diff --git a/fs/f2fs/Makefile b/fs/f2fs/Makefile
index 8a7322d229e4..3d2874633db0 100644
--- a/fs/f2fs/Makefile
+++ b/fs/f2fs/Makefile
@@ -3,7 +3,7 @@ obj-$(CONFIG_F2FS_FS) += f2fs.o
 
 f2fs-y		:= dir.o file.o inode.o namei.o hash.o super.o inline.o
 f2fs-y		+= checkpoint.o gc.o data.o node.o segment.o recovery.o
-f2fs-y		+= shrinker.o extent_cache.o sysfs.o
+f2fs-y		+= shrinker.o extent_cache.o sysfs.o discard.o
 f2fs-$(CONFIG_F2FS_STAT_FS) += debug.o
 f2fs-$(CONFIG_F2FS_FS_XATTR) += xattr.o
 f2fs-$(CONFIG_F2FS_FS_POSIX_ACL) += acl.o
diff --git a/fs/f2fs/discard.c b/fs/f2fs/discard.c
new file mode 100644
index 000000000000..794f88fc729d
--- /dev/null
+++ b/fs/f2fs/discard.c
@@ -0,0 +1,1271 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * f2fs discard support
+ *
+ * Copyright (c) 2022 Vivo Communication Technology Co.,Ltd.
+ * Author: Yangtao Li <frank.li@vivo.com>
+ */
+
+#include <linux/f2fs_fs.h>
+#include <linux/freezer.h>
+#include <linux/kthread.h>
+
+#include "f2fs.h"
+#include "segment.h"
+#include "node.h"
+#include "iostat.h"
+#include <trace/events/f2fs.h>
+
+static struct kmem_cache *discard_entry_slab;
+static struct kmem_cache *discard_cmd_slab;
+
+static struct discard_cmd *__create_discard_cmd(struct f2fs_sb_info *sbi,
+		struct block_device *bdev, block_t lstart,
+		block_t start, block_t len)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct list_head *pend_list;
+	struct discard_cmd *dc;
+
+	f2fs_bug_on(sbi, !len);
+
+	pend_list = &dcc->pend_list[plist_idx(len)];
+
+	dc = f2fs_kmem_cache_alloc(discard_cmd_slab, GFP_NOFS, true, NULL);
+	INIT_LIST_HEAD(&dc->list);
+	dc->bdev = bdev;
+	dc->lstart = lstart;
+	dc->start = start;
+	dc->len = len;
+	dc->ref = 0;
+	dc->state = D_PREP;
+	dc->queued = 0;
+	dc->error = 0;
+	init_completion(&dc->wait);
+	list_add_tail(&dc->list, pend_list);
+	spin_lock_init(&dc->lock);
+	dc->bio_ref = 0;
+	atomic_inc(&dcc->discard_cmd_cnt);
+	dcc->undiscard_blks += len;
+
+	return dc;
+}
+
+static struct discard_cmd *__attach_discard_cmd(struct f2fs_sb_info *sbi,
+				struct block_device *bdev, block_t lstart,
+				block_t start, block_t len,
+				struct rb_node *parent, struct rb_node **p,
+				bool leftmost)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct discard_cmd *dc;
+
+	dc = __create_discard_cmd(sbi, bdev, lstart, start, len);
+
+	rb_link_node(&dc->rb_node, parent, p);
+	rb_insert_color_cached(&dc->rb_node, &dcc->root, leftmost);
+
+	return dc;
+}
+
+static void __detach_discard_cmd(struct discard_cmd_control *dcc,
+							struct discard_cmd *dc)
+{
+	if (dc->state == D_DONE)
+		atomic_sub(dc->queued, &dcc->queued_discard);
+
+	list_del(&dc->list);
+	rb_erase_cached(&dc->rb_node, &dcc->root);
+	dcc->undiscard_blks -= dc->len;
+
+	kmem_cache_free(discard_cmd_slab, dc);
+
+	atomic_dec(&dcc->discard_cmd_cnt);
+}
+
+static void __remove_discard_cmd(struct f2fs_sb_info *sbi,
+							struct discard_cmd *dc)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	unsigned long flags;
+
+	trace_f2fs_remove_discard(dc->bdev, dc->start, dc->len);
+
+	spin_lock_irqsave(&dc->lock, flags);
+	if (dc->bio_ref) {
+		spin_unlock_irqrestore(&dc->lock, flags);
+		return;
+	}
+	spin_unlock_irqrestore(&dc->lock, flags);
+
+	f2fs_bug_on(sbi, dc->ref);
+
+	if (dc->error == -EOPNOTSUPP)
+		dc->error = 0;
+
+	if (dc->error)
+		printk_ratelimited(
+			"%sF2FS-fs (%s): Issue discard(%u, %u, %u) failed, ret: %d",
+			KERN_INFO, sbi->sb->s_id,
+			dc->lstart, dc->start, dc->len, dc->error);
+	__detach_discard_cmd(dcc, dc);
+}
+
+static void f2fs_submit_discard_endio(struct bio *bio)
+{
+	struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dc->lock, flags);
+	if (!dc->error)
+		dc->error = blk_status_to_errno(bio->bi_status);
+	dc->bio_ref--;
+	if (!dc->bio_ref && dc->state == D_SUBMIT) {
+		dc->state = D_DONE;
+		complete_all(&dc->wait);
+	}
+	spin_unlock_irqrestore(&dc->lock, flags);
+	bio_put(bio);
+}
+
+static void __init_discard_policy(struct f2fs_sb_info *sbi,
+				struct discard_policy *dpolicy,
+				int discard_type, unsigned int granularity)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+
+	/* common policy */
+	dpolicy->type = discard_type;
+	dpolicy->sync = true;
+	dpolicy->ordered = false;
+	dpolicy->granularity = granularity;
+
+	dpolicy->max_requests = dcc->max_discard_request;
+	dpolicy->io_aware_gran = MAX_PLIST_NUM;
+	dpolicy->timeout = false;
+
+	if (discard_type == DPOLICY_BG) {
+		dpolicy->min_interval = dcc->min_discard_issue_time;
+		dpolicy->mid_interval = dcc->mid_discard_issue_time;
+		dpolicy->max_interval = dcc->max_discard_issue_time;
+		dpolicy->io_aware = true;
+		dpolicy->sync = false;
+		dpolicy->ordered = true;
+		if (utilization(sbi) > dcc->discard_urgent_util) {
+			dpolicy->granularity = MIN_DISCARD_GRANULARITY;
+			if (atomic_read(&dcc->discard_cmd_cnt))
+				dpolicy->max_interval =
+					dcc->min_discard_issue_time;
+		}
+	} else if (discard_type == DPOLICY_FORCE) {
+		dpolicy->min_interval = dcc->min_discard_issue_time;
+		dpolicy->mid_interval = dcc->mid_discard_issue_time;
+		dpolicy->max_interval = dcc->max_discard_issue_time;
+		dpolicy->io_aware = false;
+	} else if (discard_type == DPOLICY_FSTRIM) {
+		dpolicy->io_aware = false;
+	} else if (discard_type == DPOLICY_UMOUNT) {
+		dpolicy->io_aware = false;
+		/* we need to issue all to keep CP_TRIMMED_FLAG */
+		dpolicy->granularity = MIN_DISCARD_GRANULARITY;
+		dpolicy->timeout = true;
+	}
+}
+
+static void __update_discard_tree_range(struct f2fs_sb_info *sbi,
+				struct block_device *bdev, block_t lstart,
+				block_t start, block_t len);
+/* this function is copied from blkdev_issue_discard from block/blk-lib.c */
+static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
+						struct discard_policy *dpolicy,
+						struct discard_cmd *dc,
+						unsigned int *issued)
+{
+	struct block_device *bdev = dc->bdev;
+	unsigned int max_discard_blocks =
+			SECTOR_TO_BLOCK(bdev_max_discard_sectors(bdev));
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
+					&(dcc->fstrim_list) : &(dcc->wait_list);
+	blk_opf_t flag = dpolicy->sync ? REQ_SYNC : 0;
+	block_t lstart, start, len, total_len;
+	int err = 0;
+
+	if (dc->state != D_PREP)
+		return 0;
+
+	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK))
+		return 0;
+
+	trace_f2fs_issue_discard(bdev, dc->start, dc->len);
+
+	lstart = dc->lstart;
+	start = dc->start;
+	len = dc->len;
+	total_len = len;
+
+	dc->len = 0;
+
+	while (total_len && *issued < dpolicy->max_requests && !err) {
+		struct bio *bio = NULL;
+		unsigned long flags;
+		bool last = true;
+
+		if (len > max_discard_blocks) {
+			len = max_discard_blocks;
+			last = false;
+		}
+
+		(*issued)++;
+		if (*issued == dpolicy->max_requests)
+			last = true;
+
+		dc->len += len;
+
+		if (time_to_inject(sbi, FAULT_DISCARD)) {
+			f2fs_show_injection_info(sbi, FAULT_DISCARD);
+			err = -EIO;
+		} else {
+			err = __blkdev_issue_discard(bdev,
+					SECTOR_FROM_BLOCK(start),
+					SECTOR_FROM_BLOCK(len),
+					GFP_NOFS, &bio);
+		}
+		if (err) {
+			spin_lock_irqsave(&dc->lock, flags);
+			if (dc->state == D_PARTIAL)
+				dc->state = D_SUBMIT;
+			spin_unlock_irqrestore(&dc->lock, flags);
+
+			break;
+		}
+
+		f2fs_bug_on(sbi, !bio);
+
+		/*
+		 * should keep before submission to avoid D_DONE
+		 * right away
+		 */
+		spin_lock_irqsave(&dc->lock, flags);
+		if (last)
+			dc->state = D_SUBMIT;
+		else
+			dc->state = D_PARTIAL;
+		dc->bio_ref++;
+		spin_unlock_irqrestore(&dc->lock, flags);
+
+		atomic_inc(&dcc->queued_discard);
+		dc->queued++;
+		list_move_tail(&dc->list, wait_list);
+
+		/* sanity check on discard range */
+		__check_sit_bitmap(sbi, lstart, lstart + len);
+
+		bio->bi_private = dc;
+		bio->bi_end_io = f2fs_submit_discard_endio;
+		bio->bi_opf |= flag;
+		submit_bio(bio);
+
+		atomic_inc(&dcc->issued_discard);
+
+		f2fs_update_iostat(sbi, NULL, FS_DISCARD, len * F2FS_BLKSIZE);
+
+		lstart += len;
+		start += len;
+		total_len -= len;
+		len = total_len;
+	}
+
+	if (!err && len) {
+		dcc->undiscard_blks -= len;
+		__update_discard_tree_range(sbi, bdev, lstart, start, len);
+	}
+	return err;
+}
+
+static void __insert_discard_tree(struct f2fs_sb_info *sbi,
+				struct block_device *bdev, block_t lstart,
+				block_t start, block_t len,
+				struct rb_node **insert_p,
+				struct rb_node *insert_parent)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct rb_node **p;
+	struct rb_node *parent = NULL;
+	bool leftmost = true;
+
+	if (insert_p && insert_parent) {
+		parent = insert_parent;
+		p = insert_p;
+		goto do_insert;
+	}
+
+	p = f2fs_lookup_rb_tree_for_insert(sbi, &dcc->root, &parent,
+							lstart, &leftmost);
+do_insert:
+	__attach_discard_cmd(sbi, bdev, lstart, start, len, parent,
+								p, leftmost);
+}
+
+static void __relocate_discard_cmd(struct discard_cmd_control *dcc,
+						struct discard_cmd *dc)
+{
+	list_move_tail(&dc->list, &dcc->pend_list[plist_idx(dc->len)]);
+}
+
+static void __punch_discard_cmd(struct f2fs_sb_info *sbi,
+				struct discard_cmd *dc, block_t blkaddr)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct discard_info di = dc->di;
+	bool modified = false;
+
+	if (dc->state == D_DONE || dc->len == 1) {
+		__remove_discard_cmd(sbi, dc);
+		return;
+	}
+
+	dcc->undiscard_blks -= di.len;
+
+	if (blkaddr > di.lstart) {
+		dc->len = blkaddr - dc->lstart;
+		dcc->undiscard_blks += dc->len;
+		__relocate_discard_cmd(dcc, dc);
+		modified = true;
+	}
+
+	if (blkaddr < di.lstart + di.len - 1) {
+		if (modified) {
+			__insert_discard_tree(sbi, dc->bdev, blkaddr + 1,
+					di.start + blkaddr + 1 - di.lstart,
+					di.lstart + di.len - 1 - blkaddr,
+					NULL, NULL);
+		} else {
+			dc->lstart++;
+			dc->len--;
+			dc->start++;
+			dcc->undiscard_blks += dc->len;
+			__relocate_discard_cmd(dcc, dc);
+		}
+	}
+}
+
+static void __update_discard_tree_range(struct f2fs_sb_info *sbi,
+				struct block_device *bdev, block_t lstart,
+				block_t start, block_t len)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
+	struct discard_cmd *dc;
+	struct discard_info di = {0};
+	struct rb_node **insert_p = NULL, *insert_parent = NULL;
+	unsigned int max_discard_blocks =
+			SECTOR_TO_BLOCK(bdev_max_discard_sectors(bdev));
+	block_t end = lstart + len;
+
+	dc = (struct discard_cmd *)f2fs_lookup_rb_tree_ret(&dcc->root,
+					NULL, lstart,
+					(struct rb_entry **)&prev_dc,
+					(struct rb_entry **)&next_dc,
+					&insert_p, &insert_parent, true, NULL);
+	if (dc)
+		prev_dc = dc;
+
+	if (!prev_dc) {
+		di.lstart = lstart;
+		di.len = next_dc ? next_dc->lstart - lstart : len;
+		di.len = min(di.len, len);
+		di.start = start;
+	}
+
+	while (1) {
+		struct rb_node *node;
+		bool merged = false;
+		struct discard_cmd *tdc = NULL;
+
+		if (prev_dc) {
+			di.lstart = prev_dc->lstart + prev_dc->len;
+			if (di.lstart < lstart)
+				di.lstart = lstart;
+			if (di.lstart >= end)
+				break;
+
+			if (!next_dc || next_dc->lstart > end)
+				di.len = end - di.lstart;
+			else
+				di.len = next_dc->lstart - di.lstart;
+			di.start = start + di.lstart - lstart;
+		}
+
+		if (!di.len)
+			goto next;
+
+		if (prev_dc && prev_dc->state == D_PREP &&
+			prev_dc->bdev == bdev &&
+			__is_discard_back_mergeable(&di, &prev_dc->di,
+							max_discard_blocks)) {
+			prev_dc->di.len += di.len;
+			dcc->undiscard_blks += di.len;
+			__relocate_discard_cmd(dcc, prev_dc);
+			di = prev_dc->di;
+			tdc = prev_dc;
+			merged = true;
+		}
