V4L/DVB (4316): Check __must_check warnings

Check __must_check warnings for class_device_register and class_device_create_file

video_device_create_file was declared as a void, but instead should
return the int value of class_device_create_file.

Move the check from bttv-driver.c into v4l2-dev.h, because all other
callers of video_device_create_file must also be checked.

Replace the call to class_device_create_file in videodev.c with
video_device_create_file, as defined in v4l2-dev.h, so that the
return value of class_device_create_file will be checked.

Check the return value of class_device_register in videodev.c and
pvrusb2-sysfs.c

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

4 files changed, 43 insertions, 16 deletions

diff --git a/drivers/media/video/bt8xx/bttv-driver.c b/drivers/media/video/bt8xx/bttv-driver.c
index 63e83162286c..6db5e4e73397 100644
--- a/drivers/media/video/bt8xx/bttv-driver.c
+++ b/drivers/media/video/bt8xx/bttv-driver.c
@@ -3909,8 +3909,6 @@ static void bttv_unregister_video(struct bttv *btv)
 /* register video4linux devices */
 static int __devinit bttv_register_video(struct bttv *btv)
 {
-        int ret;
-
         if (no_overlay <= 0) {
                 bttv_video_template.type |= VID_TYPE_OVERLAY;
         } else {
@@ -3925,10 +3923,8 @@ static int __devinit bttv_register_video(struct bttv *btv)
                 goto err;
         printk(KERN_INFO "bttv%d: registered device video%d\n",
                btv->c.nr,btv->video_dev->minor & 0x1f);
-        ret = video_device_create_file(btv->video_dev, &class_device_attr_card);
-        if (ret < 0)
-                printk(KERN_WARNING "bttv: video_device_create_file error: "
-                        "%d\n", ret);
+
+        video_device_create_file(btv->video_dev, &class_device_attr_card);
 
         /* vbi */
         btv->vbi_dev = vdev_init(btv, &bttv_vbi_template, "vbi");
diff --git a/drivers/media/video/pvrusb2/pvrusb2-sysfs.c b/drivers/media/video/pvrusb2/pvrusb2-sysfs.c
index 6af55a8b6f05..ef46d4f40cff 100644
--- a/drivers/media/video/pvrusb2/pvrusb2-sysfs.c
+++ b/drivers/media/video/pvrusb2/pvrusb2-sysfs.c
@@ -600,6 +600,8 @@ static ssize_t debugcmd_store(struct class_device *,const char *,size_t count);
 static void pvr2_sysfs_add_debugifc(struct pvr2_sysfs *sfp)
 {
         struct pvr2_sysfs_debugifc *dip;
+        int ret;
+
         dip = kmalloc(sizeof(*dip),GFP_KERNEL);
         if (!dip) return;
         memset(dip,0,sizeof(*dip));
@@ -613,8 +615,14 @@ static void pvr2_sysfs_add_debugifc(struct pvr2_sysfs *sfp)
         dip->attr_debuginfo.attr.mode = S_IRUGO;
         dip->attr_debuginfo.show = debuginfo_show;
         sfp->debugifc = dip;
-        class_device_create_file(sfp->class_dev,&dip->attr_debugcmd);
-        class_device_create_file(sfp->class_dev,&dip->attr_debuginfo);
+        ret = class_device_create_file(sfp->class_dev,&dip->attr_debugcmd);
+        if (ret < 0)
+                printk(KERN_WARNING "%s: class_device_create_file error: %d\n",
+                       __FUNCTION__, ret);
+        ret = class_device_create_file(sfp->class_dev,&dip->attr_debuginfo);
+        if (ret < 0)
+                printk(KERN_WARNING "%s: class_device_create_file error: %d\n",
+                       __FUNCTION__, ret);
 }
 
