1 /* 2 * SPDX-License-Identifier: MIT 3 * 4 * Copyright © 2019 Intel Corporation 5 */ 6 7 #include <linux/wait_bit.h> 8 9 #include "intel_runtime_pm.h" 10 #include "intel_wakeref.h" 11 #include "i915_drv.h" 12 13 int __intel_wakeref_get_first(struct intel_wakeref *wf) 14 { 15 intel_wakeref_t wakeref; 16 int ret = 0; 17 18 wakeref = intel_runtime_pm_get(&wf->i915->runtime_pm); 19 /* 20 * Treat get/put as different subclasses, as we may need to run 21 * the put callback from under the shrinker and do not want to 22 * cross-contanimate that callback with any extra work performed 23 * upon acquiring the wakeref. 24 */ 25 mutex_lock_nested(&wf->mutex, SINGLE_DEPTH_NESTING); 26 27 if (!atomic_read(&wf->count)) { 28 INTEL_WAKEREF_BUG_ON(wf->wakeref); 29 wf->wakeref = wakeref; 30 wakeref = 0; 31 32 ret = wf->ops->get(wf); 33 if (ret) { 34 wakeref = xchg(&wf->wakeref, 0); 35 wake_up_var(&wf->wakeref); 36 goto unlock; 37 } 38 39 smp_mb__before_atomic(); /* release wf->count */ 40 } 41 42 atomic_inc(&wf->count); 43 INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0); 44 45 unlock: 46 mutex_unlock(&wf->mutex); 47 if (unlikely(wakeref)) 48 intel_runtime_pm_put(&wf->i915->runtime_pm, wakeref); 49 50 return ret; 51 } 52 53 static void ____intel_wakeref_put_last(struct intel_wakeref *wf) 54 { 55 intel_wakeref_t wakeref = 0; 56 57 INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0); 58 if (unlikely(!atomic_dec_and_test(&wf->count))) 59 goto unlock; 60 61 /* ops->put() must reschedule its own release on error/deferral */ 62 if (likely(!wf->ops->put(wf))) { 63 INTEL_WAKEREF_BUG_ON(!wf->wakeref); 64 wakeref = xchg(&wf->wakeref, 0); 65 wake_up_var(&wf->wakeref); 66 } 67 68 unlock: 69 mutex_unlock(&wf->mutex); 70 if (wakeref) 71 intel_runtime_pm_put(&wf->i915->runtime_pm, wakeref); 72 } 73 74 void __intel_wakeref_put_last(struct intel_wakeref *wf, unsigned long flags) 75 { 76 INTEL_WAKEREF_BUG_ON(delayed_work_pending(&wf->work)); 77 78 /* Assume we are not in process context and so cannot sleep. */ 79 if (flags & INTEL_WAKEREF_PUT_ASYNC || !mutex_trylock(&wf->mutex)) { 80 mod_delayed_work(wf->i915->unordered_wq, &wf->work, 81 FIELD_GET(INTEL_WAKEREF_PUT_DELAY, flags)); 82 return; 83 } 84 85 ____intel_wakeref_put_last(wf); 86 } 87 88 static void __intel_wakeref_put_work(struct work_struct *wrk) 89 { 90 struct intel_wakeref *wf = container_of(wrk, typeof(*wf), work.work); 91 92 if (atomic_add_unless(&wf->count, -1, 1)) 93 return; 94 95 mutex_lock(&wf->mutex); 96 ____intel_wakeref_put_last(wf); 97 } 98 99 void __intel_wakeref_init(struct intel_wakeref *wf, 100 struct drm_i915_private *i915, 101 const struct intel_wakeref_ops *ops, 102 struct intel_wakeref_lockclass *key, 103 const char *name) 104 { 105 wf->i915 = i915; 106 wf->ops = ops; 107 108 __mutex_init(&wf->mutex, "wakeref.mutex", &key->mutex); 109 atomic_set(&wf->count, 0); 110 wf->wakeref = 0; 111 112 INIT_DELAYED_WORK(&wf->work, __intel_wakeref_put_work); 113 lockdep_init_map(&wf->work.work.lockdep_map, 114 "wakeref.work", &key->work, 