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* [PATCH v2] sched: Make const-safe
@ 2022-12-12 14:49 Matthew Wilcox (Oracle)
  2022-12-14  9:11 ` Peter Zijlstra
  2022-12-27 12:13 ` [tip: sched/core] " tip-bot2 for Matthew Wilcox (Oracle)
  0 siblings, 2 replies; 6+ messages in thread
From: Matthew Wilcox (Oracle) @ 2022-12-12 14:49 UTC (permalink / raw)
  To: Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot,
	Dietmar Eggemann, Steven Rostedt, Ben Segall, Mel Gorman,
	Daniel Bristot de Oliveira, Valentin Schneider, linux-kernel
  Cc: Matthew Wilcox (Oracle)

With a modified container_of() that preserves constness, the compiler
finds some pointers which should have been marked as const.  task_of()
also needs to become const-preserving for the !FAIR_GROUP_SCHED case so
that cfs_rq_of() can take a const argument.  No change to generated code.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
v2: Also update the !FAIR_GROUP_SCHED case

 kernel/sched/core.c  |  8 +++++---
 kernel/sched/fair.c  | 16 +++++++++-------
 kernel/sched/sched.h | 22 ++++++++++------------
 3 files changed, 24 insertions(+), 22 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 25b582b6ee5f..853188cb6c84 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -152,7 +152,7 @@ __read_mostly int scheduler_running;
 DEFINE_STATIC_KEY_FALSE(__sched_core_enabled);
 
 /* kernel prio, less is more */
-static inline int __task_prio(struct task_struct *p)
+static inline int __task_prio(const struct task_struct *p)
 {
 	if (p->sched_class == &stop_sched_class) /* trumps deadline */
 		return -2;
@@ -174,7 +174,8 @@ static inline int __task_prio(struct task_struct *p)
  */
 
 /* real prio, less is less */
-static inline bool prio_less(struct task_struct *a, struct task_struct *b, bool in_fi)
+static inline bool prio_less(const struct task_struct *a,
+			     const struct task_struct *b, bool in_fi)
 {
 
 	int pa = __task_prio(a), pb = __task_prio(b);
@@ -194,7 +195,8 @@ static inline bool prio_less(struct task_struct *a, struct task_struct *b, bool
 	return false;
 }
 
-static inline bool __sched_core_less(struct task_struct *a, struct task_struct *b)
+static inline bool __sched_core_less(const struct task_struct *a,
+				     const struct task_struct *b)
 {
 	if (a->core_cookie < b->core_cookie)
 		return true;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c36aa54ae071..855470310903 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -468,7 +468,7 @@ is_same_group(struct sched_entity *se, struct sched_entity *pse)
 	return NULL;
 }
 
-static inline struct sched_entity *parent_entity(struct sched_entity *se)
+static inline struct sched_entity *parent_entity(const struct sched_entity *se)
 {
 	return se->parent;
 }
@@ -595,8 +595,8 @@ static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime)
 	return min_vruntime;
 }
 
-static inline bool entity_before(struct sched_entity *a,
-				struct sched_entity *b)
+static inline bool entity_before(const struct sched_entity *a,
+				 const struct sched_entity *b)
 {
 	return (s64)(a->vruntime - b->vruntime) < 0;
 }
@@ -11728,7 +11728,8 @@ static inline void task_tick_core(struct rq *rq, struct task_struct *curr)
 /*
  * se_fi_update - Update the cfs_rq->min_vruntime_fi in a CFS hierarchy if needed.
  */
-static void se_fi_update(struct sched_entity *se, unsigned int fi_seq, bool forceidle)
+static void se_fi_update(const struct sched_entity *se, unsigned int fi_seq,
+			 bool forceidle)
 {
 	for_each_sched_entity(se) {
 		struct cfs_rq *cfs_rq = cfs_rq_of(se);
@@ -11753,11 +11754,12 @@ void task_vruntime_update(struct rq *rq, struct task_struct *p, bool in_fi)
 	se_fi_update(se, rq->core->core_forceidle_seq, in_fi);
 }
 
