[4.2.y-ckt stable] Patch "mtd: nand: denali: add missing nand_release() call in denali_remove()" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    mtd: nand: denali: add missing nand_release() call in denali_remove()

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt3.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From ed6d28af6c4e620b7a2879f00647486d895a5d8a Mon Sep 17 00:00:00 2001
From: Boris BREZILLON <boris.brezillon at free-electrons.com>
Date: Fri, 11 Dec 2015 15:02:34 +0100
Subject: mtd: nand: denali: add missing nand_release() call in denali_remove()

commit 320092a05dab2f44819c42f33d6b51efb6c474f2 upstream.

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.

Fixes: 2a0a288ec258 ("mtd: denali: split the generic driver and PCI layer")
Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
Acked-by: Dinh Nguyen <dinguyen at opensource.altera.com>
Signed-off-by: Brian Norris <computersforpeace at gmail.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/mtd/nand/denali.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c
index 870c7fc..f229554 100644
--- a/drivers/mtd/nand/denali.c
+++ b/drivers/mtd/nand/denali.c
@@ -1613,9 +1613,16 @@ EXPORT_SYMBOL(denali_init);
 /* driver exit point */
 void denali_remove(struct denali_nand_info *denali)
 {
+	/*
+	 * Pre-compute DMA buffer size to avoid any problems in case
+	 * nand_release() ever changes in a way that mtd->writesize and
+	 * mtd->oobsize are not reliable after this call.
+	 */
+	int bufsize = denali->mtd.writesize + denali->mtd.oobsize;
+
+	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,
+	dma_unmap_single(denali->dev, denali->buf.dma_buf, bufsize,
 			 DMA_BIDIRECTIONAL);
 }
 EXPORT_SYMBOL(denali_remove);
--
1.9.1