ide: add ide_setting_ioctl() helper

* Add struct ide_ioctl_devset representing ioctl device setting.

* Add ide_setting_ioctl() helper for matching given ioctl
  and its parameters against table of ioctl device settings.

* Convert ide_setting_ioctl() and idedisk_ioctl() to use
  ide_setting_ioctl().

* Un-export ide_setting_mtx.

While at it:

* {get,set}_lba_addressing() -> {get,set}_addressing()

There should be no functional changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index 43025c9..1190634 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -676,7 +676,7 @@
 	return 0;
 }
 
-ide_devset_get(lba_addressing, addressing);
+ide_devset_get(addressing, addressing);
 
 /*
  * drive->addressing:
@@ -684,7 +684,7 @@
  *	1: 48-bit
  *	2: 48-bit capable doing 28-bit
  */
-static int set_lba_addressing(ide_drive_t *drive, int arg)
+static int set_addressing(ide_drive_t *drive, int arg)
 {
 	if (arg < 0 || arg > 2)
 		return -EINVAL;
@@ -704,7 +704,7 @@
 
 #ifdef CONFIG_IDE_PROC_FS
 ide_devset_rw_nolock(acoustic,	0, 254, acoustic);
-ide_devset_rw_nolock(address,	0,   2, lba_addressing);
+ide_devset_rw_nolock(address,	0,   2, addressing);
 ide_devset_rw_nolock(multcount,	0,  16, multcount);
 ide_devset_rw_nolock(nowerr,	0,   1, nowerr);
 ide_devset_rw_nolock(wcache,	0,   1, wcache);
@@ -753,7 +753,7 @@
 			drive->doorlocking = 1;
 	}
 
-	(void)set_lba_addressing(drive, 1);
+	(void)set_addressing(drive, 1);
 
 	if (drive->addressing == 1) {
 		int max_s = 2048;
@@ -1000,51 +1000,28 @@
 	return 0;
 }
 
+static const struct ide_ioctl_devset ide_disk_ioctl_settings[] = {
+{ HDIO_GET_ADDRESS,	HDIO_SET_ADDRESS,   get_addressing, set_addressing },
+{ HDIO_GET_MULTCOUNT,	HDIO_SET_MULTCOUNT, get_multcount,  set_multcount  },
+{ HDIO_GET_NOWERR,	HDIO_SET_NOWERR,    get_nowerr,	    set_nowerr	   },
+{ HDIO_GET_WCACHE,	HDIO_SET_WCACHE,    get_wcache,	    set_wcache	   },
+{ HDIO_GET_ACOUSTIC,	HDIO_SET_ACOUSTIC,  get_acoustic,   set_acoustic   },
+{ 0 }
+};
+
 static int idedisk_ioctl(struct inode *inode, struct file *file,
 			unsigned int cmd, unsigned long arg)
 {
-	unsigned long flags;
 	struct block_device *bdev = inode->i_bdev;
 	struct ide_disk_obj *idkp = ide_disk_g(bdev->bd_disk);
 	ide_drive_t *drive = idkp->drive;
-	int err, (*getfunc)(ide_drive_t *), (*setfunc)(ide_drive_t *, int);
+	int err;
 
-	switch (cmd) {
-	case HDIO_GET_ADDRESS:	 getfunc = get_lba_addressing;	goto read_val;
-	case HDIO_GET_MULTCOUNT: getfunc = get_multcount;	goto read_val;
-	case HDIO_GET_NOWERR:	 getfunc = get_nowerr;		goto read_val;
-	case HDIO_GET_WCACHE:	 getfunc = get_wcache;		goto read_val;
-	case HDIO_GET_ACOUSTIC:	 getfunc = get_acoustic;	goto read_val;
-	case HDIO_SET_ADDRESS:	 setfunc = set_lba_addressing;	goto set_val;
-	case HDIO_SET_MULTCOUNT: setfunc = set_multcount;	goto set_val;
-	case HDIO_SET_NOWERR:	 setfunc = set_nowerr;		goto set_val;
-	case HDIO_SET_WCACHE:	 setfunc = set_wcache;		goto set_val;
-	case HDIO_SET_ACOUSTIC:	 setfunc = set_acoustic;	goto set_val;
-	}
+	err = ide_setting_ioctl(drive, bdev, cmd, arg, ide_disk_ioctl_settings);
+	if (err != -EOPNOTSUPP)
+		return err;
 
 	return generic_ide_ioctl(drive, file, bdev, cmd, arg);
-
-read_val:
-	mutex_lock(&ide_setting_mtx);
-	spin_lock_irqsave(&ide_lock, flags);
-	err = getfunc(drive);
-	spin_unlock_irqrestore(&ide_lock, flags);
-	mutex_unlock(&ide_setting_mtx);
-	return err >= 0 ? put_user(err, (long __user *)arg) : err;
-
-set_val:
-	if (bdev != bdev->bd_contains)
-		err = -EINVAL;
-	else {
-		if (!capable(CAP_SYS_ADMIN))
-			err = -EACCES;
-		else {
-			mutex_lock(&ide_setting_mtx);
-			err = setfunc(drive, arg);
-			mutex_unlock(&ide_setting_mtx);
-		}
-	}
-	return err;
 }
 
 static int idedisk_media_changed(struct gendisk *disk)