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1/*2 * Copyright 2016 Intel Corporation3 *4 * Permission is hereby granted, free of charge, to any person obtaining a5 * copy of this software and associated documentation files (the "Software")6 * to deal in the software without restriction, including without limitation7 * on the rights to use, copy, modify, merge, publish, distribute, sub8 * license, and/or sell copies of the Software, and to permit persons to whom9 * them Software is furnished to do so, subject to the following conditions:10 *11 * The above copyright notice and this permission notice (including the next12 * paragraph) shall be included in all copies or substantial portions of the13 * Software.14 *15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTIBILITY,17 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL18 * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY, WHETHER19 * IN AN ACTION OF CONTRACT, TORT, OR OTHERWISE, ARISING FROM, OUT OF OR IN20 * 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 32struct vgem_fence {33 struct dma_fence base;34 struct spinlock lock;35 struct timer_list timer;36};37 38static const char *vgem_fence_get_driver_name(struct dma_fence *fence)39{40 return "vgem";41}42 43static const char *vgem_fence_get_timeline_name(struct dma_fence *fence)44{45 return "unbound";46}47 48static 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 56static void vgem_fence_value_str(struct dma_fence *fence, char *str, int size)57{58 snprintf(str, size, "%llu", fence->seqno);59}60 61static 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 68static 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 77static 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 84static 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 exposed109 * via the dma-buf reservation object and visible to consumers of the exported110 * dma-buf. If the flags contain VGEM_FENCE_WRITE, the fence indicates the111 * vGEM buffer is being written to by the client and is exposed as an exclusive112 * fence, otherwise the fence indicates the client is current reading from the113 * buffer and all future writes should wait for the client to signal its114 * 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 handled117 * by waiting upon the dma-buf.118 *119 * This returns the handle for the new fence that must be signaled within 10120 * seconds (or otherwise it will automatically expire). See121 * 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 */125int 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 }179err_fence:180 if (ret) {181 dma_fence_signal(fence);182 dma_fence_put(fence);183 }184err: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 using193 * vgem_fence_attach_ioctl (DRM_IOCTL_VGEM_FENCE_ATTACH).194 *195 * All fences must be signaled within 10s of attachment or otherwise they196 * 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 the199 * client has completed the operation associated with the fence, and that the200 * 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 */205int 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 233int 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 241static 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 248void 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 mutex_destroy(&vfile->fence_mutex);253}254