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/dma-resv.h> 25 26 #include <drm/drm_file.h> 27 28 #include "vgem_drv.h" 29 30 #define VGEM_FENCE_TIMEOUT (10*HZ) 31 32 struct vgem_fence { 33 struct dma_fence base; 34 struct spinlock lock; 35 struct timer_list timer; 36 }; 37 38 static const char *vgem_fence_get_driver_name(struct dma_fence *fence) 39 { 40 return "vgem"; 41 } 42 43 static const char *vgem_fence_get_timeline_name(struct dma_fence *fence) 44 { 45 return "unbound"; 46 } 47 48 static void vgem_fence_release(struct dma_fence *base) 49 { 50 struct vgem_fence *fence = container_of(base, typeof(*fence), base); 51 52 del_timer_sync(&fence->timer); 53 dma_fence_free(&fence->base); 54 } 55 56 static void vgem_fence_value_str(struct dma_fence *fence, char *str, int size) 57 { 58 snprintf(str, size, "%llu", fence->seqno); 59 } 60 61 static void vgem_fence_timeline_value_str(struct dma_fence *fence, char *str, 62 int size) 63 { 64 snprintf(str, size, "%llu", 65 dma_fence_is_signaled(fence) ? fence->seqno : 0); 66 } 67 68 static const struct dma_fence_ops vgem_fence_ops = { 69 .get_driver_name = vgem_fence_get_driver_name, 70 .get_timeline_name = vgem_fence_get_timeline_name, 71 .release = vgem_fence_release, 72 73 .fence_value_str = vgem_fence_value_str, 74 .timeline_value_str = vgem_fence_timeline_value_str, 75 }; 76 77 static void vgem_fence_timeout(struct timer_list *t) 78 { 79 struct vgem_fence *fence = from_timer(fence, t, timer); 80 81 dma_fence_signal(&fence->base); 82 } 83 84 static struct dma_fence *vgem_fence_create(struct vgem_file *vfile, 85 unsigned int flags) 86 { 87 struct vgem_fence *fence; 88 89 fence = kzalloc(sizeof(*fence), GFP_KERNEL); 90 if (!fence) 91 return NULL; 92 93 spin_lock_init(&fence->lock); 94 dma_fence_init(&fence->base, &vgem_fence_ops, &fence->lock, 95 dma_fence_context_alloc(1), 1); 96 97 timer_setup(&fence->timer, vgem_fence_timeout, 0); 98 99 /* We force the fence to expire within 10s to prevent driver hangs */ 100 mod_timer(&fence->timer, jiffies + VGEM_FENCE_TIMEOUT); 101 102 return &fence->base; 103 } 104 105 /* 106 * vgem_fence_attach_ioctl (DRM_IOCTL_VGEM_FENCE_ATTACH): 107 * 108 * Create and attach a fence to the vGEM handle. This fence is then exposed 109 * via the dma-buf reservation object and visible to consumers of the exported 110 * dma-buf. If the flags contain VGEM_FENCE_WRITE, the fence indicates the 111 * vGEM buffer is being written to by the client and is exposed as an exclusive 112 * fence, otherwise the fence indicates the client is current reading from the 113 * buffer and all future writes should wait for the client to signal its 114 * completion. Note that if a conflicting fence is already on the dma-buf (i.e. 115 * an exclusive fence when adding a read, or any fence when adding a write), 116 * -EBUSY is reported. Serialisation between operations should be handled 117 * by waiting upon the dma-buf. 118 * 119 * This returns the handle for the new fence that must be signaled within 10 120 * seconds (or otherwise it will automatically expire). See 121 * vgem_fence_signal_ioctl (DRM_IOCTL_VGEM_FENCE_SIGNAL). 122 * 123 * If the vGEM handle does not exist, vgem_fence_attach_ioctl returns -ENOENT. 