+
+		if (next_dc && next_dc->state == D_PREP &&
+			next_dc->bdev == bdev &&
+			__is_discard_front_mergeable(&di, &next_dc->di,
+							max_discard_blocks)) {
+			next_dc->di.lstart = di.lstart;
+			next_dc->di.len += di.len;
+			next_dc->di.start = di.start;
+			dcc->undiscard_blks += di.len;
+			__relocate_discard_cmd(dcc, next_dc);
+			if (tdc)
+				__remove_discard_cmd(sbi, tdc);
+			merged = true;
+		}
+
+		if (!merged) {
+			__insert_discard_tree(sbi, bdev, di.lstart, di.start,
+							di.len, NULL, NULL);
+		}
+ next:
+		prev_dc = next_dc;
+		if (!prev_dc)
+			break;
+
+		node = rb_next(&prev_dc->rb_node);
+		next_dc = rb_entry_safe(node, struct discard_cmd, rb_node);
+	}
+}
+
+static void __queue_discard_cmd(struct f2fs_sb_info *sbi,
+		struct block_device *bdev, block_t blkstart, block_t blklen)
+{
+	block_t lblkstart = blkstart;
+
+	if (!f2fs_bdev_support_discard(bdev))
+		return;
+
+	trace_f2fs_queue_discard(bdev, blkstart, blklen);
+
+	if (f2fs_is_multi_device(sbi)) {
+		int devi = f2fs_target_device_index(sbi, blkstart);
+
+		blkstart -= FDEV(devi).start_blk;
+	}
+	mutex_lock(&SM_I(sbi)->dcc_info->cmd_lock);
+	__update_discard_tree_range(sbi, bdev, lblkstart, blkstart, blklen);
+	mutex_unlock(&SM_I(sbi)->dcc_info->cmd_lock);
+}
+
+static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
+					struct discard_policy *dpolicy)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
+	struct rb_node **insert_p = NULL, *insert_parent = NULL;
+	struct discard_cmd *dc;
+	struct blk_plug plug;
+	unsigned int pos = dcc->next_pos;
+	unsigned int issued = 0;
+	bool io_interrupted = false;
+
+	mutex_lock(&dcc->cmd_lock);
+	dc = (struct discard_cmd *)f2fs_lookup_rb_tree_ret(&dcc->root,
+					NULL, pos,
+					(struct rb_entry **)&prev_dc,
+					(struct rb_entry **)&next_dc,
+					&insert_p, &insert_parent, true, NULL);
+	if (!dc)
+		dc = next_dc;
+
+	blk_start_plug(&plug);
+
+	while (dc) {
+		struct rb_node *node;
+		int err = 0;
+
+		if (dc->state != D_PREP)
+			goto next;
+
+		if (dpolicy->io_aware && !is_idle(sbi, DISCARD_TIME)) {
+			io_interrupted = true;
+			break;
+		}
+
+		dcc->next_pos = dc->lstart + dc->len;
+		err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
+
+		if (issued >= dpolicy->max_requests)
+			break;
+next:
+		node = rb_next(&dc->rb_node);
+		if (err)
+			__remove_discard_cmd(sbi, dc);
+		dc = rb_entry_safe(node, struct discard_cmd, rb_node);
+	}
+
+	blk_finish_plug(&plug);
+
+	if (!dc)
+		dcc->next_pos = 0;
+
+	mutex_unlock(&dcc->cmd_lock);
+
+	if (!issued && io_interrupted)
+		issued = -1;
+
+	return issued;
+}
+
+static unsigned int __wait_all_discard_cmd(struct f2fs_sb_info *sbi,
+					struct discard_policy *dpolicy);
+
+static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
+					struct discard_policy *dpolicy)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct list_head *pend_list;
+	struct discard_cmd *dc, *tmp;
+	struct blk_plug plug;
+	int i, issued;
+	bool io_interrupted = false;
+
+	if (dpolicy->timeout)
+		f2fs_update_time(sbi, UMOUNT_DISCARD_TIMEOUT);
+
+retry:
+	issued = 0;
+	for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
+		if (dpolicy->timeout &&
+				f2fs_time_over(sbi, UMOUNT_DISCARD_TIMEOUT))
+			break;
+
+		if (i + 1 < dpolicy->granularity)
+			break;
+
+		if (i + 1 < dcc->max_ordered_discard && dpolicy->ordered)
+			return __issue_discard_cmd_orderly(sbi, dpolicy);
+
+		pend_list = &dcc->pend_list[i];
+
+		mutex_lock(&dcc->cmd_lock);
+		if (list_empty(pend_list))
+			goto next;
+		if (unlikely(dcc->rbtree_check))
+			f2fs_bug_on(sbi, !f2fs_check_rb_tree_consistence(sbi,
+							&dcc->root, false));
+		blk_start_plug(&plug);
+		list_for_each_entry_safe(dc, tmp, pend_list, list) {
+			f2fs_bug_on(sbi, dc->state != D_PREP);
+
+			if (dpolicy->timeout &&
+				f2fs_time_over(sbi, UMOUNT_DISCARD_TIMEOUT))
+				break;
+
+			if (dpolicy->io_aware && i < dpolicy->io_aware_gran &&
+						!is_idle(sbi, DISCARD_TIME)) {
+				io_interrupted = true;
+				break;
+			}
+
+			__submit_discard_cmd(sbi, dpolicy, dc, &issued);
+
+			if (issued >= dpolicy->max_requests)
+				break;
+		}
+		blk_finish_plug(&plug);
+next:
+		mutex_unlock(&dcc->cmd_lock);
+
+		if (issued >= dpolicy->max_requests || io_interrupted)
+			break;
+	}
+
+	if (dpolicy->type == DPOLICY_UMOUNT && issued) {
+		__wait_all_discard_cmd(sbi, dpolicy);
+		goto retry;
+	}
+
+	if (!issued && io_interrupted)
+		issued = -1;
+
+	return issued;
+}
+
+static bool __drop_discard_cmd(struct f2fs_sb_info *sbi)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct list_head *pend_list;
+	struct discard_cmd *dc, *tmp;
+	int i;
+	bool dropped = false;
+
+	mutex_lock(&dcc->cmd_lock);
+	for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
+		pend_list = &dcc->pend_list[i];
+		list_for_each_entry_safe(dc, tmp, pend_list, list) {
+			f2fs_bug_on(sbi, dc->state != D_PREP);
+			__remove_discard_cmd(sbi, dc);
+			dropped = true;
+		}
+	}
+	mutex_unlock(&dcc->cmd_lock);
+
+	return dropped;
+}
+
+void f2fs_drop_discard_cmd(struct f2fs_sb_info *sbi)
+{
+	__drop_discard_cmd(sbi);
+}
+
+static unsigned int __wait_one_discard_bio(struct f2fs_sb_info *sbi,
+							struct discard_cmd *dc)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	unsigned int len = 0;
+
+	wait_for_completion_io(&dc->wait);
+	mutex_lock(&dcc->cmd_lock);
+	f2fs_bug_on(sbi, dc->state != D_DONE);
+	dc->ref--;
+	if (!dc->ref) {
+		if (!dc->error)
+			len = dc->len;
+		__remove_discard_cmd(sbi, dc);
+	}
+	mutex_unlock(&dcc->cmd_lock);
+
+	return len;
+}
+
+static unsigned int __wait_discard_cmd_range(struct f2fs_sb_info *sbi,
+						struct discard_policy *dpolicy,
+						block_t start, block_t end)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
+					&(dcc->fstrim_list) : &(dcc->wait_list);
+	struct discard_cmd *dc = NULL, *iter, *tmp;
+	unsigned int trimmed = 0;
+
+next:
+	dc = NULL;
+
+	mutex_lock(&dcc->cmd_lock);
+	list_for_each_entry_safe(iter, tmp, wait_list, list) {
+		if (iter->lstart + iter->len <= start || end <= iter->lstart)
+			continue;
+		if (iter->len < dpolicy->granularity)
+			continue;
+		if (iter->state == D_DONE && !iter->ref) {
+			wait_for_completion_io(&iter->wait);
+			if (!iter->error)
+				trimmed += iter->len;
+			__remove_discard_cmd(sbi, iter);
+		} else {
+			iter->ref++;
+			dc = iter;
+			break;
+		}
+	}
+	mutex_unlock(&dcc->cmd_lock);
+
+	if (dc) {
+		trimmed += __wait_one_discard_bio(sbi, dc);
+		goto next;
+	}
+
+	return trimmed;
+}
+
+static unsigned int __wait_all_discard_cmd(struct f2fs_sb_info *sbi,
+						struct discard_policy *dpolicy)
+{
+	struct discard_policy dp;
+	unsigned int discard_blks;
+
+	if (dpolicy)
+		return __wait_discard_cmd_range(sbi, dpolicy, 0, UINT_MAX);
+
+	/* wait all */
+	__init_discard_policy(sbi, &dp, DPOLICY_FSTRIM, 1);
+	discard_blks = __wait_discard_cmd_range(sbi, &dp, 0, UINT_MAX);
+	__init_discard_policy(sbi, &dp, DPOLICY_UMOUNT, 1);
+	discard_blks += __wait_discard_cmd_range(sbi, &dp, 0, UINT_MAX);
+
+	return discard_blks;
+}
+
+/* This should be covered by global mutex, &sit_i->sentry_lock */
+void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct discard_cmd *dc;
+	bool need_wait = false;
+
+	mutex_lock(&dcc->cmd_lock);
+	dc = (struct discard_cmd *)f2fs_lookup_rb_tree(&dcc->root,
+							NULL, blkaddr);
+	if (dc) {
+		if (dc->state == D_PREP) {
+			__punch_discard_cmd(sbi, dc, blkaddr);
+		} else {
+			dc->ref++;
+			need_wait = true;
+		}
+	}
+	mutex_unlock(&dcc->cmd_lock);
+
+	if (need_wait)
+		__wait_one_discard_bio(sbi, dc);
+}
+
+void f2fs_stop_discard_thread(struct f2fs_sb_info *sbi)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+
+	if (dcc && dcc->f2fs_issue_discard) {
+		struct task_struct *discard_thread = dcc->f2fs_issue_discard;
+
+		dcc->f2fs_issue_discard = NULL;
+		kthread_stop(discard_thread);
+	}
+}
+
+/* This comes from f2fs_put_super */
+bool f2fs_issue_discard_timeout(struct f2fs_sb_info *sbi)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct discard_policy dpolicy;
+	bool dropped;
+
+	if (!atomic_read(&dcc->discard_cmd_cnt))
+		return false;
+
+	__init_discard_policy(sbi, &dpolicy, DPOLICY_UMOUNT,
+					dcc->discard_granularity);
+	__issue_discard_cmd(sbi, &dpolicy);
+	dropped = __drop_discard_cmd(sbi);
+
+	/* just to make sure there is no pending discard commands */
+	__wait_all_discard_cmd(sbi, NULL);
+
+	f2fs_bug_on(sbi, atomic_read(&dcc->discard_cmd_cnt));
+	return dropped;
+}
+
+static int issue_discard_thread(void *data)
+{
+	struct f2fs_sb_info *sbi = data;
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	wait_queue_head_t *q = &dcc->discard_wait_queue;
+	struct discard_policy dpolicy;
+	unsigned int wait_ms = dcc->min_discard_issue_time;
+	int issued;
+
+	set_freezable();
+
+	do {
+		wait_event_interruptible_timeout(*q,
+				kthread_should_stop() || freezing(current) ||
+				dcc->discard_wake,
+				msecs_to_jiffies(wait_ms));
+
+		if (sbi->gc_mode == GC_URGENT_HIGH ||
+			!f2fs_available_free_memory(sbi, DISCARD_CACHE))
+			__init_discard_policy(sbi, &dpolicy, DPOLICY_FORCE, 1);
+		else
+			__init_discard_policy(sbi, &dpolicy, DPOLICY_BG,
+						dcc->discard_granularity);
+
+		if (dcc->discard_wake)
+			dcc->discard_wake = 0;
+
+		/* clean up pending candidates before going to sleep */
+		if (atomic_read(&dcc->queued_discard))
+			__wait_all_discard_cmd(sbi, NULL);
+
+		if (try_to_freeze())
+			continue;
+		if (f2fs_readonly(sbi->sb))
+			continue;
+		if (kthread_should_stop())
+			return 0;
+		if (is_sbi_flag_set(sbi, SBI_NEED_FSCK) ||
+			!atomic_read(&dcc->discard_cmd_cnt)) {
+			wait_ms = dpolicy.max_interval;
+			continue;
+		}
+
+		sb_start_intwrite(sbi->sb);
+
+		issued = __issue_discard_cmd(sbi, &dpolicy);
+		if (issued > 0) {
+			__wait_all_discard_cmd(sbi, &dpolicy);
+			wait_ms = dpolicy.min_interval;
+		} else if (issued == -1) {
+			wait_ms = f2fs_time_to_wait(sbi, DISCARD_TIME);
+			if (!wait_ms)
+				wait_ms = dpolicy.mid_interval;
+		} else {
+			wait_ms = dpolicy.max_interval;
+		}
+		if (!atomic_read(&dcc->discard_cmd_cnt))
+			wait_ms = dpolicy.max_interval;
+
+		sb_end_intwrite(sbi->sb);
+
+	} while (!kthread_should_stop());
+	return 0;
+}
+
+int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
+					struct block_device *bdev, block_t blkstart, block_t blklen)
+{
+#ifdef CONFIG_BLK_DEV_ZONED
+	sector_t sector, nr_sects;
+	block_t lblkstart = blkstart;
+	int devi = 0;
+
+	if (f2fs_is_multi_device(sbi)) {
+		devi = f2fs_target_device_index(sbi, blkstart);
+		if (blkstart < FDEV(devi).start_blk ||
+		    blkstart > FDEV(devi).end_blk) {
+			f2fs_err(sbi, "Invalid block %x", blkstart);
+			return -EIO;
+		}
+		blkstart -= FDEV(devi).start_blk;
+	}
+
+	/* For sequential zones, reset the zone write pointer */
+	if (f2fs_blkz_is_seq(sbi, devi, blkstart)) {
+		sector = SECTOR_FROM_BLOCK(blkstart);
+		nr_sects = SECTOR_FROM_BLOCK(blklen);
+
+		if (sector & (bdev_zone_sectors(bdev) - 1) ||
+				nr_sects != bdev_zone_sectors(bdev)) {
+			f2fs_err(sbi, "(%d) %s: Unaligned zone reset attempted (block %x + %x)",
+				 devi, sbi->s_ndevs ? FDEV(devi).path : "",
+				 blkstart, blklen);
+			return -EIO;
+		}
+		trace_f2fs_issue_reset_zone(bdev, blkstart);
+		return blkdev_zone_mgmt(bdev, REQ_OP_ZONE_RESET,
+					sector, nr_sects, GFP_NOFS);
+	}
+
+	/* For conventional zones, use regular discard if supported */
+	__queue_discard_cmd(sbi, bdev, lblkstart, blklen);
+#endif
+	return 0;
+}
+
