From: Christophe Leroy Date: Thu, 16 Jan 2020 17:58:27 +0000 (+0000) Subject: lib/vdso: Only read hrtimer_res when needed in __cvdso_clock_getres() X-Git-Tag: block-5.6-2020-02-05~69^2~6 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=49a101d7169c7729c7bab6b2f896faae34bd6c3d;p=linux-2.6-block.git lib/vdso: Only read hrtimer_res when needed in __cvdso_clock_getres() Only perform READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res) for HRES and RAW clocks. Signed-off-by: Christophe Leroy Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/7ac2f0d21652f95e2bbdfa6bd514ae6c7caf53ab.1579196675.git.christophe.leroy@c-s.fr --- diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index f342ac1fce77..f8b8ec5e63ac 100644 --- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -312,7 +312,6 @@ static __maybe_unused int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res) { const struct vdso_data *vd = __arch_get_vdso_data(); - u64 hrtimer_res; u32 msk; u64 ns; @@ -323,7 +322,6 @@ int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res) if (IS_ENABLED(CONFIG_TIME_NS) && vd->clock_mode == VCLOCK_TIMENS) vd = __arch_get_timens_vdso_data(); - hrtimer_res = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res); /* * Convert the clockid to a bitmask and use it to check which * clocks are handled in the VDSO directly. @@ -333,7 +331,7 @@ int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res) /* * Preserves the behaviour of posix_get_hrtimer_res(). */ - ns = hrtimer_res; + ns = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res); } else if (msk & VDSO_COARSE) { /* * Preserves the behaviour of posix_get_coarse_res().