drivers/gpu/drm/img-rogue/pvr_buffer_sync.c - chromiumos/third_party/kernel - Git at Google

 /* -*- mode: c; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
 /* vi: set ts=8 sw=8 sts=8: */
 /*************************************************************************/ /*!
 @File
 @Title          Linux buffer sync interface
 @Codingstyle    LinuxKernel
 @Copyright      Copyright (c) Imagination Technologies Ltd. All Rights Reserved
 @License        Dual MIT/GPLv2

 The contents of this file are subject to the MIT license as set out below.

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

 Alternatively, the contents of this file may be used under the terms of
 the GNU General Public License Version 2 ("GPL") in which case the provisions
 of GPL are applicable instead of those above.

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 GPL, and not to allow others to use your version of this file under the terms
 of the MIT license, indicate your decision by deleting the provisions above
 and replace them with the notice and other provisions required by GPL as set
 out in the file called "GPL-COPYING" included in this distribution. If you do
 not delete the provisions above, a recipient may use your version of this file
 under the terms of either the MIT license or GPL.

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 "MIT-COPYING".

 EXCEPT AS OTHERWISE STATED IN A NEGOTIATED AGREEMENT: (A) THE SOFTWARE IS
 PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
 BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 PURPOSE AND NONINFRINGEMENT; AND (B) IN NO EVENT SHALL THE AUTHORS OR
 COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */ /**************************************************************************/

 #include <linux/dma-buf.h>
 #include <linux/reservation.h>

 #include "pvr_buffer_sync.h"
 #include "pvr_buffer_sync_shared.h"
 #include "pvr_fence.h"
 #include "services_kernel_client.h"

 struct pvr_buffer_sync_context {
 	struct pvr_fence_context *fence_ctx;
 	struct ww_acquire_ctx acquire_ctx;
 };

 struct pvr_buffer_sync_check_data {
 	struct dma_fence_cb base;

 	u32 nr_fences;
 	struct pvr_fence **fences;
 };

 struct pvr_buffer_sync_append_data {
 	bool appended;

 	struct pvr_buffer_sync_context *ctx;

 	u32 nr_checks;
 	struct _RGXFWIF_DEV_VIRTADDR_ *check_ufo_addrs;
 	u32 *check_values;

 	u32 nr_updates;
 	struct _RGXFWIF_DEV_VIRTADDR_ *update_ufo_addrs;
 	u32 *update_values;

 	u32 nr_pmrs;
 	struct _PMR_ **pmrs;
 	u32 *pmr_flags;

 	struct pvr_fence *update_fence;
 };


 static struct reservation_object *
 pmr_reservation_object_get(struct _PMR_ *pmr)
 {
 	struct dma_buf *dmabuf;

 	dmabuf = PhysmemGetDmaBuf(pmr);
 	if (dmabuf)
 		return dmabuf->resv;

 	return NULL;
 }

 static int
 pvr_buffer_sync_pmrs_lock(struct ww_acquire_ctx *acquire_ctx,
 			  u32 nr_pmrs,
 			  struct _PMR_ **pmrs)
 {
 	struct reservation_object *resv, *cresv = NULL, *lresv = NULL;
 	int i, err;

 	ww_acquire_init(acquire_ctx, &reservation_ww_class);
 retry:
 	for (i = 0; i < nr_pmrs; i++) {
 		resv = pmr_reservation_object_get(pmrs[i]);
 		if (!resv) {
 			pr_err("%s: Failed to get reservation object from pmr %p\n",
 			       __func__, pmrs[i]);
 			err = -EINVAL;
 			goto fail;
 		}

 		if (resv != lresv) {
 			err = ww_mutex_lock_interruptible(&resv->lock,
 							  acquire_ctx);
 			if (err) {
 				cresv = (err == -EDEADLK) ? resv : NULL;
 				goto fail;
 			}
 		} else {
 			lresv = NULL;
 		}
 	}

 	ww_acquire_done(acquire_ctx);

 	return 0;

 fail:
 	while (i--) {
 		resv = pmr_reservation_object_get(pmrs[i]);
 		if (WARN_ON_ONCE(!resv))
 			continue;
 		ww_mutex_unlock(&resv->lock);
 	}

 	if (lresv)
 		ww_mutex_unlock(&lresv->lock);

 	if (cresv) {
 		err = ww_mutex_lock_slow_interruptible(&cresv->lock,
 						       acquire_ctx);
 		if (!err) {
 			lresv = cresv;
 			cresv = NULL;
 			goto retry;
 		}
 	}

 	return err;
 }

 static void
 pvr_buffer_sync_pmrs_unlock(struct ww_acquire_ctx *acquire_ctx,
 			    u32 nr_pmrs,
 			    struct _PMR_ **pmrs)
 {
 	struct reservation_object *resv;
 	int i;

 	for (i = 0; i < nr_pmrs; i++) {
 		resv = pmr_reservation_object_get(pmrs[i]);
 		if (WARN_ON_ONCE(!resv))
 			continue;
 		ww_mutex_unlock(&resv->lock);
 	}

 	ww_acquire_fini(acquire_ctx);
 }

 static u32
 pvr_buffer_sync_pmrs_fence_count(u32 nr_pmrs, struct _PMR_ **pmrs,
 				 u32 *pmr_flags)
 {
 	struct reservation_object *resv;
 	struct reservation_object_list *resv_list;
 	struct dma_fence *fence;
 	u32 fence_count = 0;
 	bool exclusive;
 	int i;

 	for (i = 0; i < nr_pmrs; i++) {
 		exclusive = !!(pmr_flags[i] & PVR_BUFFER_FLAG_WRITE);

 		resv = pmr_reservation_object_get(pmrs[i]);
 		if (WARN_ON_ONCE(!resv))
 			continue;

 		resv_list = reservation_object_get_list(resv);
 		fence = reservation_object_get_excl(resv);

 		if (fence &&
 		    (!exclusive || !resv_list || !resv_list->shared_count))
 			fence_count++;

 		if (exclusive && resv_list)
 			fence_count += resv_list->shared_count;
 	}

 	return fence_count;
 }

 static struct pvr_buffer_sync_check_data *
 pvr_buffer_sync_check_fences_create(struct pvr_fence_context *fence_ctx,
 				    u32 nr_pmrs,
 				    struct _PMR_ **pmrs,
 				    u32 *pmr_flags)
 {
 	struct pvr_buffer_sync_check_data *data;
 	struct reservation_object *resv;
 	struct reservation_object_list *resv_list;
 	struct dma_fence *fence;
 	u32 fence_count;
 	bool exclusive;
 	int i, j;
 	int err;

