diff options
Diffstat (limited to 'drivers/dma-buf/dma-resv.c')
| -rw-r--r-- | drivers/dma-buf/dma-resv.c | 82 |
1 files changed, 38 insertions, 44 deletions
diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index 4deea75c0b9c..b51416405e86 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -256,6 +256,11 @@ void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence) dma_resv_assert_held(obj); + /* Drivers should not add containers here, instead add each fence + * individually. + */ + WARN_ON(dma_fence_is_container(fence)); + fobj = dma_resv_shared_list(obj); count = fobj->shared_count; @@ -323,12 +328,8 @@ void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence) } EXPORT_SYMBOL(dma_resv_add_excl_fence); -/** - * dma_resv_iter_restart_unlocked - restart the unlocked iterator - * @cursor: The dma_resv_iter object to restart - * - * Restart the unlocked iteration by initializing the cursor object. - */ +/* Restart the iterator by initializing all the necessary fields, but not the + * relation to the dma_resv object. */ static void dma_resv_iter_restart_unlocked(struct dma_resv_iter *cursor) { cursor->seq = read_seqcount_begin(&cursor->obj->seq); @@ -344,14 +345,7 @@ static void dma_resv_iter_restart_unlocked(struct dma_resv_iter *cursor) cursor->is_restarted = true; } -/** - * dma_resv_iter_walk_unlocked - walk over fences in a dma_resv obj - * @cursor: cursor to record the current position - * - * Return all the fences in the dma_resv object which are not yet signaled. - * The returned fence has an extra local reference so will stay alive. - * If a concurrent modify is detected the whole iteration is started over again. - */ +/* 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; @@ -387,6 +381,12 @@ static void dma_resv_iter_walk_unlocked(struct dma_resv_iter *cursor) * dma_resv_iter_first_unlocked - first fence in an unlocked dma_resv obj. * @cursor: the cursor with the current position * + * Subsequent fences are iterated with dma_resv_iter_next_unlocked(). + * + * Beware that the iterator can be restarted. Code which accumulates statistics + * or similar needs to check for this with dma_resv_iter_is_restarted(). For + * this reason prefer the locked dma_resv_iter_first() whenver possible. + * * Returns the first fence from an unlocked dma_resv obj. */ struct dma_fence *dma_resv_iter_first_unlocked(struct dma_resv_iter *cursor) @@ -406,6 +406,10 @@ EXPORT_SYMBOL(dma_resv_iter_first_unlocked); * dma_resv_iter_next_unlocked - next fence in an unlocked dma_resv obj. * @cursor: the cursor with the current position * + * Beware that the iterator can be restarted. Code which accumulates statistics + * or similar needs to check for this with dma_resv_iter_is_restarted(). For + * this reason prefer the locked dma_resv_iter_next() whenver possible. + * * Returns the next fence from an unlocked dma_resv obj. */ struct dma_fence *dma_resv_iter_next_unlocked(struct dma_resv_iter *cursor) @@ -431,6 +435,8 @@ EXPORT_SYMBOL(dma_resv_iter_next_unlocked); * dma_resv_iter_first - first fence from a locked dma_resv object * @cursor: cursor to record the current position * + * Subsequent fences are iterated with dma_resv_iter_next_unlocked(). + * * Return the first fence in the dma_resv object while holding the * &dma_resv.lock. */ @@ -542,57 +548,45 @@ EXPORT_SYMBOL(dma_resv_copy_fences); * dma_resv_get_fences - Get an object's shared and exclusive * fences without update side lock held * @obj: the reservation object - * @fence_excl: the returned exclusive fence (or NULL) - * @shared_count: the number of shared fences returned - * @shared: the array of shared fence ptrs returned (array is krealloc'd to - * the required size, and must be freed by caller) - * - * Retrieve all fences from the reservation object. If the pointer for the - * exclusive fence is not specified the fence is put into the array of the - * shared fences as well. Returns either zero or -ENOMEM. + * @write: true if we should return all fences + * @num_fences: the number of fences returned + * @fences: the array of fence ptrs returned (array is krealloc'd to the + * required size, and must be freed by caller) + * + * Retrieve all fences from the reservation object. + * Returns either zero or -ENOMEM. */ -int dma_resv_get_fences(struct dma_resv *obj, struct dma_fence **fence_excl, - unsigned int *shared_count, struct dma_fence ***shared) +int dma_resv_get_fences(struct dma_resv *obj, bool write, + unsigned int *num_fences, struct dma_fence ***fences) { struct dma_resv_iter cursor; struct dma_fence *fence; - *shared_count = 0; - *shared = NULL; - - if (fence_excl) - *fence_excl = NULL; + *num_fences = 0; + *fences = NULL; - dma_resv_iter_begin(&cursor, obj, true); + dma_resv_iter_begin(&cursor, obj, write); dma_resv_for_each_fence_unlocked(&cursor, fence) { if (dma_resv_iter_is_restarted(&cursor)) { unsigned int count; - while (*shared_count) - dma_fence_put((*shared)[--(*shared_count)]); + while (*num_fences) + dma_fence_put((*fences)[--(*num_fences)]); - if (fence_excl) - dma_fence_put(*fence_excl); - - count = cursor.shared_count; - count += fence_excl ? 0 : 1; + count = cursor.shared_count + 1; /* Eventually re-allocate the array */ - *shared = krealloc_array(*shared, count, + *fences = krealloc_array(*fences, count, sizeof(void *), GFP_KERNEL); - if (count && !*shared) { + if (count && !*fences) { dma_resv_iter_end(&cursor); return -ENOMEM; } } - dma_fence_get(fence); - if (dma_resv_iter_is_exclusive(&cursor) && fence_excl) - *fence_excl = fence; - else - (*shared)[(*shared_count)++] = fence; + (*fences)[(*num_fences)++] = dma_fence_get(fence); } dma_resv_iter_end(&cursor); |