-bool cfs_prio_less(struct task_struct *a, struct task_struct *b, bool in_fi)
+bool cfs_prio_less(const struct task_struct *a, const struct task_struct *b,
+			bool in_fi)
 {
 	struct rq *rq = task_rq(a);
-	struct sched_entity *sea = &a->se;
-	struct sched_entity *seb = &b->se;
+	const struct sched_entity *sea = &a->se;
+	const struct sched_entity *seb = &b->se;
 	struct cfs_rq *cfs_rqa;
 	struct cfs_rq *cfs_rqb;
 	s64 delta;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 771f8ddb7053..cdf9f248e5bd 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -248,7 +248,7 @@ static inline void update_avg(u64 *avg, u64 sample)
 
 #define SCHED_DL_FLAGS (SCHED_FLAG_RECLAIM | SCHED_FLAG_DL_OVERRUN | SCHED_FLAG_SUGOV)
 
-static inline bool dl_entity_is_special(struct sched_dl_entity *dl_se)
+static inline bool dl_entity_is_special(const struct sched_dl_entity *dl_se)
 {
 #ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL
 	return unlikely(dl_se->flags & SCHED_FLAG_SUGOV);
@@ -260,8 +260,8 @@ static inline bool dl_entity_is_special(struct sched_dl_entity *dl_se)
 /*
  * Tells if entity @a should preempt entity @b.
  */
-static inline bool
-dl_entity_preempt(struct sched_dl_entity *a, struct sched_dl_entity *b)
+static inline bool dl_entity_preempt(const struct sched_dl_entity *a,
+				     const struct sched_dl_entity *b)
 {
 	return dl_entity_is_special(a) ||
 	       dl_time_before(a->deadline, b->deadline);
@@ -1236,7 +1236,8 @@ static inline raw_spinlock_t *__rq_lockp(struct rq *rq)
 	return &rq->__lock;
 }
 
-bool cfs_prio_less(struct task_struct *a, struct task_struct *b, bool fi);
+bool cfs_prio_less(const struct task_struct *a, const struct task_struct *b,
+			bool fi);
 
 /*
  * Helpers to check if the CPU's core cookie matches with the task's cookie
@@ -1415,7 +1416,7 @@ static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)
 }
 
 /* runqueue on which this entity is (to be) queued */
-static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)
+static inline struct cfs_rq *cfs_rq_of(const struct sched_entity *se)
 {
 	return se->cfs_rq;
 }
@@ -1428,19 +1429,16 @@ static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
 
 #else
 
-static inline struct task_struct *task_of(struct sched_entity *se)
-{
-	return container_of(se, struct task_struct, se);
-}
+#define task_of(_se)	container_of(_se, struct task_struct, se)
 
-static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)
+static inline struct cfs_rq *task_cfs_rq(const struct task_struct *p)
 {
 	return &task_rq(p)->cfs;
 }
 
-static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)
+static inline struct cfs_rq *cfs_rq_of(const struct sched_entity *se)
 {
-	struct task_struct *p = task_of(se);
+	const struct task_struct *p = task_of(se);
 	struct rq *rq = task_rq(p);
 
 	return &rq->cfs;
-- 
2.35.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] sched: Make const-safe
  2022-12-12 14:49 [PATCH v2] sched: Make const-safe Matthew Wilcox (Oracle)
@ 2022-12-14  9:11 ` Peter Zijlstra
  2022-12-14 18:03   ` Matthew Wilcox
  2022-12-27 12:13 ` [tip: sched/core] " tip-bot2 for Matthew Wilcox (Oracle)
  1 sibling, 1 reply; 6+ messages in thread
From: Peter Zijlstra @ 2022-12-14  9:11 UTC (permalink / raw)
  To: Matthew Wilcox (Oracle)
  Cc: Ingo Molnar, Juri Lelli, Vincent Guittot, Dietmar Eggemann,
	Steven Rostedt, Ben Segall, Mel Gorman,
	Daniel Bristot de Oliveira, Valentin Schneider, linux-kernel

On Mon, Dec 12, 2022 at 02:49:46PM +0000, Matthew Wilcox (Oracle) wrote:
> With a modified container_of() that preserves constness, the compiler
> finds some pointers which should have been marked as const.  task_of()
> also needs to become const-preserving for the !FAIR_GROUP_SCHED case so
> that cfs_rq_of() can take a const argument.  No change to generated code.

