1 /* 2 * Copyright © 2012 Red Hat 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 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * 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 MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 * IN THE SOFTWARE. 22 * 23 * Authors: 24 * Dave Airlie <airlied@redhat.com> 25 * Rob Clark <rob.clark@linaro.org> 26 * 27 */ 28 29 #include <linux/export.h> 30 #include <linux/dma-buf.h> 31 #include "drmP.h" 32 33 /* 34 * DMA-BUF/GEM Object references and lifetime overview: 35 * 36 * On the export the dma_buf holds a reference to the exporting GEM 37 * object. It takes this reference in handle_to_fd_ioctl, when it 38 * first calls .prime_export and stores the exporting GEM object in 39 * the dma_buf priv. This reference is released when the dma_buf 40 * object goes away in the driver .release function. 41 * 42 * On the import the importing GEM object holds a reference to the 43 * dma_buf (which in turn holds a ref to the exporting GEM object). 44 * It takes that reference in the fd_to_handle ioctl. 45 * It calls dma_buf_get, creates an attachment to it and stores the 46 * attachment in the GEM object. When this attachment is destroyed 47 * when the imported object is destroyed, we remove the attachment 48 * and drop the reference to the dma_buf. 49 * 50 * Thus the chain of references always flows in one direction 51 * (avoiding loops): importing_gem -> dmabuf -> exporting_gem 52 * 53 * Self-importing: if userspace is using PRIME as a replacement for flink 54 * then it will get a fd->handle request for a GEM object that it created. 55 * Drivers should detect this situation and return back the gem object 56 * from the dma-buf private. 57 */ 58 59 struct drm_prime_member { 60 struct list_head entry; 61 struct dma_buf *dma_buf; 62 uint32_t handle; 63 }; 64 65 int drm_gem_prime_handle_to_fd(struct drm_device *dev, 66 struct drm_file *file_priv, uint32_t handle, uint32_t flags, 67 int *prime_fd) 68 { 69 struct drm_gem_object *obj; 70 void *buf; 71 72 obj = drm_gem_object_lookup(dev, file_priv, handle); 73 if (!obj) 74 return -ENOENT; 75 76 mutex_lock(&file_priv->prime.lock); 77 /* re-export the original imported object */ 78 if (obj->import_attach) { 79 get_dma_buf(obj->import_attach->dmabuf); 80 *prime_fd = dma_buf_fd(obj->import_attach->dmabuf, flags); 81 drm_gem_object_unreference_unlocked(obj); 82 mutex_unlock(&file_priv->prime.lock); 83 return 0; 84 } 85 86 if (obj->export_dma_buf) { 87 get_dma_buf(obj->export_dma_buf); 88 *prime_fd = dma_buf_fd(obj->export_dma_buf, flags); 89 drm_gem_object_unreference_unlocked(obj); 90 } else { 91 buf = dev->driver->gem_prime_export(dev, obj, flags); 92 if (IS_ERR(buf)) { 93 /* normally the created dma-buf takes ownership of the ref, 94 * but if that fails then drop the ref 95 */ 96 drm_gem_object_unreference_unlocked(obj); 97 mutex_unlock(&file_priv->prime.lock); 98 return PTR_ERR(buf); 99 } 100 obj->export_dma_buf = buf; 101 *prime_fd = dma_buf_fd(buf, flags); 102 } 103 mutex_unlock(&file_priv->prime.lock); 104 return 0; 105 } 106 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd); 107 108 int drm_gem_prime_fd_to_handle(struct drm_device *dev, 109 struct drm_file *file_priv, int prime_fd, uint32_t *handle) 110 { 111 struct dma_buf *dma_buf; 112 struct drm_gem_object *obj; 113 int ret; 114 115 dma_buf = dma_buf_get(prime_fd); 116 if (IS_ERR(dma_buf)) 117 return PTR_ERR(dma_buf); 118 119 mutex_lock(&file_priv->prime.lock); 120 121 ret = drm_prime_lookup_imported_buf_handle(&file_priv->prime, 122 dma_buf, handle); 123 if (!ret) { 124 ret = 0; 125 goto out_put; 126 } 127 128 /* never seen this one, need to import */ 129 obj = dev->driver->gem_prime_import(dev, dma_buf); 130 if (IS_ERR(obj)) { 131 ret = PTR_ERR(obj); 132 goto out_put; 133 } 134 135 ret = drm_gem_handle_create(file_priv, obj, handle); 136 drm_gem_object_unreference_unlocked(obj); 137 if (ret) 138 goto out_put; 139 140 ret = drm_prime_add_imported_buf_handle(&file_priv->prime, 141 dma_buf, *handle); 142 if (ret) 143 goto fail; 144 145 mutex_unlock(&file_priv->prime.lock); 146 return 0; 147 148 fail: 149 /* hmm, if driver attached, we are relying on the free-object path 