+static int __issue_discard_async(struct f2fs_sb_info *sbi,
+		struct block_device *bdev, block_t blkstart, block_t blklen)
+{
+#ifdef CONFIG_BLK_DEV_ZONED
+	if (f2fs_sb_has_blkzoned(sbi) && bdev_is_zoned(bdev))
+		return __f2fs_issue_discard_zone(sbi, bdev, blkstart, blklen);
+#endif
+	__queue_discard_cmd(sbi, bdev, blkstart, blklen);
+	return 0;
+}
+
+int f2fs_issue_discard(struct f2fs_sb_info *sbi,
+						block_t blkstart, block_t blklen)
+{
+	sector_t start = blkstart, len = 0;
+	struct block_device *bdev;
+	struct seg_entry *se;
+	unsigned int offset;
+	block_t i;
+	int err = 0;
+
+	bdev = f2fs_target_device(sbi, blkstart, NULL);
+
+	for (i = blkstart; i < blkstart + blklen; i++, len++) {
+		if (i != start) {
+			struct block_device *bdev2 =
+				f2fs_target_device(sbi, i, NULL);
+
+			if (bdev2 != bdev) {
+				err = __issue_discard_async(sbi, bdev,
+						start, len);
+				if (err)
+					return err;
+				bdev = bdev2;
+				start = i;
+				len = 0;
+			}
+		}
+
+		se = get_seg_entry(sbi, GET_SEGNO(sbi, i));
+		offset = GET_BLKOFF_FROM_SEG0(sbi, i);
+
+		if (f2fs_block_unit_discard(sbi) &&
+				!f2fs_test_and_set_bit(offset, se->discard_map))
+			sbi->discard_blks--;
+	}
+
+	if (len)
+		err = __issue_discard_async(sbi, bdev, start, len);
+	return err;
+}
+
+bool add_discard_addrs(struct f2fs_sb_info *sbi, struct cp_control *cpc,
+						bool check_only)
+{
+	int entries = SIT_VBLOCK_MAP_SIZE / sizeof(unsigned long);
+	int max_blocks = sbi->blocks_per_seg;
+	struct seg_entry *se = get_seg_entry(sbi, cpc->trim_start);
+	unsigned long *cur_map = (unsigned long *)se->cur_valid_map;
+	unsigned long *ckpt_map = (unsigned long *)se->ckpt_valid_map;
+	unsigned long *discard_map = (unsigned long *)se->discard_map;
+	unsigned long *dmap = SIT_I(sbi)->tmp_map;
+	unsigned int start = 0, end = -1;
+	bool force = (cpc->reason & CP_DISCARD);
+	struct discard_entry *de = NULL;
+	struct list_head *head = &SM_I(sbi)->dcc_info->entry_list;
+	int i;
+
+	if (se->valid_blocks == max_blocks || !f2fs_hw_support_discard(sbi) ||
+			!f2fs_block_unit_discard(sbi))
+		return false;
+
+	if (!force) {
+		if (!f2fs_realtime_discard_enable(sbi) || !se->valid_blocks ||
+			SM_I(sbi)->dcc_info->nr_discards >=
+				SM_I(sbi)->dcc_info->max_discards)
+			return false;
+	}
+
+	/* SIT_VBLOCK_MAP_SIZE should be multiple of sizeof(unsigned long) */
+	for (i = 0; i < entries; i++)
+		dmap[i] = force ? ~ckpt_map[i] & ~discard_map[i] :
+				(cur_map[i] ^ ckpt_map[i]) & ckpt_map[i];
+
+	while (force || SM_I(sbi)->dcc_info->nr_discards <=
+				SM_I(sbi)->dcc_info->max_discards) {
+		start = __find_rev_next_bit(dmap, max_blocks, end + 1);
+		if (start >= max_blocks)
+			break;
+
+		end = __find_rev_next_zero_bit(dmap, max_blocks, start + 1);
+		if (force && start && end != max_blocks
+					&& (end - start) < cpc->trim_minlen)
+			continue;
+
+		if (check_only)
+			return true;
+
+		if (!de) {
+			de = f2fs_kmem_cache_alloc(discard_entry_slab,
+						GFP_F2FS_ZERO, true, NULL);
+			de->start_blkaddr = START_BLOCK(sbi, cpc->trim_start);
+			list_add_tail(&de->list, head);
+		}
+
+		for (i = start; i < end; i++)
+			__set_bit_le(i, (void *)de->discard_map);
+
+		SM_I(sbi)->dcc_info->nr_discards += end - start;
+	}
+	return false;
+}
+
+void release_discard_addr(struct discard_entry *entry)
+{
+	list_del(&entry->list);
+	kmem_cache_free(discard_entry_slab, entry);
+}
+
+void f2fs_release_discard_addrs(struct f2fs_sb_info *sbi)
+{
+	struct list_head *head = &(SM_I(sbi)->dcc_info->entry_list);
+	struct discard_entry *entry, *this;
+
+	/* drop caches */
+	list_for_each_entry_safe(entry, this, head, list)
+		release_discard_addr(entry);
+}
+
+int f2fs_start_discard_thread(struct f2fs_sb_info *sbi)
+{
+	dev_t dev = sbi->sb->s_bdev->bd_dev;
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	int err = 0;
+
+	if (!f2fs_realtime_discard_enable(sbi))
+		return 0;
+
+	dcc->f2fs_issue_discard = kthread_run(issue_discard_thread, sbi,
+				"f2fs_discard-%u:%u", MAJOR(dev), MINOR(dev));
+	if (IS_ERR(dcc->f2fs_issue_discard)) {
+		err = PTR_ERR(dcc->f2fs_issue_discard);
+		dcc->f2fs_issue_discard = NULL;
+	}
+
+	return err;
+}
+
+int create_discard_cmd_control(struct f2fs_sb_info *sbi)
+{
+	struct discard_cmd_control *dcc;
+	int err = 0, i;
+
+	if (SM_I(sbi)->dcc_info) {
+		dcc = SM_I(sbi)->dcc_info;
+		goto init_thread;
+	}
+
+	dcc = f2fs_kzalloc(sbi, sizeof(struct discard_cmd_control), GFP_KERNEL);
+	if (!dcc)
+		return -ENOMEM;
+
+	dcc->discard_granularity = DEFAULT_DISCARD_GRANULARITY;
+	dcc->max_ordered_discard = DEFAULT_MAX_ORDERED_DISCARD_GRANULARITY;
+	if (F2FS_OPTION(sbi).discard_unit == DISCARD_UNIT_SEGMENT)
+		dcc->discard_granularity = sbi->blocks_per_seg;
+	else if (F2FS_OPTION(sbi).discard_unit == DISCARD_UNIT_SECTION)
+		dcc->discard_granularity = BLKS_PER_SEC(sbi);
+
+	INIT_LIST_HEAD(&dcc->entry_list);
+	for (i = 0; i < MAX_PLIST_NUM; i++)
+		INIT_LIST_HEAD(&dcc->pend_list[i]);
+	INIT_LIST_HEAD(&dcc->wait_list);
+	INIT_LIST_HEAD(&dcc->fstrim_list);
+	mutex_init(&dcc->cmd_lock);
+	atomic_set(&dcc->issued_discard, 0);
+	atomic_set(&dcc->queued_discard, 0);
+	atomic_set(&dcc->discard_cmd_cnt, 0);
+	dcc->nr_discards = 0;
+	dcc->max_discards = MAIN_SEGS(sbi) << sbi->log_blocks_per_seg;
+	dcc->max_discard_request = DEF_MAX_DISCARD_REQUEST;
+	dcc->min_discard_issue_time = DEF_MIN_DISCARD_ISSUE_TIME;
+	dcc->mid_discard_issue_time = DEF_MID_DISCARD_ISSUE_TIME;
+	dcc->max_discard_issue_time = DEF_MAX_DISCARD_ISSUE_TIME;
+	dcc->discard_urgent_util = DEF_DISCARD_URGENT_UTIL;
+	dcc->undiscard_blks = 0;
+	dcc->next_pos = 0;
+	dcc->root = RB_ROOT_CACHED;
+	dcc->rbtree_check = false;
+
+	init_waitqueue_head(&dcc->discard_wait_queue);
+	SM_I(sbi)->dcc_info = dcc;
+init_thread:
+	err = f2fs_start_discard_thread(sbi);
+	if (err) {
+		kfree(dcc);
+		SM_I(sbi)->dcc_info = NULL;
+	}
+
+	return err;
+}
+
+void destroy_discard_cmd_control(struct f2fs_sb_info *sbi)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+
+	if (!dcc)
+		return;
+
+	f2fs_stop_discard_thread(sbi);
+
+	/*
+	 * Recovery can cache discard commands, so in error path of
+	 * fill_super(), it needs to give a chance to handle them.
+	 */
+	f2fs_issue_discard_timeout(sbi);
+
+	kfree(dcc);
+	SM_I(sbi)->dcc_info = NULL;
+}
+
+bool f2fs_exist_trim_candidates(struct f2fs_sb_info *sbi,
+						struct cp_control *cpc)
+{
+	__u64 trim_start = cpc->trim_start;
+	bool has_candidate = false;
+
+	down_write(&SIT_I(sbi)->sentry_lock);
+	for (; cpc->trim_start <= cpc->trim_end; cpc->trim_start++) {
+		if (add_discard_addrs(sbi, cpc, true)) {
+			has_candidate = true;
+			break;
+		}
+	}
+	up_write(&SIT_I(sbi)->sentry_lock);
+
+	cpc->trim_start = trim_start;
+	return has_candidate;
+}
+
+static unsigned int __issue_discard_cmd_range(struct f2fs_sb_info *sbi,
+					struct discard_policy *dpolicy,
+					unsigned int start, unsigned int end)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
+	struct rb_node **insert_p = NULL, *insert_parent = NULL;
+	struct discard_cmd *dc;
+	struct blk_plug plug;
+	int issued;
+	unsigned int trimmed = 0;
+
+next:
+	issued = 0;
+
+	mutex_lock(&dcc->cmd_lock);
+	if (unlikely(dcc->rbtree_check))
+		f2fs_bug_on(sbi, !f2fs_check_rb_tree_consistence(sbi,
+							&dcc->root, false));
+
+	dc = (struct discard_cmd *)f2fs_lookup_rb_tree_ret(&dcc->root,
+					NULL, start,
+					(struct rb_entry **)&prev_dc,
+					(struct rb_entry **)&next_dc,
+					&insert_p, &insert_parent, true, NULL);
+	if (!dc)
+		dc = next_dc;
+
+	blk_start_plug(&plug);
+
+	while (dc && dc->lstart <= end) {
+		struct rb_node *node;
+		int err = 0;
+
+		if (dc->len < dpolicy->granularity)
+			goto skip;
+
+		if (dc->state != D_PREP) {
+			list_move_tail(&dc->list, &dcc->fstrim_list);
+			goto skip;
+		}
+
+		err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
+
+		if (issued >= dpolicy->max_requests) {
+			start = dc->lstart + dc->len;
+
+			if (err)
+				__remove_discard_cmd(sbi, dc);
+
+			blk_finish_plug(&plug);
+			mutex_unlock(&dcc->cmd_lock);
+			trimmed += __wait_all_discard_cmd(sbi, NULL);
+			f2fs_io_schedule_timeout(DEFAULT_IO_TIMEOUT);
+			goto next;
+		}
+skip:
+		node = rb_next(&dc->rb_node);
+		if (err)
+			__remove_discard_cmd(sbi, dc);
+		dc = rb_entry_safe(node, struct discard_cmd, rb_node);
+
+		if (fatal_signal_pending(current))
+			break;
+	}
+
+	blk_finish_plug(&plug);
+	mutex_unlock(&dcc->cmd_lock);
+
+	return trimmed;
+}
+
+int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
+{
+	__u64 start = F2FS_BYTES_TO_BLK(range->start);
+	__u64 end = start + F2FS_BYTES_TO_BLK(range->len) - 1;
+	unsigned int start_segno, end_segno;
+	block_t start_block, end_block;
+	struct cp_control cpc;
+	struct discard_policy dpolicy;
+	unsigned long long trimmed = 0;
+	int err = 0;
+	bool need_align = f2fs_lfs_mode(sbi) && __is_large_section(sbi);
+
+	if (start >= MAX_BLKADDR(sbi) || range->len < sbi->blocksize)
+		return -EINVAL;
+
+	if (end < MAIN_BLKADDR(sbi))
+		goto out;
+
+	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
+		f2fs_warn(sbi, "Found FS corruption, run fsck to fix.");
+		return -EFSCORRUPTED;
+	}
+
+	/* start/end segment number in main_area */
+	start_segno = (start <= MAIN_BLKADDR(sbi)) ? 0 : GET_SEGNO(sbi, start);
+	end_segno = (end >= MAX_BLKADDR(sbi)) ? MAIN_SEGS(sbi) - 1 :
+						GET_SEGNO(sbi, end);
+	if (need_align) {
+		start_segno = rounddown(start_segno, sbi->segs_per_sec);
+		end_segno = roundup(end_segno + 1, sbi->segs_per_sec) - 1;
+	}
+
+	cpc.reason = CP_DISCARD;
+	cpc.trim_minlen = max_t(__u64, 1, F2FS_BYTES_TO_BLK(range->minlen));
+	cpc.trim_start = start_segno;
+	cpc.trim_end = end_segno;
+
+	if (sbi->discard_blks == 0)
+		goto out;
+
+	f2fs_down_write(&sbi->gc_lock);
+	err = f2fs_write_checkpoint(sbi, &cpc);
+	f2fs_up_write(&sbi->gc_lock);
+	if (err)
+		goto out;
+
+	/*
+	 * We filed discard candidates, but actually we don't need to wait for
+	 * all of them, since they'll be issued in idle time along with runtime
+	 * discard option. User configuration looks like using runtime discard
+	 * or periodic fstrim instead of it.
+	 */
+	if (f2fs_realtime_discard_enable(sbi))
+		goto out;
+
+	start_block = START_BLOCK(sbi, start_segno);
+	end_block = START_BLOCK(sbi, end_segno + 1);
+
+	__init_discard_policy(sbi, &dpolicy, DPOLICY_FSTRIM, cpc.trim_minlen);
+	trimmed = __issue_discard_cmd_range(sbi, &dpolicy,
+					start_block, end_block);
+
+	trimmed += __wait_discard_cmd_range(sbi, &dpolicy,
+					start_block, end_block);
+out:
+	if (!err)
+		range->len = F2FS_BLK_TO_BYTES(trimmed);
+	return err;
+}
+
+int __init f2fs_create_discard_caches(void)
+{
+	discard_entry_slab = f2fs_kmem_cache_create("f2fs_discard_entry",
+			sizeof(struct discard_entry));
+	if (!discard_entry_slab)
+		return -ENOMEM;
+
+	discard_cmd_slab = f2fs_kmem_cache_create("f2fs_discard_cmd",
+		sizeof(struct discard_cmd));
+	if (!discard_cmd_slab)
+		goto destroy_discard_entry;
+	return 0;
+
+destroy_discard_entry:
+	kmem_cache_destroy(discard_entry_slab);
+	return -ENOMEM;
+}
+
+void f2fs_destroy_discard_caches(void)
+{
+	kmem_cache_destroy(discard_cmd_slab);
+	kmem_cache_destroy(discard_entry_slab);
+}
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 4035dab1f570..1df9dd9bb400 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3638,9 +3638,38 @@ void f2fs_destroy_node_manager(struct f2fs_sb_info *sbi);
 int __init f2fs_create_node_manager_caches(void);
 void f2fs_destroy_node_manager_caches(void);
 