More const more better I suppose.. Thanks!

Happen to have a sha for the container_of() commit handy?

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] sched: Make const-safe
  2022-12-14  9:11 ` Peter Zijlstra
@ 2022-12-14 18:03   ` Matthew Wilcox
  2022-12-16 10:46     ` Peter Zijlstra
  2022-12-20 12:59     ` Peter Zijlstra
  0 siblings, 2 replies; 6+ messages in thread
From: Matthew Wilcox @ 2022-12-14 18:03 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: Ingo Molnar, Juri Lelli, Vincent Guittot, Dietmar Eggemann,
	Steven Rostedt, Ben Segall, Mel Gorman,
	Daniel Bristot de Oliveira, Valentin Schneider, linux-kernel

On Wed, Dec 14, 2022 at 10:11:01AM +0100, Peter Zijlstra wrote:
> On Mon, Dec 12, 2022 at 02:49:46PM +0000, Matthew Wilcox (Oracle) wrote:
> > With a modified container_of() that preserves constness, the compiler
> > finds some pointers which should have been marked as const.  task_of()
> > also needs to become const-preserving for the !FAIR_GROUP_SCHED case so
> > that cfs_rq_of() can take a const argument.  No change to generated code.
> 
> More const more better I suppose.. Thanks!
> 
> Happen to have a sha for the container_of() commit handy?

There isn't one yet.  Obviously we can't make container_of()
const-preserving until we've fixed all the places which would warn.
The diff I have in my tree looks like this:

diff --git a/include/linux/container_of.h b/include/linux/container_of.h
index 1d898f9158b4..9416e6cc8c88 100644
--- a/include/linux/container_of.h
+++ b/include/linux/container_of.h
@@ -20,7 +20,10 @@
        static_assert(__same_type(*(ptr), ((type *)0)->member) ||       \
                      __same_type(*(ptr), void),                        \
                      "pointer type mismatch in container_of()");       \
-       ((type *)(__mptr - offsetof(type, member))); })
+       __mptr -= offsetof(type, member);                               \
+       _Generic(ptr,                                                   \
+               const typeof(*(ptr)) *: (const type *)__mptr,           \
+               default: ((type *)__mptr)); })

 /**
  * container_of_const - cast a member of a structure out to the containing

I have all of fs/ and net/ compiling cleanly now.  There are a few
places which really need the const-removing properties, and I've made
those call a new macro called container_of_not_const(), but I don't
like that name.

^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] sched: Make const-safe
  2022-12-14 18:03   ` Matthew Wilcox
@ 2022-12-16 10:46     ` Peter Zijlstra
  2022-12-20 12:59     ` Peter Zijlstra
  1 sibling, 0 replies; 6+ messages in thread
From: Peter Zijlstra @ 2022-12-16 10:46 UTC (permalink / raw)
  To: Matthew Wilcox
  Cc: Ingo Molnar, Juri Lelli, Vincent Guittot, Dietmar Eggemann,
	Steven Rostedt, Ben Segall, Mel Gorman,
	Daniel Bristot de Oliveira, Valentin Schneider, linux-kernel