150 * to detach.. which seems ok.. 151 */ 152 drm_gem_object_handle_unreference_unlocked(obj); 153 out_put: 154 dma_buf_put(dma_buf); 155 mutex_unlock(&file_priv->prime.lock); 156 return ret; 157 } 158 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle); 159 160 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data, 161 struct drm_file *file_priv) 162 { 163 struct drm_prime_handle *args = data; 164 uint32_t flags; 165 166 if (!drm_core_check_feature(dev, DRIVER_PRIME)) 167 return -EINVAL; 168 169 if (!dev->driver->prime_handle_to_fd) 170 return -ENOSYS; 171 172 /* check flags are valid */ 173 if (args->flags & ~DRM_CLOEXEC) 174 return -EINVAL; 175 176 /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */ 177 flags = args->flags & DRM_CLOEXEC; 178 179 return dev->driver->prime_handle_to_fd(dev, file_priv, 180 args->handle, flags, &args->fd); 181 } 182 183 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data, 184 struct drm_file *file_priv) 185 { 186 struct drm_prime_handle *args = data; 187 188 if (!drm_core_check_feature(dev, DRIVER_PRIME)) 189 return -EINVAL; 190 191 if (!dev->driver->prime_fd_to_handle) 192 return -ENOSYS; 193 194 return dev->driver->prime_fd_to_handle(dev, file_priv, 195 args->fd, &args->handle); 196 } 197 198 /* 199 * drm_prime_pages_to_sg 200 * 201 * this helper creates an sg table object from a set of pages 202 * the driver is responsible for mapping the pages into the 203 * importers address space 204 */ 205 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages) 206 { 207 struct sg_table *sg = NULL; 208 struct scatterlist *iter; 209 int i; 210 int ret; 211 212 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL); 213 if (!sg) 214 goto out; 215 216 ret = sg_alloc_table(sg, nr_pages, GFP_KERNEL); 217 if (ret) 218 goto out; 219 220 for_each_sg(sg->sgl, iter, nr_pages, i) 221 sg_set_page(iter, pages[i], PAGE_SIZE, 0); 222 223 return sg; 224 out: 225 kfree(sg); 226 return NULL; 227 } 228 EXPORT_SYMBOL(drm_prime_pages_to_sg); 229 230 /* helper function to cleanup a GEM/prime object */ 231 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg) 232 { 233 struct dma_buf_attachment *attach; 234 struct dma_buf *dma_buf; 235 attach = obj->import_attach; 236 if (sg) 237 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL); 238 dma_buf = attach->dmabuf; 239 dma_buf_detach(attach->dmabuf, attach); 240 /* remove the reference */ 241 dma_buf_put(dma_buf); 242 } 243 EXPORT_SYMBOL(drm_prime_gem_destroy); 244 245 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv) 246 { 247 INIT_LIST_HEAD(&prime_fpriv->head); 248 mutex_init(&prime_fpriv->lock); 249 } 250 EXPORT_SYMBOL(drm_prime_init_file_private); 251 252 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv) 253 { 254 struct drm_prime_member *member, *safe; 255 list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) { 256 list_del(&member->entry); 257 kfree(member); 258 } 259 } 260 EXPORT_SYMBOL(drm_prime_destroy_file_private); 261 262 int drm_prime_add_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle) 263 { 264 struct drm_prime_member *member; 265 266 member = kmalloc(sizeof(*member), GFP_KERNEL); 267 if (!member) 268 return -ENOMEM; 269 270 member->dma_buf = dma_buf; 271 member->handle = handle; 272 list_add(&member->entry, &prime_fpriv->head); 273 return 0; 274 } 275 EXPORT_SYMBOL(drm_prime_add_imported_buf_handle); 276 277 int drm_prime_lookup_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle) 278 { 279 struct drm_prime_member *member; 280 281 list_for_each_entry(member, &prime_fpriv->head, entry) { 282 if (member->dma_buf == dma_buf) { 283 *handle = member->handle; 284 return 0; 285 } 286 } 287 return -ENOENT; 288 } 289 EXPORT_SYMBOL(drm_prime_lookup_imported_buf_handle); 290 291 void drm_prime_remove_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf) 292 { 293 struct drm_prime_member *member, *safe; 294 295 mutex_lock(&prime_fpriv->lock); 296 list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) { 297 if (member->dma_buf == dma_buf) { 298 list_del(&member->entry); 299 kfree(member); 300 } 301 } 302 mutex_unlock(&prime_fpriv->lock); 303 } 304 EXPORT_SYMBOL(drm_prime_remove_imported_buf_handle); 305