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78eb4ea25c
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>
80 lines
1.9 KiB
C
80 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Implement the manual drop-all-pagecache function
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*/
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#include <linux/pagemap.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <linux/writeback.h>
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#include <linux/sysctl.h>
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#include <linux/gfp.h>
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#include <linux/swap.h>
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#include "internal.h"
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/* A global variable is a bit ugly, but it keeps the code simple */
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int sysctl_drop_caches;
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static void drop_pagecache_sb(struct super_block *sb, void *unused)
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{
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struct inode *inode, *toput_inode = NULL;
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spin_lock(&sb->s_inode_list_lock);
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list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
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spin_lock(&inode->i_lock);
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/*
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* We must skip inodes in unusual state. We may also skip
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* inodes without pages but we deliberately won't in case
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* we need to reschedule to avoid softlockups.
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*/
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if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
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(mapping_empty(inode->i_mapping) && !need_resched())) {
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spin_unlock(&inode->i_lock);
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continue;
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}
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__iget(inode);
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spin_unlock(&inode->i_lock);
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spin_unlock(&sb->s_inode_list_lock);
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invalidate_mapping_pages(inode->i_mapping, 0, -1);
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iput(toput_inode);
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toput_inode = inode;
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cond_resched();
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spin_lock(&sb->s_inode_list_lock);
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}
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spin_unlock(&sb->s_inode_list_lock);
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iput(toput_inode);
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}
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int drop_caches_sysctl_handler(const struct ctl_table *table, int write,
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void *buffer, size_t *length, loff_t *ppos)
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{
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int ret;
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ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
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if (ret)
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return ret;
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if (write) {
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static int stfu;
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if (sysctl_drop_caches & 1) {
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lru_add_drain_all();
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iterate_supers(drop_pagecache_sb, NULL);
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count_vm_event(DROP_PAGECACHE);
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}
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if (sysctl_drop_caches & 2) {
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drop_slab();
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count_vm_event(DROP_SLAB);
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}
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if (!stfu) {
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pr_info("%s (%d): drop_caches: %d\n",
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current->comm, task_pid_nr(current),
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sysctl_drop_caches);
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}
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stfu |= sysctl_drop_caches & 4;
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}
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return 0;
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}
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