ide: fix refcounting in device drivers

During host driver module removal del_gendisk() results in a final
put on drive->gendev and freeing the drive by drive_release_dev().

Convert device drivers from using struct kref to use struct device
so device driver's object holds reference on ->gendev and prevents
drive from prematurely going away.

Also fix ->remove methods to not erroneously drop reference on a
host driver by using only put_device() instead of ide*_put().

Reported-by: Stanislaw Gruszka <[e-mail]>
Tested-by: Stanislaw Gruszka <[e-mail]>
Signed-off-by: Bartlomiej Zolnierkiewicz <[e-mail]>

drivers/ide/ide-cd.c

···
 
 static DEFINE_MUTEX(idecd_ref_mutex);
 
-static void ide_cd_release(struct kref *);
+static void ide_cd_release(struct device *);
 
 static struct cdrom_info *ide_cd_get(struct gendisk *disk)
 {
···
 		if (ide_device_get(cd->drive))
 			cd = NULL;
 		else
-			kref_get(&cd->kref);
+			get_device(&cd->dev);
 
 	}
 	mutex_unlock(&idecd_ref_mutex);
···
 	ide_drive_t *drive = cd->drive;
 
 	mutex_lock(&idecd_ref_mutex);
-	kref_put(&cd->kref, ide_cd_release);
+	put_device(&cd->dev);
 	ide_device_put(drive);
 	mutex_unlock(&idecd_ref_mutex);
 }
···
 	ide_debug_log(IDE_DBG_FUNC, "Call %s\n", __func__);
 
 	ide_proc_unregister_driver(drive, info->driver);
-
+	device_del(&info->dev);
 	del_gendisk(info->disk);
 
-	ide_cd_put(info);
+	mutex_lock(&idecd_ref_mutex);
+	put_device(&info->dev);
+	mutex_unlock(&idecd_ref_mutex);
 }
 
-static void ide_cd_release(struct kref *kref)
+static void ide_cd_release(struct device *dev)
 {
-	struct cdrom_info *info = to_ide_drv(kref, cdrom_info);
+	struct cdrom_info *info = to_ide_drv(dev, cdrom_info);
 	struct cdrom_device_info *devinfo = &info->devinfo;
 	ide_drive_t *drive = info->drive;
 	struct gendisk *g = info->disk;
···
 
 	ide_init_disk(g, drive);
 
-	kref_init(&info->kref);
+	info->dev.parent = &drive->gendev;
+	info->dev.release = ide_cd_release;
+	dev_set_name(&info->dev, dev_name(&drive->gendev));
+
+	if (device_register(&info->dev))
+		goto out_free_disk;
 
 	info->drive = drive;
 	info->driver = &ide_cdrom_driver;
···
 	g->driverfs_dev = &drive->gendev;
 	g->flags = GENHD_FL_CD | GENHD_FL_REMOVABLE;
 	if (ide_cdrom_setup(drive)) {
-		ide_cd_release(&info->kref);
+		put_device(&info->dev);
 		goto failed;
 	}
 
···
 	add_disk(g);
 	return 0;
 
+out_free_disk:
+	put_disk(g);
 out_free_cd:
 	kfree(info);
 failed:

drivers/ide/ide-cd.h

···
 	ide_drive_t		*drive;
 	struct ide_driver	*driver;
 	struct gendisk		*disk;
-	struct kref		kref;
+	struct device		dev;
 
 	/* Buffer for table of contents.  NULL if we haven't allocated
 	   a TOC buffer for this device yet. */

drivers/ide/ide-gd.c

···
 
 static DEFINE_MUTEX(ide_disk_ref_mutex);
 
-static void ide_disk_release(struct kref *);
+static void ide_disk_release(struct device *);
 
 static struct ide_disk_obj *ide_disk_get(struct gendisk *disk)
 {
···
 		if (ide_device_get(idkp->drive))
 			idkp = NULL;
 		else
-			kref_get(&idkp->kref);
+			get_device(&idkp->dev);
 	}
 	mutex_unlock(&ide_disk_ref_mutex);
 	return idkp;
···
 	ide_drive_t *drive = idkp->drive;
 
 	mutex_lock(&ide_disk_ref_mutex);
-	kref_put(&idkp->kref, ide_disk_release);
+	put_device(&idkp->dev);
 	ide_device_put(drive);
 	mutex_unlock(&ide_disk_ref_mutex);
 }
···
 	struct gendisk *g = idkp->disk;
 
 	ide_proc_unregister_driver(drive, idkp->driver);
-
+	device_del(&idkp->dev);
 	del_gendisk(g);
-
 	drive->disk_ops->flush(drive);
 
-	ide_disk_put(idkp);
+	mutex_lock(&ide_disk_ref_mutex);
+	put_device(&idkp->dev);
+	mutex_unlock(&ide_disk_ref_mutex);
 }
 
-static void ide_disk_release(struct kref *kref)
+static void ide_disk_release(struct device *dev)
 {
-	struct ide_disk_obj *idkp = to_ide_drv(kref, ide_disk_obj);
+	struct ide_disk_obj *idkp = to_ide_drv(dev, ide_disk_obj);
 	ide_drive_t *drive = idkp->drive;
 	struct gendisk *g = idkp->disk;
 
···
 
 	ide_init_disk(g, drive);
 
-	kref_init(&idkp->kref);
+	idkp->dev.parent = &drive->gendev;
+	idkp->dev.release = ide_disk_release;
+	dev_set_name(&idkp->dev, dev_name(&drive->gendev));
+
+	if (device_register(&idkp->dev))
+		goto out_free_disk;
 
 	idkp->drive = drive;
 	idkp->driver = &ide_gd_driver;
···
 	add_disk(g);
 	return 0;
 
+out_free_disk:
+	put_disk(g);
 out_free_idkp:
 	kfree(idkp);
 failed:

drivers/ide/ide-gd.h

···
 	ide_drive_t		*drive;
 	struct ide_driver	*driver;
 	struct gendisk		*disk;
-	struct kref		kref;
+	struct device		dev;
 	unsigned int		openers;	/* protected by BKL for now */
 
 	/* Last failed packet command */

drivers/ide/ide-tape.c

···
 	ide_drive_t		*drive;
 	struct ide_driver	*driver;
 	struct gendisk		*disk;
-	struct kref		kref;
+	struct device		dev;
 
 	/*
 	 *	failed_pc points to the last failed packet command, or contains
···
 
 static struct class *idetape_sysfs_class;
 
-static void ide_tape_release(struct kref *);
+static void ide_tape_release(struct device *);
 
 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
 {
···
 		if (ide_device_get(tape->drive))
 			tape = NULL;
 		else
-			kref_get(&tape->kref);
+			get_device(&tape->dev);
 	}
 	mutex_unlock(&idetape_ref_mutex);
 	return tape;
···
 	ide_drive_t *drive = tape->drive;
 
 	mutex_lock(&idetape_ref_mutex);
-	kref_put(&tape->kref, ide_tape_release);
+	put_device(&tape->dev);
 	ide_device_put(drive);
 	mutex_unlock(&idetape_ref_mutex);
 }
···
 	mutex_lock(&idetape_ref_mutex);
 	tape = idetape_devs[i];
 	if (tape)
-		kref_get(&tape->kref);
+		get_device(&tape->dev);
 	mutex_unlock(&idetape_ref_mutex);
 	return tape;
 }
···
 	idetape_tape_t *tape = drive->driver_data;
 
 	ide_proc_unregister_driver(drive, tape->driver);
-
+	device_del(&tape->dev);
 	ide_unregister_region(tape->disk);
 
-	ide_tape_put(tape);
+	mutex_lock(&idetape_ref_mutex);
+	put_device(&tape->dev);
+	mutex_unlock(&idetape_ref_mutex);
 }
 
-static void ide_tape_release(struct kref *kref)
+static void ide_tape_release(struct device *dev)
 {
-	struct ide_tape_obj *tape = to_ide_drv(kref, ide_tape_obj);
+	struct ide_tape_obj *tape = to_ide_drv(dev, ide_tape_obj);
 	ide_drive_t *drive = tape->drive;
 	struct gendisk *g = tape->disk;
 
···
 
 	ide_init_disk(g, drive);
 
-	kref_init(&tape->kref);
+	tape->dev.parent = &drive->gendev;
+	tape->dev.release = ide_tape_release;
+	dev_set_name(&tape->dev, dev_name(&drive->gendev));
+
+	if (device_register(&tape->dev))
+		goto out_free_disk;
 
 	tape->drive = drive;
 	tape->driver = &idetape_driver;
···
 
 	return 0;
 
+out_free_disk:
+	put_disk(g);
 out_free_tape:
 	kfree(tape);
 failed:

include/linux/ide.h

···
 #define to_ide_device(dev)		container_of(dev, ide_drive_t, gendev)
 
 #define to_ide_drv(obj, cont_type)	\
-	container_of(obj, struct cont_type, kref)
+	container_of(obj, struct cont_type, dev)
 
 #define ide_drv_g(disk, cont_type)	\
 	container_of((disk)->private_data, struct cont_type, driver)