124 */ 125 int vgem_fence_attach_ioctl(struct drm_device *dev, 126 void *data, 127 struct drm_file *file) 128 { 129 struct drm_vgem_fence_attach *arg = data; 130 struct vgem_file *vfile = file->driver_priv; 131 struct dma_resv *resv; 132 struct drm_gem_object *obj; 133 enum dma_resv_usage usage; 134 struct dma_fence *fence; 135 int ret; 136 137 if (arg->flags & ~VGEM_FENCE_WRITE) 138 return -EINVAL; 139 140 if (arg->pad) 141 return -EINVAL; 142 143 obj = drm_gem_object_lookup(file, arg->handle); 144 if (!obj) 145 return -ENOENT; 146 147 fence = vgem_fence_create(vfile, arg->flags); 148 if (!fence) { 149 ret = -ENOMEM; 150 goto err; 151 } 152 153 /* Check for a conflicting fence */ 154 resv = obj->resv; 155 usage = dma_resv_usage_rw(arg->flags & VGEM_FENCE_WRITE); 156 if (!dma_resv_test_signaled(resv, usage)) { 157 ret = -EBUSY; 158 goto err_fence; 159 } 160 161 /* Expose the fence via the dma-buf */ 162 dma_resv_lock(resv, NULL); 163 ret = dma_resv_reserve_fences(resv, 1); 164 if (!ret) 165 dma_resv_add_fence(resv, fence, arg->flags & VGEM_FENCE_WRITE ? 166 DMA_RESV_USAGE_WRITE : DMA_RESV_USAGE_READ); 167 dma_resv_unlock(resv); 168 169 /* Record the fence in our idr for later signaling */ 170 if (ret == 0) { 171 mutex_lock(&vfile->fence_mutex); 172 ret = idr_alloc(&vfile->fence_idr, fence, 1, 0, GFP_KERNEL); 173 mutex_unlock(&vfile->fence_mutex); 174 if (ret > 0) { 175 arg->out_fence = ret; 176 ret = 0; 177 } 178 } 179 err_fence: 180 if (ret) { 181 dma_fence_signal(fence); 182 dma_fence_put(fence); 183 } 184 err: 185 drm_gem_object_put(obj); 186 return ret; 187 } 188 189 /* 190 * vgem_fence_signal_ioctl (DRM_IOCTL_VGEM_FENCE_SIGNAL): 191 * 192 * Signal and consume a fence ealier attached to a vGEM handle using 193 * vgem_fence_attach_ioctl (DRM_IOCTL_VGEM_FENCE_ATTACH). 194 * 195 * All fences must be signaled within 10s of attachment or otherwise they 196 * will automatically expire (and a vgem_fence_signal_ioctl returns -ETIMEDOUT). 197 * 198 * Signaling a fence indicates to all consumers of the dma-buf that the 199 * client has completed the operation associated with the fence, and that the 200 * buffer is then ready for consumption. 201 * 202 * If the fence does not exist (or has already been signaled by the client), 203 * vgem_fence_signal_ioctl returns -ENOENT. 204 */ 205 int vgem_fence_signal_ioctl(struct drm_device *dev, 206 void *data, 207 struct drm_file *file) 208 { 209 struct vgem_file *vfile = file->driver_priv; 210 struct drm_vgem_fence_signal *arg = data; 211 struct dma_fence *fence; 212 int ret = 0; 213 214 if (arg->flags) 215 return -EINVAL; 216 217 mutex_lock(&vfile->fence_mutex); 218 fence = idr_replace(&vfile->fence_idr, NULL, arg->fence); 219 mutex_unlock(&vfile->fence_mutex); 220 if (!fence) 221 return -ENOENT; 222 if (IS_ERR(fence)) 223 return PTR_ERR(fence); 224 225 if (dma_fence_is_signaled(fence)) 226 ret = -ETIMEDOUT; 227 228 dma_fence_signal(fence); 229 dma_fence_put(fence); 230 return ret; 231 } 232 233 int vgem_fence_open(struct vgem_file *vfile) 234 { 235 mutex_init(&vfile->fence_mutex); 236 idr_init_base(&vfile->fence_idr, 1); 237 238 return 0; 239 } 240 241 static int __vgem_fence_idr_fini(int id, void *p, void *data) 242 { 243 dma_fence_signal(p); 244 dma_fence_put(p); 245 return 0; 246 } 247 248 void vgem_fence_close(struct vgem_file *vfile) 249 { 250 idr_for_each(&vfile->fence_idr, __vgem_fence_idr_fini, vfile); 251 idr_destroy(&vfile->fence_idr); 252 } 253