+/*
+ * discard.c
+ */
+int f2fs_issue_discard(struct f2fs_sb_info *sbi,
+					block_t blkstart, block_t blklen);
+bool f2fs_issue_discard_timeout(struct f2fs_sb_info *sbi);
+void f2fs_drop_discard_cmd(struct f2fs_sb_info *sbi);
+int create_discard_cmd_control(struct f2fs_sb_info *sbi);
+void destroy_discard_cmd_control(struct f2fs_sb_info *sbi);
+int f2fs_start_discard_thread(struct f2fs_sb_info *sbi);
+void f2fs_stop_discard_thread(struct f2fs_sb_info *sbi);
+int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range);
+bool f2fs_exist_trim_candidates(struct f2fs_sb_info *sbi,
+					struct cp_control *cpc);
+void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr);
+bool add_discard_addrs(struct f2fs_sb_info *sbi, struct cp_control *cpc,
+					bool check_only);
+void release_discard_addr(struct discard_entry *entry);
+void f2fs_release_discard_addrs(struct f2fs_sb_info *sbi);
+int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
+			struct block_device *bdev, block_t blkstart, block_t blklen);
+int __init f2fs_create_discard_caches(void);
+void f2fs_destroy_discard_caches(void);
+
 /*
  * segment.c
  */
+void __check_sit_bitmap(struct f2fs_sb_info *sbi, block_t start, block_t end);
+unsigned long __find_rev_next_bit(const unsigned long *addr,
+			unsigned long size, unsigned long offset);
+unsigned long __find_rev_next_zero_bit(const unsigned long *addr,
+			unsigned long size, unsigned long offset);
 bool f2fs_need_SSR(struct f2fs_sb_info *sbi);
 int f2fs_commit_atomic_write(struct inode *inode);
 void f2fs_abort_atomic_write(struct inode *inode, bool clean);
@@ -3652,16 +3681,11 @@ int f2fs_flush_device_cache(struct f2fs_sb_info *sbi);
 void f2fs_destroy_flush_cmd_control(struct f2fs_sb_info *sbi, bool free);
 void f2fs_invalidate_blocks(struct f2fs_sb_info *sbi, block_t addr);
 bool f2fs_is_checkpointed_data(struct f2fs_sb_info *sbi, block_t blkaddr);
-int f2fs_start_discard_thread(struct f2fs_sb_info *sbi);
-void f2fs_drop_discard_cmd(struct f2fs_sb_info *sbi);
-void f2fs_stop_discard_thread(struct f2fs_sb_info *sbi);
-bool f2fs_issue_discard_timeout(struct f2fs_sb_info *sbi);
 void f2fs_clear_prefree_segments(struct f2fs_sb_info *sbi,
 					struct cp_control *cpc);
 void f2fs_dirty_to_prefree(struct f2fs_sb_info *sbi);
 block_t f2fs_get_unusable_blocks(struct f2fs_sb_info *sbi);
 int f2fs_disable_cp_again(struct f2fs_sb_info *sbi, block_t unusable);
-void f2fs_release_discard_addrs(struct f2fs_sb_info *sbi);
 int f2fs_npages_for_summary_flush(struct f2fs_sb_info *sbi, bool for_ra);
 bool f2fs_segment_has_free_slot(struct f2fs_sb_info *sbi, int segno);
 void f2fs_init_inmem_curseg(struct f2fs_sb_info *sbi);
@@ -3673,9 +3697,6 @@ void f2fs_allocate_segment_for_resize(struct f2fs_sb_info *sbi, int type,
 					unsigned int start, unsigned int end);
 void f2fs_allocate_new_section(struct f2fs_sb_info *sbi, int type, bool force);
 void f2fs_allocate_new_segments(struct f2fs_sb_info *sbi);
-int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range);
-bool f2fs_exist_trim_candidates(struct f2fs_sb_info *sbi,
-					struct cp_control *cpc);
 struct page *f2fs_get_sum_page(struct f2fs_sb_info *sbi, unsigned int segno);
 void f2fs_update_meta_page(struct f2fs_sb_info *sbi, void *src,
 					block_t blk_addr);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 25ddea478fc1..b1b4d8e21365 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -27,8 +27,6 @@
 