 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return NULL;

 	fence_count = pvr_buffer_sync_pmrs_fence_count(nr_pmrs, pmrs,
 						       pmr_flags);
 	if (fence_count) {
 		data->fences = kcalloc(fence_count, sizeof(*data->fences),
 				       GFP_KERNEL);
 		if (!data->fences)
 			goto err_check_data_free;
 	}

 	for (i = 0; i < nr_pmrs; i++) {
 		resv = pmr_reservation_object_get(pmrs[i]);
 		if (WARN_ON_ONCE(!resv))
 			continue;

 		exclusive = !!(pmr_flags[i] & PVR_BUFFER_FLAG_WRITE);
 		if (!exclusive) {
 			err = reservation_object_reserve_shared(resv);
 			if (err)
 				goto err_destroy_fences;
 		}

 		resv_list = reservation_object_get_list(resv);
 		fence = reservation_object_get_excl(resv);

 		if (fence &&
 		    (!exclusive || !resv_list || !resv_list->shared_count)) {
 			data->fences[data->nr_fences++] =
 				pvr_fence_create_from_fence(fence_ctx,
 							    fence,
 							    "exclusive check fence");
 			if (!data->fences[data->nr_fences - 1]) {
 				data->nr_fences--;
 				PVR_FENCE_TRACE(fence,
 						"waiting on exclusive fence\n");
 				WARN_ON(dma_fence_wait(fence, true) <= 0);
 			}
 		}

 		if (exclusive && resv_list) {
 			for (j = 0; j < resv_list->shared_count; j++) {
 				fence = rcu_dereference_protected(resv_list->shared[j],
 								  reservation_object_held(resv));
 				data->fences[data->nr_fences++] =
 					pvr_fence_create_from_fence(fence_ctx,
 								    fence,
 								    "check fence");
 				if (!data->fences[data->nr_fences - 1]) {
 					data->nr_fences--;
 					PVR_FENCE_TRACE(fence,
 							"waiting on non-exclusive fence\n");
 					WARN_ON(dma_fence_wait(fence, true) <= 0);
 				}
 			}
 		}
 	}

 	WARN_ON((i != nr_pmrs) || (data->nr_fences != fence_count));

 	return data;

 err_destroy_fences:
 	for (i = 0; i < data->nr_fences; i++)
 		pvr_fence_destroy(data->fences[i]);
 	kfree(data->fences);
 err_check_data_free:
 	kfree(data);
 	return NULL;
 }

 static void
 pvr_buffer_sync_check_fences_destroy(struct pvr_buffer_sync_check_data *data)
 {
 	int i;

 	for (i = 0; i < data->nr_fences; i++)
 		pvr_fence_destroy(data->fences[i]);

 	kfree(data->fences);
 	kfree(data);
 }

 static void
 pvr_buffer_sync_check_data_cleanup(struct dma_fence *fence,
 				   struct dma_fence_cb *cb)
 {
 	struct pvr_buffer_sync_check_data *data =
 		container_of(cb, struct pvr_buffer_sync_check_data, base);
 	struct pvr_fence *pvr_fence = to_pvr_fence(fence);

 	pvr_buffer_sync_check_fences_destroy(data);

 	pvr_fence_destroy(pvr_fence);
 }

 static int
 pvr_buffer_sync_append_fences(u32 nr,
 			      struct _RGXFWIF_DEV_VIRTADDR_ *ufo_addrs,
 			      u32 *values,
 			      u32 nr_fences,
 			      struct pvr_fence **pvr_fences,
 			      u32 *nr_out,
 			      struct _RGXFWIF_DEV_VIRTADDR_ **ufo_addrs_out,
 			      u32 **values_out)
 {
 	u32 nr_new = nr + nr_fences;
 	struct _RGXFWIF_DEV_VIRTADDR_ *ufo_addrs_new = NULL;
 	u32 sync_addr;
 	u32 *values_new = NULL;
 	int i;
 	int err;

 	if (!nr_new)
 		goto finish;

 	ufo_addrs_new = kmalloc_array(nr_new, sizeof(*ufo_addrs_new),
 				      GFP_KERNEL);
 	if (!ufo_addrs_new)
 		return -ENOMEM;

 	values_new = kmalloc_array(nr_new, sizeof(*values_new), GFP_KERNEL);
 	if (!values_new) {
 		err = -ENOMEM;
 		goto err_free_ufo_addrs;
 	}

 	/* Copy the original data */
 	if (nr) {
 		memcpy(ufo_addrs_new, ufo_addrs, sizeof(*ufo_addrs) * nr);
 		memcpy(values_new, values, sizeof(*values) * nr);
 	}

 	/* Append the fence data */
 	for (i = 0; i < nr_fences; i++) {
 		PVRSRV_ERROR srv_err;

 		srv_err = SyncPrimGetFirmwareAddr(pvr_fences[i]->sync,
 						  &sync_addr);
 		if (srv_err != PVRSRV_OK) {
 			err = -EINVAL;
 			goto err_free_values;
 		}
 		ufo_addrs_new[i + nr].ui32Addr = sync_addr;
 		values_new[i + nr] = PVR_FENCE_SYNC_VAL_SIGNALED;
 	}

 finish:
 	*nr_out = nr_new;
 	*ufo_addrs_out = ufo_addrs_new;
 	*values_out = values_new;

 	return 0;

 err_free_values:
 	kfree(values_new);
 err_free_ufo_addrs:
 	kfree(ufo_addrs_new);
 	return err;
 }

 struct pvr_buffer_sync_context *
 pvr_buffer_sync_context_create(void *dev_cookie)
 {
 	struct pvr_buffer_sync_context *ctx;
 	int err;

 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 	if (!ctx) {
 		err = -ENOMEM;
 		goto err_exit;
 	}

 	ctx->fence_ctx = pvr_fence_context_create(dev_cookie, "rogue-gpu");
 	if (!ctx->fence_ctx) {
 		err = -ENOMEM;
 		goto err_free_ctx;
 	}

 	return ctx;

 err_free_ctx:
 	kfree(ctx);
 err_exit:
 	return ERR_PTR(err);
 }

 void pvr_buffer_sync_context_destroy(struct pvr_buffer_sync_context *ctx)
 {
 	pvr_fence_context_destroy(ctx->fence_ctx);
 	kfree(ctx);
 }

 int
 pvr_buffer_sync_append_start(struct pvr_buffer_sync_context *ctx,
 			     u32 nr_pmrs,
 			     struct _PMR_ **pmrs,
 			     u32 *pmr_flags,
 			     u32 nr_checks,
 			     struct _RGXFWIF_DEV_VIRTADDR_ *check_ufo_addrs,
 			     u32 *check_values,
 			     u32 nr_updates,
 			     struct _RGXFWIF_DEV_VIRTADDR_ *update_ufo_addrs,
 			     u32 *update_values,
 			     struct pvr_buffer_sync_append_data **data_out)
 {
 	struct pvr_buffer_sync_append_data *data;
 	struct pvr_buffer_sync_check_data *check_data;
 	const size_t data_size = sizeof(*data);
 	const size_t pmrs_size = sizeof(*pmrs) * nr_pmrs;
 	const size_t pmr_flags_size = sizeof(*pmr_flags) * nr_pmrs;
 	int i;
 	int j;
 	int err;

 	if ((nr_pmrs && !(pmrs && pmr_flags)) ||
 	    (nr_updates && (!update_ufo_addrs || !update_values)) ||
 	    (nr_checks && (!check_ufo_addrs || !check_values)))
 		return -EINVAL;

 	for (i = 0; i < nr_pmrs; i++) {
 		if (!(pmr_flags[i] & PVR_BUFFER_FLAG_MASK)) {
 			pr_err("%s: Invalid flags %#08x for pmr %p\n",
 			       __func__, pmr_flags[i], pmrs[i]);
 			return -EINVAL;
 		}
 	}

 	data = kzalloc(data_size + pmrs_size + pmr_flags_size, GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;

 #if defined(NO_HARDWARE)
 	/*
 	 * For NO_HARDWARE there's no checking or updating of client sync prims
 	 * which means SW waits on our fences will cause a deadlock (since they
 	 * will never be signalled). Avoid this by not creating any fences.
 	 */
 	nr_pmrs = 0;
 #endif

 	if (!nr_pmrs) {
 		data->appended = false;
 		data->nr_checks = nr_checks;
 		data->check_ufo_addrs = check_ufo_addrs;
 		data->check_values = check_values;
 		data->nr_updates = nr_updates;
 		data->update_ufo_addrs = update_ufo_addrs;
 		data->update_values = update_values;
 		goto finish;
 	}

 	data->appended = true;
 	data->ctx = ctx;
 	data->pmrs = (struct _PMR_ **)((char *)data + data_size);
 	data->pmr_flags = (u32 *)((char *)data->pmrs + pmrs_size);

 	/*
 	 * It's expected that user space will provide a set of unique PMRs
 	 * but, as a PMR can have multiple handles, it's still possible to
 	 * end up here with duplicates. Take this opportunity to filter out
 	 * any remaining duplicates (updating flags when necessary) before
 	 * trying to process them further.
 	 */
 	for (i = 0; i < nr_pmrs; i++) {
 		for (j = 0; j < data->nr_pmrs; j++) {
 			if (data->pmrs[j] == pmrs[i]) {
 				data->pmr_flags[j] |= pmr_flags[i];
 				break;
 			}
 		}

 		if (j == data->nr_pmrs) {
 			data->pmrs[j] = pmrs[i];
 			data->pmr_flags[j] = pmr_flags[i];
 			data->nr_pmrs++;
 		}
 	}

 	err = pvr_buffer_sync_pmrs_lock(&ctx->acquire_ctx,
 					data->nr_pmrs,
 					data->pmrs);
 	if (err) {
 		pr_err("%s: failed to lock pmrs (errno=%d)\n",
 		       __func__, err);
 		goto err_free_data;
 	}

 	check_data = pvr_buffer_sync_check_fences_create(ctx->fence_ctx,
 							 data->nr_pmrs,
 							 data->pmrs,
 							 data->pmr_flags);
 	if (!check_data) {
 		err = -ENOMEM;
 		goto err_pmrs_unlock;
 	}

 	data->update_fence = pvr_fence_create(ctx->fence_ctx, "update fence");
 	if (!data->update_fence) {
 		err = -ENOMEM;
 		goto err_free_check_data;
 	}

 	err = pvr_buffer_sync_append_fences(nr_checks,
 					    check_ufo_addrs,
 					    check_values,
 					    check_data->nr_fences,
 					    check_data->fences,
 					    &data->nr_checks,
 					    &data->check_ufo_addrs,
 					    &data->check_values);
 	if (err)
 		goto err_cleanup_update_fence;

 	err = pvr_buffer_sync_append_fences(nr_updates,
 					    update_ufo_addrs,
 					    update_values,
 					    1,
 					    &data->update_fence,
 					    &data->nr_updates,
 					    &data->update_ufo_addrs,
 					    &data->update_values);
 	if (err)
 		goto err_free_data_checks;

