[PATCH 0/2] Fix warnings in psi

[PATCH 0/2] Fix warnings in psi

[Suren Baghdasaryan]

The patchset fixes warnings in the psi module visible only in the below
configurations:
CONFIG_PSI=y && CONFIG_CGROUPS=n
CONFIG_PSI=y && CONFIG_PROC_FS=n
Reproduced using clang version 14.0.0.

The patches are based on sched/urgent branch:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched/urgent

Suren Baghdasaryan (2):
  psi: Fix "no previous prototype" warnings when CONFIG_CGROUPS=n
  psi: Fix "defined but not used" warnings when CONFIG_PROC_FS=n

 include/linux/psi.h | 11 +++----
 kernel/sched/psi.c  | 79 +++++++++++++++++++++++----------------------
 2 files changed, 46 insertions(+), 44 deletions(-)

-- 
2.34.1.703.g22d0c6ccf7-goog

[PATCH 1/2] psi: Fix "no previous prototype" warnings when CONFIG_CGROUPS=n

[Suren Baghdasaryan]

When CONFIG_CGROUPS is disabled psi code generates the following warnings:

kernel/sched/psi.c:1112:21: warning: no previous prototype for 'psi_trigger_create' [-Wmissing-prototypes]
    1112 | struct psi_trigger *psi_trigger_create(struct psi_group *group,
         |                     ^~~~~~~~~~~~~~~~~~
kernel/sched/psi.c:1182:6: warning: no previous prototype for 'psi_trigger_destroy' [-Wmissing-prototypes]
    1182 | void psi_trigger_destroy(struct psi_trigger *t)
         |      ^~~~~~~~~~~~~~~~~~~
kernel/sched/psi.c:1249:10: warning: no previous prototype for 'psi_trigger_poll' [-Wmissing-prototypes]
    1249 | __poll_t psi_trigger_poll(void **trigger_ptr,
         |          ^~~~~~~~~~~~~~~~

Change declarations of these functions in the header to provide the
prototypes even when they are unused.

Fixes: 0e94682b73bf ("psi: introduce psi monitor")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 include/linux/psi.h | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/include/linux/psi.h b/include/linux/psi.h
index f8ce53bfdb2a..7f7d1d88c3bb 100644
--- a/include/linux/psi.h
+++ b/include/linux/psi.h
@@ -25,18 +25,17 @@ void psi_memstall_enter(unsigned long *flags);
 void psi_memstall_leave(unsigned long *flags);
 
 int psi_show(struct seq_file *s, struct psi_group *group, enum psi_res res);
-
-#ifdef CONFIG_CGROUPS
-int psi_cgroup_alloc(struct cgroup *cgrp);
-void psi_cgroup_free(struct cgroup *cgrp);
-void cgroup_move_task(struct task_struct *p, struct css_set *to);
-
 struct psi_trigger *psi_trigger_create(struct psi_group *group,
 			char *buf, size_t nbytes, enum psi_res res);
 void psi_trigger_destroy(struct psi_trigger *t);
 
 __poll_t psi_trigger_poll(void **trigger_ptr, struct file *file,
 			poll_table *wait);
+
+#ifdef CONFIG_CGROUPS
+int psi_cgroup_alloc(struct cgroup *cgrp);
+void psi_cgroup_free(struct cgroup *cgrp);
+void cgroup_move_task(struct task_struct *p, struct css_set *to);
 #endif
 
 #else /* CONFIG_PSI */
-- 
2.34.1.703.g22d0c6ccf7-goog

Re: [PATCH 1/2] psi: Fix "no previous prototype" warnings when CONFIG_CGROUPS=n

[Johannes Weiner]

On Wed, Jan 19, 2022 at 02:39:39PM -0800, Suren Baghdasaryan wrote:
> When CONFIG_CGROUPS is disabled psi code generates the following warnings:
> 
> kernel/sched/psi.c:1112:21: warning: no previous prototype for 'psi_trigger_create' [-Wmissing-prototypes]
>     1112 | struct psi_trigger *psi_trigger_create(struct psi_group *group,
>          |                     ^~~~~~~~~~~~~~~~~~
> kernel/sched/psi.c:1182:6: warning: no previous prototype for 'psi_trigger_destroy' [-Wmissing-prototypes]
>     1182 | void psi_trigger_destroy(struct psi_trigger *t)
>          |      ^~~~~~~~~~~~~~~~~~~
> kernel/sched/psi.c:1249:10: warning: no previous prototype for 'psi_trigger_poll' [-Wmissing-prototypes]
>     1249 | __poll_t psi_trigger_poll(void **trigger_ptr,
>          |          ^~~~~~~~~~~~~~~~
> 
> Change declarations of these functions in the header to provide the
> prototypes even when they are unused.
>
> Fixes: 0e94682b73bf ("psi: introduce psi monitor")
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

For a second I was confused by the "unused" in the changelog. The
functions themselves are used unconditionally: by the internal
/proc/pressure/* implementation. But I suppose that usage wouldn't
need the prototypes - hence unused prototypes.

