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 <stf_xl@wp.pl>
Tested-by: Stanislaw Gruszka <stf_xl@wp.pl>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

5 files changed, 56 insertions, 30 deletions

diff --git a/drivers/ide/ide-cd.c b/drivers/ide/ide-cd.c
index 690475b..ddfbea4 100644
--- a/drivers/ide/ide-cd.c
+++ b/drivers/ide/ide-cd.c
@@ -55,7 +55,7 @@
 
 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)
 {
@@ -67,7 +67,7 @@ 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);
@@ -79,7 +79,7 @@ static void ide_cd_put(struct cdrom_info *cd)
 	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);
 }
@@ -1798,15 +1798,17 @@ static void ide_cd_remove(ide_drive_t *drive)
 	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;
@@ -2005,7 +2007,12 @@ static int ide_cd_probe(ide_drive_t *drive)
 
 	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;
@@ -2019,7 +2026,7 @@ static int ide_cd_probe(ide_drive_t *drive)
 	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;
 	}
 
@@ -2029,6 +2036,8 @@ static int ide_cd_probe(ide_drive_t *drive)
 	add_disk(g);
 	return 0;
 
+out_free_disk:
+	put_disk(g);
 out_free_cd:
 	kfree(info);
 failed:
diff --git a/drivers/ide/ide-cd.h b/drivers/ide/ide-cd.h
index ac40d6c..c878bfc 100644
--- a/drivers/ide/ide-cd.h
+++ b/drivers/ide/ide-cd.h
@@ -80,7 +80,7 @@ struct cdrom_info {
 	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. */
diff --git a/drivers/ide/ide-gd.c b/drivers/ide/ide-gd.c
index 7857b20..0471094 100644
--- a/drivers/ide/ide-gd.c
+++ b/drivers/ide/ide-gd.c
@@ -25,7 +25,7 @@ module_param(debug_mask, ulong, 0644);
 
 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)
 {
@@ -37,7 +37,7 @@ 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;
@@ -48,7 +48,7 @@ static void ide_disk_put(struct ide_disk_obj *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);
 }
@@ -66,17 +66,18 @@ static void ide_gd_remove(ide_drive_t *drive)
 	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;
 
@@ -348,7 +349,12 @@ static int ide_gd_probe(ide_drive_t *drive)
 
 	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;
@@ -373,6 +379,8 @@ static int ide_gd_probe(ide_drive_t *drive)
 	add_disk(g);
 	return 0;
 
+out_free_disk:
+	put_disk(g);
 out_free_idkp:
 	kfree(idkp);
 failed:
diff --git a/drivers/ide/ide-gd.h b/drivers/ide/ide-gd.h
index a86779f..b604bdd 100644
--- a/drivers/ide/ide-gd.h
+++ b/drivers/ide/ide-gd.h
@@ -17,7 +17,7 @@ struct ide_disk_obj {
 	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 */
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index d7ecd3c..bb450a7 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -169,7 +169,7 @@ typedef struct ide_tape_obj {
 	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
@@ -267,7 +267,7 @@ static DEFINE_MUTEX(idetape_ref_mutex);
 
 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)
 {
@@ -279,7 +279,7 @@ 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;
@@ -290,7 +290,7 @@ static void ide_tape_put(struct ide_tape_obj *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);
 }
@@ -308,7 +308,7 @@ static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
 	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;
 }
@@ -2256,15 +2256,17 @@ static void ide_tape_remove(ide_drive_t *drive)
 	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;
 
@@ -2407,7 +2409,12 @@ static int ide_tape_probe(ide_drive_t *drive)
 
 	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;
@@ -2436,6 +2443,8 @@ static int ide_tape_probe(ide_drive_t *drive)
 
 	return 0;
 
+out_free_disk:
+	put_disk(g);
 out_free_tape:
 	kfree(tape);
 failed: