drivers/md/dm-io-tracker.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2021 Red Hat, Inc. All rights reserved.
   4  *
   5  * This file is released under the GPL.
   6  */
   7
   8 #ifndef DM_IO_TRACKER_H
   9 #define DM_IO_TRACKER_H
  10
  11 #include <linux/jiffies.h>
  12
  13 struct dm_io_tracker {
  14         spinlock_t lock;
  15
  16         /*
  17          * Sectors of in-flight IO.
  18          */
  19         sector_t in_flight;
  20
  21         /*
  22          * The time, in jiffies, when this device became idle
  23          * (if it is indeed idle).
  24          */
  25         unsigned long idle_time;
  26         unsigned long last_update_time;
  27 };
  28
  29 static inline void dm_iot_init(struct dm_io_tracker *iot)
  30 {
  31         spin_lock_init(&iot->lock);
  32         iot->in_flight = 0ul;
  33         iot->idle_time = 0ul;
  34         iot->last_update_time = jiffies;
  35 }
  36
  37 static inline bool dm_iot_idle_for(struct dm_io_tracker *iot, unsigned long j)
  38 {
  39         bool r = false;
  40
  41         spin_lock_irq(&iot->lock);
  42         if (!iot->in_flight)
  43                 r = time_after(jiffies, iot->idle_time + j);
  44         spin_unlock_irq(&iot->lock);
  45
  46         return r;
  47 }
  48
  49 static inline unsigned long dm_iot_idle_time(struct dm_io_tracker *iot)
  50 {
  51         unsigned long r = 0;
  52
  53         spin_lock_irq(&iot->lock);
  54         if (!iot->in_flight)
  55                 r = jiffies - iot->idle_time;
  56         spin_unlock_irq(&iot->lock);
  57
  58         return r;
  59 }
  60
  61 static inline void dm_iot_io_begin(struct dm_io_tracker *iot, sector_t len)
  62 {
  63         spin_lock_irq(&iot->lock);
  64         iot->in_flight += len;
  65         spin_unlock_irq(&iot->lock);
  66 }
  67
  68 static inline void dm_iot_io_end(struct dm_io_tracker *iot, sector_t len)
  69 {
  70         unsigned long flags;
  71
  72         if (!len)
  73                 return;
  74
  75         spin_lock_irqsave(&iot->lock, flags);
  76         iot->in_flight -= len;
  77         if (!iot->in_flight)
  78                 iot->idle_time = jiffies;
  79         spin_unlock_irqrestore(&iot->lock, flags);
  80 }
  81
  82 #endif