* [PATCH] clocks_calc_mult_shift(): rename minsec argument according to actual usage
@ 2011-01-11 17:18 Nicolas Pitre
2011-01-11 17:24 ` john stultz
2011-01-12 11:30 ` [tip:timers/urgent] time: Rename misnamed minsec argument of clocks_calc_mult_shift() tip-bot for Nicolas Pitre
0 siblings, 2 replies; 3+ messages in thread
From: Nicolas Pitre @ 2011-01-11 17:18 UTC (permalink / raw)
To: John Stultz; +Cc: lkml
The minsec argument to clocks_calc_mult_shift() is misnamed. It is used
to clamp the magnitude of the mult factor so that a multiplication with
any value in the given range won't overflow a 64 bit result. Let's
rename it to match the actual usage.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index c18d7ef..8588abc 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -113,7 +113,7 @@ EXPORT_SYMBOL_GPL(timecounter_cyc2time);
* @shift: pointer to shift variable
* @from: frequency to convert from
* @to: frequency to convert to
- * @minsec: guaranteed runtime conversion range in seconds
+ * @maxsec: guaranteed runtime conversion range in seconds
*
* The function evaluates the shift/mult pair for the scaled math
* operations of clocksources and clockevents.
@@ -122,7 +122,7 @@ EXPORT_SYMBOL_GPL(timecounter_cyc2time);
* NSEC_PER_SEC == 1GHz and @from is the counter frequency. For clock
* event @to is the counter frequency and @from is NSEC_PER_SEC.
*
- * The @minsec conversion range argument controls the time frame in
+ * The @maxsec conversion range argument controls the time frame in
* seconds which must be covered by the runtime conversion with the
* calculated mult and shift factors. This guarantees that no 64bit
* overflow happens when the input value of the conversion is
@@ -131,7 +131,7 @@ EXPORT_SYMBOL_GPL(timecounter_cyc2time);
* factors.
*/
void
-clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec)
+clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 maxsec)
{
u64 tmp;
u32 sft, sftacc= 32;
@@ -140,7 +140,7 @@ clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec)
* Calculate the shift factor which is limiting the conversion
* range:
*/
- tmp = ((u64)minsec * from) >> 32;
+ tmp = ((u64)maxsec * from) >> 32;
while (tmp) {
tmp >>=1;
sftacc--;
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] clocks_calc_mult_shift(): rename minsec argument according to actual usage
2011-01-11 17:18 [PATCH] clocks_calc_mult_shift(): rename minsec argument according to actual usage Nicolas Pitre
@ 2011-01-11 17:24 ` john stultz
2011-01-12 11:30 ` [tip:timers/urgent] time: Rename misnamed minsec argument of clocks_calc_mult_shift() tip-bot for Nicolas Pitre
1 sibling, 0 replies; 3+ messages in thread
From: john stultz @ 2011-01-11 17:24 UTC (permalink / raw)
To: Nicolas Pitre, Thomas Gleixner; +Cc: lkml
On Tue, 2011-01-11 at 12:18 -0500, Nicolas Pitre wrote:
> The minsec argument to clocks_calc_mult_shift() is misnamed. It is used
> to clamp the magnitude of the mult factor so that a multiplication with
> any value in the given range won't overflow a 64 bit result. Let's
> rename it to match the actual usage.
>
> Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: John Stultz <johnstul@us.ibm.com>
Thomas, mind picking this up for 2.6.38?
thanks
-john
> diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
> index c18d7ef..8588abc 100644
> --- a/kernel/time/clocksource.c
> +++ b/kernel/time/clocksource.c
> @@ -113,7 +113,7 @@ EXPORT_SYMBOL_GPL(timecounter_cyc2time);
> * @shift: pointer to shift variable
> * @from: frequency to convert from
> * @to: frequency to convert to
> - * @minsec: guaranteed runtime conversion range in seconds
> + * @maxsec: guaranteed runtime conversion range in seconds
> *
> * The function evaluates the shift/mult pair for the scaled math
> * operations of clocksources and clockevents.
> @@ -122,7 +122,7 @@ EXPORT_SYMBOL_GPL(timecounter_cyc2time);
> * NSEC_PER_SEC == 1GHz and @from is the counter frequency. For clock
> * event @to is the counter frequency and @from is NSEC_PER_SEC.
