[PATCH 04/16] dma-buf & drm/amdgpu: remove dma_resv workaround

Rework the internals of the dma_resv object to allow adding more than one write fence and remember for each fence what purpose it had.

This allows removing the workaround from amdgpu which used a container for this instead.

Signed-off-by: Christian König christian.koenig@amd.com Cc: amd-gfx@lists.freedesktop.org --- drivers/dma-buf/dma-resv.c | 353 ++++++++------------ drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h | 1 - drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 53 +-- include/linux/dma-resv.h | 47 +-- 4 files changed, 157 insertions(+), 297 deletions(-)

diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index 543dae6566d2..378d47e1cfea 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -44,12 +44,12 @@ /** * DOC: Reservation Object Overview * - * The reservation object provides a mechanism to manage shared and - * exclusive fences associated with a buffer. A reservation object - * can have attached one exclusive fence (normally associated with - * write operations) or N shared fences (read operations). The RCU - * mechanism is used to protect read access to fences from locked - * write-side updates. + * The reservation object provides a mechanism to manage a container of + * dma_fence object associated with a resource. A reservation object + * can have any number of fences attaches to it. Each fence carries an usage + * parameter determining how the operation represented by the fence is using the + * resource. The RCU mechanism is used to protect read access to fences from + * locked write-side updates. * * See struct dma_resv for more details. */ @@ -57,39 +57,59 @@ DEFINE_WD_CLASS(reservation_ww_class); EXPORT_SYMBOL(reservation_ww_class);

+/* Mask for the lower fence pointer bits */ +#define DMA_RESV_LIST_MASK 0x3 + struct dma_resv_list { struct rcu_head rcu; - u32 shared_count, shared_max; - struct dma_fence __rcu *shared[]; + u32 num_fences, max_fences; + struct dma_fence __rcu *table[]; };

-/** - * dma_resv_list_alloc - allocate fence list - * @shared_max: number of fences we need space for - * +/* Extract the fence and usage flags from an RCU protected entry in the list. */ +static void dma_resv_list_entry(struct dma_resv_list *list, unsigned int index, + struct dma_resv *resv, struct dma_fence **fence, + enum dma_resv_usage *usage) +{ + long tmp; + + tmp = (long)rcu_dereference_check(list->table[index], + resv ? dma_resv_held(resv) : true); + *fence = (struct dma_fence *)(tmp & ~DMA_RESV_LIST_MASK); + if (usage) + *usage = tmp & DMA_RESV_LIST_MASK; +} + +/* Set the fence and usage flags at the specific index in the list. */ +static void dma_resv_list_set(struct dma_resv_list *list, + unsigned int index, + struct dma_fence *fence, + enum dma_resv_usage usage) +{ + long tmp = ((long)fence) | usage; + + RCU_INIT_POINTER(list->table[index], (struct dma_fence *)tmp); +} + +/* * Allocate a new dma_resv_list and make sure to correctly initialize - * shared_max. + * max_fences. */ -static struct dma_resv_list *dma_resv_list_alloc(unsigned int shared_max) +static struct dma_resv_list *dma_resv_list_alloc(unsigned int max_fences) { struct dma_resv_list *list;

- list = kmalloc(struct_size(list, shared, shared_max), GFP_KERNEL); + list = kmalloc(struct_size(list, table, max_fences), GFP_KERNEL); if (!list) return NULL;

- list->shared_max = (ksize(list) - offsetof(typeof(*list), shared)) / - sizeof(*list->shared); + list->max_fences = (ksize(list) - offsetof(typeof(*list), table)) / + sizeof(*list->table);

return list; }

-/** - * dma_resv_list_free - free fence list - * @list: list to free - * - * Free a dma_resv_list and make sure to drop all references. - */ +/* Free a dma_resv_list and make sure to drop all references. */ static void dma_resv_list_free(struct dma_resv_list *list) { unsigned int i; @@ -97,9 +117,12 @@ static void dma_resv_list_free(struct dma_resv_list *list) if (!list) return;

