1 /* 2 * Copyright 2016 Intel Corporation 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software") 6 * to deal in the software without restriction, including without limitation 7 * on the rights to use, copy, modify, merge, publish, distribute, sub 8 * license, and/or sell copies of the Software, and to permit persons to whom 9 * them Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTIBILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY, WHETHER 19 * IN AN ACTION OF CONTRACT, TORT, OR OTHERWISE, ARISING FROM, OUT OF OR IN 20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 21 */ 22 23 #include <linux/dma-buf.h> 24 #include <linux/reservation.h> 25 26 #include "vgem_drv.h" 27 28 #define VGEM_FENCE_TIMEOUT (10*HZ) 29 30 struct vgem_fence { 31 struct dma_fence base; 32 struct spinlock lock; 33 struct timer_list timer; 34 }; 35 36 static const char *vgem_fence_get_driver_name(struct dma_fence *fence) 37 { 38 return "vgem"; 39 } 40 41 static const char *vgem_fence_get_timeline_name(struct dma_fence *fence) 42 { 43 return "unbound"; 44 } 45 46 static bool vgem_fence_signaled(struct dma_fence *fence) 47 { 48 return false; 49 } 50 51 static bool vgem_fence_enable_signaling(struct dma_fence *fence) 52 { 53 return true; 54 } 55 56 static void vgem_fence_release(struct dma_fence *base) 57 { 58 struct vgem_fence *fence = container_of(base, typeof(*fence), base); 59 60 del_timer_sync(&fence->timer); 61 dma_fence_free(&fence->base); 62 } 63 64 static void vgem_fence_value_str(struct dma_fence *fence, char *str, int size) 65 { 66 snprintf(str, size, "%u", fence->seqno); 67 } 68 69 static void vgem_fence_timeline_value_str(struct dma_fence *fence, char *str, 70 int size) 71 { 72 snprintf(str, size, "%u", 73 dma_fence_is_signaled(fence) ? fence->seqno : 0); 74 } 75 76 static const struct dma_fence_ops vgem_fence_ops = { 77 .get_driver_name = vgem_fence_get_driver_name, 78 .get_timeline_name = vgem_fence_get_timeline_name, 79 .enable_signaling = vgem_fence_enable_signaling, 80 .signaled = vgem_fence_signaled, 81 .wait = dma_fence_default_wait, 82 .release = vgem_fence_release, 83 84 .fence_value_str = vgem_fence_value_str, 85 .timeline_value_str = vgem_fence_timeline_value_str, 86 }; 87 88 static void vgem_fence_timeout(struct timer_list *t) 89 { 90 struct vgem_fence *fence = from_timer(fence, t, timer); 91 92 dma_fence_signal(&fence->base); 93 } 94 95 static struct dma_fence *vgem_fence_create(struct vgem_file *vfile, 96 unsigned int flags) 97 { 98 struct vgem_fence *fence; 99 100 fence = kzalloc(sizeof(*fence), GFP_KERNEL); 101 if (!fence) 102 return NULL; 103 104 spin_lock_init(&fence->lock); 105 dma_fence_init(&fence->base, &vgem_fence_ops, &fence->lock, 106 dma_fence_context_alloc(1), 1); 107 108 timer_setup(&fence->timer, vgem_fence_timeout, 0); 109 110 /* We force the fence to expire within 10s to prevent driver hangs */ 111 mod_timer(&fence->timer, jiffies + VGEM_FENCE_TIMEOUT); 112 113 return &fence->base; 114 } 115 116 static int attach_dmabuf(struct drm_device *dev, 117 struct drm_gem_object *obj) 118 { 119 struct dma_buf *dmabuf; 120 121 if (obj->dma_buf) 122 return 0; 123 124 dmabuf = dev->driver->gem_prime_export(dev, obj, 0); 125 if (IS_ERR(dmabuf)) 126 return PTR_ERR(dmabuf); 127 128 obj->dma_buf = dmabuf; 129 return 0; 130 } 131 132 /* 133 * vgem_fence_attach_ioctl (DRM_IOCTL_VGEM_FENCE_ATTACH): 134 * 135 * Create and attach a fence to the vGEM handle. This fence is then exposed 136 * via the dma-buf reservation object and visible to consumers of the exported 137 * dma-buf. If the flags contain VGEM_FENCE_WRITE, the fence indicates the 138 * vGEM buffer is being written to by the client and is exposed as an exclusive 139 * fence, otherwise the fence indicates the client is current reading from the 140 * buffer and all future writes should wait for the client to signal its 141 * completion. Note that if a conflicting fence is already on the dma-buf (i.e. 142 * an exclusive fence when adding a read, or any fence when adding a write), 143 * -EBUSY is reported. Serialisation between operations should be handled 144 * by waiting upon the dma-buf. 145 * 146 * This returns the handle for the new fence that must be signaled within 10 147 * seconds (or otherwise it will automatically expire). See 148 * vgem_fence_signal_ioctl (DRM_IOCTL_VGEM_FENCE_SIGNAL). 