From f78bbcae86e676fad9e6c6bb6cd9d9868ba23696 Mon Sep 17 00:00:00 2001 From: Michal Nazarewicz Date: Fri, 8 Apr 2016 10:24:11 +0200 Subject: usb: f_mass_storage: test whether thread is running before starting another MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When binding the function to usb_configuration, check whether the thread is running before starting another one. Without that, when function instance is added to multiple configurations, fsg_bing starts multiple threads with all but the latest one being forgotten by the driver. This leads to obvious thread leaks, possible lockups when trying to halt the machine and possible more issues. This fixes issues with legacy/multi¹ gadget as well as configfs gadgets when mass_storage function is added to multiple configurations. This change also simplifies API since the legacy gadgets no longer need to worry about starting the thread by themselves (which was where bug in legacy/multi was in the first place). N.B., this patch doesn’t address adding single mass_storage function instance to a single configuration twice. Thankfully, there’s no legitimate reason for such setup plus, if I’m not mistaken, configfs gadget doesn’t even allow it to be expressed. ¹ I have no example failure though. Conclusion that legacy/multi has a bug is based purely on me reading the code. Acked-by: Alan Stern Signed-off-by: Michal Nazarewicz Tested-by: Ivaylo Dimitrov Cc: Alan Stern Cc: Signed-off-by: Felipe Balbi --- drivers/usb/gadget/legacy/acm_ms.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'drivers/usb/gadget/legacy/acm_ms.c') diff --git a/drivers/usb/gadget/legacy/acm_ms.c b/drivers/usb/gadget/legacy/acm_ms.c index c16089efc322..c39de65a448b 100644 --- a/drivers/usb/gadget/legacy/acm_ms.c +++ b/drivers/usb/gadget/legacy/acm_ms.c @@ -133,10 +133,6 @@ static int acm_ms_do_config(struct usb_configuration *c) if (status < 0) goto put_msg; - status = fsg_common_run_thread(opts->common); - if (status) - goto remove_acm; - status = usb_add_function(c, f_msg); if (status) goto remove_acm; -- cgit v1.2.3