 #define __reverse_ffz(x) __reverse_ffs(~(x))
 
-static struct kmem_cache *discard_entry_slab;
-static struct kmem_cache *discard_cmd_slab;
 static struct kmem_cache *sit_entry_set_slab;
 static struct kmem_cache *revoke_entry_slab;
 
@@ -95,8 +93,8 @@ static inline unsigned long __reverse_ffs(unsigned long word)
  *   f2fs_set_bit(0, bitmap) => 1000 0000
  *   f2fs_set_bit(7, bitmap) => 0000 0001
  */
-static unsigned long __find_rev_next_bit(const unsigned long *addr,
-			unsigned long size, unsigned long offset)
+unsigned long __find_rev_next_bit(const unsigned long *addr,
+				unsigned long size, unsigned long offset)
 {
 	const unsigned long *p = addr + BIT_WORD(offset);
 	unsigned long result = size;
@@ -131,8 +129,8 @@ static unsigned long __find_rev_next_bit(const unsigned long *addr,
 	return result - size + __reverse_ffs(tmp);
 }
 
-static unsigned long __find_rev_next_zero_bit(const unsigned long *addr,
-			unsigned long size, unsigned long offset)
+unsigned long __find_rev_next_zero_bit(const unsigned long *addr,
+					unsigned long size, unsigned long offset)
 {
 	const unsigned long *p = addr + BIT_WORD(offset);
 	unsigned long result = size;
@@ -911,117 +909,7 @@ static unsigned int get_free_segment(struct f2fs_sb_info *sbi)
 	return NULL_SEGNO;
 }
 
-static struct discard_cmd *__create_discard_cmd(struct f2fs_sb_info *sbi,
-		struct block_device *bdev, block_t lstart,
-		block_t start, block_t len)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	struct list_head *pend_list;
-	struct discard_cmd *dc;
-
-	f2fs_bug_on(sbi, !len);
-
-	pend_list = &dcc->pend_list[plist_idx(len)];
-
-	dc = f2fs_kmem_cache_alloc(discard_cmd_slab, GFP_NOFS, true, NULL);
-	INIT_LIST_HEAD(&dc->list);
-	dc->bdev = bdev;
-	dc->lstart = lstart;
-	dc->start = start;
-	dc->len = len;
-	dc->ref = 0;
-	dc->state = D_PREP;
-	dc->queued = 0;
-	dc->error = 0;
-	init_completion(&dc->wait);
-	list_add_tail(&dc->list, pend_list);
-	spin_lock_init(&dc->lock);
-	dc->bio_ref = 0;
-	atomic_inc(&dcc->discard_cmd_cnt);
-	dcc->undiscard_blks += len;
-
-	return dc;
-}
-
-static struct discard_cmd *__attach_discard_cmd(struct f2fs_sb_info *sbi,
-				struct block_device *bdev, block_t lstart,
-				block_t start, block_t len,
-				struct rb_node *parent, struct rb_node **p,
-				bool leftmost)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	struct discard_cmd *dc;
-
-	dc = __create_discard_cmd(sbi, bdev, lstart, start, len);
-
-	rb_link_node(&dc->rb_node, parent, p);
-	rb_insert_color_cached(&dc->rb_node, &dcc->root, leftmost);
-
-	return dc;
-}
-
-static void __detach_discard_cmd(struct discard_cmd_control *dcc,
-							struct discard_cmd *dc)
-{
-	if (dc->state == D_DONE)
-		atomic_sub(dc->queued, &dcc->queued_discard);
-
-	list_del(&dc->list);
-	rb_erase_cached(&dc->rb_node, &dcc->root);
-	dcc->undiscard_blks -= dc->len;
-
-	kmem_cache_free(discard_cmd_slab, dc);
-
-	atomic_dec(&dcc->discard_cmd_cnt);
-}
-
-static void __remove_discard_cmd(struct f2fs_sb_info *sbi,
-							struct discard_cmd *dc)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	unsigned long flags;
-
-	trace_f2fs_remove_discard(dc->bdev, dc->start, dc->len);
-
-	spin_lock_irqsave(&dc->lock, flags);
-	if (dc->bio_ref) {
-		spin_unlock_irqrestore(&dc->lock, flags);
-		return;
-	}
-	spin_unlock_irqrestore(&dc->lock, flags);
-
-	f2fs_bug_on(sbi, dc->ref);
-
-	if (dc->error == -EOPNOTSUPP)
-		dc->error = 0;
-
-	if (dc->error)
-		printk_ratelimited(
-			"%sF2FS-fs (%s): Issue discard(%u, %u, %u) failed, ret: %d",
-			KERN_INFO, sbi->sb->s_id,
-			dc->lstart, dc->start, dc->len, dc->error);
-	__detach_discard_cmd(dcc, dc);
-}
-
-static void f2fs_submit_discard_endio(struct bio *bio)
-{
-	struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
-	unsigned long flags;
-
-	spin_lock_irqsave(&dc->lock, flags);
-	if (!dc->error)
-		dc->error = blk_status_to_errno(bio->bi_status);
-	dc->bio_ref--;
-	if (!dc->bio_ref && dc->state == D_SUBMIT) {
-		dc->state = D_DONE;
-		complete_all(&dc->wait);
-	}
-	spin_unlock_irqrestore(&dc->lock, flags);
-	bio_put(bio);
-}
-
-static void __check_sit_bitmap(struct f2fs_sb_info *sbi,
-				block_t start, block_t end)
+void __check_sit_bitmap(struct f2fs_sb_info *sbi, block_t start, block_t end)
 {
 #ifdef CONFIG_F2FS_CHECK_FS
 	struct seg_entry *sentry;
@@ -1047,870 +935,6 @@ static void __check_sit_bitmap(struct f2fs_sb_info *sbi,
 #endif
 }
 
