Message-Id: <20241015175412.60563-8-sj@kernel.org>
Date: Tue, 15 Oct 2024 10:54:12 -0700
From: SeongJae Park <sj@...nel.org>
To: 
Cc: SeongJae Park <sj@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	damon@...ts.linux.dev,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: [RFC PATCH 7/7] mm/damon: remove DAMON debugfs interface

It's time to remove DAMON debugfs interface, which has deprecated long
before in February 2023.  Read the cover letter of this patch series for
more details.

All documents and related tests are also removed.  Finally remove the
interface.

Signed-off-by: SeongJae Park <sj@...nel.org>
---
 mm/damon/Kconfig  |   18 -
 mm/damon/Makefile |    1 -
 mm/damon/dbgfs.c  | 1146 ---------------------------------------------
 3 files changed, 1165 deletions(-)
 delete mode 100644 mm/damon/dbgfs.c

diff --git a/mm/damon/Kconfig b/mm/damon/Kconfig
index 5ee5e62c0a1e..1cc1cb5ba66f 100644
--- a/mm/damon/Kconfig
+++ b/mm/damon/Kconfig
@@ -71,24 +71,6 @@ config DAMON_SYSFS_KUNIT_TEST
 
 	  If unsure, say N.
 
-config DAMON_DBGFS_DEPRECATED
-	bool "DAMON debugfs interface (DEPRECATED!)"
-	depends on DAMON_VADDR && DAMON_PADDR && DEBUG_FS
-	help
-	  This builds the debugfs interface for DAMON.  The user space admins
-	  can use the interface for arbitrary data access monitoring.
-
-	  If unsure, say N.
-
-	  This is deprecated, so users should move to the sysfs interface
-	  (DAMON_SYSFS).  If you depend on this and cannot move, please report
-	  your usecase to damon@...ts.linux.dev and linux-mm@...ck.org.
-
-config DAMON_DBGFS
-	bool
-	default y
-	depends on DAMON_DBGFS_DEPRECATED
-
 config DAMON_RECLAIM
 	bool "Build DAMON-based reclaim (DAMON_RECLAIM)"
 	depends on DAMON_PADDR
diff --git a/mm/damon/Makefile b/mm/damon/Makefile
index f7add3f4aa79..8b49012ba8c3 100644
--- a/mm/damon/Makefile
+++ b/mm/damon/Makefile
@@ -4,6 +4,5 @@ obj-y				:= core.o
 obj-$(CONFIG_DAMON_VADDR)	+= ops-common.o vaddr.o
 obj-$(CONFIG_DAMON_PADDR)	+= ops-common.o paddr.o
 obj-$(CONFIG_DAMON_SYSFS)	+= sysfs-common.o sysfs-schemes.o sysfs.o
-obj-$(CONFIG_DAMON_DBGFS)	+= dbgfs.o
 obj-$(CONFIG_DAMON_RECLAIM)	+= modules-common.o reclaim.o
 obj-$(CONFIG_DAMON_LRU_SORT)	+= modules-common.o lru_sort.o
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
deleted file mode 100644
index 5664c2cb0a5e..000000000000
--- a/mm/damon/dbgfs.c
+++ /dev/null
@@ -1,1146 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * DAMON Debugfs Interface
- *
- * Author: SeongJae Park <sj@...nel.org>
- */
-
-#define pr_fmt(fmt) "damon-dbgfs: " fmt
-
-#include <linux/damon.h>
-#include <linux/debugfs.h>
-#include <linux/file.h>
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/page_idle.h>
-#include <linux/slab.h>
-
-#define DAMON_DBGFS_DEPRECATION_NOTICE					\
-	"DAMON debugfs interface is deprecated, so users should move "	\
-	"to DAMON_SYSFS. If you cannot, please report your usecase to "	\
-	"damon@...ts.linux.dev and linux-mm@...ck.org.\n"
-
-static struct damon_ctx **dbgfs_ctxs;
-static int dbgfs_nr_ctxs;
-static struct dentry **dbgfs_dirs;
-static DEFINE_MUTEX(damon_dbgfs_lock);
-
-static void damon_dbgfs_warn_deprecation(void)
-{
-	pr_warn_once(DAMON_DBGFS_DEPRECATION_NOTICE);
-}
-
-/*
- * Returns non-empty string on success, negative error code otherwise.
