diff --git a/drivers/ieee1394/raw1394-private.h b/drivers/ieee1394/raw1394-private.h
index c93587be9cab411d5232d174046dca67b5e38821..c7731d1bcd89da69559e342be57f2fe6aa1fae3d 100644
--- a/drivers/ieee1394/raw1394-private.h
+++ b/drivers/ieee1394/raw1394-private.h
@@ -29,9 +29,8 @@ struct file_info {
struct list_head req_pending;
struct list_head req_complete;
- struct semaphore complete_sem;
spinlock_t reqlists_lock;
- wait_queue_head_t poll_wait_complete;
+ wait_queue_head_t wait_complete;
struct list_head addr_list;
diff --git a/drivers/ieee1394/raw1394.c b/drivers/ieee1394/raw1394.c
index 46c88e8a24f35e1378a14f11d7d84610acea809d..840b705fd5dd3d93a83e7abdefb24fdba7ad2807 100644
--- a/drivers/ieee1394/raw1394.c
+++ b/drivers/ieee1394/raw1394.c
@@ -133,10 +133,9 @@ static void free_pending_request(struct pending_request *req)
static void __queue_complete_req(struct pending_request *req)
{
struct file_info *fi = req->file_info;
- list_move_tail(&req->list, &fi->req_complete);
- up(&fi->complete_sem);
- wake_up_interruptible(&fi->poll_wait_complete);
+ list_move_tail(&req->list, &fi->req_complete);
+ wake_up(&fi->wait_complete);
}
static void queue_complete_req(struct pending_request *req)
@@ -464,13 +463,36 @@ raw1394_compat_read(const char __user *buf, struct raw1394_request *r)
#endif
+/* get next completed request (caller must hold fi->reqlists_lock) */
+static inline struct pending_request *__next_complete_req(struct file_info *fi)
+{
+ struct list_head *lh;
+ struct pending_request *req = NULL;
+
+ if (!list_empty(&fi->req_complete)) {
+ lh = fi->req_complete.next;
+ list_del(lh);
+ req = list_entry(lh, struct pending_request, list);
+ }
+ return req;
+}
+
+/* atomically get next completed request */
+static struct pending_request *next_complete_req(struct file_info *fi)
+{
+ unsigned long flags;
+ struct pending_request *req;
+
+ spin_lock_irqsave(&fi->reqlists_lock, flags);
+ req = __next_complete_req(fi);
+ spin_unlock_irqrestore(&fi->reqlists_lock, flags);
+ return req;
+}
static ssize_t raw1394_read(struct file *file, char __user * buffer,
size_t count, loff_t * offset_is_ignored)
{
- unsigned long flags;
struct file_info *fi = (struct file_info *)file->private_data;
- struct list_head *lh;
struct pending_request *req;
ssize_t ret;
@@ -488,22 +510,21 @@ static ssize_t raw1394_read(struct file *file, char __user * buffer,
}
if (file->f_flags & O_NONBLOCK) {
- if (down_trylock(&fi->complete_sem)) {
+ if (!(req = next_complete_req(fi)))
return -EAGAIN;
- }
} else {
- if (down_interruptible(&fi->complete_sem)) {
+ /*
+ * NB: We call the macro wait_event_interruptible() with a
+ * condition argument with side effect. This is only possible
+ * because the side effect does not occur until the condition
+ * became true, and wait_event_interruptible() won't evaluate
+ * the condition again after that.
+ */
+ if (wait_event_interruptible(fi->wait_complete,
+ (req = next_complete_req(fi))))
return -ERESTARTSYS;
- }
}
- spin_lock_irqsave(&fi->reqlists_lock, flags);
- lh = fi->req_complete.next;
- list_del(lh);
- spin_unlock_irqrestore(&fi->reqlists_lock, flags);
-
- req = list_entry(lh, struct pending_request, list);
-
if (req->req.length) {
if (copy_to_user(int2ptr(req->req.recvb), req->data,
req->req.length)) {
@@ -2745,7 +2766,7 @@ static unsigned int raw1394_poll(struct file *file, poll_table * pt)
unsigned int mask = POLLOUT | POLLWRNORM;
unsigned long flags;
- poll_wait(file, &fi->poll_wait_complete, pt);
+ poll_wait(file, &fi->wait_complete, pt);
spin_lock_irqsave(&fi->reqlists_lock, flags);
if (!list_empty(&fi->req_complete)) {
@@ -2770,9 +2791,8 @@ static int raw1394_open(struct inode *inode, struct file *file)
fi->state = opened;
INIT_LIST_HEAD(&fi->req_pending);
INIT_LIST_HEAD(&fi->req_complete);
- sema_init(&fi->complete_sem, 0);
spin_lock_init(&fi->reqlists_lock);
- init_waitqueue_head(&fi->poll_wait_complete);
+ init_waitqueue_head(&fi->wait_complete);
INIT_LIST_HEAD(&fi->addr_list);
file->private_data = fi;
@@ -2785,7 +2805,7 @@ static int raw1394_release(struct inode *inode, struct file *file)
struct file_info *fi = file->private_data;
struct list_head *lh;
struct pending_request *req;
- int done = 0, i, fail = 0;
+ int i, fail;
int retval = 0;
struct list_head *entry;
struct arm_addr *addr = NULL;
@@ -2865,25 +2885,28 @@ static int raw1394_release(struct inode *inode, struct file *file)
"error(s) occurred \n");
}
- while (!done) {
+ for (;;) {
+ /* This locked section guarantees that neither
+ * complete nor pending requests exist once i!=0 */
spin_lock_irqsave(&fi->reqlists_lock, flags);
-
- while (!list_empty(&fi->req_complete)) {
- lh = fi->req_complete.next;
- list_del(lh);
-
- req = list_entry(lh, struct pending_request, list);
-
+ while ((req = __next_complete_req(fi)))
free_pending_request(req);
- }
-
- if (list_empty(&fi->req_pending))
- done = 1;
+ i = list_empty(&fi->req_pending);
spin_unlock_irqrestore(&fi->reqlists_lock, flags);
- if (!done)
- down_interruptible(&fi->complete_sem);
+ if (i)
+ break;
+ /*
+ * Sleep until more requests can be freed.
+ *
+ * NB: We call the macro wait_event() with a condition argument
+ * with side effect. This is only possible because the side
+ * effect does not occur until the condition became true, and
+ * wait_event() won't evaluate the condition again after that.
+ */
+ wait_event(fi->wait_complete, (req = next_complete_req(fi)));
+ free_pending_request(req);
}
/* Remove any sub-trees left by user space programs */