-static void __init_discard_policy(struct f2fs_sb_info *sbi,
-				struct discard_policy *dpolicy,
-				int discard_type, unsigned int granularity)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-
-	/* common policy */
-	dpolicy->type = discard_type;
-	dpolicy->sync = true;
-	dpolicy->ordered = false;
-	dpolicy->granularity = granularity;
-
-	dpolicy->max_requests = dcc->max_discard_request;
-	dpolicy->io_aware_gran = MAX_PLIST_NUM;
-	dpolicy->timeout = false;
-
-	if (discard_type == DPOLICY_BG) {
-		dpolicy->min_interval = dcc->min_discard_issue_time;
-		dpolicy->mid_interval = dcc->mid_discard_issue_time;
-		dpolicy->max_interval = dcc->max_discard_issue_time;
-		dpolicy->io_aware = true;
-		dpolicy->sync = false;
-		dpolicy->ordered = true;
-		if (utilization(sbi) > dcc->discard_urgent_util) {
-			dpolicy->granularity = MIN_DISCARD_GRANULARITY;
-			if (atomic_read(&dcc->discard_cmd_cnt))
-				dpolicy->max_interval =
-					dcc->min_discard_issue_time;
-		}
-	} else if (discard_type == DPOLICY_FORCE) {
-		dpolicy->min_interval = dcc->min_discard_issue_time;
-		dpolicy->mid_interval = dcc->mid_discard_issue_time;
-		dpolicy->max_interval = dcc->max_discard_issue_time;
-		dpolicy->io_aware = false;
-	} else if (discard_type == DPOLICY_FSTRIM) {
-		dpolicy->io_aware = false;
-	} else if (discard_type == DPOLICY_UMOUNT) {
-		dpolicy->io_aware = false;
-		/* we need to issue all to keep CP_TRIMMED_FLAG */
-		dpolicy->granularity = MIN_DISCARD_GRANULARITY;
-		dpolicy->timeout = true;
-	}
-}
-
-static void __update_discard_tree_range(struct f2fs_sb_info *sbi,
-				struct block_device *bdev, block_t lstart,
-				block_t start, block_t len);
-/* this function is copied from blkdev_issue_discard from block/blk-lib.c */
-static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
-						struct discard_policy *dpolicy,
-						struct discard_cmd *dc,
-						unsigned int *issued)
-{
-	struct block_device *bdev = dc->bdev;
-	unsigned int max_discard_blocks =
-			SECTOR_TO_BLOCK(bdev_max_discard_sectors(bdev));
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
-					&(dcc->fstrim_list) : &(dcc->wait_list);
-	blk_opf_t flag = dpolicy->sync ? REQ_SYNC : 0;
-	block_t lstart, start, len, total_len;
-	int err = 0;
-
-	if (dc->state != D_PREP)
-		return 0;
-
-	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK))
-		return 0;
-
-	trace_f2fs_issue_discard(bdev, dc->start, dc->len);
-
-	lstart = dc->lstart;
-	start = dc->start;
-	len = dc->len;
-	total_len = len;
-
-	dc->len = 0;
-
-	while (total_len && *issued < dpolicy->max_requests && !err) {
-		struct bio *bio = NULL;
-		unsigned long flags;
-		bool last = true;
-
-		if (len > max_discard_blocks) {
-			len = max_discard_blocks;
-			last = false;
-		}
-
-		(*issued)++;
-		if (*issued == dpolicy->max_requests)
-			last = true;
-
-		dc->len += len;
-
-		if (time_to_inject(sbi, FAULT_DISCARD)) {
-			f2fs_show_injection_info(sbi, FAULT_DISCARD);
-			err = -EIO;
-		} else {
-			err = __blkdev_issue_discard(bdev,
-					SECTOR_FROM_BLOCK(start),
-					SECTOR_FROM_BLOCK(len),
-					GFP_NOFS, &bio);
-		}
-		if (err) {
-			spin_lock_irqsave(&dc->lock, flags);
-			if (dc->state == D_PARTIAL)
-				dc->state = D_SUBMIT;
-			spin_unlock_irqrestore(&dc->lock, flags);
-
-			break;
-		}
-
-		f2fs_bug_on(sbi, !bio);
-
-		/*
-		 * should keep before submission to avoid D_DONE
-		 * right away
-		 */
-		spin_lock_irqsave(&dc->lock, flags);
-		if (last)
-			dc->state = D_SUBMIT;
-		else
-			dc->state = D_PARTIAL;
-		dc->bio_ref++;
-		spin_unlock_irqrestore(&dc->lock, flags);
-
-		atomic_inc(&dcc->queued_discard);
-		dc->queued++;
-		list_move_tail(&dc->list, wait_list);
-
-		/* sanity check on discard range */
-		__check_sit_bitmap(sbi, lstart, lstart + len);
-
-		bio->bi_private = dc;
-		bio->bi_end_io = f2fs_submit_discard_endio;
-		bio->bi_opf |= flag;
-		submit_bio(bio);
-
-		atomic_inc(&dcc->issued_discard);
-
-		f2fs_update_iostat(sbi, NULL, FS_DISCARD, len * F2FS_BLKSIZE);
-
-		lstart += len;
-		start += len;
-		total_len -= len;
-		len = total_len;
-	}
-
-	if (!err && len) {
-		dcc->undiscard_blks -= len;
-		__update_discard_tree_range(sbi, bdev, lstart, start, len);
-	}
-	return err;
-}
-
-static void __insert_discard_tree(struct f2fs_sb_info *sbi,
-				struct block_device *bdev, block_t lstart,
-				block_t start, block_t len,
-				struct rb_node **insert_p,
-				struct rb_node *insert_parent)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	struct rb_node **p;
-	struct rb_node *parent = NULL;
-	bool leftmost = true;
-
-	if (insert_p && insert_parent) {
-		parent = insert_parent;
-		p = insert_p;
-		goto do_insert;
-	}
-
-	p = f2fs_lookup_rb_tree_for_insert(sbi, &dcc->root, &parent,
-							lstart, &leftmost);
-do_insert:
-	__attach_discard_cmd(sbi, bdev, lstart, start, len, parent,
-								p, leftmost);
-}
-
-static void __relocate_discard_cmd(struct discard_cmd_control *dcc,
-						struct discard_cmd *dc)
-{
-	list_move_tail(&dc->list, &dcc->pend_list[plist_idx(dc->len)]);
-}
-
-static void __punch_discard_cmd(struct f2fs_sb_info *sbi,
-				struct discard_cmd *dc, block_t blkaddr)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	struct discard_info di = dc->di;
-	bool modified = false;
-
-	if (dc->state == D_DONE || dc->len == 1) {
-		__remove_discard_cmd(sbi, dc);
-		return;
-	}
-
-	dcc->undiscard_blks -= di.len;
-
-	if (blkaddr > di.lstart) {
-		dc->len = blkaddr - dc->lstart;
-		dcc->undiscard_blks += dc->len;
-		__relocate_discard_cmd(dcc, dc);
-		modified = true;
-	}
-
-	if (blkaddr < di.lstart + di.len - 1) {
-		if (modified) {
-			__insert_discard_tree(sbi, dc->bdev, blkaddr + 1,
-					di.start + blkaddr + 1 - di.lstart,
-					di.lstart + di.len - 1 - blkaddr,
-					NULL, NULL);
-		} else {
-			dc->lstart++;
-			dc->len--;
-			dc->start++;
-			dcc->undiscard_blks += dc->len;
-			__relocate_discard_cmd(dcc, dc);
-		}
-	}
-}
-
-static void __update_discard_tree_range(struct f2fs_sb_info *sbi,
-				struct block_device *bdev, block_t lstart,
-				block_t start, block_t len)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
-	struct discard_cmd *dc;
-	struct discard_info di = {0};
-	struct rb_node **insert_p = NULL, *insert_parent = NULL;
-	unsigned int max_discard_blocks =
-			SECTOR_TO_BLOCK(bdev_max_discard_sectors(bdev));
-	block_t end = lstart + len;
-
-	dc = (struct discard_cmd *)f2fs_lookup_rb_tree_ret(&dcc->root,
-					NULL, lstart,
-					(struct rb_entry **)&prev_dc,
-					(struct rb_entry **)&next_dc,
-					&insert_p, &insert_parent, true, NULL);
-	if (dc)
-		prev_dc = dc;
-
-	if (!prev_dc) {
-		di.lstart = lstart;
-		di.len = next_dc ? next_dc->lstart - lstart : len;
-		di.len = min(di.len, len);
-		di.start = start;
-	}
-
-	while (1) {
-		struct rb_node *node;
-		bool merged = false;
-		struct discard_cmd *tdc = NULL;
-
-		if (prev_dc) {
-			di.lstart = prev_dc->lstart + prev_dc->len;
-			if (di.lstart < lstart)
-				di.lstart = lstart;
-			if (di.lstart >= end)
-				break;
-
-			if (!next_dc || next_dc->lstart > end)
-				di.len = end - di.lstart;
-			else
-				di.len = next_dc->lstart - di.lstart;
-			di.start = start + di.lstart - lstart;
-		}
-
-		if (!di.len)
-			goto next;
-
-		if (prev_dc && prev_dc->state == D_PREP &&
-			prev_dc->bdev == bdev &&
-			__is_discard_back_mergeable(&di, &prev_dc->di,
-							max_discard_blocks)) {
-			prev_dc->di.len += di.len;
-			dcc->undiscard_blks += di.len;
-			__relocate_discard_cmd(dcc, prev_dc);
-			di = prev_dc->di;
-			tdc = prev_dc;
-			merged = true;
-		}
-
-		if (next_dc && next_dc->state == D_PREP &&
-			next_dc->bdev == bdev &&
-			__is_discard_front_mergeable(&di, &next_dc->di,
-							max_discard_blocks)) {
-			next_dc->di.lstart = di.lstart;
-			next_dc->di.len += di.len;
-			next_dc->di.start = di.start;
-			dcc->undiscard_blks += di.len;
-			__relocate_discard_cmd(dcc, next_dc);
-			if (tdc)
-				__remove_discard_cmd(sbi, tdc);
-			merged = true;
-		}
-
-		if (!merged) {
-			__insert_discard_tree(sbi, bdev, di.lstart, di.start,
-							di.len, NULL, NULL);
-		}
- next:
-		prev_dc = next_dc;
-		if (!prev_dc)
-			break;
-
-		node = rb_next(&prev_dc->rb_node);
-		next_dc = rb_entry_safe(node, struct discard_cmd, rb_node);
-	}
-}
-
-static void __queue_discard_cmd(struct f2fs_sb_info *sbi,
-		struct block_device *bdev, block_t blkstart, block_t blklen)
-{
-	block_t lblkstart = blkstart;
-
-	if (!f2fs_bdev_support_discard(bdev))
-		return;
-
-	trace_f2fs_queue_discard(bdev, blkstart, blklen);
-
-	if (f2fs_is_multi_device(sbi)) {
-		int devi = f2fs_target_device_index(sbi, blkstart);
-
-		blkstart -= FDEV(devi).start_blk;
-	}
-	mutex_lock(&SM_I(sbi)->dcc_info->cmd_lock);
-	__update_discard_tree_range(sbi, bdev, lblkstart, blkstart, blklen);
-	mutex_unlock(&SM_I(sbi)->dcc_info->cmd_lock);
-}
-
-static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
-					struct discard_policy *dpolicy)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
-	struct rb_node **insert_p = NULL, *insert_parent = NULL;
-	struct discard_cmd *dc;
-	struct blk_plug plug;
-	unsigned int pos = dcc->next_pos;
-	unsigned int issued = 0;
-	bool io_interrupted = false;
-
-	mutex_lock(&dcc->cmd_lock);
-	dc = (struct discard_cmd *)f2fs_lookup_rb_tree_ret(&dcc->root,
-					NULL, pos,
-					(struct rb_entry **)&prev_dc,
-					(struct rb_entry **)&next_dc,
-					&insert_p, &insert_parent, true, NULL);
-	if (!dc)
-		dc = next_dc;
-
-	blk_start_plug(&plug);
-
-	while (dc) {
-		struct rb_node *node;
-		int err = 0;
-
-		if (dc->state != D_PREP)
-			goto next;
-
-		if (dpolicy->io_aware && !is_idle(sbi, DISCARD_TIME)) {
-			io_interrupted = true;
-			break;
-		}
-
-		dcc->next_pos = dc->lstart + dc->len;
-		err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
-
-		if (issued >= dpolicy->max_requests)
-			break;
-next:
-		node = rb_next(&dc->rb_node);
-		if (err)
-			__remove_discard_cmd(sbi, dc);
-		dc = rb_entry_safe(node, struct discard_cmd, rb_node);
-	}
-
-	blk_finish_plug(&plug);
-
-	if (!dc)
-		dcc->next_pos = 0;
-
-	mutex_unlock(&dcc->cmd_lock);
-
-	if (!issued && io_interrupted)
-		issued = -1;
-
-	return issued;
-}
-static unsigned int __wait_all_discard_cmd(struct f2fs_sb_info *sbi,
-					struct discard_policy *dpolicy);
-
-static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
-					struct discard_policy *dpolicy)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	struct list_head *pend_list;
-	struct discard_cmd *dc, *tmp;
-	struct blk_plug plug;
-	int i, issued;
-	bool io_interrupted = false;
-
-	if (dpolicy->timeout)
-		f2fs_update_time(sbi, UMOUNT_DISCARD_TIMEOUT);
-
-retry:
-	issued = 0;
-	for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
-		if (dpolicy->timeout &&
-				f2fs_time_over(sbi, UMOUNT_DISCARD_TIMEOUT))
-			break;
-
-		if (i + 1 < dpolicy->granularity)
-			break;
-
-		if (i + 1 < dcc->max_ordered_discard && dpolicy->ordered)
-			return __issue_discard_cmd_orderly(sbi, dpolicy);
-
-		pend_list = &dcc->pend_list[i];
-
-		mutex_lock(&dcc->cmd_lock);
-		if (list_empty(pend_list))
-			goto next;
-		if (unlikely(dcc->rbtree_check))
-			f2fs_bug_on(sbi, !f2fs_check_rb_tree_consistence(sbi,
-							&dcc->root, false));
-		blk_start_plug(&plug);
-		list_for_each_entry_safe(dc, tmp, pend_list, list) {
-			f2fs_bug_on(sbi, dc->state != D_PREP);
-
-			if (dpolicy->timeout &&
-				f2fs_time_over(sbi, UMOUNT_DISCARD_TIMEOUT))
-				break;
-
-			if (dpolicy->io_aware && i < dpolicy->io_aware_gran &&
-						!is_idle(sbi, DISCARD_TIME)) {
-				io_interrupted = true;
-				break;
-			}
-
-			__submit_discard_cmd(sbi, dpolicy, dc, &issued);
-
-			if (issued >= dpolicy->max_requests)
-				break;
-		}
-		blk_finish_plug(&plug);
-next:
-		mutex_unlock(&dcc->cmd_lock);
-
-		if (issued >= dpolicy->max_requests || io_interrupted)
-			break;
-	}
-
-	if (dpolicy->type == DPOLICY_UMOUNT && issued) {
-		__wait_all_discard_cmd(sbi, dpolicy);
-		goto retry;
-	}
-
-	if (!issued && io_interrupted)
-		issued = -1;
-
-	return issued;
-}
-
-static bool __drop_discard_cmd(struct f2fs_sb_info *sbi)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	struct list_head *pend_list;
-	struct discard_cmd *dc, *tmp;
-	int i;
-	bool dropped = false;
-
-	mutex_lock(&dcc->cmd_lock);
-	for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
-		pend_list = &dcc->pend_list[i];
-		list_for_each_entry_safe(dc, tmp, pend_list, list) {
-			f2fs_bug_on(sbi, dc->state != D_PREP);
-			__remove_discard_cmd(sbi, dc);
-			dropped = true;
-		}
-	}
-	mutex_unlock(&dcc->cmd_lock);
-
-	return dropped;
-}
-
-void f2fs_drop_discard_cmd(struct f2fs_sb_info *sbi)
-{
-	__drop_discard_cmd(sbi);
-}
-
-static unsigned int __wait_one_discard_bio(struct f2fs_sb_info *sbi,
-							struct discard_cmd *dc)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	unsigned int len = 0;
-
-	wait_for_completion_io(&dc->wait);
-	mutex_lock(&dcc->cmd_lock);
-	f2fs_bug_on(sbi, dc->state != D_DONE);
-	dc->ref--;
-	if (!dc->ref) {
-		if (!dc->error)
-			len = dc->len;
-		__remove_discard_cmd(sbi, dc);
-	}
-	mutex_unlock(&dcc->cmd_lock);
-
-	return len;
-}
-
-static unsigned int __wait_discard_cmd_range(struct f2fs_sb_info *sbi,
-						struct discard_policy *dpolicy,
-						block_t start, block_t end)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
-					&(dcc->fstrim_list) : &(dcc->wait_list);
-	struct discard_cmd *dc = NULL, *iter, *tmp;
-	unsigned int trimmed = 0;
-
-next:
-	dc = NULL;
-
-	mutex_lock(&dcc->cmd_lock);
-	list_for_each_entry_safe(iter, tmp, wait_list, list) {
-		if (iter->lstart + iter->len <= start || end <= iter->lstart)
-			continue;
-		if (iter->len < dpolicy->granularity)
-			continue;
-		if (iter->state == D_DONE && !iter->ref) {
-			wait_for_completion_io(&iter->wait);
-			if (!iter->error)
-				trimmed += iter->len;
-			__remove_discard_cmd(sbi, iter);
-		} else {
-			iter->ref++;
-			dc = iter;
-			break;
-		}
-	}
-	mutex_unlock(&dcc->cmd_lock);
-
-	if (dc) {
-		trimmed += __wait_one_discard_bio(sbi, dc);
-		goto next;
-	}
-
-	return trimmed;
-}
-
-static unsigned int __wait_all_discard_cmd(struct f2fs_sb_info *sbi,
-						struct discard_policy *dpolicy)
-{
-	struct discard_policy dp;
-	unsigned int discard_blks;
-
-	if (dpolicy)
-		return __wait_discard_cmd_range(sbi, dpolicy, 0, UINT_MAX);
-
-	/* wait all */
-	__init_discard_policy(sbi, &dp, DPOLICY_FSTRIM, 1);
-	discard_blks = __wait_discard_cmd_range(sbi, &dp, 0, UINT_MAX);
-	__init_discard_policy(sbi, &dp, DPOLICY_UMOUNT, 1);
-	discard_blks += __wait_discard_cmd_range(sbi, &dp, 0, UINT_MAX);
-
-	return discard_blks;
-}
-
-/* This should be covered by global mutex, &sit_i->sentry_lock */
-static void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	struct discard_cmd *dc;
-	bool need_wait = false;
-
-	mutex_lock(&dcc->cmd_lock);
-	dc = (struct discard_cmd *)f2fs_lookup_rb_tree(&dcc->root,
-							NULL, blkaddr);
-	if (dc) {
-		if (dc->state == D_PREP) {
-			__punch_discard_cmd(sbi, dc, blkaddr);
-		} else {
-			dc->ref++;
-			need_wait = true;
-		}
-	}
-	mutex_unlock(&dcc->cmd_lock);
-
-	if (need_wait)
-		__wait_one_discard_bio(sbi, dc);
-}
-
-void f2fs_stop_discard_thread(struct f2fs_sb_info *sbi)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-
-	if (dcc && dcc->f2fs_issue_discard) {
-		struct task_struct *discard_thread = dcc->f2fs_issue_discard;
-
-		dcc->f2fs_issue_discard = NULL;
-		kthread_stop(discard_thread);
-	}
-}
-
-/* This comes from f2fs_put_super */
-bool f2fs_issue_discard_timeout(struct f2fs_sb_info *sbi)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	struct discard_policy dpolicy;
-	bool dropped;
-
-	if (!atomic_read(&dcc->discard_cmd_cnt))
-		return false;
-
-	__init_discard_policy(sbi, &dpolicy, DPOLICY_UMOUNT,
-					dcc->discard_granularity);
-	__issue_discard_cmd(sbi, &dpolicy);
-	dropped = __drop_discard_cmd(sbi);
-
-	/* just to make sure there is no pending discard commands */
-	__wait_all_discard_cmd(sbi, NULL);
-
-	f2fs_bug_on(sbi, atomic_read(&dcc->discard_cmd_cnt));
-	return dropped;
-}
-
-static int issue_discard_thread(void *data)
-{
-	struct f2fs_sb_info *sbi = data;
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	wait_queue_head_t *q = &dcc->discard_wait_queue;
-	struct discard_policy dpolicy;
-	unsigned int wait_ms = dcc->min_discard_issue_time;
-	int issued;
-
-	set_freezable();
-
-	do {
-		wait_event_interruptible_timeout(*q,
-				kthread_should_stop() || freezing(current) ||
-				dcc->discard_wake,
-				msecs_to_jiffies(wait_ms));
-
-		if (sbi->gc_mode == GC_URGENT_HIGH ||
-			!f2fs_available_free_memory(sbi, DISCARD_CACHE))
-			__init_discard_policy(sbi, &dpolicy, DPOLICY_FORCE, 1);
-		else
-			__init_discard_policy(sbi, &dpolicy, DPOLICY_BG,
-						dcc->discard_granularity);
-
-		if (dcc->discard_wake)
-			dcc->discard_wake = 0;
-
-		/* clean up pending candidates before going to sleep */
-		if (atomic_read(&dcc->queued_discard))
-			__wait_all_discard_cmd(sbi, NULL);
-
-		if (try_to_freeze())
-			continue;
-		if (f2fs_readonly(sbi->sb))
-			continue;
-		if (kthread_should_stop())
-			return 0;
-		if (is_sbi_flag_set(sbi, SBI_NEED_FSCK) ||
-			!atomic_read(&dcc->discard_cmd_cnt)) {
-			wait_ms = dpolicy.max_interval;
-			continue;
-		}
-
-		sb_start_intwrite(sbi->sb);
-
-		issued = __issue_discard_cmd(sbi, &dpolicy);
-		if (issued > 0) {
-			__wait_all_discard_cmd(sbi, &dpolicy);
-			wait_ms = dpolicy.min_interval;
-		} else if (issued == -1) {
-			wait_ms = f2fs_time_to_wait(sbi, DISCARD_TIME);
-			if (!wait_ms)
-				wait_ms = dpolicy.mid_interval;
-		} else {
-			wait_ms = dpolicy.max_interval;
-		}
-		if (!atomic_read(&dcc->discard_cmd_cnt))
-			wait_ms = dpolicy.max_interval;
-
-		sb_end_intwrite(sbi->sb);
-
-	} while (!kthread_should_stop());
-	return 0;
-}
-
-#ifdef CONFIG_BLK_DEV_ZONED
-static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
-		struct block_device *bdev, block_t blkstart, block_t blklen)
-{
-	sector_t sector, nr_sects;
-	block_t lblkstart = blkstart;
-	int devi = 0;
-
-	if (f2fs_is_multi_device(sbi)) {
-		devi = f2fs_target_device_index(sbi, blkstart);
-		if (blkstart < FDEV(devi).start_blk ||
-		    blkstart > FDEV(devi).end_blk) {
-			f2fs_err(sbi, "Invalid block %x", blkstart);
-			return -EIO;
-		}
-		blkstart -= FDEV(devi).start_blk;
-	}
-
-	/* For sequential zones, reset the zone write pointer */
-	if (f2fs_blkz_is_seq(sbi, devi, blkstart)) {
-		sector = SECTOR_FROM_BLOCK(blkstart);
-		nr_sects = SECTOR_FROM_BLOCK(blklen);
-
-		if (sector & (bdev_zone_sectors(bdev) - 1) ||
-				nr_sects != bdev_zone_sectors(bdev)) {
-			f2fs_err(sbi, "(%d) %s: Unaligned zone reset attempted (block %x + %x)",
-				 devi, sbi->s_ndevs ? FDEV(devi).path : "",
-				 blkstart, blklen);
-			return -EIO;
-		}
-		trace_f2fs_issue_reset_zone(bdev, blkstart);
-		return blkdev_zone_mgmt(bdev, REQ_OP_ZONE_RESET,
-					sector, nr_sects, GFP_NOFS);
-	}
-
-	/* For conventional zones, use regular discard if supported */
-	__queue_discard_cmd(sbi, bdev, lblkstart, blklen);
-	return 0;
-}
-#endif
-
-static int __issue_discard_async(struct f2fs_sb_info *sbi,
-		struct block_device *bdev, block_t blkstart, block_t blklen)
-{
-#ifdef CONFIG_BLK_DEV_ZONED
-	if (f2fs_sb_has_blkzoned(sbi) && bdev_is_zoned(bdev))
-		return __f2fs_issue_discard_zone(sbi, bdev, blkstart, blklen);
-#endif
-	__queue_discard_cmd(sbi, bdev, blkstart, blklen);
-	return 0;
-}
-
-static int f2fs_issue_discard(struct f2fs_sb_info *sbi,
-				block_t blkstart, block_t blklen)
-{
-	sector_t start = blkstart, len = 0;
-	struct block_device *bdev;
-	struct seg_entry *se;
-	unsigned int offset;
-	block_t i;
-	int err = 0;
-
-	bdev = f2fs_target_device(sbi, blkstart, NULL);
-
-	for (i = blkstart; i < blkstart + blklen; i++, len++) {
-		if (i != start) {
-			struct block_device *bdev2 =
-				f2fs_target_device(sbi, i, NULL);
-
-			if (bdev2 != bdev) {
-				err = __issue_discard_async(sbi, bdev,
-						start, len);
-				if (err)
-					return err;
-				bdev = bdev2;
-				start = i;
-				len = 0;
-			}
-		}
-
-		se = get_seg_entry(sbi, GET_SEGNO(sbi, i));
-		offset = GET_BLKOFF_FROM_SEG0(sbi, i);
-
-		if (f2fs_block_unit_discard(sbi) &&
-				!f2fs_test_and_set_bit(offset, se->discard_map))
-			sbi->discard_blks--;
-	}
-
-	if (len)
-		err = __issue_discard_async(sbi, bdev, start, len);
-	return err;
-}
-
-static bool add_discard_addrs(struct f2fs_sb_info *sbi, struct cp_control *cpc,
-							bool check_only)
-{
-	int entries = SIT_VBLOCK_MAP_SIZE / sizeof(unsigned long);
-	int max_blocks = sbi->blocks_per_seg;
-	struct seg_entry *se = get_seg_entry(sbi, cpc->trim_start);
-	unsigned long *cur_map = (unsigned long *)se->cur_valid_map;
-	unsigned long *ckpt_map = (unsigned long *)se->ckpt_valid_map;
-	unsigned long *discard_map = (unsigned long *)se->discard_map;
-	unsigned long *dmap = SIT_I(sbi)->tmp_map;
-	unsigned int start = 0, end = -1;
-	bool force = (cpc->reason & CP_DISCARD);
-	struct discard_entry *de = NULL;
-	struct list_head *head = &SM_I(sbi)->dcc_info->entry_list;
-	int i;
-
-	if (se->valid_blocks == max_blocks || !f2fs_hw_support_discard(sbi) ||
-			!f2fs_block_unit_discard(sbi))
-		return false;
-
-	if (!force) {
-		if (!f2fs_realtime_discard_enable(sbi) || !se->valid_blocks ||
-			SM_I(sbi)->dcc_info->nr_discards >=
-				SM_I(sbi)->dcc_info->max_discards)
-			return false;
-	}
-
-	/* SIT_VBLOCK_MAP_SIZE should be multiple of sizeof(unsigned long) */
-	for (i = 0; i < entries; i++)
-		dmap[i] = force ? ~ckpt_map[i] & ~discard_map[i] :
-				(cur_map[i] ^ ckpt_map[i]) & ckpt_map[i];
-
-	while (force || SM_I(sbi)->dcc_info->nr_discards <=
-				SM_I(sbi)->dcc_info->max_discards) {
-		start = __find_rev_next_bit(dmap, max_blocks, end + 1);
-		if (start >= max_blocks)
-			break;
-
-		end = __find_rev_next_zero_bit(dmap, max_blocks, start + 1);
-		if (force && start && end != max_blocks
-					&& (end - start) < cpc->trim_minlen)
-			continue;
-
-		if (check_only)
-			return true;
-
-		if (!de) {
-			de = f2fs_kmem_cache_alloc(discard_entry_slab,
-						GFP_F2FS_ZERO, true, NULL);
-			de->start_blkaddr = START_BLOCK(sbi, cpc->trim_start);
-			list_add_tail(&de->list, head);
-		}
-
-		for (i = start; i < end; i++)
-			__set_bit_le(i, (void *)de->discard_map);
-
-		SM_I(sbi)->dcc_info->nr_discards += end - start;
-	}
-	return false;
-}
-
-static void release_discard_addr(struct discard_entry *entry)
-{
-	list_del(&entry->list);
-	kmem_cache_free(discard_entry_slab, entry);
-}
-
-void f2fs_release_discard_addrs(struct f2fs_sb_info *sbi)
-{
-	struct list_head *head = &(SM_I(sbi)->dcc_info->entry_list);
-	struct discard_entry *entry, *this;
-
-	/* drop caches */
-	list_for_each_entry_safe(entry, this, head, list)
-		release_discard_addr(entry);
-}
-
 /*
  * Should call f2fs_clear_prefree_segments after checkpoint is done.
  */
@@ -2033,98 +1057,6 @@ void f2fs_clear_prefree_segments(struct f2fs_sb_info *sbi,
 	wake_up_discard_thread(sbi, false);
 }
 