- for (i = 0; i < list->shared_count; ++i) - dma_fence_put(rcu_dereference_protected(list->shared[i], true)); + for (i = 0; i < list->num_fences; ++i) { + struct dma_fence *fence;

+ dma_resv_list_entry(list, i, NULL, &fence, NULL); + dma_fence_put(fence); + } kfree_rcu(list, rcu); }

@@ -112,8 +135,7 @@ void dma_resv_init(struct dma_resv *obj) ww_mutex_init(&obj->lock, &reservation_ww_class); seqcount_ww_mutex_init(&obj->seq, &obj->lock);

- RCU_INIT_POINTER(obj->fence, NULL); - RCU_INIT_POINTER(obj->fence_excl, NULL); + RCU_INIT_POINTER(obj->fences, NULL); } EXPORT_SYMBOL(dma_resv_init);

@@ -123,46 +145,32 @@ EXPORT_SYMBOL(dma_resv_init); */ void dma_resv_fini(struct dma_resv *obj) { - struct dma_resv_list *fobj; - struct dma_fence *excl; - /* * This object should be dead and all references must have * been released to it, so no need to be protected with rcu. */ - excl = rcu_dereference_protected(obj->fence_excl, 1); - if (excl) - dma_fence_put(excl); - - fobj = rcu_dereference_protected(obj->fence, 1); - dma_resv_list_free(fobj); + dma_resv_list_free(rcu_dereference_protected(obj->fences, true)); ww_mutex_destroy(&obj->lock); } EXPORT_SYMBOL(dma_resv_fini);

-static inline struct dma_fence * -dma_resv_excl_fence(struct dma_resv *obj) -{ - return rcu_dereference_check(obj->fence_excl, dma_resv_held(obj)); -} - -static inline struct dma_resv_list *dma_resv_shared_list(struct dma_resv *obj) +/* Dereference the fences while ensuring RCU rules */ +static inline struct dma_resv_list *dma_resv_fences_list(struct dma_resv *obj) { - return rcu_dereference_check(obj->fence, dma_resv_held(obj)); + return rcu_dereference_check(obj->fences, dma_resv_held(obj)); }

/** - * dma_resv_reserve_fences - Reserve space to add shared fences to - * a dma_resv. + * dma_resv_reserve_fences - Reserve space to add fences to a dma_resv object. * @obj: reservation object * @num_fences: number of fences we want to add * - * Should be called before dma_resv_add_shared_fence(). Must - * be called with @obj locked through dma_resv_lock(). + * Should be called before dma_resv_add_fence(). Must be called with @obj + * locked through dma_resv_lock(). * * Note that the preallocated slots need to be re-reserved if @obj is unlocked - * at any time before calling dma_resv_add_shared_fence(). This is validated - * when CONFIG_DEBUG_MUTEXES is enabled. + * at any time before calling dma_resv_add_fence(). This is validated when + * CONFIG_DEBUG_MUTEXES is enabled. * * RETURNS * Zero for success, or -errno @@ -174,11 +182,11 @@ int dma_resv_reserve_fences(struct dma_resv *obj, unsigned int num_fences)

dma_resv_assert_held(obj);

- old = dma_resv_shared_list(obj); - if (old && old->shared_max) { - if ((old->shared_count + num_fences) <= old->shared_max) + old = dma_resv_fences_list(obj); + if (old && old->max_fences) { + if ((old->num_fences + num_fences) <= old->max_fences) return 0; - max = max(old->shared_count + num_fences, old->shared_max * 2); + max = max(old->num_fences + num_fences, old->max_fences * 2); } else { max = max(4ul, roundup_pow_of_two(num_fences)); } @@ -193,27 +201,27 @@ int dma_resv_reserve_fences(struct dma_resv *obj, unsigned int num_fences) * references from the old struct are carried over to * the new. */ - for (i = 0, j = 0, k = max; i < (old ? old->shared_count : 0); ++i) { + for (i = 0, j = 0, k = max; i < (old ? old->num_fences : 0); ++i) { + enum dma_resv_usage usage; struct dma_fence *fence;

