sysctl: treewide: constify the ctl_table argument of proc_handlers

const qualify the struct ctl_table argument in the proc_handler function
signatures. This is a prerequisite to moving the static ctl_table
structs into .rodata data which will ensure that proc_handler function
pointers cannot be modified.

This patch has been generated by the following coccinelle script:

```
  virtual patch

  @r1@
  identifier ctl, write, buffer, lenp, ppos;
  identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)";
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int write, void *buffer, size_t *lenp, loff_t *ppos);

  @r2@
  identifier func, ctl, write, buffer, lenp, ppos;
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int write, void *buffer, size_t *lenp, loff_t *ppos)
  { ... }

  @r3@
  identifier func;
  @@

  int func(
  - struct ctl_table *
  + const struct ctl_table *
    ,int , void *, size_t *, loff_t *);

  @r4@
  identifier func, ctl;
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int , void *, size_t *, loff_t *);

  @r5@
  identifier func, write, buffer, lenp, ppos;
  @@

  int func(
  - struct ctl_table *
  + const struct ctl_table *
    ,int write, void *buffer, size_t *lenp, loff_t *ppos);

```

* Code formatting was adjusted in xfs_sysctl.c to comply with code
  conventions. The xfs_stats_clear_proc_handler,
  xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where
  adjusted.

* The ctl_table argument in proc_watchdog_common was const qualified.
  This is called from a proc_handler itself and is calling back into
  another proc_handler, making it necessary to change it as part of the
  proc_handler migration.

Co-developed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Co-developed-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Joel Granados <j.granados@samsung.com>

6 files changed, 23 insertions, 23 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 6cb901b63482..eb95e9b435d0 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -2962,7 +2962,7 @@ static int compact_nodes(void)
 	return 0;
 }
 
-static int compaction_proactiveness_sysctl_handler(struct ctl_table *table, int write,
+static int compaction_proactiveness_sysctl_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *length, loff_t *ppos)
 {
 	int rc, nid;
@@ -2992,7 +2992,7 @@ static int compaction_proactiveness_sysctl_handler(struct ctl_table *table, int
  * This is the entry point for compacting all nodes via
  * /proc/sys/vm/compact_memory
  */
-static int sysctl_compaction_handler(struct ctl_table *table, int write,
+static int sysctl_compaction_handler(const struct ctl_table *table, int write,
 			void *buffer, size_t *length, loff_t *ppos)
 {
 	int ret;
@@ -3303,7 +3303,7 @@ static int kcompactd_cpu_online(unsigned int cpu)
 	return 0;
 }
 
-static int proc_dointvec_minmax_warn_RT_change(struct ctl_table *table,
+static int proc_dointvec_minmax_warn_RT_change(const struct ctl_table *table,
 		int write, void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret, old;
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0858a1827207..aaf508be0a2b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4925,7 +4925,7 @@ out:
 	return ret;
 }
 
-static int hugetlb_sysctl_handler(struct ctl_table *table, int write,
+static int hugetlb_sysctl_handler(const struct ctl_table *table, int write,
 			  void *buffer, size_t *length, loff_t *ppos)
 {
 
@@ -4934,7 +4934,7 @@ static int hugetlb_sysctl_handler(struct ctl_table *table, int write,
 }
 
 #ifdef CONFIG_NUMA
-static int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
+static int hugetlb_mempolicy_sysctl_handler(const struct ctl_table *table, int write,
 			  void *buffer, size_t *length, loff_t *ppos)
 {
 	return hugetlb_sysctl_handler_common(true, table, write,
@@ -4942,7 +4942,7 @@ static int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
 }
 #endif /* CONFIG_NUMA */
 
-static int hugetlb_overcommit_handler(struct ctl_table *table, int write,
+static int hugetlb_overcommit_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *length, loff_t *ppos)
 {
 	struct hstate *h = &default_hstate;
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index acff24e9fae4..4430ac68e4c4 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -506,7 +506,7 @@ bool node_dirty_ok(struct pglist_data *pgdat)
 }
 
 #ifdef CONFIG_SYSCTL
-static int dirty_background_ratio_handler(struct ctl_table *table, int write,
+static int dirty_background_ratio_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret;
@@ -517,7 +517,7 @@ static int dirty_background_ratio_handler(struct ctl_table *table, int write,
 	return ret;
 }
 
-static int dirty_background_bytes_handler(struct ctl_table *table, int write,
+static int dirty_background_bytes_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret;
@@ -535,7 +535,7 @@ static int dirty_background_bytes_handler(struct ctl_table *table, int write,
 	return ret;
 }
 
-static int dirty_ratio_handler(struct ctl_table *table, int write, void *buffer,
+static int dirty_ratio_handler(const struct ctl_table *table, int write, void *buffer,
 		size_t *lenp, loff_t *ppos)
 {
 	int old_ratio = vm_dirty_ratio;
@@ -549,7 +549,7 @@ static int dirty_ratio_handler(struct ctl_table *table, int write, void *buffer,
 	return ret;
 }
 
