1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * dma-fence-array: aggregate fences to be waited together 4 * 5 * Copyright (C) 2016 Collabora Ltd 6 * Copyright (C) 2016 Advanced Micro Devices, Inc. 7 * Authors: 8 * Gustavo Padovan <gustavo@padovan.org> 9 * Christian König <christian.koenig@amd.com> 10 */ 11 12 #include <linux/export.h> 13 #include <linux/slab.h> 14 #include <linux/dma-fence-array.h> 15 16 #define PENDING_ERROR 1 17 18 static const char *dma_fence_array_get_driver_name(struct dma_fence *fence) 19 { 20 return "dma_fence_array"; 21 } 22 23 static const char *dma_fence_array_get_timeline_name(struct dma_fence *fence) 24 { 25 return "unbound"; 26 } 27 28 static void dma_fence_array_set_pending_error(struct dma_fence_array *array, 29 int error) 30 { 31 /* 32 * Propagate the first error reported by any of our fences, but only 33 * before we ourselves are signaled. 34 */ 35 if (error) 36 cmpxchg(&array->base.error, PENDING_ERROR, error); 37 } 38 39 static void dma_fence_array_clear_pending_error(struct dma_fence_array *array) 40 { 41 /* Clear the error flag if not actually set. */ 42 cmpxchg(&array->base.error, PENDING_ERROR, 0); 43 } 44 45 static void irq_dma_fence_array_work(struct irq_work *wrk) 46 { 47 struct dma_fence_array *array = container_of(wrk, typeof(*array), work); 48 49 dma_fence_array_clear_pending_error(array); 50 51 dma_fence_signal(&array->base); 52 dma_fence_put(&array->base); 53 } 54 55 static void dma_fence_array_cb_func(struct dma_fence *f, 56 struct dma_fence_cb *cb) 57 { 58 struct dma_fence_array_cb *array_cb = 59 container_of(cb, struct dma_fence_array_cb, cb); 60 struct dma_fence_array *array = array_cb->array; 61 62 dma_fence_array_set_pending_error(array, f->error); 63 64 if (atomic_dec_and_test(&array->num_pending)) 65 irq_work_queue(&array->work); 66 else 67 dma_fence_put(&array->base); 68 } 69 70 static bool dma_fence_array_enable_signaling(struct dma_fence *fence) 71 { 72 struct dma_fence_array *array = to_dma_fence_array(fence); 73 struct dma_fence_array_cb *cb = array->callbacks; 74 unsigned i; 75 76 for (i = 0; i < array->num_fences; ++i) { 77 cb[i].array = array; 78 /* 79 * As we may report that the fence is signaled before all 80 * callbacks are complete, we need to take an additional 81 * reference count on the array so that we do not free it too 82 * early. The core fence handling will only hold the reference 83 * until we signal the array as complete (but that is now 84 * insufficient). 85 */ 86 dma_fence_get(&array->base); 87 if (dma_fence_add_callback(array->fences[i], &cb[i].cb, 88 dma_fence_array_cb_func)) { 89 int error = array->fences[i]->error; 90 91 dma_fence_array_set_pending_error(array, error); 92 dma_fence_put(&array->base); 93 if (atomic_dec_and_test(&array->num_pending)) { 94 dma_fence_array_clear_pending_error(array); 95 return false; 96 } 97 } 98 } 99 100 return true; 101 } 102 103 static bool dma_fence_array_signaled(struct dma_fence *fence) 104 { 105 struct dma_fence_array *array = to_dma_fence_array(fence); 106 int num_pending; 107 unsigned int i; 108 109 /* 110 * We need to read num_pending before checking the enable_signal bit 111 * to avoid racing with the enable_signaling() implementation, which 112 * might decrement the counter, and cause a partial check. 113 * atomic_read_acquire() pairs with atomic_dec_and_test() in 114 * dma_fence_array_enable_signaling() 115 * 116 * The !--num_pending check is here to account for the any_signaled case 117 * if we race with enable_signaling(), that means the !num_pending check 118 * in the is_signalling_enabled branch might be outdated (num_pending 119 * might have been decremented), but that's fine. The user will get the 120 * right value when testing again later. 121 */ 122 num_pending = atomic_read_acquire(&array->num_pending); 123 if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &array->base.flags)) { 124 if (num_pending <= 0) 125 goto signal; 126 return false; 127 } 128 129 for (i = 0; i < array->num_fences; ++i) { 130 if (dma_fence_is_signaled(array->fences[i]) && !--num_pending) 131 goto signal; 132 } 133 return false; 134 135 signal: 136 dma_fence_array_clear_pending_error(array); 137 return true; 138 } 139 140 static void dma_fence_array_release(struct dma_fence *fence) 141 { 142 struct dma_fence_array *array = to_dma_fence_array(fence); 143 unsigned i; 144 145 for (i = 0; i < array->num_fences; ++i) 146 dma_fence_put(array->fences[i]); 147 148 kfree(array->fences); 149 dma_fence_free(fence); 150 } 151 152 static void dma_fence_array_set_deadline(struct dma_fence *fence, 153 ktime_t deadline) 154 { 155 struct dma_fence_array *array = to_dma_fence_array(fence); 156 unsigned i; 157 158 for (i = 0; i < array->num_fences; ++i) 159 dma_fence_set_deadline(array->fences[i], deadline); 160 } 161 162 const struct dma_fence_ops dma_fence_array_ops = { 163 .get_driver_name = dma_fence_array_get_driver_name, 164 .get_timeline_name = dma_fence_array_get_timeline_name, 165 .enable_signaling = dma_fence_array_enable_signaling, 166 .signaled = dma_fence_array_signaled, 167 .release = dma_fence_array_release, 168 .set_deadline = dma_fence_array_set_deadline, 169 }; 170 EXPORT_SYMBOL(dma_fence_array_ops); 171 172 /** 173 * dma_fence_array_alloc - Allocate a custom fence array 174 * @num_fences: [in] number of fences to add in the array 175 * 176 * Return dma fence array on success, NULL on failure 177 */ 178 struct dma_fence_array *dma_fence_array_alloc(int num_fences) 179 { 180 struct dma_fence_array *array; 181 182 return kzalloc(struct_size(array, callbacks, num_fences), GFP_KERNEL); 183 } 184 EXPORT_SYMBOL(dma_fence_array_alloc); 185 186 /** 187 * dma_fence_array_init - Init a custom fence array 188 * @array: [in] dma fence array to arm 189 * @num_fences: [in] number of fences to add in the array 190 * @fences: [in] array containing the fences 191 * @context: [in] fence context to use 192 * @seqno: [in] sequence number to use 193 * @signal_on_any: [in] signal on any fence in the array 194 * 195 * Implementation of @dma_fence_array_create without allocation. Useful to init 196 * a preallocated dma fence array in the path of reclaim or dma fence signaling. 197 */ 198 void dma_fence_array_init(struct dma_fence_array *array, 199 int num_fences, struct dma_fence **fences, 200 u64 context, unsigned seqno, 201 bool signal_on_any) 202 { 203 WARN_ON(!num_fences || !fences); 204 205 array->num_fences = num_fences; 206 207 spin_lock_init(&array->lock); 208 dma_fence_init(&array->base, &dma_fence_array_ops, &array->lock, 209 context, seqno); 210 init_irq_work(&array->work, irq_dma_fence_array_work); 211 212 atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences); 213 array->fences = fences; 214 215 array->base.error = PENDING_ERROR; 216 217 /* 218 * dma_fence_array objects should never contain any other fence 219 * containers or otherwise we run into recursion and potential kernel 220 * stack overflow on operations on the dma_fence_array. 221 * 222 * The correct way of handling this is to flatten out the array by the 223 * caller instead. 224 * 225 * Enforce this here by checking that we don't create a dma_fence_array 226 * with any container inside. 227 */ 228 while (num_fences--) 229 WARN_ON(dma_fence_is_container(fences[num_fences])); 230 } 231 EXPORT_SYMBOL(dma_fence_array_init); 232 233 /** 234 * dma_fence_array_create - Create a custom fence array 235 * @num_fences: [in] number of fences to add in the array 236 * @fences: [in] array containing the fences 237 * @context: [in] fence context to use 238 * @seqno: [in] sequence number to use 239 * @signal_on_any: [in] signal on any fence in the array 240 * 241 * Allocate a dma_fence_array object and initialize the base fence with 242 * dma_fence_init(). 243 * In case of error it returns NULL. 244 * 245 * The caller should allocate the fences array with num_fences size 246 * and fill it with the fences it wants to add to the object. Ownership of this 247 * array is taken and dma_fence_put() is used on each fence on release. 248 * 249 * If @signal_on_any is true the fence array signals if any fence in the array 250 * signals, otherwise it signals when all fences in the array signal. 251 */ 252 struct dma_fence_array *dma_fence_array_create(int num_fences, 253 struct dma_fence **fences, 254 u64 context, unsigned seqno, 255 bool signal_on_any) 256 { 257 struct dma_fence_array *array; 258 259 array = dma_fence_array_alloc(num_fences); 260 if (!array) 261 return NULL; 262 263 dma_fence_array_init(array, num_fences, fences, 264 context, seqno, signal_on_any); 265 266 return array; 267 } 268 EXPORT_SYMBOL(dma_fence_array_create); 269 270 /** 271 * dma_fence_match_context - Check if all fences are from the given context 272 * @fence: [in] fence or fence array 273 * @context: [in] fence context to check all fences against 274 * 275 * Checks the provided fence or, for a fence array, all fences in the array 276 * against the given context. Returns false if any fence is from a different 277 * context. 278 */ 279 bool dma_fence_match_context(struct dma_fence *fence, u64 context) 280 { 281 struct dma_fence_array *array = to_dma_fence_array(fence); 282 unsigned i; 283 284 if (!dma_fence_is_array(fence)) 285 return fence->context == context; 286 287 for (i = 0; i < array->num_fences; i++) { 288 if (array->fences[i]->context != context) 289 return false; 290 } 291 292 return true; 293 } 294 EXPORT_SYMBOL(dma_fence_match_context); 295 296 struct dma_fence *dma_fence_array_first(struct dma_fence *head) 297 { 298 struct dma_fence_array *array; 299 300 if (!head) 301 return NULL; 302 303 array = to_dma_fence_array(head); 304 if (!array) 305 return head; 306 307 if (!array->num_fences) 308 return NULL; 309 310 return array->fences[0]; 311 } 312 EXPORT_SYMBOL(dma_fence_array_first); 313 314 struct dma_fence *dma_fence_array_next(struct dma_fence *head, 315 unsigned int index) 316 { 317 struct dma_fence_array *array = to_dma_fence_array(head); 318 319 if (!array || index >= array->num_fences) 320 return NULL; 321 322 return array->fences[index]; 323 } 324 EXPORT_SYMBOL(dma_fence_array_next); 325