[PATCH] rcu: add declarations of undeclared items

[PATCH] rcu: add declarations of undeclared items

[Ben Dooks]

The rcu_state, rcu_rnp_online_cpus and rcu_dynticks_curr_cpu_in_eqs
do not have declarations in a header. Add these to remove the
following sparse warnings:

kernel/rcu/tree.c:87:18: warning: symbol 'rcu_state' was not declared. Should it be static?
kernel/rcu/tree.c:191:15: warning: symbol 'rcu_rnp_online_cpus' was not declared. Should it be static?
kernel/rcu/tree.c:297:6: warning: symbol 'rcu_dynticks_curr_cpu_in_eqs' was not declared. Should it be static?

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
---
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
 kernel/rcu/tree.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index c612f306fe89..1f88351b9014 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -352,6 +352,8 @@ struct rcu_state {
 						/*  GP pre-initialization. */
 };
 
+extern struct rcu_state rcu_state;
+
 /* Values for rcu_state structure's gp_flags field. */
 #define RCU_GP_FLAG_INIT 0x1	/* Need grace-period initialization. */
 #define RCU_GP_FLAG_FQS  0x2	/* Need grace-period quiescent-state forcing. */
@@ -472,3 +474,7 @@ static void rcu_iw_handler(struct irq_work *iwp);
 static void check_cpu_stall(struct rcu_data *rdp);
 static void rcu_check_gp_start_stall(struct rcu_node *rnp, struct rcu_data *rdp,
 				     const unsigned long gpssdelay);
+
+extern unsigned long rcu_rnp_online_cpus(struct rcu_node *rnp);
+extern bool rcu_dynticks_curr_cpu_in_eqs(void);
+
-- 
2.23.0

Re: [PATCH] rcu: add declarations of undeclared items

[Paul E. McKenney]

On Fri, Oct 11, 2019 at 06:08:24PM +0100, Ben Dooks wrote:
> The rcu_state, rcu_rnp_online_cpus and rcu_dynticks_curr_cpu_in_eqs
> do not have declarations in a header. Add these to remove the
> following sparse warnings:
> 
> kernel/rcu/tree.c:87:18: warning: symbol 'rcu_state' was not declared. Should it be static?
> kernel/rcu/tree.c:191:15: warning: symbol 'rcu_rnp_online_cpus' was not declared. Should it be static?
> kernel/rcu/tree.c:297:6: warning: symbol 'rcu_dynticks_curr_cpu_in_eqs' was not declared. Should it be static?
> 
> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>

Good catch!

However, these guys (plus one more) are actually used only in the
kernel/rcu/tree.o translation unit, so they can be marked static.
I made this change as shown below with your Reported-by.

Seem reasonable?

							Thanx, Paul

------------------------------------------------------------------------

commit 02995691aa76f3e52599d4f9d9d1ab23c3574f32
Author: Paul E. McKenney <paulmck@kernel.org>
Date:   Fri Oct 11 21:40:09 2019 -0700

    rcu: Mark non-global functions and variables as static
    
    Each of rcu_state, rcu_rnp_online_cpus(), rcu_dynticks_curr_cpu_in_eqs(),
    and rcu_dynticks_snap() are used only in the kernel/rcu/tree.o translation
    unit, and may thus be marked static.  This commit therefore makes this
    change.
    
    Reported-by: Ben Dooks <ben.dooks@codethink.co.uk>
    Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index b18fa3d..278798e 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -85,7 +85,7 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(struct rcu_data, rcu_data) = {
 	.dynticks_nmi_nesting = DYNTICK_IRQ_NONIDLE,
 	.dynticks = ATOMIC_INIT(RCU_DYNTICK_CTRL_CTR),
 };
-struct rcu_state rcu_state = {
+static struct rcu_state rcu_state = {
 	.level = { &rcu_state.node[0] },
 	.gp_state = RCU_GP_IDLE,
 	.gp_seq = (0UL - 300UL) << RCU_SEQ_CTR_SHIFT,
@@ -189,7 +189,7 @@ EXPORT_SYMBOL_GPL(rcu_get_gp_kthreads_prio);
  * held, but the bit corresponding to the current CPU will be stable
  * in most contexts.
  */
-unsigned long rcu_rnp_online_cpus(struct rcu_node *rnp)
+static unsigned long rcu_rnp_online_cpus(struct rcu_node *rnp)
 {
 	return READ_ONCE(rnp->qsmaskinitnext);
 }
@@ -295,7 +295,7 @@ static void rcu_dynticks_eqs_online(void)
  *
  * No ordering, as we are sampling CPU-local information.
  */
-bool rcu_dynticks_curr_cpu_in_eqs(void)
+static bool rcu_dynticks_curr_cpu_in_eqs(void)
 {
 	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
 