[tip: sched/core] psi: Fix "no previous prototype" warnings when CONFIG_CGROUPS=n

[tip-bot2 for Suren Baghdasaryan]

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

Commit-ID:     ec2444530612a886b406e2830d7f314d1a07d4bb
Gitweb:        https://git.kernel.org/tip/ec2444530612a886b406e2830d7f314d1a07d4bb
Author:        Suren Baghdasaryan <surenb@google.com>
AuthorDate:    Wed, 19 Jan 2022 14:39:39 -08:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Thu, 27 Jan 2022 12:57:19 +01:00

psi: Fix "no previous prototype" warnings when CONFIG_CGROUPS=n

When CONFIG_CGROUPS is disabled psi code generates the following warnings:

kernel/sched/psi.c:1112:21: warning: no previous prototype for 'psi_trigger_create' [-Wmissing-prototypes]
    1112 | struct psi_trigger *psi_trigger_create(struct psi_group *group,
         |                     ^~~~~~~~~~~~~~~~~~
kernel/sched/psi.c:1182:6: warning: no previous prototype for 'psi_trigger_destroy' [-Wmissing-prototypes]
    1182 | void psi_trigger_destroy(struct psi_trigger *t)
         |      ^~~~~~~~~~~~~~~~~~~
kernel/sched/psi.c:1249:10: warning: no previous prototype for 'psi_trigger_poll' [-Wmissing-prototypes]
    1249 | __poll_t psi_trigger_poll(void **trigger_ptr,
         |          ^~~~~~~~~~~~~~~~

Change declarations of these functions in the header to provide the
prototypes even when they are unused.

Fixes: 0e94682b73bf ("psi: introduce psi monitor")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220119223940.787748-2-surenb@google.com
---
 include/linux/psi.h | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/include/linux/psi.h b/include/linux/psi.h
index a70ca83..8279702 100644
--- a/include/linux/psi.h
+++ b/include/linux/psi.h
@@ -25,18 +25,17 @@ void psi_memstall_enter(unsigned long *flags);
 void psi_memstall_leave(unsigned long *flags);
 
 int psi_show(struct seq_file *s, struct psi_group *group, enum psi_res res);
-
-#ifdef CONFIG_CGROUPS
-int psi_cgroup_alloc(struct cgroup *cgrp);
-void psi_cgroup_free(struct cgroup *cgrp);
-void cgroup_move_task(struct task_struct *p, struct css_set *to);
-
 struct psi_trigger *psi_trigger_create(struct psi_group *group,
 			char *buf, size_t nbytes, enum psi_res res);
 void psi_trigger_replace(void **trigger_ptr, struct psi_trigger *t);
 
 __poll_t psi_trigger_poll(void **trigger_ptr, struct file *file,
 			poll_table *wait);
+
+#ifdef CONFIG_CGROUPS
+int psi_cgroup_alloc(struct cgroup *cgrp);
+void psi_cgroup_free(struct cgroup *cgrp);
+void cgroup_move_task(struct task_struct *p, struct css_set *to);
 #endif
 
 #else /* CONFIG_PSI */

[PATCH 2/2] psi: Fix "defined but not used" warnings when CONFIG_PROC_FS=n

[Suren Baghdasaryan]

When CONFIG_PROC_FS is disabled psi code generates the following warnings:

kernel/sched/psi.c:1364:30: warning: 'psi_cpu_proc_ops' defined but not used [-Wunused-const-variable=]
    1364 | static const struct proc_ops psi_cpu_proc_ops = {
         |                              ^~~~~~~~~~~~~~~~
kernel/sched/psi.c:1355:30: warning: 'psi_memory_proc_ops' defined but not used [-Wunused-const-variable=]
    1355 | static const struct proc_ops psi_memory_proc_ops = {
         |                              ^~~~~~~~~~~~~~~~~~~
kernel/sched/psi.c:1346:30: warning: 'psi_io_proc_ops' defined but not used [-Wunused-const-variable=]
    1346 | static const struct proc_ops psi_io_proc_ops = {
         |                              ^~~~~~~~~~~~~~~

Make definitions of these structures and related functions conditional on
CONFIG_PROC_FS config.