- fence = rcu_dereference_protected(old->shared[i], - dma_resv_held(obj)); + dma_resv_list_entry(old, i, obj, &fence, &usage); if (dma_fence_is_signaled(fence)) - RCU_INIT_POINTER(new->shared[--k], fence); + RCU_INIT_POINTER(new->table[--k], fence); else - RCU_INIT_POINTER(new->shared[j++], fence); + dma_resv_list_set(new, j++, fence, usage); } - new->shared_count = j; + new->num_fences = j;

/* * We are not changing the effective set of fences here so can * merely update the pointer to the new array; both existing * readers and new readers will see exactly the same set of - * active (unsignaled) shared fences. Individual fences and the + * active (unsignaled) fences. Individual fences and the * old array are protected by RCU and so will not vanish under * the gaze of the rcu_read_lock() readers. */ - rcu_assign_pointer(obj->fence, new); + rcu_assign_pointer(obj->fences, new);

if (!old) return 0; @@ -222,7 +230,7 @@ int dma_resv_reserve_fences(struct dma_resv *obj, unsigned int num_fences) for (i = k; i < max; ++i) { struct dma_fence *fence;

- fence = rcu_dereference_protected(new->shared[i], + fence = rcu_dereference_protected(new->table[i], dma_resv_held(obj)); dma_fence_put(fence); } @@ -234,38 +242,39 @@ EXPORT_SYMBOL(dma_resv_reserve_fences);

#ifdef CONFIG_DEBUG_MUTEXES /** - * dma_resv_reset_max_fences - reset shared fences for debugging + * dma_resv_reset_max_fences - reset fences for debugging * @obj: the dma_resv object to reset * - * Reset the number of pre-reserved shared slots to test that drivers do + * Reset the number of pre-reserved fence slots to test that drivers do * correct slot allocation using dma_resv_reserve_fences(). See also - * &dma_resv_list.shared_max. + * &dma_resv_list.max_fences. */ void dma_resv_reset_max_fences(struct dma_resv *obj) { - struct dma_resv_list *fences = dma_resv_shared_list(obj); + struct dma_resv_list *fences = dma_resv_fences_list(obj);

dma_resv_assert_held(obj);

- /* Test shared fence slot reservation */ + /* Test fence slot reservation */ if (fences) - fences->shared_max = fences->shared_count; + fences->max_fences = fences->num_fences; } EXPORT_SYMBOL(dma_resv_reset_max_fences); #endif

/** - * dma_resv_add_shared_fence - Add a fence to a shared slot + * dma_resv_add_fence - Add a fence to the dma_resv obj * @obj: the reservation object - * @fence: the shared fence to add + * @fence: the fence to add + * @usage: how the fence is used, see enum dma_resv_usage * - * Add a fence to a shared slot, @obj must be locked with dma_resv_lock(), and + * Add a fence to a slot, @obj must be locked with dma_resv_lock(), and * dma_resv_reserve_fences() has been called. * * See also &dma_resv.fence for a discussion of the semantics. */ -static void dma_resv_add_shared_fence(struct dma_resv *obj, - struct dma_fence *fence) +void dma_resv_add_fence(struct dma_resv *obj, struct dma_fence *fence, + enum dma_resv_usage usage) { struct dma_resv_list *fobj; struct dma_fence *old; @@ -280,32 +289,33 @@ static void dma_resv_add_shared_fence(struct dma_resv *obj, */ WARN_ON(dma_fence_is_container(fence));

- fobj = dma_resv_shared_list(obj); - count = fobj->shared_count; + fobj = dma_resv_fences_list(obj); + count = fobj->num_fences;

write_seqcount_begin(&obj->seq);

for (i = 0; i < count; ++i) { + enum dma_resv_usage old_usage;

- old = rcu_dereference_protected(fobj->shared[i], - dma_resv_held(obj)); - if (old->context == fence->context || + dma_resv_list_entry(fobj, i, obj, &old, &old_usage); + if ((old->context == fence->context && old_usage >= usage) || dma_fence_is_signaled(old)) goto replace; }