 
@@ -709,6 +717,8 @@ static void class_dev_create(struct pvr2_sysfs *sfp,
 {
         struct usb_device *usb_dev;
         struct class_device *class_dev;
+        int ret;
+
         usb_dev = pvr2_hdw_get_dev(sfp->channel.hdw);
         if (!usb_dev) return;
         class_dev = kmalloc(sizeof(*class_dev),GFP_KERNEL);
@@ -733,20 +743,33 @@ static void class_dev_create(struct pvr2_sysfs *sfp,
 
         sfp->class_dev = class_dev;
         class_dev->class_data = sfp;
-        class_device_register(class_dev);
+        ret = class_device_register(class_dev);
+        if (ret) {
+                printk(KERN_ERR "%s: class_device_register failed\n",
+                       __FUNCTION__);
+                kfree(class_dev);
+                return;
+        }
 
         sfp->attr_v4l_minor_number.attr.owner = THIS_MODULE;
         sfp->attr_v4l_minor_number.attr.name = "v4l_minor_number";
         sfp->attr_v4l_minor_number.attr.mode = S_IRUGO;
         sfp->attr_v4l_minor_number.show = v4l_minor_number_show;
         sfp->attr_v4l_minor_number.store = NULL;
-        class_device_create_file(sfp->class_dev,&sfp->attr_v4l_minor_number);
+        ret = class_device_create_file(sfp->class_dev,&sfp->attr_v4l_minor_number);
+        if (ret < 0)
+                printk(KERN_WARNING "%s: class_device_create_file error: %d\n",
+                       __FUNCTION__, ret);
+
         sfp->attr_unit_number.attr.owner = THIS_MODULE;
         sfp->attr_unit_number.attr.name = "unit_number";
         sfp->attr_unit_number.attr.mode = S_IRUGO;
         sfp->attr_unit_number.show = unit_number_show;
         sfp->attr_unit_number.store = NULL;
-        class_device_create_file(sfp->class_dev,&sfp->attr_unit_number);
+        ret = class_device_create_file(sfp->class_dev,&sfp->attr_unit_number);
+        if (ret < 0)
+                printk(KERN_WARNING "%s: class_device_create_file error: %d\n",
+                       __FUNCTION__, ret);
 
         pvr2_sysfs_add_controls(sfp);
 #ifdef CONFIG_VIDEO_PVRUSB2_DEBUGIFC
diff --git a/drivers/media/video/videodev.c b/drivers/media/video/videodev.c
index b26ebaff226f..4c3f92605a82 100644
--- a/drivers/media/video/videodev.c
+++ b/drivers/media/video/videodev.c
@@ -1512,6 +1512,7 @@ int video_register_device(struct video_device *vfd, int type, int nr)
         int i=0;
         int base;
         int end;
+        int ret;
         char *name_base;
 
         switch(type)
@@ -1571,9 +1572,13 @@ int video_register_device(struct video_device *vfd, int type, int nr)
         vfd->class_dev.class       = &video_class;
         vfd->class_dev.devt        = MKDEV(VIDEO_MAJOR, vfd->minor);
         sprintf(vfd->class_dev.class_id, "%s%d", name_base, i - base);
-        class_device_register(&vfd->class_dev);
-        class_device_create_file(&vfd->class_dev,
-                                &class_device_attr_name);
+        ret = class_device_register(&vfd->class_dev);
+        if (ret) {
+                printk(KERN_ERR "%s: class_device_register failed\n",
+                       __FUNCTION__);
+                return ret;
+        }
+        video_device_create_file(vfd, &class_device_attr_name);
 
 #if 1
         /* needed until all drivers are fixed */
diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
index 62dae1a8c441..f8665326ed9f 100644
--- a/include/media/v4l2-dev.h
+++ b/include/media/v4l2-dev.h
@@ -341,11 +341,14 @@ extern int video_usercopy(struct inode *inode, struct file *file,
 extern struct video_device* video_devdata(struct file*);
 
 #define to_video_device(cd) container_of(cd, struct video_device, class_dev)
-static inline void
+static inline int
 video_device_create_file(struct video_device *vfd,
                          struct class_device_attribute *attr)
 {
-        class_device_create_file(&vfd->class_dev, attr);
+        int ret = class_device_create_file(&vfd->class_dev, attr);
+        if (ret < 0)
+                printk(KERN_WARNING "%s error: %d\n", __FUNCTION__, ret);
+        return ret;
 }
 static inline void
 video_device_remove_file(struct video_device *vfd,