On Wed, Dec 14, 2022 at 06:03:04PM +0000, Matthew Wilcox wrote:
> On Wed, Dec 14, 2022 at 10:11:01AM +0100, Peter Zijlstra wrote:
> > On Mon, Dec 12, 2022 at 02:49:46PM +0000, Matthew Wilcox (Oracle) wrote:
> > > With a modified container_of() that preserves constness, the compiler
> > > finds some pointers which should have been marked as const.  task_of()
> > > also needs to become const-preserving for the !FAIR_GROUP_SCHED case so
> > > that cfs_rq_of() can take a const argument.  No change to generated code.
> > 
> > More const more better I suppose.. Thanks!
> > 
> > Happen to have a sha for the container_of() commit handy?
> 
> There isn't one yet.  Obviously we can't make container_of()
> const-preserving until we've fixed all the places which would warn.
> The diff I have in my tree looks like this:
> 
> diff --git a/include/linux/container_of.h b/include/linux/container_of.h
> index 1d898f9158b4..9416e6cc8c88 100644
> --- a/include/linux/container_of.h
> +++ b/include/linux/container_of.h
> @@ -20,7 +20,10 @@
>         static_assert(__same_type(*(ptr), ((type *)0)->member) ||       \
>                       __same_type(*(ptr), void),                        \
>                       "pointer type mismatch in container_of()");       \
> -       ((type *)(__mptr - offsetof(type, member))); })
> +       __mptr -= offsetof(type, member);                               \
> +       _Generic(ptr,                                                   \
> +               const typeof(*(ptr)) *: (const type *)__mptr,           \
> +               default: ((type *)__mptr)); })

Ah nice. Thanks!

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] sched: Make const-safe
  2022-12-14 18:03   ` Matthew Wilcox
  2022-12-16 10:46     ` Peter Zijlstra
@ 2022-12-20 12:59     ` Peter Zijlstra
  1 sibling, 0 replies; 6+ messages in thread
From: Peter Zijlstra @ 2022-12-20 12:59 UTC (permalink / raw)
  To: Matthew Wilcox
  Cc: Ingo Molnar, Juri Lelli, Vincent Guittot, Dietmar Eggemann,
	Steven Rostedt, Ben Segall, Mel Gorman,
	Daniel Bristot de Oliveira, Valentin Schneider, linux-kernel

On Wed, Dec 14, 2022 at 06:03:04PM +0000, Matthew Wilcox wrote:
> On Wed, Dec 14, 2022 at 10:11:01AM +0100, Peter Zijlstra wrote:
> > On Mon, Dec 12, 2022 at 02:49:46PM +0000, Matthew Wilcox (Oracle) wrote:
> > > With a modified container_of() that preserves constness, the compiler
> > > finds some pointers which should have been marked as const.  task_of()
> > > also needs to become const-preserving for the !FAIR_GROUP_SCHED case so
> > > that cfs_rq_of() can take a const argument.  No change to generated code.
> > 
> > More const more better I suppose.. Thanks!
> > 
> > Happen to have a sha for the container_of() commit handy?
> 
> There isn't one yet.  Obviously we can't make container_of()
> const-preserving until we've fixed all the places which would warn.
> The diff I have in my tree looks like this:
> 
> diff --git a/include/linux/container_of.h b/include/linux/container_of.h
> index 1d898f9158b4..9416e6cc8c88 100644
> --- a/include/linux/container_of.h
> +++ b/include/linux/container_of.h
> @@ -20,7 +20,10 @@
>         static_assert(__same_type(*(ptr), ((type *)0)->member) ||       \
>                       __same_type(*(ptr), void),                        \
>                       "pointer type mismatch in container_of()");       \
> -       ((type *)(__mptr - offsetof(type, member))); })
> +       __mptr -= offsetof(type, member);                               \
> +       _Generic(ptr,                                                   \
> +               const typeof(*(ptr)) *: (const type *)__mptr,           \
> +               default: ((type *)__mptr)); })
> 
>  /**
>   * container_of_const - cast a member of a structure out to the containing
> 
> I have all of fs/ and net/ compiling cleanly now.  There are a few
> places which really need the const-removing properties, and I've made
> those call a new macro called container_of_not_const(), but I don't
> like that name.

#define const_cast(T, exp)	_Generic((exp), const T : (T)(exp), default: (exp))

perhaps? Then one can write something like:

	struct task_struct *p = const_cast(struct task_struct *,
					   constainer_of(node, struct task_struct *, run_node));

The repetition is a bit naf, but at least the construct is more
generally useful.

