2019-11-08 20:37:55

by Arnd Bergmann

[permalink] [raw]
Subject: [PATCH 4/8] ipmi: kill off 'timespec' usage again

'struct timespec' is getting removed from the kernel. The usage in ipmi
was fixed before in commit 48862ea2ce86 ("ipmi: Update timespec usage
to timespec64"), but unfortunately it crept back in.

The busy looping code can better use ktime_t anyway, so use that
there to simplify the implementation.

Fixes: cbb19cb1eef0 ("ipmi_si: Convert timespec64 to timespec")
Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/char/ipmi/ipmi_si_intf.c | 40 +++++++++++---------------------
1 file changed, 13 insertions(+), 27 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index 6b9a0593d2eb..c7cc8538b84a 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -265,10 +265,10 @@ static void cleanup_ipmi_si(void);
#ifdef DEBUG_TIMING
void debug_timestamp(char *msg)
{
- struct timespec t;
+ struct timespec64 t;

- ktime_get_ts(&t);
- pr_debug("**%s: %ld.%9.9ld\n", msg, (long) t.tv_sec, t.tv_nsec);
+ ktime_get_ts64(&t);
+ pr_debug("**%s: %lld.%9.9ld\n", msg, t.tv_sec, t.tv_nsec);
}
#else
#define debug_timestamp(x)
@@ -935,38 +935,25 @@ static void set_run_to_completion(void *send_info, bool i_run_to_completion)
}

/*
- * Use -1 in the nsec value of the busy waiting timespec to tell that
- * we are spinning in kipmid looking for something and not delaying
- * between checks
+ * Use -1 as a special constant to tell that we are spinning in kipmid
+ * looking for something and not delaying between checks
*/
-static inline void ipmi_si_set_not_busy(struct timespec *ts)
-{
- ts->tv_nsec = -1;
-}
-static inline int ipmi_si_is_busy(struct timespec *ts)
-{
- return ts->tv_nsec != -1;
-}
-
+#define IPMI_TIME_NOT_BUSY ns_to_ktime(-1ull)
static inline bool ipmi_thread_busy_wait(enum si_sm_result smi_result,
const struct smi_info *smi_info,
- struct timespec *busy_until)
+ ktime_t *busy_until)
{
unsigned int max_busy_us = 0;

if (smi_info->si_num < num_max_busy_us)
max_busy_us = kipmid_max_busy_us[smi_info->si_num];
if (max_busy_us == 0 || smi_result != SI_SM_CALL_WITH_DELAY)
- ipmi_si_set_not_busy(busy_until);
- else if (!ipmi_si_is_busy(busy_until)) {
- ktime_get_ts(busy_until);
- timespec_add_ns(busy_until, max_busy_us * NSEC_PER_USEC);
+ *busy_until = IPMI_TIME_NOT_BUSY;
+ else if (*busy_until == IPMI_TIME_NOT_BUSY) {
+ *busy_until = ktime_get() + max_busy_us * NSEC_PER_USEC;
} else {
- struct timespec now;
-
- ktime_get_ts(&now);
- if (unlikely(timespec_compare(&now, busy_until) > 0)) {
- ipmi_si_set_not_busy(busy_until);
+ if (unlikely(ktime_get() > *busy_until)) {
+ *busy_until = IPMI_TIME_NOT_BUSY;
return false;
}
}
@@ -988,9 +975,8 @@ static int ipmi_thread(void *data)
struct smi_info *smi_info = data;
unsigned long flags;
enum si_sm_result smi_result;
- struct timespec busy_until = { 0, 0 };
+ ktime_t busy_until = IPMI_TIME_NOT_BUSY;

- ipmi_si_set_not_busy(&busy_until);
set_user_nice(current, MAX_NICE);
while (!kthread_should_stop()) {
int busy_wait;
--
2.20.0


2019-11-08 22:12:30

by Corey Minyard

[permalink] [raw]
Subject: Re: [PATCH 4/8] ipmi: kill off 'timespec' usage again

On Fri, Nov 08, 2019 at 09:34:27PM +0100, Arnd Bergmann wrote:
> 'struct timespec' is getting removed from the kernel. The usage in ipmi
> was fixed before in commit 48862ea2ce86 ("ipmi: Update timespec usage
> to timespec64"), but unfortunately it crept back in.
>
> The busy looping code can better use ktime_t anyway, so use that
> there to simplify the implementation.

Thanks, this is a big improvement. I have this queued, but if you
are going to submit this, I can remove it, and:

Reviewed-by: Corey Minyard <[email protected]>

Do you think this should go in to 5.4?