-static int dirty_bytes_handler(struct ctl_table *table, int write,
+static int dirty_bytes_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	unsigned long old_bytes = vm_dirty_bytes;
@@ -2203,7 +2203,7 @@ bool wb_over_bg_thresh(struct bdi_writeback *wb)
 /*
  * sysctl handler for /proc/sys/vm/dirty_writeback_centisecs
  */
-static int dirty_writeback_centisecs_handler(struct ctl_table *table, int write,
+static int dirty_writeback_centisecs_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *length, loff_t *ppos)
 {
 	unsigned int old_interval = dirty_writeback_interval;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3398d914ed83..8337926b89d4 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5127,7 +5127,7 @@ static char numa_zonelist_order[] = "Node";
 /*
  * sysctl handler for numa_zonelist_order
  */
-static int numa_zonelist_order_handler(struct ctl_table *table, int write,
+static int numa_zonelist_order_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *length, loff_t *ppos)
 {
 	if (write)
@@ -6091,7 +6091,7 @@ postcore_initcall(init_per_zone_wmark_min)
  *	that we can call two helper functions whenever min_free_kbytes
  *	changes.
  */
-static int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write,
+static int min_free_kbytes_sysctl_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *length, loff_t *ppos)
 {
 	int rc;
@@ -6107,7 +6107,7 @@ static int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write,
 	return 0;
 }
 
-static int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write,
+static int watermark_scale_factor_sysctl_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *length, loff_t *ppos)
 {
 	int rc;
@@ -6137,7 +6137,7 @@ static void setup_min_unmapped_ratio(void)
 }
 
 
-static int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
+static int sysctl_min_unmapped_ratio_sysctl_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *length, loff_t *ppos)
 {
 	int rc;
@@ -6164,7 +6164,7 @@ static void setup_min_slab_ratio(void)
 						     sysctl_min_slab_ratio) / 100;
 }
 
-static int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
+static int sysctl_min_slab_ratio_sysctl_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *length, loff_t *ppos)
 {
 	int rc;
@@ -6188,7 +6188,7 @@ static int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int wri
  * minimum watermarks. The lowmem reserve ratio can only make sense
  * if in function of the boot time zone sizes.
  */
-static int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table,
+static int lowmem_reserve_ratio_sysctl_handler(const struct ctl_table *table,
 		int write, void *buffer, size_t *length, loff_t *ppos)
 {
 	int i;
@@ -6209,7 +6209,7 @@ static int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table,
  * cpu. It is the fraction of total pages in each zone that a hot per cpu
  * pagelist can have before it gets flushed back to buddy allocator.
  */
-static int percpu_pagelist_high_fraction_sysctl_handler(struct ctl_table *table,
+static int percpu_pagelist_high_fraction_sysctl_handler(const struct ctl_table *table,
 		int write, void *buffer, size_t *length, loff_t *ppos)
 {
 	struct zone *zone;
diff --git a/mm/util.c b/mm/util.c
index bc488f0121a7..bd283e2132e0 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -868,7 +868,7 @@ int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
 unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */
 unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */
 
-int overcommit_ratio_handler(struct ctl_table *table, int write, void *buffer,
+int overcommit_ratio_handler(const struct ctl_table *table, int write, void *buffer,
 		size_t *lenp, loff_t *ppos)
 {
 	int ret;
@@ -884,7 +884,7 @@ static void sync_overcommit_as(struct work_struct *dummy)
 	percpu_counter_sync(&vm_committed_as);
 }
 
-int overcommit_policy_handler(struct ctl_table *table, int write, void *buffer,
+int overcommit_policy_handler(const struct ctl_table *table, int write, void *buffer,
 		size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table t;
@@ -920,7 +920,7 @@ int overcommit_policy_handler(struct ctl_table *table, int write, void *buffer,
 	return ret;
 }
 
-int overcommit_kbytes_handler(struct ctl_table *table, int write, void *buffer,
+int overcommit_kbytes_handler(const struct ctl_table *table, int write, void *buffer,
 		size_t *lenp, loff_t *ppos)
 {
 	int ret;
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 73d791d1caad..04a1cb6cc636 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -74,7 +74,7 @@ static void invalid_numa_statistics(void)
 
 static DEFINE_MUTEX(vm_numa_stat_lock);
 
-int sysctl_vm_numa_stat_handler(struct ctl_table *table, int write,
+int sysctl_vm_numa_stat_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *length, loff_t *ppos)
 {
 	int ret, oldval;
@@ -1888,7 +1888,7 @@ static void refresh_vm_stats(struct work_struct *work)
 	refresh_cpu_vm_stats(true);
 }
 
-int vmstat_refresh(struct ctl_table *table, int write,
+int vmstat_refresh(const struct ctl_table *table, int write,
 		   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	long val;