 	/*
 	 * We need to clean up the fences once the HW has finished with them.
 	 * We can do this using fence callbacks. However, instead of adding a
 	 * callback to every fence, which would result in more work, we can
 	 * simply add one to the update fence since this will be the last fence
 	 * to be signalled. This callback can do all the necessary clean up.
 	 *
 	 * Note: we take an additional reference on the update fence in case
 	 * it signals before we can add it to a reservation object.
 	 */
 	dma_fence_get(&data->update_fence->base);

 	err = dma_fence_add_callback(&data->update_fence->base,
 				     &check_data->base,
 				     pvr_buffer_sync_check_data_cleanup);
 	if (err) {
 		/*
 		 * We should only ever get -ENOENT if the fence has already
 		 * signalled, which should *never* be the case as we've not
 		 * even inserted the fence into a CCB yet!
 		 */
 		WARN_ON(err != -ENOENT);
 		goto err_free_data_updates;
 	}

 finish:
 	*data_out = data;
 	return 0;

 err_free_data_updates:
 	kfree(data->update_ufo_addrs);
 	kfree(data->update_values);
 err_free_data_checks:
 	kfree(data->check_ufo_addrs);
 	kfree(data->check_values);
 err_cleanup_update_fence:
 	pvr_fence_destroy(data->update_fence);
 err_free_check_data:
 	pvr_buffer_sync_check_fences_destroy(check_data);
 err_pmrs_unlock:
 	pvr_buffer_sync_pmrs_unlock(&ctx->acquire_ctx,
 				    data->nr_pmrs,
 				    data->pmrs);
 err_free_data:
 	kfree(data);
 	return err;
 }

 void
 pvr_buffer_sync_append_finish(struct pvr_buffer_sync_append_data *data)
 {
 	struct reservation_object *resv;
 	int i;

 	if (!data->appended)
 		goto finish;

 	for (i = 0; i < data->nr_pmrs; i++) {
 		resv = pmr_reservation_object_get(data->pmrs[i]);
 		if (WARN_ON_ONCE(!resv))
 			continue;

 		if (data->pmr_flags[i] & PVR_BUFFER_FLAG_WRITE) {
 			PVR_FENCE_TRACE(&data->update_fence->base,
 					"added exclusive fence (%s) to resv %p\n",
 					data->update_fence->name, resv);
 			reservation_object_add_excl_fence(resv,
 							  &data->update_fence->base);
 		} else if (data->pmr_flags[i] & PVR_BUFFER_FLAG_READ) {
 			PVR_FENCE_TRACE(&data->update_fence->base,
 					"added non-exclusive fence (%s) to resv %p\n",
 					data->update_fence->name, resv);
 			reservation_object_add_shared_fence(resv,
 							    &data->update_fence->base);
 		}
 	}

 	/*
 	 * Now that the fence has been added to the necessary reservation
 	 * objects we can safely drop the extra reference we took in
 	 * pvr_buffer_sync_append_start.
 	 */
 	dma_fence_put(&data->update_fence->base);

 	pvr_buffer_sync_pmrs_unlock(&data->ctx->acquire_ctx,
 				    data->nr_pmrs,
 				    data->pmrs);

 	kfree(data->check_ufo_addrs);
 	kfree(data->check_values);
 	kfree(data->update_ufo_addrs);
 	kfree(data->update_values);

 finish:
 	kfree(data);
 }

 void
 pvr_buffer_sync_append_abort(struct pvr_buffer_sync_append_data *data)
 {
 	if (!data)
 		return;

 	if (!data->appended)
 		goto finish;

 	/*
 	 * Signal the fence to trigger clean-up and drop the additional
 	 * reference taken in pvr_buffer_sync_append_start.
 	 */
 	pvr_fence_sync_sw_signal(data->update_fence);
 	dma_fence_put(&data->update_fence->base);
 	pvr_buffer_sync_pmrs_unlock(&data->ctx->acquire_ctx,
 				    data->nr_pmrs,
 				    data->pmrs);

 	kfree(data->check_ufo_addrs);
 	kfree(data->check_values);
 	kfree(data->update_ufo_addrs);
 	kfree(data->update_values);

 finish:
 	kfree(data);
 }

 void
 pvr_buffer_sync_append_checks_get(struct pvr_buffer_sync_append_data *data,
 				  u32 *nr_checks_out,
 				  struct _RGXFWIF_DEV_VIRTADDR_ **check_ufo_addrs_out,
 				  u32 **check_values_out)
 {
 	*nr_checks_out = data->nr_checks;
 	*check_ufo_addrs_out = data->check_ufo_addrs;
 	*check_values_out = data->check_values;
 }

 void
 pvr_buffer_sync_append_updates_get(struct pvr_buffer_sync_append_data *data,
 				   u32 *nr_updates_out,
 				   struct _RGXFWIF_DEV_VIRTADDR_ **update_ufo_addrs_out,
 				   u32 **update_values_out)
 {
 	*nr_updates_out = data->nr_updates;
 	*update_ufo_addrs_out = data->update_ufo_addrs;
 	*update_values_out = data->update_values;
 }

 int
 pvr_buffer_sync_wait(struct pvr_buffer_sync_context *ctx,
 		     struct _PMR_ *pmr,
 		     bool intr,
 		     unsigned long timeout)
 {
 	struct reservation_object *resv;
 	struct reservation_object_list *resv_list = NULL;
 	struct dma_fence *fence, *wait_fence = NULL;
 	unsigned int seq;
 	int i;
 	long lerr;

 	if (!timeout)
 		return -EINVAL;

 	resv = pmr_reservation_object_get(pmr);
 	if (!resv)
 		return 0;

 retry:
 	seq = read_seqcount_begin(&resv->seq);
 	rcu_read_lock();
 	resv_list = rcu_dereference(resv->fence);

 	if (read_seqcount_retry(&resv->seq, seq))
 		goto unlock_retry;

 	if (resv_list) {
 		for (i = 0; i < resv_list->shared_count; i++) {
 			fence = rcu_dereference(resv_list->shared[i]);
 			if (is_our_fence(ctx->fence_ctx, fence) &&
 			    !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
 				      &fence->flags)) {
 				wait_fence = dma_fence_get_rcu(fence);
 				if (!wait_fence)
 					goto unlock_retry;
 				break;
 			}
 		}
 	}

 	if (!wait_fence) {
 		fence = rcu_dereference(resv->fence_excl);

 		if (read_seqcount_retry(&resv->seq, seq))
 			goto unlock_retry;

