[RFC PATCH v4 03/11] lib: vdso: only read hrtimer_res when needed in __cvdso_clock_getres()
From: Christophe Leroy <hidden>
Date: 2020-01-16 17:58:39
Also in:
linux-mips, linuxppc-dev, lkml
Subsystem:
generic vdso library, library code, the rest · Maintainers:
Andy Lutomirski, Thomas Gleixner, Vincenzo Frascino, Andrew Morton, Linus Torvalds
Only perform READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res) for HRES and RAW clocks. Signed-off-by: Christophe Leroy <redacted> --- lib/vdso/gettimeofday.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c
index 9563be3cb5fa..8b3084d9a3ec 100644
--- a/lib/vdso/gettimeofday.c
+++ b/lib/vdso/gettimeofday.c@@ -326,7 +326,6 @@ 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;
@@ -338,7 +337,6 @@ int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res) vd->clock_mode == VDSO_CLOCKMODE_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.
@@ -348,7 +346,7 @@ 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().
--
2.13.3
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