Rationalize fasync return values

Most fasync implementations do something like:

     return fasync_helper(...);

But fasync_helper() will return a positive value at times - a feature used
in at least one place.  Thus, a number of other drivers do:

     err = fasync_helper(...);
     if (err < 0)
             return err;
     return 0;

In the interests of consistency and more concise code, it makes sense to
map positive return values onto zero where ->fasync() is called.

Cc: Al Viro <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>

Author: Jonathan Corbet

drivers/char/sonypi.c

@@ -888,12 +888,7 @@ static irqreturn_t sonypi_irq(int irq, void *dev_id)
 
 static int sonypi_misc_fasync(int fd, struct file *filp, int on)
 {
-	int retval;
-
-	retval = fasync_helper(fd, filp, on, &sonypi_device.fifo_async);
-	if (retval < 0)
-		return retval;
-	return 0;
+	return fasync_helper(fd, filp, on, &sonypi_device.fifo_async);
 }
 
 static int sonypi_misc_release(struct inode *inode, struct file *file)

drivers/gpu/drm/drm_fops.c

@@ -337,14 +337,10 @@ int drm_fasync(int fd, struct file *filp, int on)
 {
 	struct drm_file *priv = filp->private_data;
 	struct drm_device *dev = priv->minor->dev;
-	int retcode;
 
 	DRM_DEBUG("fd = %d, device = 0x%lx\n", fd,
 		  (long)old_encode_dev(priv->minor->device));
-	retcode = fasync_helper(fd, filp, on, &dev->buf_async);
-	if (retcode < 0)
-		return retcode;
-	return 0;
+	return fasync_helper(fd, filp, on, &dev->buf_async);
 }
 EXPORT_SYMBOL(drm_fasync);
 

drivers/hid/usbhid/hiddev.c

@@ -227,12 +227,9 @@ void hiddev_report_event(struct hid_device *hid, struct hid_report *report)
  */
 static int hiddev_fasync(int fd, struct file *file, int on)
 {
-	int retval;
 	struct hiddev_list *list = file->private_data;
 
-	retval = fasync_helper(fd, file, on, &list->fasync);
-
-	return retval < 0 ? retval : 0;
+	return fasync_helper(fd, file, on, &list->fasync);
 }
 
 

drivers/ieee1394/dv1394.c

@@ -1325,11 +1325,7 @@ static int dv1394_fasync(int fd, struct file *file, int on)
 
 	struct video_card *video = file_to_video_card(file);
 
-	int retval = fasync_helper(fd, file, on, &video->fasync);
-
-	if (retval < 0)
-		return retval;
-        return 0;
+	return fasync_helper(fd, file, on, &video->fasync);
 }
 
 static ssize_t dv1394_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)

drivers/input/evdev.c

@@ -94,11 +94,8 @@ static void evdev_event(struct input_handle *handle,
 static int evdev_fasync(int fd, struct file *file, int on)
 {
 	struct evdev_client *client = file->private_data;
-	int retval;
-
-	retval = fasync_helper(fd, file, on, &client->fasync);
 
-	return retval < 0 ? retval : 0;
+	return fasync_helper(fd, file, on, &client->fasync);
 }
 
 static int evdev_flush(struct file *file, fl_owner_t id)

drivers/input/joydev.c

@@ -159,12 +159,9 @@ static void joydev_event(struct input_handle *handle,
 
 static int joydev_fasync(int fd, struct file *file, int on)
 {
-	int retval;
 	struct joydev_client *client = file->private_data;
 
-	retval = fasync_helper(fd, file, on, &client->fasync);
-
-	return retval < 0 ? retval : 0;
+	return fasync_helper(fd, file, on, &client->fasync);
 }
 
 static void joydev_free(struct device *dev)

drivers/input/mousedev.c

@@ -403,12 +403,9 @@ static void mousedev_event(struct input_handle *handle,
 
 static int mousedev_fasync(int fd, struct file *file, int on)
 {
-	int retval;
 	struct mousedev_client *client = file->private_data;
 
-	retval = fasync_helper(fd, file, on, &client->fasync);
-
-	return retval < 0 ? retval : 0;
+	return fasync_helper(fd, file, on, &client->fasync);
 }
 
 static void mousedev_free(struct device *dev)

drivers/input/serio/serio_raw.c

@@ -58,10 +58,8 @@ static unsigned int serio_raw_no;
 static int serio_raw_fasync(int fd, struct file *file, int on)
 {
 	struct serio_raw_list *list = file->private_data;
-	int retval;
 
-	retval = fasync_helper(fd, file, on, &list->fasync);
-	return retval < 0 ? retval : 0;
+	return fasync_helper(fd, file, on, &list->fasync);
 }
 
 static struct serio_raw *serio_raw_locate(int minor)

drivers/net/wan/cosa.c

@@ -993,8 +993,8 @@ static struct fasync_struct *fasync[256] = { NULL, };
 static int cosa_fasync(struct inode *inode, struct file *file, int on)
 {
         int port = iminor(inode);
-        int rv = fasync_helper(inode, file, on, &fasync[port]);
-        return rv < 0 ? rv : 0;
+
+	return fasync_helper(inode, file, on, &fasync[port]);
 }
 #endif
 

drivers/platform/x86/sony-laptop.c

@@ -1917,12 +1917,7 @@ static struct sonypi_compat_s sonypi_compat = {
 
 static int sonypi_misc_fasync(int fd, struct file *filp, int on)
 {
-	int retval;
-
-	retval = fasync_helper(fd, filp, on, &sonypi_compat.fifo_async);
-	if (retval < 0)
-		return retval;
-	return 0;
+	return fasync_helper(fd, filp, on, &sonypi_compat.fifo_async);
 }
 
 static int sonypi_misc_release(struct inode *inode, struct file *file)