> *
> - * The @minsec conversion range argument controls the time frame in
> + * The @maxsec conversion range argument controls the time frame in
> * seconds which must be covered by the runtime conversion with the
> * calculated mult and shift factors. This guarantees that no 64bit
> * overflow happens when the input value of the conversion is
> @@ -131,7 +131,7 @@ EXPORT_SYMBOL_GPL(timecounter_cyc2time);
> * factors.
> */
> void
> -clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec)
> +clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 maxsec)
> {
> u64 tmp;
> u32 sft, sftacc= 32;
> @@ -140,7 +140,7 @@ clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec)
> * Calculate the shift factor which is limiting the conversion
> * range:
> */
> - tmp = ((u64)minsec * from) >> 32;
> + tmp = ((u64)maxsec * from) >> 32;
> while (tmp) {
> tmp >>=1;
> sftacc--;
^ permalink raw reply [flat|nested] 3+ messages in thread
* [tip:timers/urgent] time: Rename misnamed minsec argument of clocks_calc_mult_shift()
2011-01-11 17:18 [PATCH] clocks_calc_mult_shift(): rename minsec argument according to actual usage Nicolas Pitre
2011-01-11 17:24 ` john stultz
@ 2011-01-12 11:30 ` tip-bot for Nicolas Pitre
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot for Nicolas Pitre @ 2011-01-12 11:30 UTC (permalink / raw)
To: linux-tip-commits
Cc: linux-kernel, hpa, mingo, johnstul, nicolas.pitre, tglx, nico
Commit-ID: 5fdade95f26372154459347dfb9f60721d22cfc7
Gitweb: http://git.kernel.org/tip/5fdade95f26372154459347dfb9f60721d22cfc7
Author: Nicolas Pitre <nico@fluxnic.net>
AuthorDate: Tue, 11 Jan 2011 12:18:12 -0500
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Wed, 12 Jan 2011 12:23:12 +0100
time: Rename misnamed minsec argument of clocks_calc_mult_shift()
The minsec argument to clocks_calc_mult_shift() is misnamed. It is used
to clamp the magnitude of the mult factor so that a multiplication with
any value in the given range won't overflow a 64 bit result. Let's
rename it to match the actual usage.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <alpine.LFD.2.00.1101111207140.17086@xanadu.home>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/time/clocksource.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index c18d7ef..8588abc 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -113,7 +113,7 @@ EXPORT_SYMBOL_GPL(timecounter_cyc2time);
* @shift: pointer to shift variable
* @from: frequency to convert from
* @to: frequency to convert to
- * @minsec: guaranteed runtime conversion range in seconds
+ * @maxsec: guaranteed runtime conversion range in seconds
*
* The function evaluates the shift/mult pair for the scaled math
* operations of clocksources and clockevents.
@@ -122,7 +122,7 @@ EXPORT_SYMBOL_GPL(timecounter_cyc2time);
* NSEC_PER_SEC == 1GHz and @from is the counter frequency. For clock
* event @to is the counter frequency and @from is NSEC_PER_SEC.
*
- * The @minsec conversion range argument controls the time frame in
+ * The @maxsec conversion range argument controls the time frame in
* seconds which must be covered by the runtime conversion with the
* calculated mult and shift factors. This guarantees that no 64bit
* overflow happens when the input value of the conversion is
@@ -131,7 +131,7 @@ EXPORT_SYMBOL_GPL(timecounter_cyc2time);
* factors.
*/
void
-clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec)
+clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 maxsec)
{
u64 tmp;
u32 sft, sftacc= 32;
@@ -140,7 +140,7 @@ clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec)
* Calculate the shift factor which is limiting the conversion
* range:
*/
- tmp = ((u64)minsec * from) >> 32;
+ tmp = ((u64)maxsec * from) >> 32;
while (tmp) {
tmp >>=1;
sftacc--;
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2011-01-11 17:18 [PATCH] clocks_calc_mult_shift(): rename minsec argument according to actual usage Nicolas Pitre
2011-01-11 17:24 ` john stultz
2011-01-12 11:30 ` [tip:timers/urgent] time: Rename misnamed minsec argument of clocks_calc_mult_shift() tip-bot for Nicolas Pitre
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