[PATCH v3 1/3] usb: core: hub: fix unhandled return by employing a void function

Eugeniu Rosca
2020-02-26T17:51:30Z

Address below Coverity complaint (Feb 25, 2020, 8:06 AM CET):

*** CID 1458999: Error handling issues (CHECKED_RETURN)
/drivers/usb/core/hub.c: 1869 in hub_probe()
1863
1864 if (id->driver_info & HUB_QUIRK_CHECK_PORT_AUTOSUSPEND)
1865 hub->quirk_check_port_auto_suspend = 1;
1866
1867 if (id->driver_info & HUB_QUIRK_DISABLE_AUTOSUSPEND) {
1868 hub->quirk_disable_autosuspend = 1;
>>> CID 1458999: Error handling issues (CHECKED_RETURN)
>>> Calling "usb_autopm_get_interface" without checking return value (as is done elsewhere 97 out of 111 times).
1869 usb_autopm_get_interface(intf);
1870 }
1871
1872 if (hub_configure(hub, &desc->endpoint[0].desc) >= 0)
1873 return 0;
1874

Rather than checking the return value of 'usb_autopm_get_interface()',
switch to the usb_autopm_get_interface_no_resume() API, as per:

On Tue, Feb 25, 2020 at 10:32:32AM -0500, Alan Stern wrote:
------ 8< ------
> This change (i.e. 'ret = usb_autopm_get_interface') is not necessary,
> because the resume operation cannot fail at this point (interfaces
> are always powered-up during probe). A better solution would be to
> call usb_autopm_get_interface_no_resume() instead.
------ 8< ------

Fixes: 1208f9e1d758c9 ("USB: hub: Fix the broken detection of USB3 device in SMSC hub")
Cc: Hardik Gajjar <hgajjar@de.adit-jv.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org # v4.14+
Reported-by: scan-admin@coverity.com
Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
---
v3:
- Make the summary line more clear
- s/autpm/autopm/ in patch description
- Cc <stable> with v4.14+ since v4.14.x is the earliest stable kernel
which accepted commit 1208f9e1d758c9 ("USB: hub: Fix the broken
detection of USB3 device in SMSC hub")

v2:
- [Alan Stern] Use usb_autopm_get_interface_no_resume() instead of
usb_autopm_get_interface()
- Augment commit description to provide background
- Link: https://lore.kernel.org/lkml/20200225183057.31953-1-erosca@de.adit-jv.com

v1:
- Link: https://lore.kernel.org/lkml/20200225130846.20236-1-erosca@de.adit-jv.com
---
drivers/usb/core/hub.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 1d212f82c69b..1105983b5c1c 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1866,7 +1866,7 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)

if (id->driver_info & HUB_QUIRK_DISABLE_AUTOSUSPEND) {
hub->quirk_disable_autosuspend = 1;
- usb_autopm_get_interface(intf);
+ usb_autopm_get_interface_no_resume(intf);
}

if (hub_configure(hub, &desc->endpoint[0].desc) >= 0)
--
2.25.1