[PATCH 4.4 068/105] axonram: Fix gendisk handling

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jan Kara <j...@suse.cz>


[ Upstream commit 672a2c87c83649fb0167202342ce85af9a3b4f1c ]

It is invalid to call del_gendisk() when disk->queue is NULL. Fix error
handling in axon_ram_probe() to avoid doing that.

Also del_gendisk() does not drop a reference to gendisk allocated by
alloc_disk(). That has to be done by put_disk(). Add that call where
needed.

Reported-by: Dan Carpenter <dan.carpen...@oracle.com>
Signed-off-by: Jan Kara <j...@suse.cz>
Signed-off-by: Jens Axboe <ax...@fb.com>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 arch/powerpc/sysdev/axonram.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/arch/powerpc/sysdev/axonram.c
+++ b/arch/powerpc/sysdev/axonram.c
@@ -276,7 +276,9 @@ failed:
                        if (bank->disk->major > 0)
                                unregister_blkdev(bank->disk->major,
                                                bank->disk->disk_name);
-                       del_gendisk(bank->disk);
+                       if (bank->disk->flags & GENHD_FL_UP)
+                               del_gendisk(bank->disk);
+                       put_disk(bank->disk);
                }
                device->dev.platform_data = NULL;
                if (bank->io_addr != 0)
@@ -301,6 +303,7 @@ axon_ram_remove(struct platform_device *
        device_remove_file(&device->dev, &dev_attr_ecc);
        free_irq(bank->irq_id, device);
        del_gendisk(bank->disk);
+       put_disk(bank->disk);
        iounmap((void __iomem *) bank->io_addr);
        kfree(bank);