- */
-static char *user_input_str(const char __user *buf, size_t count, loff_t *ppos)
-{
-	char *kbuf;
-	ssize_t ret;
-
-	/* We do not accept continuous write */
-	if (*ppos)
-		return ERR_PTR(-EINVAL);
-
-	kbuf = kmalloc(count + 1, GFP_KERNEL | __GFP_NOWARN);
-	if (!kbuf)
-		return ERR_PTR(-ENOMEM);
-
-	ret = simple_write_to_buffer(kbuf, count + 1, ppos, buf, count);
-	if (ret != count) {
-		kfree(kbuf);
-		return ERR_PTR(-EIO);
-	}
-	kbuf[ret] = '\0';
-
-	return kbuf;
-}
-
-static ssize_t dbgfs_attrs_read(struct file *file,
-		char __user *buf, size_t count, loff_t *ppos)
-{
-	struct damon_ctx *ctx = file->private_data;
-	char kbuf[128];
-	int ret;
-
-	mutex_lock(&ctx->kdamond_lock);
-	ret = scnprintf(kbuf, ARRAY_SIZE(kbuf), "%lu %lu %lu %lu %lu\n",
-			ctx->attrs.sample_interval, ctx->attrs.aggr_interval,
-			ctx->attrs.ops_update_interval,
-			ctx->attrs.min_nr_regions, ctx->attrs.max_nr_regions);
-	mutex_unlock(&ctx->kdamond_lock);
-
-	return simple_read_from_buffer(buf, count, ppos, kbuf, ret);
-}
-
-static ssize_t dbgfs_attrs_write(struct file *file,
-		const char __user *buf, size_t count, loff_t *ppos)
-{
-	struct damon_ctx *ctx = file->private_data;
-	struct damon_attrs attrs;
-	char *kbuf;
-	ssize_t ret;
-
-	kbuf = user_input_str(buf, count, ppos);
-	if (IS_ERR(kbuf))
-		return PTR_ERR(kbuf);
-
-	if (sscanf(kbuf, "%lu %lu %lu %lu %lu",
-				&attrs.sample_interval, &attrs.aggr_interval,
-				&attrs.ops_update_interval,
-				&attrs.min_nr_regions,
-				&attrs.max_nr_regions) != 5) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	mutex_lock(&ctx->kdamond_lock);
-	if (ctx->kdamond) {
-		ret = -EBUSY;
-		goto unlock_out;
-	}
-
-	ret = damon_set_attrs(ctx, &attrs);
-	if (!ret)
-		ret = count;
-unlock_out:
-	mutex_unlock(&ctx->kdamond_lock);
-out:
-	kfree(kbuf);
-	return ret;
-}
-
-/*
- * Return corresponding dbgfs' scheme action value (int) for the given
- * damos_action if the given damos_action value is valid and supported by
- * dbgfs, negative error code otherwise.
- */
-static int damos_action_to_dbgfs_scheme_action(enum damos_action action)
-{
-	switch (action) {
-	case DAMOS_WILLNEED:
-		return 0;
-	case DAMOS_COLD:
-		return 1;
-	case DAMOS_PAGEOUT:
-		return 2;
-	case DAMOS_HUGEPAGE:
-		return 3;
-	case DAMOS_NOHUGEPAGE:
-		return 4;
-	case DAMOS_STAT:
-		return 5;
-	default:
-		return -EINVAL;
-	}
-}
-
-static ssize_t sprint_schemes(struct damon_ctx *c, char *buf, ssize_t len)
-{
-	struct damos *s;
-	int written = 0;
-	int rc;
-
-	damon_for_each_scheme(s, c) {
-		rc = scnprintf(&buf[written], len - written,
-				"%lu %lu %u %u %u %u %d %lu %lu %lu %u %u %u %d %lu %lu %lu %lu %lu %lu %lu %lu %lu\n",
-				s->pattern.min_sz_region,
-				s->pattern.max_sz_region,
-				s->pattern.min_nr_accesses,
-				s->pattern.max_nr_accesses,
-				s->pattern.min_age_region,
-				s->pattern.max_age_region,
-				damos_action_to_dbgfs_scheme_action(s->action),
-				s->quota.ms, s->quota.sz,
-				s->quota.reset_interval,
-				s->quota.weight_sz,
-				s->quota.weight_nr_accesses,
-				s->quota.weight_age,
-				s->wmarks.metric, s->wmarks.interval,
-				s->wmarks.high, s->wmarks.mid, s->wmarks.low,
-				s->stat.nr_tried, s->stat.sz_tried,
-				s->stat.nr_applied, s->stat.sz_applied,
-				s->stat.qt_exceeds);
-		if (!rc)
-			return -ENOMEM;
-
-		written += rc;
-	}
-	return written;
-}
-
-static ssize_t dbgfs_schemes_read(struct file *file, char __user *buf,
-		size_t count, loff_t *ppos)
-{
-	struct damon_ctx *ctx = file->private_data;
-	char *kbuf;
-	ssize_t len;
-
-	kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN);
-	if (!kbuf)
-		return -ENOMEM;
-
-	mutex_lock(&ctx->kdamond_lock);
-	len = sprint_schemes(ctx, kbuf, count);
-	mutex_unlock(&ctx->kdamond_lock);
-	if (len < 0)
-		goto out;
-	len = simple_read_from_buffer(buf, count, ppos, kbuf, len);
-
-out:
-	kfree(kbuf);
-	return len;
-}
-
-static void free_schemes_arr(struct damos **schemes, ssize_t nr_schemes)
-{
-	ssize_t i;
-
-	for (i = 0; i < nr_schemes; i++)
-		kfree(schemes[i]);
-	kfree(schemes);
-}
-
-/*
- * Return corresponding damos_action for the given dbgfs input for a scheme
- * action if the input is valid, negative error code otherwise.