-int f2fs_start_discard_thread(struct f2fs_sb_info *sbi)
-{
-	dev_t dev = sbi->sb->s_bdev->bd_dev;
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	int err = 0;
-
-	if (!f2fs_realtime_discard_enable(sbi))
-		return 0;
-
-	dcc->f2fs_issue_discard = kthread_run(issue_discard_thread, sbi,
-				"f2fs_discard-%u:%u", MAJOR(dev), MINOR(dev));
-	if (IS_ERR(dcc->f2fs_issue_discard)) {
-		err = PTR_ERR(dcc->f2fs_issue_discard);
-		dcc->f2fs_issue_discard = NULL;
-	}
-
-	return err;
-}
-
-static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
-{
-	struct discard_cmd_control *dcc;
-	int err = 0, i;
-
-	if (SM_I(sbi)->dcc_info) {
-		dcc = SM_I(sbi)->dcc_info;
-		goto init_thread;
-	}
-
-	dcc = f2fs_kzalloc(sbi, sizeof(struct discard_cmd_control), GFP_KERNEL);
-	if (!dcc)
-		return -ENOMEM;
-
-	dcc->discard_granularity = DEFAULT_DISCARD_GRANULARITY;
-	dcc->max_ordered_discard = DEFAULT_MAX_ORDERED_DISCARD_GRANULARITY;
-	if (F2FS_OPTION(sbi).discard_unit == DISCARD_UNIT_SEGMENT)
-		dcc->discard_granularity = sbi->blocks_per_seg;
-	else if (F2FS_OPTION(sbi).discard_unit == DISCARD_UNIT_SECTION)
-		dcc->discard_granularity = BLKS_PER_SEC(sbi);
-
-	INIT_LIST_HEAD(&dcc->entry_list);
-	for (i = 0; i < MAX_PLIST_NUM; i++)
-		INIT_LIST_HEAD(&dcc->pend_list[i]);
-	INIT_LIST_HEAD(&dcc->wait_list);
-	INIT_LIST_HEAD(&dcc->fstrim_list);
-	mutex_init(&dcc->cmd_lock);
-	atomic_set(&dcc->issued_discard, 0);
-	atomic_set(&dcc->queued_discard, 0);
-	atomic_set(&dcc->discard_cmd_cnt, 0);
-	dcc->nr_discards = 0;
-	dcc->max_discards = MAIN_SEGS(sbi) << sbi->log_blocks_per_seg;
-	dcc->max_discard_request = DEF_MAX_DISCARD_REQUEST;
-	dcc->min_discard_issue_time = DEF_MIN_DISCARD_ISSUE_TIME;
-	dcc->mid_discard_issue_time = DEF_MID_DISCARD_ISSUE_TIME;
-	dcc->max_discard_issue_time = DEF_MAX_DISCARD_ISSUE_TIME;
-	dcc->discard_urgent_util = DEF_DISCARD_URGENT_UTIL;
-	dcc->undiscard_blks = 0;
-	dcc->next_pos = 0;
-	dcc->root = RB_ROOT_CACHED;
-	dcc->rbtree_check = false;
-
-	init_waitqueue_head(&dcc->discard_wait_queue);
-	SM_I(sbi)->dcc_info = dcc;
-init_thread:
-	err = f2fs_start_discard_thread(sbi);
-	if (err) {
-		kfree(dcc);
-		SM_I(sbi)->dcc_info = NULL;
-	}
-
-	return err;
-}
-
-static void destroy_discard_cmd_control(struct f2fs_sb_info *sbi)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-
-	if (!dcc)
-		return;
-
-	f2fs_stop_discard_thread(sbi);
-
-	/*
-	 * Recovery can cache discard commands, so in error path of
-	 * fill_super(), it needs to give a chance to handle them.
-	 */
-	f2fs_issue_discard_timeout(sbi);
-
-	kfree(dcc);
-	SM_I(sbi)->dcc_info = NULL;
-}
-
 static bool __mark_sit_entry_dirty(struct f2fs_sb_info *sbi, unsigned int segno)
 {
 	struct sit_info *sit_i = SIT_I(sbi);
@@ -2953,167 +1885,6 @@ void f2fs_allocate_new_segments(struct f2fs_sb_info *sbi)
 	f2fs_up_read(&SM_I(sbi)->curseg_lock);
 }
 