 		if (fence &&
 		    !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
 			wait_fence = dma_fence_get_rcu(fence);
 			if (!wait_fence)
 				goto unlock_retry;
 		}
 	}
 	rcu_read_unlock();

 	if (wait_fence) {
 		if (dma_fence_is_signaled(wait_fence))
 			lerr = timeout;
 		else
 			lerr = dma_fence_wait_timeout(wait_fence, intr,
 						      timeout);

 		dma_fence_put(wait_fence);
 		if (!lerr)
 			return -EBUSY;
 		else if (lerr < 0)
 			return (int)lerr;
 	}

 	return 0;

 unlock_retry:
 	rcu_read_unlock();
 	goto retry;
 }
	/* -- mode: c; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -- */
	/* vi: set ts=8 sw=8 sts=8: */
	/************************************************************************/ /!
	@File
	@Title Linux buffer sync interface
	@Codingstyle LinuxKernel
	@Copyright Copyright (c) Imagination Technologies Ltd. All Rights Reserved
	@License Dual MIT/GPLv2

	The contents of this file are subject to the MIT license as set out below.

	Permission is hereby granted, free of charge, to any person obtaining a copy
	of this software and associated documentation files (the "Software"), to deal
	in the Software without restriction, including without limitation the rights
	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	copies of the Software, and to permit persons to whom the Software is
	furnished to do so, subject to the following conditions:

	The above copyright notice and this permission notice shall be included in
	all copies or substantial portions of the Software.

	Alternatively, the contents of this file may be used under the terms of
	the GNU General Public License Version 2 ("GPL") in which case the provisions
	of GPL are applicable instead of those above.

	If you wish to allow use of your version of this file only under the terms of
	GPL, and not to allow others to use your version of this file under the terms
	of the MIT license, indicate your decision by deleting the provisions above
	and replace them with the notice and other provisions required by GPL as set
	out in the file called "GPL-COPYING" included in this distribution. If you do
	not delete the provisions above, a recipient may use your version of this file
	under the terms of either the MIT license or GPL.

	This License is also included in this distribution in the file called
	"MIT-COPYING".

	EXCEPT AS OTHERWISE STATED IN A NEGOTIATED AGREEMENT: (A) THE SOFTWARE IS
	PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
	BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
	PURPOSE AND NONINFRINGEMENT; AND (B) IN NO EVENT SHALL THE AUTHORS OR
	COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
	IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
	CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
	/ /*************************************************************************/

	#include <linux/dma-buf.h>
	#include <linux/reservation.h>

	#include "pvr_buffer_sync.h"
	#include "pvr_buffer_sync_shared.h"
	#include "pvr_fence.h"
	#include "services_kernel_client.h"

	struct pvr_buffer_sync_context {
	struct pvr_fence_context *fence_ctx;
	struct ww_acquire_ctx acquire_ctx;
	};

	struct pvr_buffer_sync_check_data {
	struct dma_fence_cb base;

	u32 nr_fences;
	struct pvr_fence **fences;
	};

	struct pvr_buffer_sync_append_data {
	bool appended;

	struct pvr_buffer_sync_context *ctx;

	u32 nr_checks;
	struct _RGXFWIF_DEV_VIRTADDR_ *check_ufo_addrs;
	u32 *check_values;

	u32 nr_updates;
	struct _RGXFWIF_DEV_VIRTADDR_ *update_ufo_addrs;
	u32 *update_values;

	u32 nr_pmrs;
	struct _PMR_ **pmrs;
	u32 *pmr_flags;

	struct pvr_fence *update_fence;
	};


	static struct reservation_object *
	pmr_reservation_object_get(struct _PMR_ *pmr)
	{
	struct dma_buf *dmabuf;

	dmabuf = PhysmemGetDmaBuf(pmr);
	if (dmabuf)
	return dmabuf->resv;

	return NULL;
	}

	static int
	pvr_buffer_sync_pmrs_lock(struct ww_acquire_ctx *acquire_ctx,
	u32 nr_pmrs,
	struct _PMR_ **pmrs)
	{
	struct reservation_object resv, cresv = NULL, *lresv = NULL;
	int i, err;

	ww_acquire_init(acquire_ctx, &reservation_ww_class);
	retry:
	for (i = 0; i < nr_pmrs; i++) {
	resv = pmr_reservation_object_get(pmrs[i]);
	if (!resv) {
	pr_err("%s: Failed to get reservation object from pmr %p\n",
	__func__, pmrs[i]);
	err = -EINVAL;
	goto fail;
	}

	if (resv != lresv) {
	err = ww_mutex_lock_interruptible(&resv->lock,
	acquire_ctx);
	if (err) {
	cresv = (err == -EDEADLK) ? resv : NULL;
	goto fail;
	}
	} else {
	lresv = NULL;
	}
	}

	ww_acquire_done(acquire_ctx);

	return 0;

	fail:
	while (i--) {
	resv = pmr_reservation_object_get(pmrs[i]);
	if (WARN_ON_ONCE(!resv))
	continue;
	ww_mutex_unlock(&resv->lock);
	}

	if (lresv)
	ww_mutex_unlock(&lresv->lock);

	if (cresv) {
	err = ww_mutex_lock_slow_interruptible(&cresv->lock,
	acquire_ctx);
	if (!err) {
	lresv = cresv;
	cresv = NULL;
	goto retry;
	}
	}

	return err;
	}

	static void
	pvr_buffer_sync_pmrs_unlock(struct ww_acquire_ctx *acquire_ctx,
	u32 nr_pmrs,
	struct _PMR_ **pmrs)
	{
	struct reservation_object *resv;
	int i;

	for (i = 0; i < nr_pmrs; i++) {
	resv = pmr_reservation_object_get(pmrs[i]);
	if (WARN_ON_ONCE(!resv))
	continue;
	ww_mutex_unlock(&resv->lock);
	}

	ww_acquire_fini(acquire_ctx);
	}

	static u32
	pvr_buffer_sync_pmrs_fence_count(u32 nr_pmrs, struct _PMR_ **pmrs,
	u32 *pmr_flags)
	{
	struct reservation_object *resv;
	struct reservation_object_list *resv_list;
	struct dma_fence *fence;
	u32 fence_count = 0;
	bool exclusive;
	int i;

