2018-11-27 11:47:25

by Mukesh Ojha

Subject: [PATCH] perf/core: declare the percpu variable properly

Sparse reports the current declaration of percpu variable with
below warning

warning: incorrect type in initializer (different address spaces)
expected void const [noderef] <asn:3>*__vpp_verify
got struct perf_cpu_context *<noident>

Fix it by declaring it properly.

Signed-off-by: Mukesh Ojha <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>

---
include/linux/perf_event.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 53c500f..1d5c551 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -262,8 +262,8 @@ struct pmu {
*/
int capabilities;

- int * __percpu pmu_disable_count;
- struct perf_cpu_context * __percpu pmu_cpu_context;
+ int __percpu *pmu_disable_count;
+ struct perf_cpu_context __percpu *pmu_cpu_context;
atomic_t exclusive_cnt; /* < 0: cpu; > 0: tsk */
int task_ctx_nr;
int hrtimer_interval_ms;
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center,
Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project

2018-12-05 07:44:29

by Mukesh Ojha

Subject: Re: [PATCH] perf/core: declare the percpu variable properly

Hi All,

Can you please review the change ?

Thanks,
Mukesh


On 11/27/2018 2:43 PM, Mukesh Ojha wrote:
> Sparse reports the current declaration of percpu variable with
> below warning
>
> warning: incorrect type in initializer (different address spaces)
> expected void const [noderef] <asn:3>*__vpp_verify
> got struct perf_cpu_context *<noident>
>
> Fix it by declaring it properly.
>
> Signed-off-by: Mukesh Ojha <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Arnaldo Carvalho de Melo <[email protected]>
> Cc: Jiri Olsa <[email protected]>
> Cc: Namhyung Kim <[email protected]>
>
> ---
> include/linux/perf_event.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index 53c500f..1d5c551 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -262,8 +262,8 @@ struct pmu {
> */
> int capabilities;
>
> - int * __percpu pmu_disable_count;
> - struct perf_cpu_context * __percpu pmu_cpu_context;
> + int __percpu *pmu_disable_count;
> + struct perf_cpu_context __percpu *pmu_cpu_context;
> atomic_t exclusive_cnt; /* < 0: cpu; > 0: tsk */
> int task_ctx_nr;
> int hrtimer_interval_ms;

2018-12-11 17:14:10

by tip-bot for Vasyl Gomonovych

Subject: [tip:perf/core] perf/core: Declare the __percpu attribute on non-deref types

Commit-ID: 43b9e4febc66b98d83cc1560196d56ac7fef3c32
Gitweb: https://git.kernel.org/tip/43b9e4febc66b98d83cc1560196d56ac7fef3c32
Author: Mukesh Ojha <[email protected]>
AuthorDate: Tue, 27 Nov 2018 14:43:32 +0530
Committer: Ingo Molnar <[email protected]>
CommitDate: Tue, 11 Dec 2018 15:01:48 +0100

perf/core: Declare the __percpu attribute on non-deref types

Sparse reports the current declaration of two perf percpu variables
with this warning:

warning: incorrect type in initializer (different address spaces)
expected void const [noderef] <asn:3>*__vpp_verify
got struct perf_cpu_context *<noident>

While it's normally perfectly fine to place GCC attributes anywhere
in the definition, this particular attribute is for a checking
compiler's such as Sparse's benefit, which doesn't want __percpu
on pointers.

So reorder the attribute to come after the structure type, not after
the pointer type.

[ mingo: Rewrote the changelog. ]

Signed-off-by: Mukesh Ojha <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
include/linux/perf_event.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 53c500f0ca79..1d5c551a5add 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -262,8 +262,8 @@ struct pmu {
*/
int capabilities;

- int * __percpu pmu_disable_count;
- struct perf_cpu_context * __percpu pmu_cpu_context;
+ int __percpu *pmu_disable_count;
+ struct perf_cpu_context __percpu *pmu_cpu_context;
atomic_t exclusive_cnt; /* < 0: cpu; > 0: tsk */
int task_ctx_nr;
int hrtimer_interval_ms;