Fixes: 0e94682b73bf ("psi: introduce psi monitor")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 kernel/sched/psi.c | 79 ++++++++++++++++++++++++----------------------
 1 file changed, 41 insertions(+), 38 deletions(-)

diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index c137c4d6983e..e14358178849 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -1082,44 +1082,6 @@ int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res)
 	return 0;
 }
 
-static int psi_io_show(struct seq_file *m, void *v)
-{
-	return psi_show(m, &psi_system, PSI_IO);
-}
-
-static int psi_memory_show(struct seq_file *m, void *v)
-{
-	return psi_show(m, &psi_system, PSI_MEM);
-}
-
-static int psi_cpu_show(struct seq_file *m, void *v)
-{
-	return psi_show(m, &psi_system, PSI_CPU);
-}
-
-static int psi_open(struct file *file, int (*psi_show)(struct seq_file *, void *))
-{
-	if (file->f_mode & FMODE_WRITE && !capable(CAP_SYS_RESOURCE))
-		return -EPERM;
-
-	return single_open(file, psi_show, NULL);
-}
-
-static int psi_io_open(struct inode *inode, struct file *file)
-{
-	return psi_open(file, psi_io_show);
-}
-
-static int psi_memory_open(struct inode *inode, struct file *file)
-{
-	return psi_open(file, psi_memory_show);
-}
-
-static int psi_cpu_open(struct inode *inode, struct file *file)
-{
-	return psi_open(file, psi_cpu_show);
-}
-
 struct psi_trigger *psi_trigger_create(struct psi_group *group,
 			char *buf, size_t nbytes, enum psi_res res)
 {
@@ -1278,6 +1240,45 @@ __poll_t psi_trigger_poll(void **trigger_ptr,
 	return ret;
 }
 
+#ifdef CONFIG_PROC_FS
+static int psi_io_show(struct seq_file *m, void *v)
+{
+	return psi_show(m, &psi_system, PSI_IO);
+}
+
+static int psi_memory_show(struct seq_file *m, void *v)
+{
+	return psi_show(m, &psi_system, PSI_MEM);
+}
+
+static int psi_cpu_show(struct seq_file *m, void *v)
+{
+	return psi_show(m, &psi_system, PSI_CPU);
+}
+
+static int psi_open(struct file *file, int (*psi_show)(struct seq_file *, void *))
+{
+	if (file->f_mode & FMODE_WRITE && !capable(CAP_SYS_RESOURCE))
+		return -EPERM;
+
+	return single_open(file, psi_show, NULL);
+}
+
+static int psi_io_open(struct inode *inode, struct file *file)
+{
+	return psi_open(file, psi_io_show);
+}
+
+static int psi_memory_open(struct inode *inode, struct file *file)
+{
+	return psi_open(file, psi_memory_show);
+}
+
+static int psi_cpu_open(struct inode *inode, struct file *file)
+{
+	return psi_open(file, psi_cpu_show);
+}
+
 static ssize_t psi_write(struct file *file, const char __user *user_buf,
 			 size_t nbytes, enum psi_res res)
 {
@@ -1392,3 +1393,5 @@ static int __init psi_proc_init(void)
 	return 0;
 }
 module_init(psi_proc_init);
+
+#endif /* CONFIG_PROC_FS */
-- 
2.34.1.703.g22d0c6ccf7-goog

Re: [PATCH 2/2] psi: Fix "defined but not used" warnings when CONFIG_PROC_FS=n

[Johannes Weiner]

On Wed, Jan 19, 2022 at 02:39:40PM -0800, Suren Baghdasaryan wrote:
> When CONFIG_PROC_FS is disabled psi code generates the following warnings:
> 
> kernel/sched/psi.c:1364:30: warning: 'psi_cpu_proc_ops' defined but not used [-Wunused-const-variable=]
>     1364 | static const struct proc_ops psi_cpu_proc_ops = {
>          |                              ^~~~~~~~~~~~~~~~
> kernel/sched/psi.c:1355:30: warning: 'psi_memory_proc_ops' defined but not used [-Wunused-const-variable=]
>     1355 | static const struct proc_ops psi_memory_proc_ops = {
>          |                              ^~~~~~~~~~~~~~~~~~~
> kernel/sched/psi.c:1346:30: warning: 'psi_io_proc_ops' defined but not used [-Wunused-const-variable=]
>     1346 | static const struct proc_ops psi_io_proc_ops = {
>          |                              ^~~~~~~~~~~~~~~
> 
> Make definitions of these structures and related functions conditional on
> CONFIG_PROC_FS config.
> 
> Fixes: 0e94682b73bf ("psi: introduce psi monitor")
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

[tip: sched/core] psi: Fix "defined but not used" warnings when CONFIG_PROC_FS=n

[tip-bot2 for Suren Baghdasaryan]

