen_pcibk_device *pdev)
char dev_str[64];
char state_str[64];
+ mutex_lock(&pdev->dev_lock);
/* It's possible we could get the call to setup twice, so make sure
* we're not already connected.
*/
@@ -641,10 +637,10 @@ static int xen_pcibk_setup_backend(struct xen_pcibk_device *pdev)
"Error switching to initialised state!");
out:
+ mutex_unlock(&pdev->dev_lock);
if (!err)
/* see if pcifront is already configured (if not, we'll wait) */
xen_pcibk_attach(pdev);
-
return err;
}