@@ -306,7 +306,7 @@ bool rcu_dynticks_curr_cpu_in_eqs(void)
  * Snapshot the ->dynticks counter with full ordering so as to allow
  * stable comparison of this counter with past and future snapshots.
  */
-int rcu_dynticks_snap(struct rcu_data *rdp)
+static int rcu_dynticks_snap(struct rcu_data *rdp)
 {
 	int snap = atomic_add_return(0, &rdp->dynticks);
 
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 1540542..f8e6c70 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -402,8 +402,6 @@ static const char *tp_rcu_varname __used __tracepoint_string = rcu_name;
 #define RCU_NAME rcu_name
 #endif /* #else #ifdef CONFIG_TRACING */
 
-int rcu_dynticks_snap(struct rcu_data *rdp);
-
 /* Forward declarations for tree_plugin.h */
 static void rcu_bootup_announce(void);
 static void rcu_qs(void);

Re: [PATCH] rcu: add declarations of undeclared items

[Ben Dooks]

On 2019-10-12 05:44, Paul E. McKenney wrote:
> On Fri, Oct 11, 2019 at 06:08:24PM +0100, Ben Dooks wrote:
>> The rcu_state, rcu_rnp_online_cpus and rcu_dynticks_curr_cpu_in_eqs
>> do not have declarations in a header. Add these to remove the
>> following sparse warnings:
>> 
>> kernel/rcu/tree.c:87:18: warning: symbol 'rcu_state' was not declared. 
>> Should it be static?
>> kernel/rcu/tree.c:191:15: warning: symbol 'rcu_rnp_online_cpus' was 
>> not declared. Should it be static?
>> kernel/rcu/tree.c:297:6: warning: symbol 
>> 'rcu_dynticks_curr_cpu_in_eqs' was not declared. Should it be static?
>> 
>> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
> 
> Good catch!
> 
> However, these guys (plus one more) are actually used only in the
> kernel/rcu/tree.o translation unit, so they can be marked static.
> I made this change as shown below with your Reported-by.
> 
> Seem reasonable?

yes, thanks.

Re: [PATCH] rcu: add declarations of undeclared items

[Joel Fernandes]

On Fri, Oct 11, 2019 at 09:44:30PM -0700, Paul E. McKenney wrote:
> On Fri, Oct 11, 2019 at 06:08:24PM +0100, Ben Dooks wrote:
> > The rcu_state, rcu_rnp_online_cpus and rcu_dynticks_curr_cpu_in_eqs
> > do not have declarations in a header. Add these to remove the
> > following sparse warnings:
> > 
> > kernel/rcu/tree.c:87:18: warning: symbol 'rcu_state' was not declared. Should it be static?
> > kernel/rcu/tree.c:191:15: warning: symbol 'rcu_rnp_online_cpus' was not declared. Should it be static?
> > kernel/rcu/tree.c:297:6: warning: symbol 'rcu_dynticks_curr_cpu_in_eqs' was not declared. Should it be static?
> > 
> > Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
> 
> Good catch!
> 
> However, these guys (plus one more) are actually used only in the
> kernel/rcu/tree.o translation unit, so they can be marked static.
> I made this change as shown below with your Reported-by.
> 
> Seem reasonable?
> 

LGTM.

Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>

thanks,

 - Joel

> 							Thanx, Paul
> 
> ------------------------------------------------------------------------
> 
> commit 02995691aa76f3e52599d4f9d9d1ab23c3574f32
> Author: Paul E. McKenney <paulmck@kernel.org>
> Date:   Fri Oct 11 21:40:09 2019 -0700
> 
>     rcu: Mark non-global functions and variables as static
>     
>     Each of rcu_state, rcu_rnp_online_cpus(), rcu_dynticks_curr_cpu_in_eqs(),
>     and rcu_dynticks_snap() are used only in the kernel/rcu/tree.o translation
>     unit, and may thus be marked static.  This commit therefore makes this
>     change.
>     
>     Reported-by: Ben Dooks <ben.dooks@codethink.co.uk>
>     Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> 
> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> index b18fa3d..278798e 100644
> --- a/kernel/rcu/tree.c
> +++ b/kernel/rcu/tree.c
> @@ -85,7 +85,7 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(struct rcu_data, rcu_data) = {
>  	.dynticks_nmi_nesting = DYNTICK_IRQ_NONIDLE,
>  	.dynticks = ATOMIC_INIT(RCU_DYNTICK_CTRL_CTR),
>  };
> -struct rcu_state rcu_state = {
> +static struct rcu_state rcu_state = {
>  	.level = { &rcu_state.node[0] },
>  	.gp_state = RCU_GP_IDLE,
>  	.gp_seq = (0UL - 300UL) << RCU_SEQ_CTR_SHIFT,
> @@ -189,7 +189,7 @@ EXPORT_SYMBOL_GPL(rcu_get_gp_kthreads_prio);
>   * held, but the bit corresponding to the current CPU will be stable
>   * in most contexts.
>   */
> -unsigned long rcu_rnp_online_cpus(struct rcu_node *rnp)
> +static unsigned long rcu_rnp_online_cpus(struct rcu_node *rnp)
>  {
>  	return READ_ONCE(rnp->qsmaskinitnext);
>  }
> @@ -295,7 +295,7 @@ static void rcu_dynticks_eqs_online(void)
>   *
>   * No ordering, as we are sampling CPU-local information.
>   */
> -bool rcu_dynticks_curr_cpu_in_eqs(void)
> +static bool rcu_dynticks_curr_cpu_in_eqs(void)
>  {
>  	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
>  
> @@ -306,7 +306,7 @@ bool rcu_dynticks_curr_cpu_in_eqs(void)
>   * Snapshot the ->dynticks counter with full ordering so as to allow
>   * stable comparison of this counter with past and future snapshots.
>   */
> -int rcu_dynticks_snap(struct rcu_data *rdp)
> +static int rcu_dynticks_snap(struct rcu_data *rdp)
>  {
>  	int snap = atomic_add_return(0, &rdp->dynticks);
>  
> diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
> index 1540542..f8e6c70 100644
> --- a/kernel/rcu/tree.h
> +++ b/kernel/rcu/tree.h
> @@ -402,8 +402,6 @@ static const char *tp_rcu_varname __used __tracepoint_string = rcu_name;
>  #define RCU_NAME rcu_name
>  #endif /* #else #ifdef CONFIG_TRACING */
>  
> -int rcu_dynticks_snap(struct rcu_data *rdp);
> -
>  /* Forward declarations for tree_plugin.h */
>  static void rcu_bootup_announce(void);
>  static void rcu_qs(void);

Re: [PATCH] rcu: add declarations of undeclared items

[Paul E. McKenney]

On Mon, Oct 14, 2019 at 01:51:23PM -0400, Joel Fernandes wrote:
> On Fri, Oct 11, 2019 at 09:44:30PM -0700, Paul E. McKenney wrote:
> > On Fri, Oct 11, 2019 at 06:08:24PM +0100, Ben Dooks wrote:
> > > The rcu_state, rcu_rnp_online_cpus and rcu_dynticks_curr_cpu_in_eqs
> > > do not have declarations in a header. Add these to remove the
> > > following sparse warnings:
> > > 
> > > kernel/rcu/tree.c:87:18: warning: symbol 'rcu_state' was not declared. Should it be static?
> > > kernel/rcu/tree.c:191:15: warning: symbol 'rcu_rnp_online_cpus' was not declared. Should it be static?
> > > kernel/rcu/tree.c:297:6: warning: symbol 'rcu_dynticks_curr_cpu_in_eqs' was not declared. Should it be static?
> > > 
> > > Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
> > 
> > Good catch!
> > 
> > However, these guys (plus one more) are actually used only in the
> > kernel/rcu/tree.o translation unit, so they can be marked static.
> > I made this change as shown below with your Reported-by.
> > 
> > Seem reasonable?
> > 
> 
> LGTM.
> 
> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>

Applied, thank you!

