From: Thomas Gleixner Date: Thu, 14 Jan 2016 16:54:46 +0000 (+0000) Subject: timerfd: Handle relative timers with CONFIG_TIME_LOW_RES proper X-Git-Tag: v3.2.78~65 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=a8e186eb50cb58896853169088c4cf24c014791b timerfd: Handle relative timers with CONFIG_TIME_LOW_RES proper commit b62526ed11a1fe3861ab98d40b7fdab8981d788a upstream. Helge reported that a relative timer can return a remaining time larger than the programmed relative time on parisc and other architectures which have CONFIG_TIME_LOW_RES set. This happens because we add a jiffie to the resulting expiry time to prevent short timeouts. Use the new function hrtimer_expires_remaining_adjusted() to calculate the remaining time. It takes that extra added time into account for relative timers. Reported-and-tested-by: Helge Deller Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: John Stultz Cc: linux-m68k@lists.linux-m68k.org Cc: dhowells@redhat.com Link: http://lkml.kernel.org/r/20160114164159.354500742@linutronix.de Signed-off-by: Thomas Gleixner [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- diff --git a/fs/timerfd.c b/fs/timerfd.c index dffeb3795af1..113208c3a874 100644 --- a/fs/timerfd.c +++ b/fs/timerfd.c @@ -123,7 +123,7 @@ static ktime_t timerfd_get_remaining(struct timerfd_ctx *ctx) { ktime_t remaining; - remaining = hrtimer_expires_remaining(&ctx->tmr); + remaining = hrtimer_expires_remaining_adjusted(&ctx->tmr); return remaining.tv64 < 0 ? ktime_set(0, 0): remaining; }