linux-kernel - [PATCH 3.16 034/136] USB: usblp: fix runtime PM after driver unbind

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Message-ID: <lsq.1576543535.937533705@decadent.org.uk>
Date:   Tue, 17 Dec 2019 00:46:08 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
        "Johan Hovold" <johan@...nel.org>
Subject: [PATCH 3.16 034/136] USB: usblp: fix runtime PM after driver unbind

3.16.80-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Johan Hovold <johan@...nel.org>

commit 9a31535859bfd8d1c3ed391f5e9247cd87bb7909 upstream.

Since commit c2b71462d294 ("USB: core: Fix bug caused by duplicate
interface PM usage counter") USB drivers must always balance their
runtime PM gets and puts, including when the driver has already been
unbound from the interface.

Leaving the interface with a positive PM usage counter would prevent a
later bound driver from suspending the device.

Fixes: c2b71462d294 ("USB: core: Fix bug caused by duplicate interface PM usage counter")
Signed-off-by: Johan Hovold <johan@...nel.org>
Link: https://lore.kernel.org/r/20191001084908.2003-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/usb/class/usblp.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/usb/class/usblp.c
+++ b/drivers/usb/class/usblp.c
@@ -463,10 +463,12 @@ static int usblp_release(struct inode *i
 
 	mutex_lock(&usblp_mutex);
 	usblp->used = 0;
-	if (usblp->present) {
+	if (usblp->present)
 		usblp_unlink_urbs(usblp);
-		usb_autopm_put_interface(usblp->intf);
-	} else		/* finish cleanup from disconnect */
+
+	usb_autopm_put_interface(usblp->intf);
+
+	if (!usblp->present)		/* finish cleanup from disconnect */
 		usblp_cleanup(usblp);
 	mutex_unlock(&usblp_mutex);
 	return 0;