- BUG_ON(fobj->shared_count >= fobj->shared_max); + BUG_ON(fobj->num_fences >= fobj->max_fences); old = NULL; count++;

replace: - RCU_INIT_POINTER(fobj->shared[i], fence); - /* pointer update must be visible before we extend the shared_count */ - smp_store_mb(fobj->shared_count, count); + dma_resv_list_set(fobj, i, fence, usage); + /* pointer update must be visible before we extend the num_fences */ + smp_store_mb(fobj->num_fences, count);

write_seqcount_end(&obj->seq); dma_fence_put(old); } +EXPORT_SYMBOL(dma_resv_add_fence);

/** * dma_resv_replace_fences - replace fences in the dma_resv obj @@ -326,128 +336,63 @@ void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context, enum dma_resv_usage usage) { struct dma_resv_list *list; - struct dma_fence *old; unsigned int i;

- /* Only readers supported for now */ - WARN_ON(usage != DMA_RESV_USAGE_READ); - dma_resv_assert_held(obj);

+ list = dma_resv_fences_list(obj); write_seqcount_begin(&obj->seq); + for (i = 0; list && i < list->num_fences; ++i) { + struct dma_fence *old;

- old = dma_resv_excl_fence(obj); - if (old->context == context) { - RCU_INIT_POINTER(obj->fence_excl, dma_fence_get(replacement)); - dma_fence_put(old); - } - - list = dma_resv_shared_list(obj); - for (i = 0; list && i < list->shared_count; ++i) { - old = rcu_dereference_protected(list->shared[i], - dma_resv_held(obj)); + dma_resv_list_entry(list, i, obj, &old, NULL); if (old->context != context) continue;

- rcu_assign_pointer(list->shared[i], dma_fence_get(replacement)); + dma_resv_list_set(list, i, replacement, usage); dma_fence_put(old); } - write_seqcount_end(&obj->seq); } EXPORT_SYMBOL(dma_resv_replace_fences);

-/** - * dma_resv_add_excl_fence - Add an exclusive fence. - * @obj: the reservation object - * @fence: the exclusive fence to add - * - * Add a fence to the exclusive slot. @obj must be locked with dma_resv_lock(). - * See also &dma_resv.fence_excl for a discussion of the semantics. - */ -static void dma_resv_add_excl_fence(struct dma_resv *obj, - struct dma_fence *fence) -{ - struct dma_fence *old_fence = dma_resv_excl_fence(obj); - - dma_resv_assert_held(obj); - - dma_fence_get(fence); - - write_seqcount_begin(&obj->seq); - /* write_seqcount_begin provides the necessary memory barrier */ - RCU_INIT_POINTER(obj->fence_excl, fence); - write_seqcount_end(&obj->seq); - - dma_fence_put(old_fence); -} - -/** - * dma_resv_add_fence - Add a fence to the dma_resv obj - * @obj: the reservation object - * @fence: the fence to add - * @usage: how the fence is used, see enum dma_resv_usage - * - * Add a fence to a slot, @obj must be locked with dma_resv_lock(), and - * dma_resv_reserve_fences() has been called. - * - * See also &dma_resv.fence for a discussion of the semantics. - */ -void dma_resv_add_fence(struct dma_resv *obj, struct dma_fence *fence, - enum dma_resv_usage usage) -{ - if (usage == DMA_RESV_USAGE_WRITE) - dma_resv_add_excl_fence(obj, fence); - else - dma_resv_add_shared_fence(obj, fence); -} -EXPORT_SYMBOL(dma_resv_add_fence); - -/* Restart the iterator by initializing all the necessary fields, but not the - * relation to the dma_resv object. */ +/* Restart the unlocked iteration by initializing the cursor object. */ static void dma_resv_iter_restart_unlocked(struct dma_resv_iter *cursor) { cursor->seq = read_seqcount_begin(&cursor->obj->seq); - cursor->index = -1; - cursor->shared_count = 0; - if (cursor->usage >= DMA_RESV_USAGE_READ) { - cursor->fences = dma_resv_shared_list(cursor->obj); - if (cursor->fences) - cursor->shared_count = cursor->fences->shared_count; - } else { - cursor->fences = NULL; - } + cursor->index = 0; + cursor->num_fences = 0; + cursor->fences = dma_resv_fences_list(cursor->obj); + if (cursor->fences) + cursor->num_fences = cursor->fences->num_fences; cursor->is_restarted = true; }

