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 = (void *)(&array[1]); 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); 106 107 if (atomic_read(&array->num_pending) > 0) 108 return false; 109 110 dma_fence_array_clear_pending_error(array); 111 return true; 112 } 113 114 static void dma_fence_array_release(struct dma_fence *fence) 115 { 116 struct dma_fence_array *array = to_dma_fence_array(fence); 117 unsigned i; 118 119 for (i = 0; i < array->num_fences; ++i) 120 dma_fence_put(array->fences[i]); 121 122 kfree(array->fences); 123 dma_fence_free(fence); 124 } 125 126 const struct dma_fence_ops dma_fence_array_ops = { 127 .get_driver_name = dma_fence_array_get_driver_name, 128 .get_timeline_name = dma_fence_array_get_timeline_name, 129 .enable_signaling = dma_fence_array_enable_signaling, 130 .signaled = dma_fence_array_signaled, 131 .release = dma_fence_array_release, 132 }; 133 EXPORT_SYMBOL(dma_fence_array_ops); 134 135 /** 136 * dma_fence_array_create - Create a custom fence array 137 * @num_fences: [in] number of fences to add in the array 138 * @fences: [in] array containing the fences 139 * @context: [in] fence context to use 140 * @seqno: [in] sequence number to use 141 * @signal_on_any: [in] signal on any fence in the array 142 * 143 * Allocate a dma_fence_array object and initialize the base fence with 144 * dma_fence_init(). 145 * In case of error it returns NULL. 146 * 147 * The caller should allocate the fences array with num_fences size 148 * and fill it with the fences it wants to add to the object. Ownership of this 149 * array is taken and dma_fence_put() is used on each fence on release. 150 * 151 * If @signal_on_any is true the fence array signals if any fence in the array 152 * signals, otherwise it signals when all fences in the array signal. 153 */ 154 struct dma_fence_array *dma_fence_array_create(int num_fences, 155 struct dma_fence **fences, 156 u64 context, unsigned seqno, 157 bool signal_on_any) 158 { 159 struct dma_fence_array *array; 160 size_t size = sizeof(*array); 161 162 WARN_ON(!num_fences || !fences); 163 164 /* Allocate the callback structures behind the array. */ 165 size += num_fences * sizeof(struct dma_fence_array_cb); 166 array = kzalloc(size, GFP_KERNEL); 167 if (!array) 168 return NULL; 169 170 spin_lock_init(&array->lock); 171 dma_fence_init(&array->base, &dma_fence_array_ops, &array->lock, 172 context, seqno); 173 init_irq_work(&array->work, irq_dma_fence_array_work); 174 175 array->num_fences = num_fences; 176 atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences); 177 array->fences = fences; 178 179 array->base.error = PENDING_ERROR; 180 181 /* 182 * dma_fence_array objects should never contain any other fence 183 * containers or otherwise we run into recursion and potential kernel 184 * stack overflow on operations on the dma_fence_array. 185 * 186 * The correct way of handling this is to flatten out the array by the 187 * caller instead. 188 * 189 * Enforce this here by checking that we don't create a dma_fence_array 190 * with any container inside. 191 */ 192 while (num_fences--) 193 WARN_ON(dma_fence_is_container(fences[num_fences])); 194 195 return array; 196 } 197 EXPORT_SYMBOL(dma_fence_array_create); 198 199 /** 200 * dma_fence_match_context - Check if all fences are from the given context 201 * @fence: [in] fence or fence array 202 * @context: [in] fence context to check all fences against 203 * 204 * Checks the provided fence or, for a fence array, all fences in the array 205 * against the given context. Returns false if any fence is from a different 206 * context. 207 */ 208 bool dma_fence_match_context(struct dma_fence *fence, u64 context) 209 { 210 struct dma_fence_array *array = to_dma_fence_array(fence); 211 unsigned i; 212 213 if (!dma_fence_is_array(fence)) 214 return fence->context == context; 215 216 for (i = 0; i < array->num_fences; i++) { 217 if (array->fences[i]->context != context) 218 return false; 219 } 220 221 return true; 222 } 223 EXPORT_SYMBOL(dma_fence_match_context); 224 225 struct dma_fence *dma_fence_array_first(struct dma_fence *head) 226 { 227 struct dma_fence_array *array; 228 229 if (!head) 230 return NULL; 231 232 array = to_dma_fence_array(head); 233 if (!array) 234 return head; 235 236 if (!array->num_fences) 237 return NULL; 238 239 return array->fences[0]; 240 } 241 EXPORT_SYMBOL(dma_fence_array_first); 242 243 struct dma_fence *dma_fence_array_next(struct dma_fence *head, 244 unsigned int index) 245 { 246 struct dma_fence_array *array = to_dma_fence_array(head); 247 248 if (!array || index >= array->num_fences) 249 return NULL; 250 251 return array->fences[index]; 252 } 253 EXPORT_SYMBOL(dma_fence_array_next); 254