Subject: [PATCH v4 01/58] mtd: nand: denali: add missing nand_release() call in denali_remove()

From: [email-masked] (Brian Norris)
Date: Thu, 10 Dec 2015 16:40:08 -0800

On Thu, Dec 10, 2015 at 08:59:45AM +0100, Boris Brezillon wrote:
> Unregister the NAND device from the NAND subsystem when removing a denali
> NAND controller, otherwise the MTD attached to the NAND device is still
> exposed by the MTD layer, and accesses to this device will likely crash
> the system.
> 
> Signed-off-by: Boris Brezillon <[email-masked]>
> Cc: <[email-masked]> #3.8+

Does this follow these rules, from
Documentation/stable_kernel_rules.txt?

 - It must be obviously correct and tested.

 - It must fix a real bug that bothers people (not a, "This could be a
   problem..." type thing).

> Fixes: 2a0a288ec258 ("mtd: denali: split the generic driver and PCI layer")
> ---
>  drivers/mtd/nand/denali.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c
> index 67eb2be..8feece3 100644
> --- a/drivers/mtd/nand/denali.c
> +++ b/drivers/mtd/nand/denali.c
> @@ -1622,6 +1622,7 @@ EXPORT_SYMBOL(denali_init);
>  /* driver exit point */
>  void denali_remove(struct denali_nand_info *denali)
>  {
> +	nand_release(&denali->mtd);
>  	denali_irq_cleanup(denali->irq, denali);
>  	dma_unmap_single(denali->dev, denali->buf.dma_buf,
>  			 denali->mtd.writesize + denali->mtd.oobsize,

It feels a bit odd to allow usage of MTD fields after it has been
unregistered. Maybe precompute this before the nand_release()?

Brian