- */
-static enum damos_action dbgfs_scheme_action_to_damos_action(int dbgfs_action)
-{
-	switch (dbgfs_action) {
-	case 0:
-		return DAMOS_WILLNEED;
-	case 1:
-		return DAMOS_COLD;
-	case 2:
-		return DAMOS_PAGEOUT;
-	case 3:
-		return DAMOS_HUGEPAGE;
-	case 4:
-		return DAMOS_NOHUGEPAGE;
-	case 5:
-		return DAMOS_STAT;
-	default:
-		return -EINVAL;
-	}
-}
-
-/*
- * Converts a string into an array of struct damos pointers
- *
- * Returns an array of struct damos pointers that converted if the conversion
- * success, or NULL otherwise.
- */
-static struct damos **str_to_schemes(const char *str, ssize_t len,
-				ssize_t *nr_schemes)
-{
-	struct damos *scheme, **schemes;
-	const int max_nr_schemes = 256;
-	int pos = 0, parsed, ret;
-	unsigned int action_input;
-	enum damos_action action;
-
-	schemes = kmalloc_array(max_nr_schemes, sizeof(scheme),
-			GFP_KERNEL);
-	if (!schemes)
-		return NULL;
-
-	*nr_schemes = 0;
-	while (pos < len && *nr_schemes < max_nr_schemes) {
-		struct damos_access_pattern pattern = {};
-		struct damos_quota quota = {};
-		struct damos_watermarks wmarks;
-
-		ret = sscanf(&str[pos],
-				"%lu %lu %u %u %u %u %u %lu %lu %lu %u %u %u %u %lu %lu %lu %lu%n",
-				&pattern.min_sz_region, &pattern.max_sz_region,
-				&pattern.min_nr_accesses,
-				&pattern.max_nr_accesses,
-				&pattern.min_age_region,
-				&pattern.max_age_region,
-				&action_input, &quota.ms,
-				&quota.sz, &quota.reset_interval,
-				&quota.weight_sz, &quota.weight_nr_accesses,
-				&quota.weight_age, &wmarks.metric,
-				&wmarks.interval, &wmarks.high, &wmarks.mid,
-				&wmarks.low, &parsed);
-		if (ret != 18)
-			break;
-		action = dbgfs_scheme_action_to_damos_action(action_input);
-		if ((int)action < 0)
-			goto fail;
-
-		if (pattern.min_sz_region > pattern.max_sz_region ||
-		    pattern.min_nr_accesses > pattern.max_nr_accesses ||
-		    pattern.min_age_region > pattern.max_age_region)
-			goto fail;
-
-		if (wmarks.high < wmarks.mid || wmarks.high < wmarks.low ||
-		    wmarks.mid <  wmarks.low)
-			goto fail;
-
-		pos += parsed;
-		scheme = damon_new_scheme(&pattern, action, 0, &quota,
-				&wmarks, NUMA_NO_NODE);
-		if (!scheme)
-			goto fail;
-
-		schemes[*nr_schemes] = scheme;
-		*nr_schemes += 1;
-	}
-	return schemes;
-fail:
-	free_schemes_arr(schemes, *nr_schemes);
-	return NULL;
-}
-
-static ssize_t dbgfs_schemes_write(struct file *file, const char __user *buf,
-		size_t count, loff_t *ppos)
-{
-	struct damon_ctx *ctx = file->private_data;
-	char *kbuf;
-	struct damos **schemes;
-	ssize_t nr_schemes = 0, ret;
-
-	kbuf = user_input_str(buf, count, ppos);
-	if (IS_ERR(kbuf))
-		return PTR_ERR(kbuf);
-
-	schemes = str_to_schemes(kbuf, count, &nr_schemes);
-	if (!schemes) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	mutex_lock(&ctx->kdamond_lock);
-	if (ctx->kdamond) {
-		ret = -EBUSY;
-		goto unlock_out;
-	}
-
-	damon_set_schemes(ctx, schemes, nr_schemes);
-	ret = count;
-	nr_schemes = 0;
-
-unlock_out:
-	mutex_unlock(&ctx->kdamond_lock);
-	free_schemes_arr(schemes, nr_schemes);
-out:
-	kfree(kbuf);
-	return ret;
-}
-
-static ssize_t sprint_target_ids(struct damon_ctx *ctx, char *buf, ssize_t len)
-{
-	struct damon_target *t;
-	int id;
-	int written = 0;
-	int rc;
-
-	damon_for_each_target(t, ctx) {
-		if (damon_target_has_pid(ctx))
-			/* Show pid numbers to debugfs users */
-			id = pid_vnr(t->pid);
-		else
-			/* Show 42 for physical address space, just for fun */
-			id = 42;
-
-		rc = scnprintf(&buf[written], len - written, "%d ", id);
-		if (!rc)
-			return -ENOMEM;
-		written += rc;
-	}
-	if (written)
-		written -= 1;
-	written += scnprintf(&buf[written], len - written, "\n");
-	return written;
-}
-
-static ssize_t dbgfs_target_ids_read(struct file *file,
-		char __user *buf, size_t count, loff_t *ppos)
-{
-	struct damon_ctx *ctx = file->private_data;
-	ssize_t len;
-	char ids_buf[320];
-
-	mutex_lock(&ctx->kdamond_lock);
-	len = sprint_target_ids(ctx, ids_buf, 320);
-	mutex_unlock(&ctx->kdamond_lock);
-	if (len < 0)
-		return len;
-
-	return simple_read_from_buffer(buf, count, ppos, ids_buf, len);
-}
-
-/*
- * Converts a string into an integers array
- *
- * Returns an array of integers array if the conversion success, or NULL
- * otherwise.
- */
-static int *str_to_ints(const char *str, ssize_t len, ssize_t *nr_ints)
-{
-	int *array;
-	const int max_nr_ints = 32;
-	int nr;
-	int pos = 0, parsed, ret;
-
-	*nr_ints = 0;
-	array = kmalloc_array(max_nr_ints, sizeof(*array), GFP_KERNEL);
-	if (!array)
-		return NULL;
-	while (*nr_ints < max_nr_ints && pos < len) {
-		ret = sscanf(&str[pos], "%d%n", &nr, &parsed);
-		pos += parsed;
-		if (ret != 1)
-			break;
-		array[*nr_ints] = nr;
-		*nr_ints += 1;
-	}
-
-	return array;
-}
-
-static void dbgfs_put_pids(struct pid **pids, int nr_pids)
-{
-	int i;
-
-	for (i = 0; i < nr_pids; i++)
-		put_pid(pids[i]);
-}
-
-/*
- * Converts a string into an struct pid pointers array
- *
- * Returns an array of struct pid pointers if the conversion success, or NULL
- * otherwise.
- */
-static struct pid **str_to_pids(const char *str, ssize_t len, ssize_t *nr_pids)
-{
-	int *ints;
-	ssize_t nr_ints;
-	struct pid **pids;
-
-	*nr_pids = 0;
-
-	ints = str_to_ints(str, len, &nr_ints);
-	if (!ints)
-		return NULL;
-
-	pids = kmalloc_array(nr_ints, sizeof(*pids), GFP_KERNEL);
-	if (!pids)
-		goto out;
-
-	for (; *nr_pids < nr_ints; (*nr_pids)++) {
-		pids[*nr_pids] = find_get_pid(ints[*nr_pids]);
-		if (!pids[*nr_pids]) {
-			dbgfs_put_pids(pids, *nr_pids);
-			kfree(ints);
-			kfree(pids);
-			return NULL;
-		}
-	}
-
-out:
-	kfree(ints);
-	return pids;
-}
-
-/*
- * dbgfs_set_targets() - Set monitoring targets.
- * @ctx:	monitoring context
- * @nr_targets:	number of targets
- * @pids:	array of target pids (size is same to @nr_targets)
- *
- * This function should not be called while the kdamond is running.  @pids is
- * ignored if the context is not configured to have pid in each target.  On
- * failure, reference counts of all pids in @pids are decremented.
- *
- * Return: 0 on success, negative error code otherwise.
- */
-static int dbgfs_set_targets(struct damon_ctx *ctx, ssize_t nr_targets,
-		struct pid **pids)
-{
-	ssize_t i;
-	struct damon_target *t, *next;
-
-	damon_for_each_target_safe(t, next, ctx) {
-		if (damon_target_has_pid(ctx))
-			put_pid(t->pid);
-		damon_destroy_target(t);
-	}
-
-	for (i = 0; i < nr_targets; i++) {
-		t = damon_new_target();
-		if (!t) {
-			damon_for_each_target_safe(t, next, ctx)
-				damon_destroy_target(t);
-			if (damon_target_has_pid(ctx))
-				dbgfs_put_pids(pids, nr_targets);
-			return -ENOMEM;
-		}
-		if (damon_target_has_pid(ctx))
-			t->pid = pids[i];
-		damon_add_target(ctx, t);
-	}
-
-	return 0;
-}
-
-static ssize_t dbgfs_target_ids_write(struct file *file,
-		const char __user *buf, size_t count, loff_t *ppos)
-{
-	struct damon_ctx *ctx = file->private_data;
-	bool id_is_pid = true;
-	char *kbuf;
-	struct pid **target_pids = NULL;
-	ssize_t nr_targets;
-	ssize_t ret;
-
-	kbuf = user_input_str(buf, count, ppos);
-	if (IS_ERR(kbuf))
-		return PTR_ERR(kbuf);
-
-	if (!strncmp(kbuf, "paddr\n", count)) {
-		id_is_pid = false;
-		nr_targets = 1;
-	}
-
-	if (id_is_pid) {
-		target_pids = str_to_pids(kbuf, count, &nr_targets);
-		if (!target_pids) {
-			ret = -ENOMEM;
-			goto out;
-		}
-	}
-
-	mutex_lock(&ctx->kdamond_lock);
-	if (ctx->kdamond) {
-		if (id_is_pid)
-			dbgfs_put_pids(target_pids, nr_targets);
-		ret = -EBUSY;
-		goto unlock_out;
-	}
-
-	/* remove previously set targets */
-	dbgfs_set_targets(ctx, 0, NULL);
-	if (!nr_targets) {
-		ret = count;
-		goto unlock_out;
-	}
-
-	/* Configure the context for the address space type */
-	if (id_is_pid)
-		ret = damon_select_ops(ctx, DAMON_OPS_VADDR);
-	else
-		ret = damon_select_ops(ctx, DAMON_OPS_PADDR);
-	if (ret)
-		goto unlock_out;
-
-	ret = dbgfs_set_targets(ctx, nr_targets, target_pids);
-	if (!ret)
-		ret = count;
-
-unlock_out:
-	mutex_unlock(&ctx->kdamond_lock);
-	kfree(target_pids);
-out:
-	kfree(kbuf);
-	return ret;
-}
-
-static ssize_t sprint_init_regions(struct damon_ctx *c, char *buf, ssize_t len)
-{
-	struct damon_target *t;
-	struct damon_region *r;
-	int target_idx = 0;
-	int written = 0;
-	int rc;
-
-	damon_for_each_target(t, c) {
-		damon_for_each_region(r, t) {
-			rc = scnprintf(&buf[written], len - written,
-					"%d %lu %lu\n",
-					target_idx, r->ar.start, r->ar.end);
-			if (!rc)
-				return -ENOMEM;
-			written += rc;
-		}
-		target_idx++;
-	}
-	return written;
-}
-
-static ssize_t dbgfs_init_regions_read(struct file *file, char __user *buf,
-		size_t count, loff_t *ppos)
-{
-	struct damon_ctx *ctx = file->private_data;
-	char *kbuf;
-	ssize_t len;
-
-	kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN);
-	if (!kbuf)
-		return -ENOMEM;
-
-	mutex_lock(&ctx->kdamond_lock);
-	if (ctx->kdamond) {
-		mutex_unlock(&ctx->kdamond_lock);
-		len = -EBUSY;
-		goto out;
-	}
-
-	len = sprint_init_regions(ctx, kbuf, count);
-	mutex_unlock(&ctx->kdamond_lock);
-	if (len < 0)
-		goto out;
-	len = simple_read_from_buffer(buf, count, ppos, kbuf, len);
-
-out:
-	kfree(kbuf);
-	return len;
-}
-
-static int add_init_region(struct damon_ctx *c, int target_idx,
-		struct damon_addr_range *ar)
-{
-	struct damon_target *t;
-	struct damon_region *r, *prev;
-	unsigned long idx = 0;
-	int rc = -EINVAL;
-
-	if (ar->start >= ar->end)
-		return -EINVAL;
-
-	damon_for_each_target(t, c) {
-		if (idx++ == target_idx) {
-			r = damon_new_region(ar->start, ar->end);
-			if (!r)
-				return -ENOMEM;
-			damon_add_region(r, t);
-			if (damon_nr_regions(t) > 1) {
-				prev = damon_prev_region(r);
-				if (prev->ar.end > r->ar.start) {
-					damon_destroy_region(r, t);
-					return -EINVAL;
-				}
-			}
-			rc = 0;
-		}
-	}
-	return rc;
-}
-
-static int set_init_regions(struct damon_ctx *c, const char *str, ssize_t len)
-{
-	struct damon_target *t;
-	struct damon_region *r, *next;
-	int pos = 0, parsed, ret;
-	int target_idx;
-	struct damon_addr_range ar;
-	int err;
-
-	damon_for_each_target(t, c) {
-		damon_for_each_region_safe(r, next, t)
-			damon_destroy_region(r, t);
-	}
-
-	while (pos < len) {
-		ret = sscanf(&str[pos], "%d %lu %lu%n",
-				&target_idx, &ar.start, &ar.end, &parsed);
-		if (ret != 3)
-			break;
-		err = add_init_region(c, target_idx, &ar);
-		if (err)
-			goto fail;
-		pos += parsed;
-	}
-
-	return 0;
-
-fail:
-	damon_for_each_target(t, c) {
-		damon_for_each_region_safe(r, next, t)
-			damon_destroy_region(r, t);
-	}
-	return err;
-}
-
-static ssize_t dbgfs_init_regions_write(struct file *file,
-					  const char __user *buf, size_t count,
-					  loff_t *ppos)
-{
-	struct damon_ctx *ctx = file->private_data;
-	char *kbuf;
-	ssize_t ret = count;
-	int err;
-
-	kbuf = user_input_str(buf, count, ppos);
-	if (IS_ERR(kbuf))
-		return PTR_ERR(kbuf);
-
-	mutex_lock(&ctx->kdamond_lock);
-	if (ctx->kdamond) {
-		ret = -EBUSY;
-		goto unlock_out;
-	}
-
-	err = set_init_regions(ctx, kbuf, ret);
-	if (err)
-		ret = err;
-
-unlock_out:
-	mutex_unlock(&ctx->kdamond_lock);
-	kfree(kbuf);
-	return ret;
-}
-
-static ssize_t dbgfs_kdamond_pid_read(struct file *file,
-		char __user *buf, size_t count, loff_t *ppos)
-{
-	struct damon_ctx *ctx = file->private_data;
-	char *kbuf;
-	ssize_t len;
-
-	kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN);
-	if (!kbuf)
-		return -ENOMEM;
-
-	mutex_lock(&ctx->kdamond_lock);
-	if (ctx->kdamond)
-		len = scnprintf(kbuf, count, "%d\n", ctx->kdamond->pid);
-	else
-		len = scnprintf(kbuf, count, "none\n");
-	mutex_unlock(&ctx->kdamond_lock);
-	if (!len)
-		goto out;
-	len = simple_read_from_buffer(buf, count, ppos, kbuf, len);
-
-out:
-	kfree(kbuf);
-	return len;
-}
-
-static int damon_dbgfs_open(struct inode *inode, struct file *file)
-{
-	damon_dbgfs_warn_deprecation();
-
-	file->private_data = inode->i_private;
-
-	return nonseekable_open(inode, file);
-}
-
-static const struct file_operations attrs_fops = {
-	.open = damon_dbgfs_open,
-	.read = dbgfs_attrs_read,
-	.write = dbgfs_attrs_write,
-};
-
-static const struct file_operations schemes_fops = {
-	.open = damon_dbgfs_open,
-	.read = dbgfs_schemes_read,
-	.write = dbgfs_schemes_write,
-};
-
-static const struct file_operations target_ids_fops = {
-	.open = damon_dbgfs_open,
-	.read = dbgfs_target_ids_read,
-	.write = dbgfs_target_ids_write,
-};
-
-static const struct file_operations init_regions_fops = {
-	.open = damon_dbgfs_open,
-	.read = dbgfs_init_regions_read,
-	.write = dbgfs_init_regions_write,
-};
-
-static const struct file_operations kdamond_pid_fops = {
-	.open = damon_dbgfs_open,
-	.read = dbgfs_kdamond_pid_read,
-};
-
-static void dbgfs_fill_ctx_dir(struct dentry *dir, struct damon_ctx *ctx)
-{
-	const char * const file_names[] = {"attrs", "schemes", "target_ids",
-		"init_regions", "kdamond_pid"};
-	const struct file_operations *fops[] = {&attrs_fops, &schemes_fops,
-		&target_ids_fops, &init_regions_fops, &kdamond_pid_fops};
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(file_names); i++)
-		debugfs_create_file(file_names[i], 0600, dir, ctx, fops[i]);
-}
-
-static void dbgfs_before_terminate(struct damon_ctx *ctx)
-{
-	struct damon_target *t, *next;
-
-	if (!damon_target_has_pid(ctx))
-		return;
-
-	mutex_lock(&ctx->kdamond_lock);
-	damon_for_each_target_safe(t, next, ctx) {
-		put_pid(t->pid);
-		damon_destroy_target(t);
-	}
-	mutex_unlock(&ctx->kdamond_lock);
-}
-
-static struct damon_ctx *dbgfs_new_ctx(void)
-{
-	struct damon_ctx *ctx;
-
-	ctx = damon_new_ctx();
-	if (!ctx)
-		return NULL;
-
-	if (damon_select_ops(ctx, DAMON_OPS_VADDR) &&
-			damon_select_ops(ctx, DAMON_OPS_PADDR)) {
-		damon_destroy_ctx(ctx);
-		return NULL;
-	}
-	ctx->callback.before_terminate = dbgfs_before_terminate;
-	return ctx;
-}
-
-static void dbgfs_destroy_ctx(struct damon_ctx *ctx)
-{
-	damon_destroy_ctx(ctx);
-}
-
-static ssize_t damon_dbgfs_deprecated_read(struct file *file,
-		char __user *buf, size_t count, loff_t *ppos)
-{
-	static const char kbuf[512] = DAMON_DBGFS_DEPRECATION_NOTICE;
-
-	return simple_read_from_buffer(buf, count, ppos, kbuf, strlen(kbuf));
-}
-
-/*
- * Make a context of @name and create a debugfs directory for it.
- *
- * This function should be called while holding damon_dbgfs_lock.
- *
- * Returns 0 on success, negative error code otherwise.