(I really wish there was a qualifier stripping typeof() variant -- and
yes, I know about the _Atomic thing).

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [tip: sched/core] sched: Make const-safe
  2022-12-12 14:49 [PATCH v2] sched: Make const-safe Matthew Wilcox (Oracle)
  2022-12-14  9:11 ` Peter Zijlstra
@ 2022-12-27 12:13 ` tip-bot2 for Matthew Wilcox (Oracle)
  1 sibling, 0 replies; 6+ messages in thread
From: tip-bot2 for Matthew Wilcox (Oracle) @ 2022-12-27 12:13 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: Matthew Wilcox (Oracle), Peter Zijlstra (Intel), x86,
	linux-kernel

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     904cbab71dda1689d41a240541179f21ff433c40
Gitweb:        https://git.kernel.org/tip/904cbab71dda1689d41a240541179f21ff433c40
Author:        Matthew Wilcox (Oracle) <willy@infradead.org>
AuthorDate:    Mon, 12 Dec 2022 14:49:46 
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Tue, 27 Dec 2022 12:52:16 +01:00

sched: Make const-safe

With a modified container_of() that preserves constness, the compiler
finds some pointers which should have been marked as const.  task_of()
also needs to become const-preserving for the !FAIR_GROUP_SCHED case so
that cfs_rq_of() can take a const argument.  No change to generated code.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221212144946.2657785-1-willy@infradead.org
---
 kernel/sched/core.c  |  8 +++++---
 kernel/sched/fair.c  | 16 +++++++++-------
 kernel/sched/sched.h | 22 ++++++++++------------
 3 files changed, 24 insertions(+), 22 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 75830b7..1f3259c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -152,7 +152,7 @@ __read_mostly int scheduler_running;
 DEFINE_STATIC_KEY_FALSE(__sched_core_enabled);
 
 /* kernel prio, less is more */
-static inline int __task_prio(struct task_struct *p)
+static inline int __task_prio(const struct task_struct *p)
 {
 	if (p->sched_class == &stop_sched_class) /* trumps deadline */
 		return -2;
@@ -174,7 +174,8 @@ static inline int __task_prio(struct task_struct *p)
  */
 
 /* real prio, less is less */
-static inline bool prio_less(struct task_struct *a, struct task_struct *b, bool in_fi)
+static inline bool prio_less(const struct task_struct *a,
+			     const struct task_struct *b, bool in_fi)
 {
 
 	int pa = __task_prio(a), pb = __task_prio(b);
@@ -194,7 +195,8 @@ static inline bool prio_less(struct task_struct *a, struct task_struct *b, bool 
 	return false;
 }
 
-static inline bool __sched_core_less(struct task_struct *a, struct task_struct *b)
+static inline bool __sched_core_less(const struct task_struct *a,
+				     const struct task_struct *b)
 {
 	if (a->core_cookie < b->core_cookie)
 		return true;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ea81d48..d0e2a48 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -468,7 +468,7 @@ is_same_group(struct sched_entity *se, struct sched_entity *pse)
 	return NULL;
 }
 
-static inline struct sched_entity *parent_entity(struct sched_entity *se)
+static inline struct sched_entity *parent_entity(const struct sched_entity *se)
 {
 	return se->parent;
 }
@@ -595,8 +595,8 @@ static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime)
 	return min_vruntime;
 }
 
-static inline bool entity_before(struct sched_entity *a,
-				struct sched_entity *b)
+static inline bool entity_before(const struct sched_entity *a,
+				 const struct sched_entity *b)
 {
 	return (s64)(a->vruntime - b->vruntime) < 0;
 }
@@ -11852,7 +11852,8 @@ static inline void task_tick_core(struct rq *rq, struct task_struct *curr)
 /*
  * se_fi_update - Update the cfs_rq->min_vruntime_fi in a CFS hierarchy if needed.
  */
-static void se_fi_update(struct sched_entity *se, unsigned int fi_seq, bool forceidle)
+static void se_fi_update(const struct sched_entity *se, unsigned int fi_seq,
+			 bool forceidle)
 {
 	for_each_sched_entity(se) {
 		struct cfs_rq *cfs_rq = cfs_rq_of(se);
@@ -11877,11 +11878,12 @@ void task_vruntime_update(struct rq *rq, struct task_struct *p, bool in_fi)
 	se_fi_update(se, rq->core->core_forceidle_seq, in_fi);
 }
 
