[PATCH RFC 4/8] clock device: convert clock_settime

From: Richard Cochran
Date: Thu Nov 04 2010 - 15:29:35 EST


This patch lets the clock_settime system call use dynamic clock devices.

Signed-off-by: Richard Cochran <richard.cochran@xxxxxxxxxx>
---
include/linux/posix-timers.h | 1 +
kernel/posix-timers.c | 4 ++--
kernel/time/clockdevice.c | 26 ++++++++++++++++++++++++++
3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index 7d6a4f0..864ed7b 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -138,5 +138,6 @@ void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new);

int posix_clock_gettime(const clockid_t clock, struct timespec __user *tp);
int posix_clock_getres(const clockid_t clock, struct timespec __user *tp);
+int posix_clock_settime(const clockid_t clock, const struct timespec __user *t);

#endif
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index baa6a2e..ef4e222 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -939,8 +939,8 @@ int do_posix_clock_nonanosleep(const clockid_t clock, int flags,
}
EXPORT_SYMBOL_GPL(do_posix_clock_nonanosleep);

-SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
- const struct timespec __user *, tp)
+int posix_clock_settime(const clockid_t which_clock,
+ const struct timespec __user *tp)
{
struct timespec new_tp;

diff --git a/kernel/time/clockdevice.c b/kernel/time/clockdevice.c
index 6629ae7..3f2870d 100644
--- a/kernel/time/clockdevice.c
+++ b/kernel/time/clockdevice.c
@@ -238,3 +238,29 @@ SYSCALL_DEFINE2(clock_getres,
mutex_unlock(&clk->mux);
return err;
}
+
+SYSCALL_DEFINE2(clock_settime,
+ const clockid_t, id, const struct timespec __user *, user_ts)
+{
+ struct timespec ts;
+ struct clock_device *clk;
+ int err;
+
+ clk = clockid_to_clock_device(id);
+ if (!clk)
+ return posix_clock_settime(id, user_ts);
+
+ mutex_lock(&clk->mux);
+
+ if (clk->zombie)
+ err = -ENODEV;
+ else if (!clk->ops->clock_settime)
+ err = -EOPNOTSUPP;
+ else if (copy_from_user(&ts, user_ts, sizeof(ts)))
+ err = -EFAULT;
+ else
+ err = clk->ops->clock_settime(clk->priv, &ts);
+
+ mutex_unlock(&clk->mux);
+ return err;
+}
--
1.7.0.4

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