	for (i = 0; i < nr_pmrs; i++) {
	exclusive = !!(pmr_flags[i] & PVR_BUFFER_FLAG_WRITE);

	resv = pmr_reservation_object_get(pmrs[i]);
	if (WARN_ON_ONCE(!resv))
	continue;

	resv_list = reservation_object_get_list(resv);
	fence = reservation_object_get_excl(resv);

	if (fence &&
	(!exclusive \|\| !resv_list \|\| !resv_list->shared_count))
	fence_count++;

	if (exclusive && resv_list)
	fence_count += resv_list->shared_count;
	}

	return fence_count;
	}

	static struct pvr_buffer_sync_check_data *
	pvr_buffer_sync_check_fences_create(struct pvr_fence_context *fence_ctx,
	u32 nr_pmrs,
	struct _PMR_ **pmrs,
	u32 *pmr_flags)
	{
	struct pvr_buffer_sync_check_data *data;
	struct reservation_object *resv;
	struct reservation_object_list *resv_list;
	struct dma_fence *fence;
	u32 fence_count;
	bool exclusive;
	int i, j;
	int err;

	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (!data)
	return NULL;

	fence_count = pvr_buffer_sync_pmrs_fence_count(nr_pmrs, pmrs,
	pmr_flags);
	if (fence_count) {
	data->fences = kcalloc(fence_count, sizeof(*data->fences),
	GFP_KERNEL);
	if (!data->fences)
	goto err_check_data_free;
	}

	for (i = 0; i < nr_pmrs; i++) {
	resv = pmr_reservation_object_get(pmrs[i]);
	if (WARN_ON_ONCE(!resv))
	continue;

	exclusive = !!(pmr_flags[i] & PVR_BUFFER_FLAG_WRITE);
	if (!exclusive) {
	err = reservation_object_reserve_shared(resv);
	if (err)
	goto err_destroy_fences;
	}

	resv_list = reservation_object_get_list(resv);
	fence = reservation_object_get_excl(resv);

	if (fence &&
	(!exclusive \|\| !resv_list \|\| !resv_list->shared_count)) {
	data->fences[data->nr_fences++] =
	pvr_fence_create_from_fence(fence_ctx,
	fence,
	"exclusive check fence");
	if (!data->fences[data->nr_fences - 1]) {
	data->nr_fences--;
	PVR_FENCE_TRACE(fence,
	"waiting on exclusive fence\n");
	WARN_ON(dma_fence_wait(fence, true) <= 0);
	}
	}

	if (exclusive && resv_list) {
	for (j = 0; j < resv_list->shared_count; j++) {
	fence = rcu_dereference_protected(resv_list->shared[j],
	reservation_object_held(resv));
	data->fences[data->nr_fences++] =
	pvr_fence_create_from_fence(fence_ctx,
	fence,
	"check fence");
	if (!data->fences[data->nr_fences - 1]) {
	data->nr_fences--;
	PVR_FENCE_TRACE(fence,
	"waiting on non-exclusive fence\n");
	WARN_ON(dma_fence_wait(fence, true) <= 0);
	}
	}
	}
	}

	WARN_ON((i != nr_pmrs) \|\| (data->nr_fences != fence_count));

	return data;

	err_destroy_fences:
	for (i = 0; i < data->nr_fences; i++)
	pvr_fence_destroy(data->fences[i]);
	kfree(data->fences);
	err_check_data_free:
	kfree(data);
	return NULL;
	}

	static void
	pvr_buffer_sync_check_fences_destroy(struct pvr_buffer_sync_check_data *data)
	{
	int i;

	for (i = 0; i < data->nr_fences; i++)
	pvr_fence_destroy(data->fences[i]);

	kfree(data->fences);
	kfree(data);
	}

	static void
	pvr_buffer_sync_check_data_cleanup(struct dma_fence *fence,
	struct dma_fence_cb *cb)
	{
	struct pvr_buffer_sync_check_data *data =
	container_of(cb, struct pvr_buffer_sync_check_data, base);
	struct pvr_fence *pvr_fence = to_pvr_fence(fence);

	pvr_buffer_sync_check_fences_destroy(data);

	pvr_fence_destroy(pvr_fence);
	}

	static int
	pvr_buffer_sync_append_fences(u32 nr,
	struct _RGXFWIF_DEV_VIRTADDR_ *ufo_addrs,
	u32 *values,
	u32 nr_fences,
	struct pvr_fence **pvr_fences,
	u32 *nr_out,
	struct _RGXFWIF_DEV_VIRTADDR_ **ufo_addrs_out,
	u32 **values_out)
	{
	u32 nr_new = nr + nr_fences;
	struct _RGXFWIF_DEV_VIRTADDR_ *ufo_addrs_new = NULL;
	u32 sync_addr;
	u32 *values_new = NULL;
	int i;
	int err;

	if (!nr_new)
	goto finish;

	ufo_addrs_new = kmalloc_array(nr_new, sizeof(*ufo_addrs_new),
	GFP_KERNEL);
	if (!ufo_addrs_new)
	return -ENOMEM;

	values_new = kmalloc_array(nr_new, sizeof(*values_new), GFP_KERNEL);
	if (!values_new) {
	err = -ENOMEM;
	goto err_free_ufo_addrs;
	}

	/* Copy the original data */
	if (nr) {
	memcpy(ufo_addrs_new, ufo_addrs, sizeof(ufo_addrs) nr);
	memcpy(values_new, values, sizeof(values) nr);
	}

	/* Append the fence data */
	for (i = 0; i < nr_fences; i++) {
	PVRSRV_ERROR srv_err;

	srv_err = SyncPrimGetFirmwareAddr(pvr_fences[i]->sync,
	&sync_addr);
	if (srv_err != PVRSRV_OK) {
	err = -EINVAL;
	goto err_free_values;
	}
	ufo_addrs_new[i + nr].ui32Addr = sync_addr;
	values_new[i + nr] = PVR_FENCE_SYNC_VAL_SIGNALED;
	}

	finish:
	*nr_out = nr_new;
	*ufo_addrs_out = ufo_addrs_new;
	*values_out = values_new;

	return 0;

	err_free_values:
	kfree(values_new);
	err_free_ufo_addrs:
	kfree(ufo_addrs_new);
	return err;
	}

	struct pvr_buffer_sync_context *
	pvr_buffer_sync_context_create(void *dev_cookie)
	{
	struct pvr_buffer_sync_context *ctx;
	int err;