149 * 150 * If the vGEM handle does not exist, vgem_fence_attach_ioctl returns -ENOENT. 151 */ 152 int vgem_fence_attach_ioctl(struct drm_device *dev, 153 void *data, 154 struct drm_file *file) 155 { 156 struct drm_vgem_fence_attach *arg = data; 157 struct vgem_file *vfile = file->driver_priv; 158 struct reservation_object *resv; 159 struct drm_gem_object *obj; 160 struct dma_fence *fence; 161 int ret; 162 163 if (arg->flags & ~VGEM_FENCE_WRITE) 164 return -EINVAL; 165 166 if (arg->pad) 167 return -EINVAL; 168 169 obj = drm_gem_object_lookup(file, arg->handle); 170 if (!obj) 171 return -ENOENT; 172 173 ret = attach_dmabuf(dev, obj); 174 if (ret) 175 goto err; 176 177 fence = vgem_fence_create(vfile, arg->flags); 178 if (!fence) { 179 ret = -ENOMEM; 180 goto err; 181 } 182 183 /* Check for a conflicting fence */ 184 resv = obj->dma_buf->resv; 185 if (!reservation_object_test_signaled_rcu(resv, 186 arg->flags & VGEM_FENCE_WRITE)) { 187 ret = -EBUSY; 188 goto err_fence; 189 } 190 191 /* Expose the fence via the dma-buf */ 192 ret = 0; 193 reservation_object_lock(resv, NULL); 194 if (arg->flags & VGEM_FENCE_WRITE) 195 reservation_object_add_excl_fence(resv, fence); 196 else if ((ret = reservation_object_reserve_shared(resv)) == 0) 197 reservation_object_add_shared_fence(resv, fence); 198 reservation_object_unlock(resv); 199 200 /* Record the fence in our idr for later signaling */ 201 if (ret == 0) { 202 mutex_lock(&vfile->fence_mutex); 203 ret = idr_alloc(&vfile->fence_idr, fence, 1, 0, GFP_KERNEL); 204 mutex_unlock(&vfile->fence_mutex); 205 if (ret > 0) { 206 arg->out_fence = ret; 207 ret = 0; 208 } 209 } 210 err_fence: 211 if (ret) { 212 dma_fence_signal(fence); 213 dma_fence_put(fence); 214 } 215 err: 216 drm_gem_object_put_unlocked(obj); 217 return ret; 218 } 219 220 /* 221 * vgem_fence_signal_ioctl (DRM_IOCTL_VGEM_FENCE_SIGNAL): 222 * 223 * Signal and consume a fence ealier attached to a vGEM handle using 224 * vgem_fence_attach_ioctl (DRM_IOCTL_VGEM_FENCE_ATTACH). 225 * 226 * All fences must be signaled within 10s of attachment or otherwise they 227 * will automatically expire (and a vgem_fence_signal_ioctl returns -ETIMEDOUT). 228 * 229 * Signaling a fence indicates to all consumers of the dma-buf that the 230 * client has completed the operation associated with the fence, and that the 231 * buffer is then ready for consumption. 232 * 233 * If the fence does not exist (or has already been signaled by the client), 234 * vgem_fence_signal_ioctl returns -ENOENT. 235 */ 236 int vgem_fence_signal_ioctl(struct drm_device *dev, 237 void *data, 238 struct drm_file *file) 239 { 240 struct vgem_file *vfile = file->driver_priv; 241 struct drm_vgem_fence_signal *arg = data; 242 struct dma_fence *fence; 243 int ret = 0; 244 245 if (arg->flags) 246 return -EINVAL; 247 248 mutex_lock(&vfile->fence_mutex); 249 fence = idr_replace(&vfile->fence_idr, NULL, arg->fence); 250 mutex_unlock(&vfile->fence_mutex); 251 if (!fence) 252 return -ENOENT; 253 if (IS_ERR(fence)) 254 return PTR_ERR(fence); 255 256 if (dma_fence_is_signaled(fence)) 257 ret = -ETIMEDOUT; 258 259 dma_fence_signal(fence); 260 dma_fence_put(fence); 261 return ret; 262 } 263 264 int vgem_fence_open(struct vgem_file *vfile) 265 { 266 mutex_init(&vfile->fence_mutex); 267 idr_init(&vfile->fence_idr); 268 269 return 0; 270 } 271 272 static int __vgem_fence_idr_fini(int id, void *p, void *data) 273 { 274 dma_fence_signal(p); 275 dma_fence_put(p); 276 return 0; 277 } 278 279 void vgem_fence_close(struct vgem_file *vfile) 280 { 281 idr_for_each(&vfile->fence_idr, __vgem_fence_idr_fini, vfile); 282 idr_destroy(&vfile->fence_idr); 283 } 284