-corey

>
> Fixes: cbb19cb1eef0 ("ipmi_si: Convert timespec64 to timespec")
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> drivers/char/ipmi/ipmi_si_intf.c | 40 +++++++++++---------------------
> 1 file changed, 13 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
> index 6b9a0593d2eb..c7cc8538b84a 100644
> --- a/drivers/char/ipmi/ipmi_si_intf.c
> +++ b/drivers/char/ipmi/ipmi_si_intf.c
> @@ -265,10 +265,10 @@ static void cleanup_ipmi_si(void);
> #ifdef DEBUG_TIMING
> void debug_timestamp(char *msg)
> {
> - struct timespec t;
> + struct timespec64 t;
>
> - ktime_get_ts(&t);
> - pr_debug("**%s: %ld.%9.9ld\n", msg, (long) t.tv_sec, t.tv_nsec);
> + ktime_get_ts64(&t);
> + pr_debug("**%s: %lld.%9.9ld\n", msg, t.tv_sec, t.tv_nsec);
> }
> #else
> #define debug_timestamp(x)
> @@ -935,38 +935,25 @@ static void set_run_to_completion(void *send_info, bool i_run_to_completion)
> }
>
> /*
> - * Use -1 in the nsec value of the busy waiting timespec to tell that
> - * we are spinning in kipmid looking for something and not delaying
> - * between checks
> + * Use -1 as a special constant to tell that we are spinning in kipmid
> + * looking for something and not delaying between checks
> */
> -static inline void ipmi_si_set_not_busy(struct timespec *ts)
> -{
> - ts->tv_nsec = -1;
> -}
> -static inline int ipmi_si_is_busy(struct timespec *ts)
> -{
> - return ts->tv_nsec != -1;
> -}
> -
> +#define IPMI_TIME_NOT_BUSY ns_to_ktime(-1ull)
> static inline bool ipmi_thread_busy_wait(enum si_sm_result smi_result,
> const struct smi_info *smi_info,
> - struct timespec *busy_until)
> + ktime_t *busy_until)
> {
> unsigned int max_busy_us = 0;
>
> if (smi_info->si_num < num_max_busy_us)
> max_busy_us = kipmid_max_busy_us[smi_info->si_num];
> if (max_busy_us == 0 || smi_result != SI_SM_CALL_WITH_DELAY)
> - ipmi_si_set_not_busy(busy_until);
> - else if (!ipmi_si_is_busy(busy_until)) {
> - ktime_get_ts(busy_until);
> - timespec_add_ns(busy_until, max_busy_us * NSEC_PER_USEC);
> + *busy_until = IPMI_TIME_NOT_BUSY;
> + else if (*busy_until == IPMI_TIME_NOT_BUSY) {
> + *busy_until = ktime_get() + max_busy_us * NSEC_PER_USEC;
> } else {
> - struct timespec now;
> -
> - ktime_get_ts(&now);
> - if (unlikely(timespec_compare(&now, busy_until) > 0)) {
> - ipmi_si_set_not_busy(busy_until);
> + if (unlikely(ktime_get() > *busy_until)) {
> + *busy_until = IPMI_TIME_NOT_BUSY;
> return false;
> }
> }
> @@ -988,9 +975,8 @@ static int ipmi_thread(void *data)
> struct smi_info *smi_info = data;
> unsigned long flags;
> enum si_sm_result smi_result;
> - struct timespec busy_until = { 0, 0 };
> + ktime_t busy_until = IPMI_TIME_NOT_BUSY;
>
> - ipmi_si_set_not_busy(&busy_until);
> set_user_nice(current, MAX_NICE);
> while (!kthread_should_stop()) {
> int busy_wait;
> --
> 2.20.0
>

2019-11-09 11:25:40

by Arnd Bergmann

[permalink] [raw]
Subject: Re: [PATCH 4/8] ipmi: kill off 'timespec' usage again

On Fri, Nov 8, 2019 at 11:11 PM Corey Minyard <[email protected]> wrote:
>
> On Fri, Nov 08, 2019 at 09:34:27PM +0100, Arnd Bergmann wrote:
> > 'struct timespec' is getting removed from the kernel. The usage in ipmi
> > was fixed before in commit 48862ea2ce86 ("ipmi: Update timespec usage
> > to timespec64"), but unfortunately it crept back in.
> >
> > The busy looping code can better use ktime_t anyway, so use that
> > there to simplify the implementation.
>
> Thanks, this is a big improvement. I have this queued, but if you
> are going to submit this, I can remove it, and:
>
> Reviewed-by: Corey Minyard <[email protected]>

I'd prefer to have this go through your tree, one less thing for me
to worry about (out of the 90 patches).

> Do you think this should go in to 5.4?

Up to you, it probably depends on how well you can test that the change
is correct beyond the review.

Arnd