- */
-static int dbgfs_mk_context(char *name)
-{
-	struct dentry *root, **new_dirs, *new_dir;
-	struct damon_ctx **new_ctxs, *new_ctx;
-
-	if (damon_nr_running_ctxs())
-		return -EBUSY;
-
-	new_ctxs = krealloc(dbgfs_ctxs, sizeof(*dbgfs_ctxs) *
-			(dbgfs_nr_ctxs + 1), GFP_KERNEL);
-	if (!new_ctxs)
-		return -ENOMEM;
-	dbgfs_ctxs = new_ctxs;
-
-	new_dirs = krealloc(dbgfs_dirs, sizeof(*dbgfs_dirs) *
-			(dbgfs_nr_ctxs + 1), GFP_KERNEL);
-	if (!new_dirs)
-		return -ENOMEM;
-	dbgfs_dirs = new_dirs;
-
-	root = dbgfs_dirs[0];
-	if (!root)
-		return -ENOENT;
-
-	new_dir = debugfs_create_dir(name, root);
-	/* Below check is required for a potential duplicated name case */
-	if (IS_ERR(new_dir))
-		return PTR_ERR(new_dir);
-	dbgfs_dirs[dbgfs_nr_ctxs] = new_dir;
-
-	new_ctx = dbgfs_new_ctx();
-	if (!new_ctx) {
-		debugfs_remove(new_dir);
-		dbgfs_dirs[dbgfs_nr_ctxs] = NULL;
-		return -ENOMEM;
-	}
-
-	dbgfs_ctxs[dbgfs_nr_ctxs] = new_ctx;
-	dbgfs_fill_ctx_dir(dbgfs_dirs[dbgfs_nr_ctxs],
-			dbgfs_ctxs[dbgfs_nr_ctxs]);
-	dbgfs_nr_ctxs++;
-
-	return 0;
-}
-
-static ssize_t dbgfs_mk_context_write(struct file *file,
-		const char __user *buf, size_t count, loff_t *ppos)
-{
-	char *kbuf;
-	char *ctx_name;
-	ssize_t ret;
-
-	kbuf = user_input_str(buf, count, ppos);
-	if (IS_ERR(kbuf))
-		return PTR_ERR(kbuf);
-	ctx_name = kmalloc(count + 1, GFP_KERNEL);
-	if (!ctx_name) {
-		kfree(kbuf);
-		return -ENOMEM;
-	}
-
-	/* Trim white space */
-	if (sscanf(kbuf, "%s", ctx_name) != 1) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	mutex_lock(&damon_dbgfs_lock);
-	ret = dbgfs_mk_context(ctx_name);
-	if (!ret)
-		ret = count;
-	mutex_unlock(&damon_dbgfs_lock);
-
-out:
-	kfree(kbuf);
-	kfree(ctx_name);
-	return ret;
-}
-
-/*
- * Remove a context of @name and its debugfs directory.
- *
- * This function should be called while holding damon_dbgfs_lock.
- *
- * Return 0 on success, negative error code otherwise.
- */
-static int dbgfs_rm_context(char *name)
-{
-	struct dentry *root, *dir, **new_dirs;
-	struct inode *inode;
-	struct damon_ctx **new_ctxs;
-	int i, j;
-	int ret = 0;
-
-	if (damon_nr_running_ctxs())
-		return -EBUSY;
-
-	root = dbgfs_dirs[0];
-	if (!root)
-		return -ENOENT;
-
-	dir = debugfs_lookup(name, root);
-	if (!dir)
-		return -ENOENT;
-
-	inode = d_inode(dir);
-	if (!S_ISDIR(inode->i_mode)) {
-		ret = -EINVAL;
-		goto out_dput;
-	}
-
-	new_dirs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_dirs),
-			GFP_KERNEL);
-	if (!new_dirs) {
-		ret = -ENOMEM;
-		goto out_dput;
-	}
-
-	new_ctxs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_ctxs),
-			GFP_KERNEL);
-	if (!new_ctxs) {
-		ret = -ENOMEM;
-		goto out_new_dirs;
-	}
-
-	for (i = 0, j = 0; i < dbgfs_nr_ctxs; i++) {
-		if (dbgfs_dirs[i] == dir) {
-			debugfs_remove(dbgfs_dirs[i]);
-			dbgfs_destroy_ctx(dbgfs_ctxs[i]);
-			continue;
-		}
-		new_dirs[j] = dbgfs_dirs[i];
-		new_ctxs[j++] = dbgfs_ctxs[i];
-	}
-
-	kfree(dbgfs_dirs);
-	kfree(dbgfs_ctxs);
-
-	dbgfs_dirs = new_dirs;
-	dbgfs_ctxs = new_ctxs;
-	dbgfs_nr_ctxs--;
-
-	goto out_dput;
-
-out_new_dirs:
-	kfree(new_dirs);
-out_dput:
-	dput(dir);
-	return ret;
-}
-
-static ssize_t dbgfs_rm_context_write(struct file *file,
-		const char __user *buf, size_t count, loff_t *ppos)
-{
-	char *kbuf;
-	ssize_t ret;
-	char *ctx_name;
-
-	kbuf = user_input_str(buf, count, ppos);
-	if (IS_ERR(kbuf))
-		return PTR_ERR(kbuf);
-	ctx_name = kmalloc(count + 1, GFP_KERNEL);
-	if (!ctx_name) {
-		kfree(kbuf);
-		return -ENOMEM;
-	}
-
-	/* Trim white space */
-	if (sscanf(kbuf, "%s", ctx_name) != 1) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	mutex_lock(&damon_dbgfs_lock);