-bool f2fs_exist_trim_candidates(struct f2fs_sb_info *sbi,
-						struct cp_control *cpc)
-{
-	__u64 trim_start = cpc->trim_start;
-	bool has_candidate = false;
-
-	down_write(&SIT_I(sbi)->sentry_lock);
-	for (; cpc->trim_start <= cpc->trim_end; cpc->trim_start++) {
-		if (add_discard_addrs(sbi, cpc, true)) {
-			has_candidate = true;
-			break;
-		}
-	}
-	up_write(&SIT_I(sbi)->sentry_lock);
-
-	cpc->trim_start = trim_start;
-	return has_candidate;
-}
-
-static unsigned int __issue_discard_cmd_range(struct f2fs_sb_info *sbi,
-					struct discard_policy *dpolicy,
-					unsigned int start, unsigned int end)
-{
-	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
-	struct rb_node **insert_p = NULL, *insert_parent = NULL;
-	struct discard_cmd *dc;
-	struct blk_plug plug;
-	int issued;
-	unsigned int trimmed = 0;
-
-next:
-	issued = 0;
-
-	mutex_lock(&dcc->cmd_lock);
-	if (unlikely(dcc->rbtree_check))
-		f2fs_bug_on(sbi, !f2fs_check_rb_tree_consistence(sbi,
-							&dcc->root, false));
-
-	dc = (struct discard_cmd *)f2fs_lookup_rb_tree_ret(&dcc->root,
-					NULL, start,
-					(struct rb_entry **)&prev_dc,
-					(struct rb_entry **)&next_dc,
-					&insert_p, &insert_parent, true, NULL);
-	if (!dc)
-		dc = next_dc;
-
-	blk_start_plug(&plug);
-
-	while (dc && dc->lstart <= end) {
-		struct rb_node *node;
-		int err = 0;
-
-		if (dc->len < dpolicy->granularity)
-			goto skip;
-
-		if (dc->state != D_PREP) {
-			list_move_tail(&dc->list, &dcc->fstrim_list);
-			goto skip;
-		}
-
-		err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
-
-		if (issued >= dpolicy->max_requests) {
-			start = dc->lstart + dc->len;
-
-			if (err)
-				__remove_discard_cmd(sbi, dc);
-
-			blk_finish_plug(&plug);
-			mutex_unlock(&dcc->cmd_lock);
-			trimmed += __wait_all_discard_cmd(sbi, NULL);
-			f2fs_io_schedule_timeout(DEFAULT_IO_TIMEOUT);
-			goto next;
-		}
-skip:
-		node = rb_next(&dc->rb_node);
-		if (err)
-			__remove_discard_cmd(sbi, dc);
-		dc = rb_entry_safe(node, struct discard_cmd, rb_node);
-
-		if (fatal_signal_pending(current))
-			break;
-	}
-
-	blk_finish_plug(&plug);
-	mutex_unlock(&dcc->cmd_lock);
-
-	return trimmed;
-}
-
-int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
-{
-	__u64 start = F2FS_BYTES_TO_BLK(range->start);
-	__u64 end = start + F2FS_BYTES_TO_BLK(range->len) - 1;
-	unsigned int start_segno, end_segno;
-	block_t start_block, end_block;
-	struct cp_control cpc;
-	struct discard_policy dpolicy;
-	unsigned long long trimmed = 0;
-	int err = 0;
-	bool need_align = f2fs_lfs_mode(sbi) && __is_large_section(sbi);
-
-	if (start >= MAX_BLKADDR(sbi) || range->len < sbi->blocksize)
-		return -EINVAL;
-
-	if (end < MAIN_BLKADDR(sbi))
-		goto out;
-
-	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
-		f2fs_warn(sbi, "Found FS corruption, run fsck to fix.");
-		return -EFSCORRUPTED;
-	}
-
-	/* start/end segment number in main_area */
-	start_segno = (start <= MAIN_BLKADDR(sbi)) ? 0 : GET_SEGNO(sbi, start);
-	end_segno = (end >= MAX_BLKADDR(sbi)) ? MAIN_SEGS(sbi) - 1 :
-						GET_SEGNO(sbi, end);
-	if (need_align) {
-		start_segno = rounddown(start_segno, sbi->segs_per_sec);
-		end_segno = roundup(end_segno + 1, sbi->segs_per_sec) - 1;
-	}
-
-	cpc.reason = CP_DISCARD;
-	cpc.trim_minlen = max_t(__u64, 1, F2FS_BYTES_TO_BLK(range->minlen));
-	cpc.trim_start = start_segno;
-	cpc.trim_end = end_segno;
-
-	if (sbi->discard_blks == 0)
-		goto out;
-
-	f2fs_down_write(&sbi->gc_lock);
-	err = f2fs_write_checkpoint(sbi, &cpc);
-	f2fs_up_write(&sbi->gc_lock);
-	if (err)
-		goto out;
-
-	/*
-	 * We filed discard candidates, but actually we don't need to wait for
-	 * all of them, since they'll be issued in idle time along with runtime
-	 * discard option. User configuration looks like using runtime discard
-	 * or periodic fstrim instead of it.
-	 */
-	if (f2fs_realtime_discard_enable(sbi))
-		goto out;
-
-	start_block = START_BLOCK(sbi, start_segno);
-	end_block = START_BLOCK(sbi, end_segno + 1);
-
-	__init_discard_policy(sbi, &dpolicy, DPOLICY_FSTRIM, cpc.trim_minlen);
-	trimmed = __issue_discard_cmd_range(sbi, &dpolicy,
-					start_block, end_block);
-
-	trimmed += __wait_discard_cmd_range(sbi, &dpolicy,
-					start_block, end_block);
-out:
-	if (!err)
-		range->len = F2FS_BLK_TO_BYTES(trimmed);
-	return err;
-}
-
 static bool __has_curseg_space(struct f2fs_sb_info *sbi,
 					struct curseg_info *curseg)
 {
@@ -5287,41 +4058,34 @@ void f2fs_destroy_segment_manager(struct f2fs_sb_info *sbi)
 
 int __init f2fs_create_segment_manager_caches(void)
 {
-	discard_entry_slab = f2fs_kmem_cache_create("f2fs_discard_entry",
-			sizeof(struct discard_entry));
-	if (!discard_entry_slab)
-		goto fail;
-
-	discard_cmd_slab = f2fs_kmem_cache_create("f2fs_discard_cmd",
-			sizeof(struct discard_cmd));
-	if (!discard_cmd_slab)
-		goto destroy_discard_entry;
+	int ret;
 
 	sit_entry_set_slab = f2fs_kmem_cache_create("f2fs_sit_entry_set",
 			sizeof(struct sit_entry_set));
 	if (!sit_entry_set_slab)
-		goto destroy_discard_cmd;
+		return -ENOMEM;
 
 	revoke_entry_slab = f2fs_kmem_cache_create("f2fs_revoke_entry",
 			sizeof(struct revoke_entry));
 	if (!revoke_entry_slab)
 		goto destroy_sit_entry_set;
-	return 0;
 
+	ret = f2fs_create_discard_caches();
+	if (ret)
+		goto destroy_revoke_entry;
+
+	return ret;
+
+destroy_revoke_entry:
+	kmem_cache_destroy(revoke_entry_slab);
 destroy_sit_entry_set:
 	kmem_cache_destroy(sit_entry_set_slab);
-destroy_discard_cmd:
-	kmem_cache_destroy(discard_cmd_slab);
-destroy_discard_entry:
-	kmem_cache_destroy(discard_entry_slab);
-fail:
 	return -ENOMEM;
 }
 
 void f2fs_destroy_segment_manager_caches(void)
 {
+	f2fs_destroy_discard_caches();
 	kmem_cache_destroy(sit_entry_set_slab);
-	kmem_cache_destroy(discard_cmd_slab);
-	kmem_cache_destroy(discard_entry_slab);
 	kmem_cache_destroy(revoke_entry_slab);
 }
