firewire: add a client_list_lock
This adds a client_list_lock, which only protects the device's
client_list, so that future versions of the driver can call code that
takes the card->lock while holding the client_list_lock. Adding this
lock is much simpler than adding __ versions of all the functions that
the future version may need. The one ordering issue is to make sure
code never takes the client_list_lock with card->lock held. Since
client_list_lock is only used in three places, that isn't hard.
Signed-off-by: Jay Fenlason <fenlason@redhat.com>
Update fill_bus_reset_event() accordingly. Include linux/spinlock.h.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/firewire/fw-cdev.c b/drivers/firewire/fw-cdev.c
index ed03234..40cc973 100644
--- a/drivers/firewire/fw-cdev.c
+++ b/drivers/firewire/fw-cdev.c
@@ -27,6 +27,7 @@
#include <linux/poll.h>
#include <linux/preempt.h>
#include <linux/time.h>
+#include <linux/spinlock.h>
#include <linux/delay.h>
#include <linux/mm.h>
#include <linux/idr.h>
@@ -132,9 +133,9 @@
file->private_data = client;
- spin_lock_irqsave(&device->card->lock, flags);
+ spin_lock_irqsave(&device->client_list_lock, flags);
list_add_tail(&client->link, &device->client_list);
- spin_unlock_irqrestore(&device->card->lock, flags);
+ spin_unlock_irqrestore(&device->client_list_lock, flags);
return 0;
}
@@ -205,12 +206,14 @@
return dequeue_event(client, buffer, count);
}
-/* caller must hold card->lock so that node pointers can be dereferenced here */
static void
fill_bus_reset_event(struct fw_cdev_event_bus_reset *event,
struct client *client)
{
struct fw_card *card = client->device->card;
+ unsigned long flags;
+
+ spin_lock_irqsave(&card->lock, flags);
event->closure = client->bus_reset_closure;
event->type = FW_CDEV_EVENT_BUS_RESET;
@@ -220,22 +223,23 @@
event->bm_node_id = 0; /* FIXME: We don't track the BM. */
event->irm_node_id = card->irm_node->node_id;
event->root_node_id = card->root_node->node_id;
+
+ spin_unlock_irqrestore(&card->lock, flags);
}
static void
for_each_client(struct fw_device *device,
void (*callback)(struct client *client))
{
- struct fw_card *card = device->card;
struct client *c;
unsigned long flags;
- spin_lock_irqsave(&card->lock, flags);
+ spin_lock_irqsave(&device->client_list_lock, flags);
list_for_each_entry(c, &device->client_list, link)
callback(c);
- spin_unlock_irqrestore(&card->lock, flags);
+ spin_unlock_irqrestore(&device->client_list_lock, flags);
}
static void
@@ -274,11 +278,11 @@
{
struct fw_cdev_get_info *get_info = buffer;
struct fw_cdev_event_bus_reset bus_reset;
- struct fw_card *card = client->device->card;
unsigned long ret = 0;
client->version = get_info->version;
get_info->version = FW_CDEV_VERSION;
+ get_info->card = client->device->card->index;
down_read(&fw_device_rwsem);
@@ -300,18 +304,12 @@
client->bus_reset_closure = get_info->bus_reset_closure;
if (get_info->bus_reset != 0) {
void __user *uptr = u64_to_uptr(get_info->bus_reset);
- unsigned long flags;
- spin_lock_irqsave(&card->lock, flags);
fill_bus_reset_event(&bus_reset, client);
- spin_unlock_irqrestore(&card->lock, flags);
-
if (copy_to_user(uptr, &bus_reset, sizeof(bus_reset)))
return -EFAULT;
}
- get_info->card = card->index;
-
return 0;
}
@@ -1009,9 +1007,9 @@
list_for_each_entry_safe(e, next_e, &client->event_list, link)
kfree(e);
- spin_lock_irqsave(&client->device->card->lock, flags);
+ spin_lock_irqsave(&client->device->client_list_lock, flags);
list_del(&client->link);
- spin_unlock_irqrestore(&client->device->card->lock, flags);
+ spin_unlock_irqrestore(&client->device->client_list_lock, flags);
fw_device_put(client->device);
kfree(client);