	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
	if (!ctx) {
	err = -ENOMEM;
	goto err_exit;
	}

	ctx->fence_ctx = pvr_fence_context_create(dev_cookie, "rogue-gpu");
	if (!ctx->fence_ctx) {
	err = -ENOMEM;
	goto err_free_ctx;
	}

	return ctx;

	err_free_ctx:
	kfree(ctx);
	err_exit:
	return ERR_PTR(err);
	}

	void pvr_buffer_sync_context_destroy(struct pvr_buffer_sync_context *ctx)
	{
	pvr_fence_context_destroy(ctx->fence_ctx);
	kfree(ctx);
	}

	int
	pvr_buffer_sync_append_start(struct pvr_buffer_sync_context *ctx,
	u32 nr_pmrs,
	struct _PMR_ **pmrs,
	u32 *pmr_flags,
	u32 nr_checks,
	struct _RGXFWIF_DEV_VIRTADDR_ *check_ufo_addrs,
	u32 *check_values,
	u32 nr_updates,
	struct _RGXFWIF_DEV_VIRTADDR_ *update_ufo_addrs,
	u32 *update_values,
	struct pvr_buffer_sync_append_data **data_out)
	{
	struct pvr_buffer_sync_append_data *data;
	struct pvr_buffer_sync_check_data *check_data;
	const size_t data_size = sizeof(*data);
	const size_t pmrs_size = sizeof(pmrs) nr_pmrs;
	const size_t pmr_flags_size = sizeof(pmr_flags) nr_pmrs;
	int i;
	int j;
	int err;

	if ((nr_pmrs && !(pmrs && pmr_flags)) \|\|
	(nr_updates && (!update_ufo_addrs \|\| !update_values)) \|\|
	(nr_checks && (!check_ufo_addrs \|\| !check_values)))
	return -EINVAL;

	for (i = 0; i < nr_pmrs; i++) {
	if (!(pmr_flags[i] & PVR_BUFFER_FLAG_MASK)) {
	pr_err("%s: Invalid flags %#08x for pmr %p\n",
	__func__, pmr_flags[i], pmrs[i]);
	return -EINVAL;
	}
	}

	data = kzalloc(data_size + pmrs_size + pmr_flags_size, GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	#if defined(NO_HARDWARE)
	/*
	* For NO_HARDWARE there's no checking or updating of client sync prims
	* which means SW waits on our fences will cause a deadlock (since they
	* will never be signalled). Avoid this by not creating any fences.
	*/
	nr_pmrs = 0;
	#endif

	if (!nr_pmrs) {
	data->appended = false;
	data->nr_checks = nr_checks;
	data->check_ufo_addrs = check_ufo_addrs;
	data->check_values = check_values;
	data->nr_updates = nr_updates;
	data->update_ufo_addrs = update_ufo_addrs;
	data->update_values = update_values;
	goto finish;
	}

	data->appended = true;
	data->ctx = ctx;
	data->pmrs = (struct _PMR_ *)((char )data + data_size);
	data->pmr_flags = (u32 )((char )data->pmrs + pmrs_size);

	/*
	* It's expected that user space will provide a set of unique PMRs
	* but, as a PMR can have multiple handles, it's still possible to
	* end up here with duplicates. Take this opportunity to filter out
	* any remaining duplicates (updating flags when necessary) before
	* trying to process them further.
	*/
	for (i = 0; i < nr_pmrs; i++) {
	for (j = 0; j < data->nr_pmrs; j++) {
	if (data->pmrs[j] == pmrs[i]) {
	data->pmr_flags[j] \|= pmr_flags[i];
	break;
	}
	}

	if (j == data->nr_pmrs) {
	data->pmrs[j] = pmrs[i];
	data->pmr_flags[j] = pmr_flags[i];
	data->nr_pmrs++;
	}
	}

	err = pvr_buffer_sync_pmrs_lock(&ctx->acquire_ctx,
	data->nr_pmrs,
	data->pmrs);
	if (err) {
	pr_err("%s: failed to lock pmrs (errno=%d)\n",
	__func__, err);
	goto err_free_data;
	}

	check_data = pvr_buffer_sync_check_fences_create(ctx->fence_ctx,
	data->nr_pmrs,
	data->pmrs,
	data->pmr_flags);
	if (!check_data) {
	err = -ENOMEM;
	goto err_pmrs_unlock;
	}

	data->update_fence = pvr_fence_create(ctx->fence_ctx, "update fence");
	if (!data->update_fence) {
	err = -ENOMEM;
	goto err_free_check_data;
	}

	err = pvr_buffer_sync_append_fences(nr_checks,
	check_ufo_addrs,
	check_values,
	check_data->nr_fences,
	check_data->fences,
	&data->nr_checks,
	&data->check_ufo_addrs,
	&data->check_values);
	if (err)
	goto err_cleanup_update_fence;

	err = pvr_buffer_sync_append_fences(nr_updates,
	update_ufo_addrs,
	update_values,
	1,
	&data->update_fence,
	&data->nr_updates,
	&data->update_ufo_addrs,
	&data->update_values);
	if (err)
	goto err_free_data_checks;