/* Walk to the next not signaled fence and grab a reference to it */ static void dma_resv_iter_walk_unlocked(struct dma_resv_iter *cursor) { - struct dma_resv *obj = cursor->obj; + if (!cursor->fences) + return;

do { /* Drop the reference from the previous round */ dma_fence_put(cursor->fence);

- if (cursor->index == -1) { - cursor->fence = dma_resv_excl_fence(obj); - cursor->index++; - if (!cursor->fence) - continue; - - } else if (!cursor->fences || - cursor->index >= cursor->shared_count) { + if (cursor->index >= cursor->num_fences) { cursor->fence = NULL; break;

- } else { - struct dma_resv_list *fences = cursor->fences; - unsigned int idx = cursor->index++; - - cursor->fence = rcu_dereference(fences->shared[idx]); } + + dma_resv_list_entry(cursor->fences, cursor->index++, + cursor->obj, &cursor->fence, + &cursor->fence_usage); cursor->fence = dma_fence_get_rcu(cursor->fence); - if (!cursor->fence || !dma_fence_is_signaled(cursor->fence)) + if (!cursor->fence) + break; + + if (!dma_fence_is_signaled(cursor->fence) && + cursor->usage >= cursor->fence_usage) break; } while (true); } @@ -522,15 +467,9 @@ struct dma_fence *dma_resv_iter_first(struct dma_resv_iter *cursor) dma_resv_assert_held(cursor->obj);

cursor->index = 0; - if (cursor->usage >= DMA_RESV_USAGE_READ) - cursor->fences = dma_resv_shared_list(cursor->obj); - else - cursor->fences = NULL; - - fence = dma_resv_excl_fence(cursor->obj); - if (!fence) - fence = dma_resv_iter_next(cursor); + cursor->fences = dma_resv_fences_list(cursor->obj);

+ fence = dma_resv_iter_next(cursor); cursor->is_restarted = true; return fence; } @@ -545,17 +484,22 @@ EXPORT_SYMBOL_GPL(dma_resv_iter_first); */ struct dma_fence *dma_resv_iter_next(struct dma_resv_iter *cursor) { - unsigned int idx; + struct dma_fence *fence;

dma_resv_assert_held(cursor->obj);

cursor->is_restarted = false; - if (!cursor->fences || cursor->index >= cursor->fences->shared_count) - return NULL;

- idx = cursor->index++; - return rcu_dereference_protected(cursor->fences->shared[idx], - dma_resv_held(cursor->obj)); + do { + if (!cursor->fences || + cursor->index >= cursor->fences->num_fences) + return NULL; + + dma_resv_list_entry(cursor->fences, cursor->index++, + cursor->obj, &fence, &cursor->fence_usage); + } while (cursor->fence_usage > cursor->usage); + + return fence; } EXPORT_SYMBOL_GPL(dma_resv_iter_next);

@@ -570,57 +514,43 @@ int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src) { struct dma_resv_iter cursor; struct dma_resv_list *list; - struct dma_fence *f, *excl; + struct dma_fence *f;

dma_resv_assert_held(dst);

list = NULL; - excl = NULL;

dma_resv_iter_begin(&cursor, src, DMA_RESV_USAGE_READ); dma_resv_for_each_fence_unlocked(&cursor, f) {

if (dma_resv_iter_is_restarted(&cursor)) { dma_resv_list_free(list); - dma_fence_put(excl); - - if (cursor.shared_count) { - list = dma_resv_list_alloc(cursor.shared_count); - if (!list) { - dma_resv_iter_end(&cursor); - return -ENOMEM; - }