-bool cfs_prio_less(struct task_struct *a, struct task_struct *b, bool in_fi)
+bool cfs_prio_less(const struct task_struct *a, const struct task_struct *b,
+			bool in_fi)
 {
 	struct rq *rq = task_rq(a);
-	struct sched_entity *sea = &a->se;
-	struct sched_entity *seb = &b->se;
+	const struct sched_entity *sea = &a->se;
+	const struct sched_entity *seb = &b->se;
 	struct cfs_rq *cfs_rqa;
 	struct cfs_rq *cfs_rqb;
 	s64 delta;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index c2d7467..1072502 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -248,7 +248,7 @@ static inline void update_avg(u64 *avg, u64 sample)
 
 #define SCHED_DL_FLAGS (SCHED_FLAG_RECLAIM | SCHED_FLAG_DL_OVERRUN | SCHED_FLAG_SUGOV)
 
-static inline bool dl_entity_is_special(struct sched_dl_entity *dl_se)
+static inline bool dl_entity_is_special(const struct sched_dl_entity *dl_se)
 {
 #ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL
 	return unlikely(dl_se->flags & SCHED_FLAG_SUGOV);
@@ -260,8 +260,8 @@ static inline bool dl_entity_is_special(struct sched_dl_entity *dl_se)
 /*
  * Tells if entity @a should preempt entity @b.
  */
-static inline bool
-dl_entity_preempt(struct sched_dl_entity *a, struct sched_dl_entity *b)
+static inline bool dl_entity_preempt(const struct sched_dl_entity *a,
+				     const struct sched_dl_entity *b)
 {
 	return dl_entity_is_special(a) ||
 	       dl_time_before(a->deadline, b->deadline);
@@ -1244,7 +1244,8 @@ static inline raw_spinlock_t *__rq_lockp(struct rq *rq)
 	return &rq->__lock;
 }
 
-bool cfs_prio_less(struct task_struct *a, struct task_struct *b, bool fi);
+bool cfs_prio_less(const struct task_struct *a, const struct task_struct *b,
+			bool fi);
 
 /*
  * Helpers to check if the CPU's core cookie matches with the task's cookie
@@ -1423,7 +1424,7 @@ static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)
 }
 
 /* runqueue on which this entity is (to be) queued */
-static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)
+static inline struct cfs_rq *cfs_rq_of(const struct sched_entity *se)
 {
 	return se->cfs_rq;
 }
@@ -1436,19 +1437,16 @@ static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
 
 #else
 
-static inline struct task_struct *task_of(struct sched_entity *se)
-{
-	return container_of(se, struct task_struct, se);
-}
+#define task_of(_se)	container_of(_se, struct task_struct, se)
 
-static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)
+static inline struct cfs_rq *task_cfs_rq(const struct task_struct *p)
 {
 	return &task_rq(p)->cfs;
 }
 
-static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)
+static inline struct cfs_rq *cfs_rq_of(const struct sched_entity *se)
 {
-	struct task_struct *p = task_of(se);
+	const struct task_struct *p = task_of(se);
 	struct rq *rq = task_rq(p);
 
 	return &rq->cfs;

^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2022-12-27 12:16 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-12-12 14:49 [PATCH v2] sched: Make const-safe Matthew Wilcox (Oracle)
2022-12-14  9:11 ` Peter Zijlstra
2022-12-14 18:03   ` Matthew Wilcox
2022-12-16 10:46     ` Peter Zijlstra
2022-12-20 12:59     ` Peter Zijlstra
2022-12-27 12:13 ` [tip: sched/core] " tip-bot2 for Matthew Wilcox (Oracle)

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