2018-09-23 03:31:59

by Nathan Chancellor

Subject: [PATCH v2] RDS: IB: Use DECLARE_PER_CPU_SHARED_ALIGNED for rds_ib_stats

Clang warns when two declarations' section attributes don't match.

net/rds/ib_stats.c:40:1: warning: section does not match previous
declaration [-Wsection]
DEFINE_PER_CPU_SHARED_ALIGNED(struct rds_ib_statistics, rds_ib_stats);
^
./include/linux/percpu-defs.h:142:2: note: expanded from macro
'DEFINE_PER_CPU_SHARED_ALIGNED'
DEFINE_PER_CPU_SECTION(type, name,
PER_CPU_SHARED_ALIGNED_SECTION) \
^
./include/linux/percpu-defs.h:93:9: note: expanded from macro
'DEFINE_PER_CPU_SECTION'
extern __PCPU_ATTRS(sec) __typeof__(type) name;
\
^
./include/linux/percpu-defs.h:49:26: note: expanded from macro
'__PCPU_ATTRS'
__percpu __attribute__((section(PER_CPU_BASE_SECTION sec)))
\
^
net/rds/ib.h:446:1: note: previous attribute is here
DECLARE_PER_CPU(struct rds_ib_statistics, rds_ib_stats);
^
./include/linux/percpu-defs.h:111:2: note: expanded from macro
'DECLARE_PER_CPU'
DECLARE_PER_CPU_SECTION(type, name, "")
^
./include/linux/percpu-defs.h:87:9: note: expanded from macro
'DECLARE_PER_CPU_SECTION'
extern __PCPU_ATTRS(sec) __typeof__(type) name
^
./include/linux/percpu-defs.h:49:26: note: expanded from macro
'__PCPU_ATTRS'
__percpu __attribute__((section(PER_CPU_BASE_SECTION sec)))
\
^
1 warning generated.

The initial definition was added in commit ec16227e1414 ("RDS/IB:
Infiniband transport") and the cache aligned definition was added in
commit e6babe4cc4ce ("RDS/IB: Stats and sysctls") right after. The
definition probably should have been updated in net/rds/ib.h, which is
what this patch does.

Link: https://github.com/ClangBuiltLinux/linux/issues/114
Signed-off-by: Nathan Chancellor <[email protected]>
---

v1 -> v2:

Fix reported build error by using DECLARE instead of DEFINE

net/rds/ib.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/rds/ib.h b/net/rds/ib.h
index 73427ff439f9..71ff356ee702 100644
--- a/net/rds/ib.h
+++ b/net/rds/ib.h
@@ -443,7 +443,7 @@ int rds_ib_send_grab_credits(struct rds_ib_connection *ic, u32 wanted,
int rds_ib_xmit_atomic(struct rds_connection *conn, struct rm_atomic_op *op);

/* ib_stats.c */
-DECLARE_PER_CPU(struct rds_ib_statistics, rds_ib_stats);
+DECLARE_PER_CPU_SHARED_ALIGNED(struct rds_ib_statistics, rds_ib_stats);
#define rds_ib_stats_inc(member) rds_stats_inc_which(rds_ib_stats, member)
#define rds_ib_stats_add(member, count) \
rds_stats_add_which(rds_ib_stats, member, count)
--
2.19.0

2018-09-23 07:40:59

by Santosh Shilimkar

Subject: Re: [PATCH v2] RDS: IB: Use DECLARE_PER_CPU_SHARED_ALIGNED for rds_ib_stats

On 9/22/18 8:29 PM, Nathan Chancellor wrote:
> Clang warns when two declarations' section attributes don't match.
>
> net/rds/ib_stats.c:40:1: warning: section does not match previous
> declaration [-Wsection]
> DEFINE_PER_CPU_SHARED_ALIGNED(struct rds_ib_statistics, rds_ib_stats);
> ^
> ./include/linux/percpu-defs.h:142:2: note: expanded from macro
> 'DEFINE_PER_CPU_SHARED_ALIGNED'
> DEFINE_PER_CPU_SECTION(type, name,
> PER_CPU_SHARED_ALIGNED_SECTION) \
> ^
> ./include/linux/percpu-defs.h:93:9: note: expanded from macro
> 'DEFINE_PER_CPU_SECTION'
> extern __PCPU_ATTRS(sec) __typeof__(type) name;
> \
> ^
> ./include/linux/percpu-defs.h:49:26: note: expanded from macro
> '__PCPU_ATTRS'
> __percpu __attribute__((section(PER_CPU_BASE_SECTION sec)))
> \
> ^
> net/rds/ib.h:446:1: note: previous attribute is here
> DECLARE_PER_CPU(struct rds_ib_statistics, rds_ib_stats);
> ^
> ./include/linux/percpu-defs.h:111:2: note: expanded from macro
> 'DECLARE_PER_CPU'
> DECLARE_PER_CPU_SECTION(type, name, "")
> ^
> ./include/linux/percpu-defs.h:87:9: note: expanded from macro
> 'DECLARE_PER_CPU_SECTION'
> extern __PCPU_ATTRS(sec) __typeof__(type) name
> ^
> ./include/linux/percpu-defs.h:49:26: note: expanded from macro
> '__PCPU_ATTRS'
> __percpu __attribute__((section(PER_CPU_BASE_SECTION sec)))
> \
> ^
> 1 warning generated.
>
> The initial definition was added in commit ec16227e1414 ("RDS/IB:
> Infiniband transport") and the cache aligned definition was added in
> commit e6babe4cc4ce ("RDS/IB: Stats and sysctls") right after. The
> definition probably should have been updated in net/rds/ib.h, which is
> what this patch does.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/114
> Signed-off-by: Nathan Chancellor <[email protected]>
> ---
>
> v1 -> v2:
>
> Fix reported build error by using DECLARE instead of DEFINE
>
Thanks for update !!
Acked-by: Santosh shilimkar <[email protected]>