- list->shared_count = 0; - - } else { - list = NULL; + list = dma_resv_list_alloc(cursor.num_fences); + if (!list) { + dma_resv_iter_end(&cursor); + return -ENOMEM; } - excl = NULL; + list->num_fences = 0; }

dma_fence_get(f); - if (dma_resv_iter_usage(&cursor) == DMA_RESV_USAGE_WRITE) - excl = f; - else - RCU_INIT_POINTER(list->shared[list->shared_count++], f); + dma_resv_list_set(list, list->num_fences++, f, + dma_resv_iter_usage(&cursor)); } dma_resv_iter_end(&cursor);

write_seqcount_begin(&dst->seq); - excl = rcu_replace_pointer(dst->fence_excl, excl, dma_resv_held(dst)); - list = rcu_replace_pointer(dst->fence, list, dma_resv_held(dst)); + list = rcu_replace_pointer(dst->fences, list, dma_resv_held(dst)); write_seqcount_end(&dst->seq);

dma_resv_list_free(list); - dma_fence_put(excl); - return 0; } EXPORT_SYMBOL(dma_resv_copy_fences);

/** - * dma_resv_get_fences - Get an object's shared and exclusive + * dma_resv_get_fences - Get an object's fences * fences without update side lock held * @obj: the reservation object * @usage: controls which fences to include, see enum dma_resv_usage. @@ -649,7 +579,7 @@ int dma_resv_get_fences(struct dma_resv *obj, enum dma_resv_usage usage, while (*num_fences) dma_fence_put((*fences)[--(*num_fences)]);

- count = cursor.shared_count + 1; + count = cursor.num_fences + 1;

/* Eventually re-allocate the array */ *fences = krealloc_array(*fences, count, @@ -723,8 +653,7 @@ int dma_resv_get_singleton(struct dma_resv *obj, enum dma_resv_usage usage, EXPORT_SYMBOL_GPL(dma_resv_get_singleton);

/** - * dma_resv_wait_timeout - Wait on reservation's objects - * shared and/or exclusive fences. + * dma_resv_wait_timeout - Wait on reservation's objects fences * @obj: the reservation object * @usage: controls which fences to include, see enum dma_resv_usage. * @intr: if true, do interruptible wait diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h index 044b41f0bfd9..529d52a204cf 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h @@ -34,7 +34,6 @@ struct amdgpu_fpriv; struct amdgpu_bo_list_entry { struct ttm_validate_buffer tv; struct amdgpu_bo_va *bo_va; - struct dma_fence_chain *chain; uint32_t priority; struct page **user_pages; bool user_invalidated; diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c index 76fd916424d6..8de283997769 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c @@ -574,14 +574,6 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p, struct amdgpu_bo *bo = ttm_to_amdgpu_bo(e->tv.bo);

e->bo_va = amdgpu_vm_bo_find(vm, bo); - - if (bo->tbo.base.dma_buf && !amdgpu_bo_explicit_sync(bo)) { - e->chain = dma_fence_chain_alloc(); - if (!e->chain) { - r = -ENOMEM; - goto error_validate; - } - } }

/* Move fence waiting after getting reservation lock of @@ -642,13 +634,8 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p, }

error_validate: - if (r) { - amdgpu_bo_list_for_each_entry(e, p->bo_list) { - dma_fence_chain_free(e->chain); - e->chain = NULL; - } + if (r) ttm_eu_backoff_reservation(&p->ticket, &p->validated); - } out: return r; } @@ -688,17 +675,9 @@ static void amdgpu_cs_parser_fini(struct amdgpu_cs_parser *parser, int error, { unsigned i;

- if (error && backoff) { - struct amdgpu_bo_list_entry *e; - - amdgpu_bo_list_for_each_entry(e, parser->bo_list) { - dma_fence_chain_free(e->chain); - e->chain = NULL; - } - + if (error && backoff) ttm_eu_backoff_reservation(&parser->ticket, &parser->validated); - }

for (i = 0; i < parser->num_post_deps; i++) { drm_syncobj_put(parser->post_deps[i].syncobj); @@ -1272,31 +1251,9 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,

amdgpu_vm_move_to_lru_tail(p->adev, &fpriv->vm);