-	ret = dbgfs_rm_context(ctx_name);
-	if (!ret)
-		ret = count;
-	mutex_unlock(&damon_dbgfs_lock);
-
-out:
-	kfree(kbuf);
-	kfree(ctx_name);
-	return ret;
-}
-
-static ssize_t dbgfs_monitor_on_read(struct file *file,
-		char __user *buf, size_t count, loff_t *ppos)
-{
-	char monitor_on_buf[5];
-	bool monitor_on = damon_nr_running_ctxs() != 0;
-	int len;
-
-	len = scnprintf(monitor_on_buf, 5, monitor_on ? "on\n" : "off\n");
-
-	return simple_read_from_buffer(buf, count, ppos, monitor_on_buf, len);
-}
-
-static ssize_t dbgfs_monitor_on_write(struct file *file,
-		const char __user *buf, size_t count, loff_t *ppos)
-{
-	ssize_t ret;
-	char *kbuf;
-
-	kbuf = user_input_str(buf, count, ppos);
-	if (IS_ERR(kbuf))
-		return PTR_ERR(kbuf);
-
-	/* Remove white space */
-	if (sscanf(kbuf, "%s", kbuf) != 1) {
-		kfree(kbuf);
-		return -EINVAL;
-	}
-
-	mutex_lock(&damon_dbgfs_lock);
-	if (!strncmp(kbuf, "on", count)) {
-		int i;
-
-		for (i = 0; i < dbgfs_nr_ctxs; i++) {
-			if (damon_targets_empty(dbgfs_ctxs[i])) {
-				kfree(kbuf);
-				mutex_unlock(&damon_dbgfs_lock);
-				return -EINVAL;
-			}
-		}
-		ret = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs, true);
-	} else if (!strncmp(kbuf, "off", count)) {
-		ret = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs);
-	} else {
-		ret = -EINVAL;
-	}
-	mutex_unlock(&damon_dbgfs_lock);
-
-	if (!ret)
-		ret = count;
-	kfree(kbuf);
-	return ret;
-}
-
-static int damon_dbgfs_static_file_open(struct inode *inode, struct file *file)
-{
-	damon_dbgfs_warn_deprecation();
-	return nonseekable_open(inode, file);
-}
-
-static const struct file_operations deprecated_fops = {
-	.read = damon_dbgfs_deprecated_read,
-};
-
-static const struct file_operations mk_contexts_fops = {
-	.open = damon_dbgfs_static_file_open,
-	.write = dbgfs_mk_context_write,
-};
-
-static const struct file_operations rm_contexts_fops = {
-	.open = damon_dbgfs_static_file_open,
-	.write = dbgfs_rm_context_write,
-};
-
-static const struct file_operations monitor_on_fops = {
-	.open = damon_dbgfs_static_file_open,
-	.read = dbgfs_monitor_on_read,
-	.write = dbgfs_monitor_on_write,
-};
-
-static int __init __damon_dbgfs_init(void)
-{
-	struct dentry *dbgfs_root;
-	const char * const file_names[] = {"mk_contexts", "rm_contexts",
-		"monitor_on_DEPRECATED", "DEPRECATED"};
-	const struct file_operations *fops[] = {&mk_contexts_fops,
-		&rm_contexts_fops, &monitor_on_fops, &deprecated_fops};
-	int i;
-
-	dbgfs_root = debugfs_create_dir("damon", NULL);
-
-	for (i = 0; i < ARRAY_SIZE(file_names); i++)
-		debugfs_create_file(file_names[i], 0600, dbgfs_root, NULL,
-				fops[i]);
-	dbgfs_fill_ctx_dir(dbgfs_root, dbgfs_ctxs[0]);
-
-	dbgfs_dirs = kmalloc(sizeof(dbgfs_root), GFP_KERNEL);
-	if (!dbgfs_dirs) {
-		debugfs_remove(dbgfs_root);
-		return -ENOMEM;
-	}
-	dbgfs_dirs[0] = dbgfs_root;
-
-	return 0;
-}
-
-/*
- * Functions for the initialization
- */
-
-static int __init damon_dbgfs_init(void)
-{
-	int rc = -ENOMEM;
-
-	mutex_lock(&damon_dbgfs_lock);
-	dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL);
-	if (!dbgfs_ctxs)
-		goto out;
-	dbgfs_ctxs[0] = dbgfs_new_ctx();
-	if (!dbgfs_ctxs[0]) {
-		kfree(dbgfs_ctxs);
-		goto out;
-	}
-	dbgfs_nr_ctxs = 1;
-
-	rc = __damon_dbgfs_init();
-	if (rc) {
-		kfree(dbgfs_ctxs[0]);
-		kfree(dbgfs_ctxs);
-		pr_err("%s: dbgfs init failed\n", __func__);
-	}
-
-out:
-	mutex_unlock(&damon_dbgfs_lock);
-	return rc;
-}
-
-module_init(damon_dbgfs_init);
-- 
2.39.5

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