0); 115 116 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF) 117 ref_tracker_dir_init(&wf->debug, INTEL_REFTRACK_DEAD_COUNT, name); 118 #endif 119 } 120 121 int intel_wakeref_wait_for_idle(struct intel_wakeref *wf) 122 { 123 int err; 124 125 might_sleep(); 126 127 err = wait_var_event_killable(&wf->wakeref, 128 !intel_wakeref_is_active(wf)); 129 if (err) 130 return err; 131 132 intel_wakeref_unlock_wait(wf); 133 return 0; 134 } 135 136 static void wakeref_auto_timeout(struct timer_list *t) 137 { 138 struct intel_wakeref_auto *wf = from_timer(wf, t, timer); 139 intel_wakeref_t wakeref; 140 unsigned long flags; 141 142 if (!refcount_dec_and_lock_irqsave(&wf->count, &wf->lock, &flags)) 143 return; 144 145 wakeref = fetch_and_zero(&wf->wakeref); 146 spin_unlock_irqrestore(&wf->lock, flags); 147 148 intel_runtime_pm_put(&wf->i915->runtime_pm, wakeref); 149 } 150 151 void intel_wakeref_auto_init(struct intel_wakeref_auto *wf, 152 struct drm_i915_private *i915) 153 { 154 spin_lock_init(&wf->lock); 155 timer_setup(&wf->timer, wakeref_auto_timeout, 0); 156 refcount_set(&wf->count, 0); 157 wf->wakeref = 0; 158 wf->i915 = i915; 159 } 160 161 void intel_wakeref_auto(struct intel_wakeref_auto *wf, unsigned long timeout) 162 { 163 unsigned long flags; 164 165 if (!timeout) { 166 if (del_timer_sync(&wf->timer)) 167 wakeref_auto_timeout(&wf->timer); 168 return; 169 } 170 171 /* Our mission is that we only extend an already active wakeref */ 172 assert_rpm_wakelock_held(&wf->i915->runtime_pm); 173 174 if (!refcount_inc_not_zero(&wf->count)) { 175 spin_lock_irqsave(&wf->lock, flags); 176 if (!refcount_inc_not_zero(&wf->count)) { 177 INTEL_WAKEREF_BUG_ON(wf->wakeref); 178 wf->wakeref = 179 intel_runtime_pm_get_if_in_use(&wf->i915->runtime_pm); 180 refcount_set(&wf->count, 1); 181 } 182 spin_unlock_irqrestore(&wf->lock, flags); 183 } 184 185 /* 186 * If we extend a pending timer, we will only get a single timer 187 * callback and so need to cancel the local inc by running the 188 * elided callback to keep the wf->count balanced. 189 */ 190 if (mod_timer(&wf->timer, jiffies + timeout)) 191 wakeref_auto_timeout(&wf->timer); 192 } 193 194 void intel_wakeref_auto_fini(struct intel_wakeref_auto *wf) 195 { 196 intel_wakeref_auto(wf, 0); 197 INTEL_WAKEREF_BUG_ON(wf->wakeref); 198 } 199 200 void intel_ref_tracker_show(struct ref_tracker_dir *dir, 201 struct drm_printer *p) 202 { 203 const size_t buf_size = PAGE_SIZE; 204 char *buf, *sb, *se; 205 size_t count; 206 207 buf = kmalloc(buf_size, GFP_NOWAIT); 208 if (!buf) 209 return; 210 211 count = ref_tracker_dir_snprint(dir, buf, buf_size); 212 if (!count) 213 goto free; 214 /* printk does not like big buffers, so we split it */ 215 for (sb = buf; *sb; sb = se + 1) { 216 se = strchrnul(sb, '\n'); 217 drm_printf(p, "%.*s", (int)(se - sb + 1), sb); 218 if (!*se) 219 break; 220 } 221 if (count >= buf_size) 222 drm_printf(p, "\n...dropped %zd extra bytes of leak report.\n", 223 count + 1 - buf_size); 224 free: 225 kfree(buf); 226 } 227