- amdgpu_bo_list_for_each_entry(e, p->bo_list) { - struct dma_resv *resv = e->tv.bo->base.resv; - struct dma_fence_chain *chain = e->chain; - struct dma_resv_iter cursor; - struct dma_fence *fence; - - if (!chain) - continue; - - /* - * Temporary workaround dma_resv shortcommings by wrapping up - * the submission in a dma_fence_chain and add it as exclusive - * fence. - * - * TODO: Remove together with dma_resv rework. - */ - dma_resv_for_each_fence(&cursor, resv, - DMA_RESV_USAGE_WRITE, - fence) { - break; - } - dma_fence_chain_init(chain, fence, dma_fence_get(p->fence), 1); - rcu_assign_pointer(resv->fence_excl, &chain->base); - e->chain = NULL; - } + /* Make sure all BOs are remembered as writers */ + amdgpu_bo_list_for_each_entry(e, p->bo_list) + e->tv.num_shared = 0;

ttm_eu_fence_buffer_objects(&p->ticket, &p->validated, p->fence); mutex_unlock(&p->adev->notifier_lock); diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index 98dc5234b487..7bb7e7edbb6f 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -99,8 +99,8 @@ static inline enum dma_resv_usage dma_resv_usage_rw(bool write) /** * struct dma_resv - a reservation object manages fences for a buffer * - * There are multiple uses for this, with sometimes slightly different rules in - * how the fence slots are used. + * This is a container for dma_fence objects which needs to handle multiple use + * cases. * * One use is to synchronize cross-driver access to a struct dma_buf, either for * dynamic buffer management or just to handle implicit synchronization between @@ -130,47 +130,22 @@ struct dma_resv { * @seq: * * Sequence count for managing RCU read-side synchronization, allows - * read-only access to @fence_excl and @fence while ensuring we take a - * consistent snapshot. + * read-only access to @fences while ensuring we take a consistent + * snapshot. */ seqcount_ww_mutex_t seq;

/** - * @fence_excl: + * @fences: * - * The exclusive fence, if there is one currently. + * Array of fences which where added to the dma_resv object * - * To guarantee that no fences are lost, this new fence must signal - * only after the previous exclusive fence has signalled. If - * semantically only a new access is added without actually treating the - * previous one as a dependency the exclusive fences can be strung - * together using struct dma_fence_chain. - * - * Note that actual semantics of what an exclusive or shared fence mean - * is defined by the user, for reservation objects shared across drivers - * see &dma_buf.resv. - */ - struct dma_fence __rcu *fence_excl; - - /** - * @fence: - * - * List of current shared fences. - * - * There are no ordering constraints of shared fences against the - * exclusive fence slot. If a waiter needs to wait for all access, it - * has to wait for both sets of fences to signal. - * - * A new fence is added by calling dma_resv_add_shared_fence(). Since - * this often needs to be done past the point of no return in command + * A new fence is added by calling dma_resv_add_fence(). Since this + * often needs to be done past the point of no return in command * submission it cannot fail, and therefore sufficient slots need to be * reserved by calling dma_resv_reserve_fences(). - * - * Note that actual semantics of what an exclusive or shared fence mean - * is defined by the user, for reservation objects shared across drivers - * see &dma_buf.resv. */ - struct dma_resv_list __rcu *fence; + struct dma_resv_list __rcu *fences; };

/** @@ -207,8 +182,8 @@ struct dma_resv_iter { /** @fences: the shared fences; private, *MUST* not dereference */ struct dma_resv_list *fences;

- /** @shared_count: number of shared fences */ - unsigned int shared_count; + /** @num_fences: number of fences */ + unsigned int num_fences;

/** @is_restarted: true if this is the first returned fence */ bool is_restarted;