	/*
	* We need to clean up the fences once the HW has finished with them.
	* We can do this using fence callbacks. However, instead of adding a
	* callback to every fence, which would result in more work, we can
	* simply add one to the update fence since this will be the last fence
	* to be signalled. This callback can do all the necessary clean up.
	*
	* Note: we take an additional reference on the update fence in case
	* it signals before we can add it to a reservation object.
	*/
	dma_fence_get(&data->update_fence->base);

	err = dma_fence_add_callback(&data->update_fence->base,
	&check_data->base,
	pvr_buffer_sync_check_data_cleanup);
	if (err) {
	/*
	* We should only ever get -ENOENT if the fence has already
	* signalled, which should never be the case as we've not
	* even inserted the fence into a CCB yet!
	*/
	WARN_ON(err != -ENOENT);
	goto err_free_data_updates;
	}

	finish:
	*data_out = data;
	return 0;

	err_free_data_updates:
	kfree(data->update_ufo_addrs);
	kfree(data->update_values);
	err_free_data_checks:
	kfree(data->check_ufo_addrs);
	kfree(data->check_values);
	err_cleanup_update_fence:
	pvr_fence_destroy(data->update_fence);
	err_free_check_data:
	pvr_buffer_sync_check_fences_destroy(check_data);
	err_pmrs_unlock:
	pvr_buffer_sync_pmrs_unlock(&ctx->acquire_ctx,
	data->nr_pmrs,
	data->pmrs);
	err_free_data:
	kfree(data);
	return err;
	}

	void
	pvr_buffer_sync_append_finish(struct pvr_buffer_sync_append_data *data)
	{
	struct reservation_object *resv;
	int i;

	if (!data->appended)
	goto finish;

	for (i = 0; i < data->nr_pmrs; i++) {
	resv = pmr_reservation_object_get(data->pmrs[i]);
	if (WARN_ON_ONCE(!resv))
	continue;

	if (data->pmr_flags[i] & PVR_BUFFER_FLAG_WRITE) {
	PVR_FENCE_TRACE(&data->update_fence->base,
	"added exclusive fence (%s) to resv %p\n",
	data->update_fence->name, resv);
	reservation_object_add_excl_fence(resv,
	&data->update_fence->base);
	} else if (data->pmr_flags[i] & PVR_BUFFER_FLAG_READ) {
	PVR_FENCE_TRACE(&data->update_fence->base,
	"added non-exclusive fence (%s) to resv %p\n",
	data->update_fence->name, resv);
	reservation_object_add_shared_fence(resv,
	&data->update_fence->base);
	}
	}

	/*
	* Now that the fence has been added to the necessary reservation
	* objects we can safely drop the extra reference we took in
	* pvr_buffer_sync_append_start.
	*/
	dma_fence_put(&data->update_fence->base);

	pvr_buffer_sync_pmrs_unlock(&data->ctx->acquire_ctx,
	data->nr_pmrs,
	data->pmrs);

	kfree(data->check_ufo_addrs);
	kfree(data->check_values);
	kfree(data->update_ufo_addrs);
	kfree(data->update_values);

	finish:
	kfree(data);
	}

	void
	pvr_buffer_sync_append_abort(struct pvr_buffer_sync_append_data *data)
	{
	if (!data)
	return;

	if (!data->appended)
	goto finish;

	/*
	* Signal the fence to trigger clean-up and drop the additional
	* reference taken in pvr_buffer_sync_append_start.
	*/
	pvr_fence_sync_sw_signal(data->update_fence);
	dma_fence_put(&data->update_fence->base);
	pvr_buffer_sync_pmrs_unlock(&data->ctx->acquire_ctx,
	data->nr_pmrs,
	data->pmrs);

	kfree(data->check_ufo_addrs);
	kfree(data->check_values);
	kfree(data->update_ufo_addrs);
	kfree(data->update_values);

	finish:
	kfree(data);
	}

	void
	pvr_buffer_sync_append_checks_get(struct pvr_buffer_sync_append_data *data,
	u32 *nr_checks_out,
	struct _RGXFWIF_DEV_VIRTADDR_ **check_ufo_addrs_out,
	u32 **check_values_out)
	{
	*nr_checks_out = data->nr_checks;
	*check_ufo_addrs_out = data->check_ufo_addrs;
	*check_values_out = data->check_values;
	}

	void
	pvr_buffer_sync_append_updates_get(struct pvr_buffer_sync_append_data *data,
	u32 *nr_updates_out,
	struct _RGXFWIF_DEV_VIRTADDR_ **update_ufo_addrs_out,
	u32 **update_values_out)
	{
	*nr_updates_out = data->nr_updates;
	*update_ufo_addrs_out = data->update_ufo_addrs;
	*update_values_out = data->update_values;
	}

	int
	pvr_buffer_sync_wait(struct pvr_buffer_sync_context *ctx,
	struct _PMR_ *pmr,
	bool intr,
	unsigned long timeout)
	{
	struct reservation_object *resv;
	struct reservation_object_list *resv_list = NULL;
	struct dma_fence fence, wait_fence = NULL;
	unsigned int seq;
	int i;
	long lerr;

	if (!timeout)
	return -EINVAL;

	resv = pmr_reservation_object_get(pmr);
	if (!resv)
	return 0;

	retry:
	seq = read_seqcount_begin(&resv->seq);
	rcu_read_lock();
	resv_list = rcu_dereference(resv->fence);

	if (read_seqcount_retry(&resv->seq, seq))
	goto unlock_retry;

	if (resv_list) {
	for (i = 0; i < resv_list->shared_count; i++) {
	fence = rcu_dereference(resv_list->shared[i]);
	if (is_our_fence(ctx->fence_ctx, fence) &&
	!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
	&fence->flags)) {
	wait_fence = dma_fence_get_rcu(fence);
	if (!wait_fence)
	goto unlock_retry;
	break;
	}
	}
	}

	if (!wait_fence) {
	fence = rcu_dereference(resv->fence_excl);

	if (read_seqcount_retry(&resv->seq, seq))
	goto unlock_retry;

	if (fence &&
	!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
	wait_fence = dma_fence_get_rcu(fence);
	if (!wait_fence)
	goto unlock_retry;
	}
	}
	rcu_read_unlock();

	if (wait_fence) {
	if (dma_fence_is_signaled(wait_fence))
	lerr = timeout;
	else
	lerr = dma_fence_wait_timeout(wait_fence, intr,
	timeout);

	dma_fence_put(wait_fence);
	if (!lerr)
	return -EBUSY;
	else if (lerr < 0)
	return (int)lerr;
	}

	return 0;

	unlock_retry:
	rcu_read_unlock();
	goto retry;
	}