							Thanx, Paul

> thanks,
> 
>  - Joel
> 
> > 							Thanx, Paul
> > 
> > ------------------------------------------------------------------------
> > 
> > commit 02995691aa76f3e52599d4f9d9d1ab23c3574f32
> > Author: Paul E. McKenney <paulmck@kernel.org>
> > Date:   Fri Oct 11 21:40:09 2019 -0700
> > 
> >     rcu: Mark non-global functions and variables as static
> >     
> >     Each of rcu_state, rcu_rnp_online_cpus(), rcu_dynticks_curr_cpu_in_eqs(),
> >     and rcu_dynticks_snap() are used only in the kernel/rcu/tree.o translation
> >     unit, and may thus be marked static.  This commit therefore makes this
> >     change.
> >     
> >     Reported-by: Ben Dooks <ben.dooks@codethink.co.uk>
> >     Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> > 
> > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > index b18fa3d..278798e 100644
> > --- a/kernel/rcu/tree.c
> > +++ b/kernel/rcu/tree.c
> > @@ -85,7 +85,7 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(struct rcu_data, rcu_data) = {
> >  	.dynticks_nmi_nesting = DYNTICK_IRQ_NONIDLE,
> >  	.dynticks = ATOMIC_INIT(RCU_DYNTICK_CTRL_CTR),
> >  };
> > -struct rcu_state rcu_state = {
> > +static struct rcu_state rcu_state = {
> >  	.level = { &rcu_state.node[0] },
> >  	.gp_state = RCU_GP_IDLE,
> >  	.gp_seq = (0UL - 300UL) << RCU_SEQ_CTR_SHIFT,
> > @@ -189,7 +189,7 @@ EXPORT_SYMBOL_GPL(rcu_get_gp_kthreads_prio);
> >   * held, but the bit corresponding to the current CPU will be stable
> >   * in most contexts.
> >   */
> > -unsigned long rcu_rnp_online_cpus(struct rcu_node *rnp)
> > +static unsigned long rcu_rnp_online_cpus(struct rcu_node *rnp)
> >  {
> >  	return READ_ONCE(rnp->qsmaskinitnext);
> >  }
> > @@ -295,7 +295,7 @@ static void rcu_dynticks_eqs_online(void)
> >   *
> >   * No ordering, as we are sampling CPU-local information.
> >   */
> > -bool rcu_dynticks_curr_cpu_in_eqs(void)
> > +static bool rcu_dynticks_curr_cpu_in_eqs(void)
> >  {
> >  	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
> >  
> > @@ -306,7 +306,7 @@ bool rcu_dynticks_curr_cpu_in_eqs(void)
> >   * Snapshot the ->dynticks counter with full ordering so as to allow
> >   * stable comparison of this counter with past and future snapshots.
> >   */
> > -int rcu_dynticks_snap(struct rcu_data *rdp)
> > +static int rcu_dynticks_snap(struct rcu_data *rdp)
> >  {
> >  	int snap = atomic_add_return(0, &rdp->dynticks);
> >  
> > diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
> > index 1540542..f8e6c70 100644
> > --- a/kernel/rcu/tree.h
> > +++ b/kernel/rcu/tree.h
> > @@ -402,8 +402,6 @@ static const char *tp_rcu_varname __used __tracepoint_string = rcu_name;
> >  #define RCU_NAME rcu_name
> >  #endif /* #else #ifdef CONFIG_TRACING */
> >  
> > -int rcu_dynticks_snap(struct rcu_data *rdp);
> > -
> >  /* Forward declarations for tree_plugin.h */
> >  static void rcu_bootup_announce(void);
> >  static void rcu_qs(void);