USB hub_probe: remove ugly goto-into-compound-statement
PATCH v2 1/1 USB hub_probe: remove ugly goto-into-compound-statement
Rework smelling code (goto inside compound statement). Perhaps this is legacy. Anyway such code is not appropriate for Linux kernel.
--- drivers/usb/core/hub.c | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-)
drivers/usb/core/hub.c +11 -13
@@ -1802,23 +1802,21 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)/* Some hubs have a subclass of 1, which AFAICT according to the */ /* specs is not defined, but it works */ -if ((desc->desc.bInterfaceSubClass !=0 ) && - (desc->desc.bInterfaceSubClass !=1 )) { -descriptor_error: + +/* Reject in following cases: +* - Interface subclass is not 0 or 1 +* - Multiple endpoints +* - Not an interrupt in endpoint +*/ + endpoint = &desc->endpoint[0 ].desc; +if ((desc->desc.bInterfaceSubClass !=0 && + desc->desc.bInterfaceSubClass !=1 ) || + desc->desc.bNumEndpoints !=1 || + !usb_endpoint_is_int_in (endpoint)) {dev_err (&intf->dev,"bad descriptor, ignoring hub\n" );return -EIO ; } -/* Multiple endpoints? What kind of mutant ninja-hub is this? */ -if (desc->desc.bNumEndpoints !=1 ) - goto descriptor_error; - - endpoint = &desc->endpoint[0 ].desc; - -/* If it's not an interrupt in endpoint, we'd better punt! */ -if (!usb_endpoint_is_int_in (endpoint)) - goto descriptor_error; -/* We found a hub */ dev_info (&intf->dev,"USB hub found\n" );
Signature · 1 line
2.10.2
Greg Kroah-Hartman
maintainerQuoted 7 lines · Eugene Korenevsky
Rework smelling code (goto inside compound statement). Perhaps this is legacy. Anyway such code is not appropriate for Linux kernel.
Signed-off-by Eugene Korenevsky <[email protected]>--- drivers/usb/core/hub.c | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-)
What changed from v1?
Quoted 27 lines
drivers/usb/core/hub.c +11
-3@@ -1802,23 +1802,21 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)/* Some hubs have a subclass of 1, which AFAICT according to the */ /* specs is not defined, but it works */ -if ((desc->desc.bInterfaceSubClass !=0 ) && - (desc->desc.bInterfaceSubClass !=1 )) { -descriptor_error: + +/* Reject in following cases: +* - Interface subclass is not 0 or 1 +* - Multiple endpoints +* - Not an interrupt in endpoint +*/ + endpoint = &desc->endpoint[0 ].desc; +if ((desc->desc.bInterfaceSubClass !=0 && + desc->desc.bInterfaceSubClass !=1 ) || + desc->desc.bNumEndpoints !=1 || + !usb_endpoint_is_int_in (endpoint)) {dev_err (&intf->dev,"bad descriptor, ignoring hub\n" );return -EIO ; }
drivers/usb/core/hub.c static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id) · line 1821
Quoted 10 lines
drivers/usb/core/hub.c +0
-10-/* Multiple endpoints? What kind of mutant ninja-hub is this? */ -if (desc->desc.bNumEndpoints !=1 ) - goto descriptor_error; - - endpoint = &desc->endpoint[0 ].desc; - -/* If it's not an interrupt in endpoint, we'd better punt! */ -if (!usb_endpoint_is_int_in (endpoint)) - goto descriptor_error; -
As "horrible" as the original code might be, it's much easier to read and follow, which is the key thing here, right? What's so bad about a goto backwards?
thanks,
greg k-h
Quoted 9 lines · Greg Kroah-Hartman
Quoted 7 lines
Rework smelling code (goto inside compound statement). Perhaps this is legacy. Anyway such code is not appropriate for Linux kernel.
Signed-off-by Eugene Korenevsky <[email protected]>--- drivers/usb/core/hub.c | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-)What changed from v1?
Fixed faults: missed 'Signed-off-by', spaces instead of tab.
Quoted 26 lines
Quoted 26 lines
drivers/usb/core/hub.c +11
-3@@ -1802,23 +1802,21 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)/* Some hubs have a subclass of 1, which AFAICT according to the */ /* specs is not defined, but it works */ -if ((desc->desc.bInterfaceSubClass !=0 ) && - (desc->desc.bInterfaceSubClass !=1 )) { -descriptor_error: + +/* Reject in following cases: +* - Interface subclass is not 0 or 1 +* - Multiple endpoints +* - Not an interrupt in endpoint +*/ + endpoint = &desc->endpoint[0 ].desc; +if ((desc->desc.bInterfaceSubClass !=0 && + desc->desc.bInterfaceSubClass !=1 ) || + desc->desc.bNumEndpoints !=1 || + !usb_endpoint_is_int_in (endpoint)) {dev_err (&intf->dev,"bad descriptor, ignoring hub\n" );return -EIO ; }
Quoted 14 lines
drivers/usb/core/hub.c static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id) · line 1821
Quoted 10 lines
drivers/usb/core/hub.c +0
-10-/* Multiple endpoints? What kind of mutant ninja-hub is this? */ -if (desc->desc.bNumEndpoints !=1 ) - goto descriptor_error; - - endpoint = &desc->endpoint[0 ].desc; - -/* If it's not an interrupt in endpoint, we'd better punt! */ -if (!usb_endpoint_is_int_in (endpoint)) - goto descriptor_error; -As "horrible" as the original code might be, it's much easier to read and follow, which is the key thing here, right? What's so bad about a goto backwards?
OK, this patch is still not perfect. But jumping *back* into *compound* *statement* hurts reader's eyes. Really. Maybe it's better to extract this code to static function, compiler will inline it. See v3 patchset.
Signature · 1 line
Eugene