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Subject[PATCH v6-resend 04/17] PCI Hotplug: serialize pci_hp_register and pci_hp_deregister
Date
From: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>

Convert the pci_hotplug_slot_list_lock, which only protected the
list of hotplug slots, to a pci_hp_mutex which now protects both
interfaces.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
---
drivers/pci/hotplug/pci_hotplug_core.c | 51 ++++++++++++++++++--------------
1 files changed, 28 insertions(+), 23 deletions(-)
diff --git a/drivers/pci/hotplug/pci_hotplug_core.c b/drivers/pci/hotplug/pci_hotplug_core.c
index 1cdeb64..e715248 100644
--- a/drivers/pci/hotplug/pci_hotplug_core.c
+++ b/drivers/pci/hotplug/pci_hotplug_core.c
@@ -37,6 +37,7 @@
#include <linux/init.h>
#include <linux/mount.h>
#include <linux/namei.h>
+#include <linux/mutex.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <asm/uaccess.h>
@@ -61,7 +62,7 @@ static int debug;
//////////////////////////////////////////////////////////////////

static LIST_HEAD(pci_hotplug_slot_list);
-static DEFINE_SPINLOCK(pci_hotplug_slot_list_lock);
+static DEFINE_MUTEX(pci_hp_mutex);

/* these strings match up with the values in pci_bus_speed */
static char *pci_bus_speed_strings[] = {
@@ -530,16 +531,12 @@ static struct hotplug_slot *get_slot_from_name (const char *name)
struct hotplug_slot *slot;
struct list_head *tmp;

- spin_lock(&pci_hotplug_slot_list_lock);
list_for_each (tmp, &pci_hotplug_slot_list) {
slot = list_entry (tmp, struct hotplug_slot, slot_list);
if (strcmp(slot->name, name) == 0)
- goto out;
+ return slot;
}
- slot = NULL;
-out:
- spin_unlock(&pci_hotplug_slot_list_lock);
- return slot;
+ return NULL;
}

/**
@@ -570,9 +567,13 @@ int pci_hp_register(struct hotplug_slot *slot, struct pci_bus *bus, int slot_nr,
return -EINVAL;
}

+ mutex_lock(&pci_hp_mutex);
+
/* Check if we have already registered a slot with the same name. */
- if (get_slot_from_name(name))
- return -EEXIST;
+ if (get_slot_from_name(name)) {
+ result = -EEXIST;
+ goto out;
+ }

/*
* No problems if we call this interface from both ACPI_PCI_SLOT
@@ -580,13 +581,15 @@ int pci_hp_register(struct hotplug_slot *slot, struct pci_bus *bus, int slot_nr,
* pci_slot, the interface will simply bump the refcount.
*/
pci_slot = pci_create_slot(bus, slot_nr, name, slot);
- if (IS_ERR(pci_slot))
- return PTR_ERR(pci_slot);
+ if (IS_ERR(pci_slot)) {
+ result = PTR_ERR(pci_slot);
+ goto cleanup;
+ }

if (pci_slot->hotplug) {
dbg("%s: already claimed\n", __func__);
- pci_destroy_slot(pci_slot);
- return -EBUSY;
+ result = -EBUSY;
+ goto cleanup;
}

slot->pci_slot = pci_slot;
@@ -597,21 +600,21 @@ int pci_hp_register(struct hotplug_slot *slot, struct pci_bus *bus, int slot_nr,
*/
if (strcmp(kobject_name(&pci_slot->kobj), name)) {
result = kobject_rename(&pci_slot->kobj, name);
- if (result) {
- pci_destroy_slot(pci_slot);
- return result;
- }
+ if (result)
+ goto cleanup;
}

- spin_lock(&pci_hotplug_slot_list_lock);
list_add(&slot->slot_list, &pci_hotplug_slot_list);
- spin_unlock(&pci_hotplug_slot_list_lock);

result = fs_add_slot(pci_slot);
kobject_uevent(&pci_slot->kobj, KOBJ_ADD);
dbg("Added slot %s to the list\n", name);
-
+out:
+ mutex_unlock(&pci_hp_mutex);
return result;
+cleanup:
+ pci_destroy_slot(pci_slot);
+ goto out;
}

/**
@@ -631,13 +634,14 @@ int pci_hp_deregister(struct hotplug_slot *hotplug)
if (!hotplug)
return -ENODEV;

+ mutex_lock(&pci_hp_mutex);
temp = get_slot_from_name(hotplug->name);
- if (temp != hotplug)
+ if (temp != hotplug) {
+ mutex_unlock(&pci_hp_mutex);
return -ENODEV;
+ }

- spin_lock(&pci_hotplug_slot_list_lock);
list_del(&hotplug->slot_list);
- spin_unlock(&pci_hotplug_slot_list_lock);

slot = hotplug->pci_slot;
fs_remove_slot(slot);
@@ -646,6 +650,7 @@ int pci_hp_deregister(struct hotplug_slot *hotplug)
hotplug->release(hotplug);
slot->hotplug = NULL;
pci_destroy_slot(slot);
+ mutex_unlock(&pci_hp_mutex);

return 0;
}


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