ACPI: video - remove unsafe uses of list_for_each_safe()
list_for_each_safe() only protects list from list alterations
performed by the same thread. One still needs to implement
proper locking when list is being accessed from several threads.
Signed-off-by: Dmitry Torokhov <dtor@xxxxxxx>
---
drivers/acpi/video.c | 71 ++++++++++++++++++++++++---------------------------
1 file changed, 34 insertions(+), 37 deletions(-)
Index: work/drivers/acpi/video.c
===================================================================
--- work.orig/drivers/acpi/video.c
+++ work/drivers/acpi/video.c
@@ -1462,12 +1462,14 @@ acpi_video_bus_get_one_device(struct acp
static void acpi_video_device_rebind(struct acpi_video_bus *video)
{
- struct list_head *node, *next;
- list_for_each_safe(node, next, &video->video_device_list) {
- struct acpi_video_device *dev =
- container_of(node, struct acpi_video_device, entry);
+ struct acpi_video_device *dev;
+
+ down(&video->sem);
+
+ list_for_each_entry(dev, &video->video_device_list, entry)
acpi_video_device_bind(video, dev);
- }
+
+ up(&video->sem);
}
/*
@@ -1592,30 +1594,33 @@ static int acpi_video_device_enumerate(s
static int acpi_video_switch_output(struct acpi_video_bus *video, int event)
{
- struct list_head *node, *next;
+ struct list_head *node;
struct acpi_video_device *dev = NULL;
struct acpi_video_device *dev_next = NULL;
struct acpi_video_device *dev_prev = NULL;
unsigned long state;
int status = 0;
+ down(&video->sem);
- list_for_each_safe(node, next, &video->video_device_list) {
+ list_for_each(node, &video->video_device_list) {
dev = container_of(node, struct acpi_video_device, entry);
status = acpi_video_device_get_state(dev, &state);
if (state & 0x2) {
- dev_next =
- container_of(node->next, struct acpi_video_device,
- entry);
- dev_prev =
- container_of(node->prev, struct acpi_video_device,
- entry);
+ dev_next = container_of(node->next,
+ struct acpi_video_device, entry);
+ dev_prev = container_of(node->prev,
+ struct acpi_video_device, entry);
goto out;
}
}
+
dev_next = container_of(node->next, struct acpi_video_device, entry);
dev_prev = container_of(node->prev, struct acpi_video_device, entry);
- out:
+
+ out:
+ up(&video->sem);
+
switch (event) {
case ACPI_VIDEO_NOTIFY_CYCLE:
case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:
@@ -1691,24 +1696,17 @@ acpi_video_bus_get_devices(struct acpi_v
struct acpi_device *device)
{
int status = 0;
- struct list_head *node, *next;
-
+ struct acpi_device *dev;
acpi_video_device_enumerate(video);
- list_for_each_safe(node, next, &device->children) {
- struct acpi_device *dev =
- list_entry(node, struct acpi_device, node);
-
- if (!dev)
- continue;
+ list_for_each_entry(dev, &device->children, node) {
status = acpi_video_bus_get_one_device(dev, video);
if (ACPI_FAILURE(status)) {
ACPI_EXCEPTION((AE_INFO, status, "Cant attach device"));
continue;
}
-
}
return status;
}
@@ -1724,9 +1722,6 @@ static int acpi_video_bus_put_one_device
video = device->video;
- down(&video->sem);
- list_del(&device->entry);
- up(&video->sem);
acpi_video_device_remove_fs(device->dev);
status = acpi_remove_notify_handler(device->dev->handle,
@@ -1734,32 +1729,34 @@ static int acpi_video_bus_put_one_device
acpi_video_device_notify);
backlight_device_unregister(device->backlight);
video_output_unregister(device->output_dev);
+
return 0;
}
static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
{
int status;
- struct list_head *node, *next;
+ struct acpi_video_device *dev, *next;
+ down(&video->sem);
- list_for_each_safe(node, next, &video->video_device_list) {
- struct acpi_video_device *data =
- list_entry(node, struct acpi_video_device, entry);
- if (!data)
- continue;
+ list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
- status = acpi_video_bus_put_one_device(data);
+ status = acpi_video_bus_put_one_device(dev);
if (ACPI_FAILURE(status))
printk(KERN_WARNING PREFIX
"hhuuhhuu bug in acpi video driver.\n");
- if (data->brightness)
- kfree(data->brightness->levels);
- kfree(data->brightness);
- kfree(data);
+ if (dev->brightness) {
+ kfree(dev->brightness->levels);
+ kfree(dev->brightness);
+ }
+ list_del(&dev->entry);
+ kfree(dev);
}
+ up(&video->sem);
+
return 0;
}
--
Dmitry
-
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