Am Montag, 3. November 2008 20:58:11 schrieb Jiri Slaby:
> Hi.
>
> > this is the cleanup of hiddev against current vanilla. What do you think?
>
> See my comments below.
Hi,
I've addressed all comments I understood. In addition it seems to me that
the read method is not thread-safe.
Regards
Oliver
Signed-off-by: Oliver Neukum <oneukum@xxxxxxx>
---
diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c
index 3ac3207..a35576b 100644
--- a/drivers/hid/usbhid/hiddev.c
+++ b/drivers/hid/usbhid/hiddev.c
@@ -63,6 +63,7 @@ struct hiddev_list {
struct fasync_struct *fasync;
struct hiddev *hiddev;
struct list_head node;
+ struct mutex thread_lock;
};
static struct hiddev *hiddev_table[HIDDEV_MINORS];
@@ -266,29 +267,38 @@ static int hiddev_release(struct inode * inode, struct file * file)
static int hiddev_open(struct inode *inode, struct file *file)
{
struct hiddev_list *list;
- unsigned long flags;
+ int res;
int i = iminor(inode) - HIDDEV_MINOR_BASE;
- if (i >= HIDDEV_MINORS || !hiddev_table[i])
+ if (i >= HIDDEV_MINORS || i < 0 || !hiddev_table[i])
return -ENODEV;
if (!(list = kzalloc(sizeof(struct hiddev_list), GFP_KERNEL)))
return -ENOMEM;
+ mutex_init(&list->thread_lock);
list->hiddev = hiddev_table[i];
- spin_lock_irqsave(&list->hiddev->list_lock, flags);
- list_add_tail(&list->node, &hiddev_table[i]->list);
- spin_unlock_irqrestore(&list->hiddev->list_lock, flags);
-
file->private_data = list;
- if (!list->hiddev->open++)
- if (list->hiddev->exist)
- usbhid_open(hiddev_table[i]->hid);
+ if (!list->hiddev->open++) {
+ if (list->hiddev->exist) {
+ res = usbhid_open(hiddev_table[i]->hid);
+ if (res < 0)
+ goto bail;
+ }
+ }
+
+ spin_lock_irq(&list->hiddev->list_lock);
+ list_add_tail(&list->node, &hiddev_table[i]->list);
+ spin_unlock_irq(&list->hiddev->list_lock);
return 0;
+bail:
+ file->private_data = NULL;
+ kfree(list->hiddev);
+ return -EIO;
}
/*
@@ -307,7 +317,7 @@ static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t coun
DECLARE_WAITQUEUE(wait, current);
struct hiddev_list *list = file->private_data;
int event_size;
- int retval = 0;
+ int retval;
event_size = ((list->flags & HIDDEV_FLAG_UREF) != 0) ?
sizeof(struct hiddev_usage_ref) : sizeof(struct hiddev_event);
@@ -315,10 +325,14 @@ static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t coun
if (count < event_size)
return 0;
+ /* lock against other threads */
+ retval = mutex_lock_interruptible(&list->thread_lock);
+ if (retval)
+ return -ERESTARTSYS;
+
while (retval == 0) {
if (list->head == list->tail) {
- add_wait_queue(&list->hiddev->wait, &wait);
- set_current_state(TASK_INTERRUPTIBLE);
+ prepare_to_wait(&list->hiddev->wait, &wait, TASK_INTERRUPTIBLE);
while (list->head == list->tail) {
if (file->f_flags & O_NONBLOCK) {
@@ -337,32 +351,38 @@ static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t coun
schedule();
set_current_state(TASK_INTERRUPTIBLE);
}
+ finish_wait(&list->hiddev->wait, &wait);
- set_current_state(TASK_RUNNING);
- remove_wait_queue(&list->hiddev->wait, &wait);
}
- if (retval)
+ if (retval) {
+ mutex_unlock(&list->thread_lock);
return retval;
+ }
while (list->head != list->tail &&
retval + event_size <= count) {
if ((list->flags & HIDDEV_FLAG_UREF) == 0) {
- if (list->buffer[list->tail].field_index !=
- HID_FIELD_INDEX_NONE) {
+ if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE) {
struct hiddev_event event;
+
event.hid = list->buffer[list->tail].usage_code;
event.value = list->buffer[list->tail].value;
- if (copy_to_user(buffer + retval, &event, sizeof(struct hiddev_event)))
+ if (copy_to_user(buffer + retval, &event, sizeof(struct hiddev_event))) {
+ mutex_unlock(&list->thread_lock);
return -EFAULT;
+ }
retval += sizeof(struct hiddev_event);
}
} else {
if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE ||
(list->flags & HIDDEV_FLAG_REPORT) != 0) {
- if (copy_to_user(buffer + retval, list->buffer + list->tail, sizeof(struct hiddev_usage_ref)))
+
+ if (copy_to_user(buffer + retval, list->buffer + list->tail, sizeof(struct hiddev_usage_ref))) {
+ mutex_unlock(&list->thread_lock);
return -EFAULT;
+ }
retval += sizeof(struct hiddev_usage_ref);
}
}
@@ -370,6 +390,7 @@ static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t coun
}
}
+ mutex_unlock(&list->thread_lock);
return retval;
}
@@ -810,13 +831,6 @@ int hiddev_connect(struct hid_device *hid, unsigned int force)
if (!(hiddev = kzalloc(sizeof(struct hiddev), GFP_KERNEL)))
return -1;
- retval = usb_register_dev(usbhid->intf, &hiddev_class);
- if (retval) {
- err_hid("Not able to get a minor for this device.");
- kfree(hiddev);
- return -1;
- }
-
init_waitqueue_head(&hiddev->wait);
INIT_LIST_HEAD(&hiddev->list);
spin_lock_init(&hiddev->list_lock);
@@ -828,6 +842,14 @@ int hiddev_connect(struct hid_device *hid, unsigned int force)
hiddev_table[usbhid->intf->minor - HIDDEV_MINOR_BASE] = hiddev;
+ retval = usb_register_dev(usbhid->intf, &hiddev_class);
+ if (retval) {
+ err_hid("Not able to get a minor for this device.");
+ hiddev_table[usbhid->intf->minor - HIDDEV_MINOR_BASE] = NULL;
+ kfree(hiddev);
+ return -1;
+ }
+
return 0;
}
--
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