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(unsigned long data) 89 { 90 struct vgem_fence *fence = (struct vgem_fence *)data; 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 setup_timer(&fence->timer, vgem_fence_timeout, (unsigned long)fence); 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 drm_gem_object_reference(obj); 130 return 0; 131 } 132 133 /* 134 * vgem_fence_attach_ioctl (DRM_IOCTL_VGEM_FENCE_ATTACH): 135 * 136 * Create and attach a fence to the vGEM handle. This fence is then exposed 137 * via the dma-buf reservation object and visible to consumers of the exported 138 * dma-buf. If the flags contain VGEM_FENCE_WRITE, the fence indicates the 139 * vGEM buffer is being written to by the client and is exposed as an exclusive 140 * fence, otherwise the fence indicates the client is current reading from the 141 * buffer and all future writes should wait for the client to signal its 142 * completion. Note that if a conflicting fence is already on the dma-buf (i.e. 143 * an exclusive fence when adding a read, or any fence when adding a write), 144 * -EBUSY is reported. Serialisation between operations should be handled 145 * by waiting upon the dma-buf. 146 * 147 * This returns the handle for the new fence that must be signaled within 10 148 * seconds (or otherwise it will automatically expire). See 149 * vgem_fence_signal_ioctl (DRM_IOCTL_VGEM_FENCE_SIGNAL). 150 * 151 * If the vGEM handle does not exist, vgem_fence_attach_ioctl returns -ENOENT. 152 */ 153 int vgem_fence_attach_ioctl(struct drm_device *dev, 154 void *data, 155 struct drm_file *file) 156 { 157 struct drm_vgem_fence_attach *arg = data; 158 struct vgem_file *vfile = file->driver_priv; 159 struct reservation_object *resv; 160 struct drm_gem_object *obj; 161 struct dma_fence *fence; 162 int ret; 163 164 if (arg->flags & ~VGEM_FENCE_WRITE) 165 return -EINVAL; 166 167 if (arg->pad) 168 return -EINVAL; 169 170 obj = drm_gem_object_lookup(file, arg->handle); 171 if (!obj) 172 return -ENOENT; 173 174 ret = attach_dmabuf(dev, obj); 175 if (ret) 176 goto err; 177 178 fence = vgem_fence_create(vfile, arg->flags); 179 if (!fence) { 180 ret = -ENOMEM; 181 goto err; 182 } 183 184 /* Check for a conflicting fence */ 185 resv = obj->dma_buf->resv; 186 if (!reservation_object_test_signaled_rcu(resv, 187 arg->flags & VGEM_FENCE_WRITE)) { 188 ret = -EBUSY; 189 goto err_fence; 190 } 191 192 /* Expose the fence via the dma-buf */ 193 ret = 0; 194 mutex_lock(&resv->lock.base); 195 if (arg->flags & VGEM_FENCE_WRITE) 196 reservation_object_add_excl_fence(resv, fence); 197 else if ((ret = reservation_object_reserve_shared(resv)) == 0) 198 reservation_object_add_shared_fence(resv, fence); 199 mutex_unlock(&resv->lock.base); 200 201 /* Record the fence in our idr for later signaling */ 202 if (ret == 0) { 203 mutex_lock(&vfile->fence_mutex); 204 ret = idr_alloc(&vfile->fence_idr, fence, 1, 0, GFP_KERNEL); 205 mutex_unlock(&vfile->fence_mutex); 206 if (ret > 0) { 207 arg->out_fence = ret; 208 ret = 0; 209 } 210 } 211 err_fence: 212 if (ret) { 213 dma_fence_signal(fence); 214 dma_fence_put(fence); 215 } 216 err: 217 drm_gem_object_unreference_unlocked(obj); 218 return ret; 219 } 220 221 /* 222 * vgem_fence_signal_ioctl (DRM_IOCTL_VGEM_FENCE_SIGNAL): 223 * 224 * Signal and consume a fence ealier attached to a vGEM handle using 225 * vgem_fence_attach_ioctl (DRM_IOCTL_VGEM_FENCE_ATTACH). 226 * 227 * All fences must be signaled within 10s of attachment or otherwise they 228 * will automatically expire (and a vgem_fence_signal_ioctl returns -ETIMEDOUT). 229 * 230 * Signaling a fence indicates to all consumers of the dma-buf that the 231 * client has completed the operation associated with the fence, and that the 232 * buffer is then ready for consumption. 233 * 234 * If the fence does not exist (or has already been signaled by the client), 235 * vgem_fence_signal_ioctl returns -ENOENT. 236 */ 237 int vgem_fence_signal_ioctl(struct drm_device *dev, 238 void *data, 239 struct drm_file *file) 240 { 241 struct vgem_file *vfile = file->driver_priv; 242 struct drm_vgem_fence_signal *arg = data; 243 struct dma_fence *fence; 244 int ret = 0; 245 246 if (arg->flags) 247 return -EINVAL; 248 249 mutex_lock(&vfile->fence_mutex); 250 fence = idr_replace(&vfile->fence_idr, NULL, arg->fence); 251 mutex_unlock(&vfile->fence_mutex); 252 if (!fence) 253 return -ENOENT; 254 if (IS_ERR(fence)) 255 return PTR_ERR(fence); 256 257 if (dma_fence_is_signaled(fence)) 258 ret = -ETIMEDOUT; 259 260 dma_fence_signal(fence); 261 dma_fence_put(fence); 262 return ret; 263 } 264 265 int vgem_fence_open(struct vgem_file *vfile) 266 { 267 mutex_init(&vfile->fence_mutex); 268 idr_init(&vfile->fence_idr); 269 270 return 0; 271 } 272 273 static int __vgem_fence_idr_fini(int id, void *p, void *data) 274 { 275 dma_fence_signal(p); 276 dma_fence_put(p); 277 return 0; 278 } 279 280 void vgem_fence_close(struct vgem_file *vfile) 281 { 282 idr_for_each(&vfile->fence_idr, __vgem_fence_idr_fini, vfile); 283 idr_destroy(&vfile->fence_idr); 284 } 285