From a733a41a5057b47ed4a1f43d33166770ef83bc10 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Wed, 18 Nov 2015 12:55:47 -0200 Subject: [PATCH] [media] fix dvb_frontend_sleep_until() logic As pointed by Laurent Navet: "Calling ktime_add_us() seems useless as is only useful for it's return value which is ignored." That's reported by coverity CID 1309761. Laurent proposed to just remove ktime_add_us, but the fact is that the logic of this function is broken. Instead, we need to use the value of the timeout, and ensure that it will work on the loops to emulate the legacy DiSEqC ioctl (FE_DISHNETWORK_SEND_LEGACY_CMD). Please notice that the logic was also broken if, for any reason, msleep() would sleep a little less than what it was expected, as newdelta would be smaller than delta, and udelay() would not be called. It should also be noticed that nobody noticed that trouble before likely because the FE_DISHNETWORK_SEND_LEGACY_CMD is not used anymore by modern DVB applications. Reported-by: Laurent Navet Signed-off-by: Mauro Carvalho Chehab --- drivers/media/dvb-core/dvb_frontend.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c index fe6fa80a2621..b64f33776b74 100644 --- a/drivers/media/dvb-core/dvb_frontend.c +++ b/drivers/media/dvb-core/dvb_frontend.c @@ -899,14 +899,13 @@ static void dvb_frontend_stop(struct dvb_frontend *fe) */ void dvb_frontend_sleep_until(ktime_t *waketime, u32 add_usec) { - s32 delta, newdelta; + s32 delta; - ktime_add_us(*waketime, add_usec); + *waketime = ktime_add_us(*waketime, add_usec); delta = ktime_us_delta(ktime_get_real(), *waketime); if (delta > 2500) { msleep((delta - 1500) / 1000); - newdelta = ktime_us_delta(ktime_get_real(), *waketime); - delta = (newdelta > delta) ? 0 : newdelta; + delta = ktime_us_delta(ktime_get_real(), *waketime); } if (delta > 0) udelay(delta); -- 2.20.1