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

Commit-ID:     5102bb1c9f82857a3164af9d7ab7ad628cb783ed
Gitweb:        https://git.kernel.org/tip/5102bb1c9f82857a3164af9d7ab7ad628cb783ed
Author:        Suren Baghdasaryan <surenb@google.com>
AuthorDate:    Wed, 19 Jan 2022 14:39:40 -08:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Thu, 27 Jan 2022 12:57:19 +01:00

psi: Fix "defined but not used" warnings when CONFIG_PROC_FS=n

When CONFIG_PROC_FS is disabled psi code generates the following warnings:

kernel/sched/psi.c:1364:30: warning: 'psi_cpu_proc_ops' defined but not used [-Wunused-const-variable=]
    1364 | static const struct proc_ops psi_cpu_proc_ops = {
         |                              ^~~~~~~~~~~~~~~~
kernel/sched/psi.c:1355:30: warning: 'psi_memory_proc_ops' defined but not used [-Wunused-const-variable=]
    1355 | static const struct proc_ops psi_memory_proc_ops = {
         |                              ^~~~~~~~~~~~~~~~~~~
kernel/sched/psi.c:1346:30: warning: 'psi_io_proc_ops' defined but not used [-Wunused-const-variable=]
    1346 | static const struct proc_ops psi_io_proc_ops = {
         |                              ^~~~~~~~~~~~~~~

Make definitions of these structures and related functions conditional on
CONFIG_PROC_FS config.

Fixes: 0e94682b73bf ("psi: introduce psi monitor")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220119223940.787748-3-surenb@google.com
---
 kernel/sched/psi.c | 79 +++++++++++++++++++++++----------------------
 1 file changed, 41 insertions(+), 38 deletions(-)

diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index a679613..cfe76f7 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -1082,44 +1082,6 @@ int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res)
 	return 0;
 }
 
-static int psi_io_show(struct seq_file *m, void *v)
-{
-	return psi_show(m, &psi_system, PSI_IO);
-}
-
-static int psi_memory_show(struct seq_file *m, void *v)
-{
-	return psi_show(m, &psi_system, PSI_MEM);
-}
-
-static int psi_cpu_show(struct seq_file *m, void *v)
-{
-	return psi_show(m, &psi_system, PSI_CPU);
-}
-
-static int psi_open(struct file *file, int (*psi_show)(struct seq_file *, void *))
-{
-	if (file->f_mode & FMODE_WRITE && !capable(CAP_SYS_RESOURCE))
-		return -EPERM;
-
-	return single_open(file, psi_show, NULL);
-}
-
-static int psi_io_open(struct inode *inode, struct file *file)
-{
-	return psi_open(file, psi_io_show);
-}
-
-static int psi_memory_open(struct inode *inode, struct file *file)
-{
-	return psi_open(file, psi_memory_show);
-}
-
-static int psi_cpu_open(struct inode *inode, struct file *file)
-{
-	return psi_open(file, psi_cpu_show);
-}
-
 struct psi_trigger *psi_trigger_create(struct psi_group *group,
 			char *buf, size_t nbytes, enum psi_res res)
 {
@@ -1296,6 +1258,45 @@ __poll_t psi_trigger_poll(void **trigger_ptr,
 	return ret;
 }
 
+#ifdef CONFIG_PROC_FS
+static int psi_io_show(struct seq_file *m, void *v)
+{
+	return psi_show(m, &psi_system, PSI_IO);
+}
+
+static int psi_memory_show(struct seq_file *m, void *v)
+{
+	return psi_show(m, &psi_system, PSI_MEM);
+}
+
+static int psi_cpu_show(struct seq_file *m, void *v)
+{
+	return psi_show(m, &psi_system, PSI_CPU);
+}
+
+static int psi_open(struct file *file, int (*psi_show)(struct seq_file *, void *))
+{
+	if (file->f_mode & FMODE_WRITE && !capable(CAP_SYS_RESOURCE))
+		return -EPERM;
+
+	return single_open(file, psi_show, NULL);
+}
+
+static int psi_io_open(struct inode *inode, struct file *file)
+{
+	return psi_open(file, psi_io_show);
+}
+
+static int psi_memory_open(struct inode *inode, struct file *file)
+{
+	return psi_open(file, psi_memory_show);
+}
+
+static int psi_cpu_open(struct inode *inode, struct file *file)
+{
+	return psi_open(file, psi_cpu_show);
+}
+
 static ssize_t psi_write(struct file *file, const char __user *user_buf,
 			 size_t nbytes, enum psi_res res)
 {
@@ -1400,3 +1401,5 @@ static int __init psi_proc_init(void)
 	return 0;
 }
 module_init(psi_proc_init);
+
+#endif /* CONFIG_PROC_FS */