usb: gadget: function: f_fs: Move epfile waitqueue to ffs_data.

There were individual waitqueues for each epfile but eps_enable
would iterate through all of them, resulting in essentially the
same wakeup time.

The waitqueue represents the function being enabled, so a central
waitqueue in ffs_data makes more sense and is less redundant.

Also use wake_up_interruptible to reflect use of
wait_event_interruptible.
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Jerry Zhang <zhangjerry@google.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/gadget/function/f_fs.c

@@ -127,7 +127,6 @@ struct ffs_ep {
 struct ffs_epfile {
 	/* Protects ep->ep and ep->req. */
 	struct mutex			mutex;
-	wait_queue_head_t		wait;
 
 	struct ffs_data			*ffs;
 	struct ffs_ep			*ep;	/* P: ffs->eps_lock */
@@ -889,7 +888,8 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 		if (file->f_flags & O_NONBLOCK)
 			return -EAGAIN;
 
-		ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
+		ret = wait_event_interruptible(
+				epfile->ffs->wait, (ep = epfile->ep));
 		if (ret)
 			return -EINTR;
 	}
@@ -1203,7 +1203,8 @@ static long ffs_epfile_ioctl(struct file *file, unsigned code,
 		if (file->f_flags & O_NONBLOCK)
 			return -EAGAIN;
 
-		ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
+		ret = wait_event_interruptible(
+				epfile->ffs->wait, (ep = epfile->ep));
 		if (ret)
 			return -EINTR;
 	}
@@ -1608,7 +1609,8 @@ static void ffs_data_put(struct ffs_data *ffs)
 		pr_info("%s(): freeing\n", __func__);
 		ffs_data_clear(ffs);
 		BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
-		       waitqueue_active(&ffs->ep0req_completion.wait));
+		       waitqueue_active(&ffs->ep0req_completion.wait) ||
+		       waitqueue_active(&ffs->wait));
 		kfree(ffs->dev_name);
 		kfree(ffs);
 	}
@@ -1655,6 +1657,7 @@ static struct ffs_data *ffs_data_new(void)
 	mutex_init(&ffs->mutex);
 	spin_lock_init(&ffs->eps_lock);
 	init_waitqueue_head(&ffs->ev.waitq);
+	init_waitqueue_head(&ffs->wait);
 	init_completion(&ffs->ep0req_completion);
 
 	/* XXX REVISIT need to update it in some places, or do we? */
@@ -1776,7 +1779,6 @@ static int ffs_epfiles_create(struct ffs_data *ffs)
 	for (i = 1; i <= count; ++i, ++epfile) {
 		epfile->ffs = ffs;
 		mutex_init(&epfile->mutex);
-		init_waitqueue_head(&epfile->wait);
 		if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
 			sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
 		else
@@ -1801,8 +1803,7 @@ static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
 	ENTER();
 
 	for (; count; --count, ++epfile) {
-		BUG_ON(mutex_is_locked(&epfile->mutex) ||
-		       waitqueue_active(&epfile->wait));
+		BUG_ON(mutex_is_locked(&epfile->mutex));
 		if (epfile->dentry) {
 			d_delete(epfile->dentry);
 			dput(epfile->dentry);
@@ -1889,11 +1890,11 @@ static int ffs_func_eps_enable(struct ffs_function *func)
 			break;
 		}
 
-		wake_up(&epfile->wait);
-
 		++ep;
 		++epfile;
 	}
+
+	wake_up_interruptible(&ffs->wait);
 	spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
 
 	return ret;

drivers/usb/gadget/function/u_fs.h

@@ -216,6 +216,9 @@ struct ffs_data {
 #define FFS_FL_CALL_CLOSED_CALLBACK 0
 #define FFS_FL_BOUND                1
 
+	/* For waking up blocked threads when function is enabled. */
+	wait_queue_head_t		wait;
+
 	/* Active function */
 	struct ffs_function		*func;