1 // SPDX-License-Identifier: GPL-2.0
24  * In typical usage, this swap_cgroup is accessed via memcg's charge/uncharge
28  *  - we have no race in "exchange" when we're accessed via SwapCache because
30  *  - When called via swap_free(), there is no user of this entry and no race.
42 	struct swap_cgroup_ctrl *ctrl;  in swap_cgroup_prepare()  local
45 	ctrl = &swap_cgroup_ctrl[type];  in swap_cgroup_prepare()
47 	for (idx = 0; idx < ctrl->length; idx++) {  in swap_cgroup_prepare()
51 		ctrl->map[idx] = page;  in swap_cgroup_prepare()
60 		__free_page(ctrl->map[idx]);  in swap_cgroup_prepare()
62 	return -ENOMEM;  in swap_cgroup_prepare()
65 static struct swap_cgroup *__lookup_swap_cgroup(struct swap_cgroup_ctrl *ctrl,  in __lookup_swap_cgroup()  argument
71 	mappage = ctrl->map[offset / SC_PER_PAGE];  in __lookup_swap_cgroup()
80 	struct swap_cgroup_ctrl *ctrl;  in lookup_swap_cgroup()  local
82 	ctrl = &swap_cgroup_ctrl[swp_type(ent)];  in lookup_swap_cgroup()
84 		*ctrlp = ctrl;  in lookup_swap_cgroup()
85 	return __lookup_swap_cgroup(ctrl, offset);  in lookup_swap_cgroup()
89  * swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry.
100 	struct swap_cgroup_ctrl *ctrl;  in swap_cgroup_cmpxchg()  local
105 	sc = lookup_swap_cgroup(ent, &ctrl);  in swap_cgroup_cmpxchg()
107 	spin_lock_irqsave(&ctrl->lock, flags);  in swap_cgroup_cmpxchg()
108 	retval = sc->id;  in swap_cgroup_cmpxchg()
110 		sc->id = new;  in swap_cgroup_cmpxchg()
113 	spin_unlock_irqrestore(&ctrl->lock, flags);  in swap_cgroup_cmpxchg()
118  * swap_cgroup_record - record mem_cgroup for a set of swap entries
123  * Returns old value at success, 0 at failure.
124  * (Of course, old value can be 0.)
129 	struct swap_cgroup_ctrl *ctrl;  in swap_cgroup_record()  local
136 	sc = lookup_swap_cgroup(ent, &ctrl);  in swap_cgroup_record()
138 	spin_lock_irqsave(&ctrl->lock, flags);  in swap_cgroup_record()
139 	old = sc->id;  in swap_cgroup_record()
141 		VM_BUG_ON(sc->id != old);  in swap_cgroup_record()
142 		sc->id = id;  in swap_cgroup_record()
149 			sc = __lookup_swap_cgroup(ctrl, offset);  in swap_cgroup_record()
151 	spin_unlock_irqrestore(&ctrl->lock, flags);  in swap_cgroup_record()
157  * lookup_swap_cgroup_id - lookup mem_cgroup id tied to swap entry
164 	return lookup_swap_cgroup(ent, NULL)->id;  in lookup_swap_cgroup_id()
172 	struct swap_cgroup_ctrl *ctrl;  in swap_cgroup_swapon()  local
181 	ctrl = &swap_cgroup_ctrl[type];  in swap_cgroup_swapon()
183 	ctrl->length = length;  in swap_cgroup_swapon()
184 	ctrl->map = array;  in swap_cgroup_swapon()
185 	spin_lock_init(&ctrl->lock);  in swap_cgroup_swapon()
188 		ctrl->map = NULL;  in swap_cgroup_swapon()
189 		ctrl->length = 0;  in swap_cgroup_swapon()
200 	return -ENOMEM;  in swap_cgroup_swapon()
207 	struct swap_cgroup_ctrl *ctrl;  in swap_cgroup_swapoff()  local
210 	ctrl = &swap_cgroup_ctrl[type];  in swap_cgroup_swapoff()
211 	map = ctrl->map;  in swap_cgroup_swapoff()
212 	length = ctrl->length;  in swap_cgroup_swapoff()
213 	ctrl->map = NULL;  in swap_cgroup_swapoff()
214 	ctrl->length = 0;  in swap_cgroup_swapoff()