Use PCI hotplug lock to globally serialize hotplug operations triggered by
PCI hotplug sysfs interfaces.
Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
---
drivers/pci/hotplug/pci_hotplug_core.c | 18 ++++++++++++++++--
1 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/hotplug/pci_hotplug_core.c b/drivers/pci/hotplug/pci_hotplug_core.c
index 1572665..9bbbe3e 100644
--- a/drivers/pci/hotplug/pci_hotplug_core.c
+++ b/drivers/pci/hotplug/pci_hotplug_core.c
@@ -39,6 +39,7 @@
#include <linux/mutex.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
+#include <linux/delay.h>
#include <asm/uaccess.h>
#include "../pci.h"
@@ -121,6 +122,17 @@ static ssize_t power_write_file(struct pci_slot *pci_slot, const char *buf,
retval = -ENODEV;
goto exit;
}
+
+ /* Avoid deadlock with pci_hp_deregister() */
+ while (!pci_hotplug_try_enter()) {
+ /* Check whether the slot has been deregistered. */
+ if (list_empty(&slot->slot_list)) {
+ retval = -ENODEV;
+ goto exit_put;
+ }
+ msleep(1);
+ }
+
switch (power) {
case 0:
if (slot->ops->disable_slot)
@@ -136,8 +148,10 @@ static ssize_t power_write_file(struct pci_slot *pci_slot, const char *buf,
err ("Illegal value specified for power\n");
retval = -EINVAL;
}
- module_put(slot->ops->owner);
+ pci_hotplug_exit();
+exit_put:
+ module_put(slot->ops->owner);
exit:
if (retval)
return retval;
@@ -500,7 +514,7 @@ int pci_hp_deregister(struct hotplug_slot *hotplug)
return -ENODEV;
}
- list_del(&hotplug->slot_list);
+ list_del_init(&hotplug->slot_list);
slot = hotplug->pci_slot;
fs_remove_slot(slot);
--
1.7.5.4
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