Introduce a dma_fence_merge() macro which allows to unwrap fences which potentially can be containers as well and then merge them back together into a flat dma_fence_array.
Signed-off-by: Christian König christian.koenig@amd.com --- drivers/dma-buf/dma-fence-unwrap.c | 95 ++++++++++++++++++++ drivers/dma-buf/st-dma-fence-unwrap.c | 47 ++++++++++ drivers/dma-buf/sync_file.c | 119 ++------------------------ include/linux/dma-fence-unwrap.h | 24 ++++++ 4 files changed, 172 insertions(+), 113 deletions(-)
diff --git a/drivers/dma-buf/dma-fence-unwrap.c b/drivers/dma-buf/dma-fence-unwrap.c index 711be125428c..c9becc74896d 100644 --- a/drivers/dma-buf/dma-fence-unwrap.c +++ b/drivers/dma-buf/dma-fence-unwrap.c @@ -11,6 +11,7 @@ #include <linux/dma-fence-array.h> #include <linux/dma-fence-chain.h> #include <linux/dma-fence-unwrap.h> +#include <linux/slab.h>
/* Internal helper to start new array iteration, don't use directly */ static struct dma_fence * @@ -57,3 +58,97 @@ struct dma_fence *dma_fence_unwrap_next(struct dma_fence_unwrap *cursor) return __dma_fence_unwrap_array(cursor); } EXPORT_SYMBOL_GPL(dma_fence_unwrap_next); + +/* Implementation for the dma_fence_merge() marco, don't use directly */ +struct dma_fence *__dma_fence_merge(unsigned int num_fences, + struct dma_fence **fences, + struct dma_fence_unwrap *iter) +{ + struct dma_fence_array *result; + struct dma_fence *tmp, **array; + unsigned int i, count; + + count = 0; + for (i = 0; i < num_fences; ++i) { + dma_fence_unwrap_for_each(tmp, &iter[i], fences[i]) + if (!dma_fence_is_signaled(tmp)) + ++count; + } + + if (count == 0) + return dma_fence_get_stub(); + + if (count > INT_MAX) + return NULL; + + array = kmalloc_array(count, sizeof(*array), GFP_KERNEL); + if (!array) + return NULL; + + /* + * We can't guarantee that inpute fences are ordered by context, but + * it is still quite likely when this function is used multiple times. + * So attempt to order the fences by context as we pass over them and + * merge fences with the same context. + */ + for (i = 0; i < num_fences; ++i) + fences[i] = dma_fence_unwrap_first(fences[i], &iter[i]); + + count = 0; + do { + unsigned int sel; + +restart: + tmp = NULL; + for (i = 0; i < num_fences; ++i) { + struct dma_fence *next = fences[i]; + + if (!next || dma_fence_is_signaled(next)) + continue; + + if (!tmp || tmp->context > next->context) { + tmp = next; + sel = i; + + } else if (tmp->context < next->context) { + continue; + + } else if (dma_fence_is_later(tmp, next)) { + fences[i] = dma_fence_unwrap_next(&iter[i]); + goto restart; + } else { + fences[sel] = dma_fence_unwrap_next(&iter[sel]); + goto restart; + } + } + + if (tmp) { + array[count++] = dma_fence_get(tmp); + fences[sel] = dma_fence_unwrap_next(&iter[sel]); + } + } while (tmp); + + if (count == 0) { + tmp = dma_fence_get_stub(); + goto return_tmp; + } + + if (count == 1) { + tmp = array[0]; + goto return_tmp; + } + + result = dma_fence_array_create(count, array, + dma_fence_context_alloc(1), + 1, false); + if (!result) { + tmp = NULL; + goto return_tmp; + } + return &result->base; + +return_tmp: + kfree(array); + return tmp; +} +EXPORT_SYMBOL_GPL(__dma_fence_merge); diff --git a/drivers/dma-buf/st-dma-fence-unwrap.c b/drivers/dma-buf/st-dma-fence-unwrap.c index 59628add93f5..23ab134417ed 100644 --- a/drivers/dma-buf/st-dma-fence-unwrap.c +++ b/drivers/dma-buf/st-dma-fence-unwrap.c @@ -240,6 +240,52 @@ static int unwrap_chain_array(void *arg) return err; }
+static int unwrap_merge(void *arg) +{ + struct dma_fence *fence, *f1, *f2, *f3; + struct dma_fence_unwrap iter; + int err = 0; + + f1 = mock_fence(); + if (!f1) + return -ENOMEM; + + f2 = mock_fence(); + if (!f2) { + err = -ENOMEM; + goto error_put_f1; + } + + f3 = dma_fence_merge(f1, f2); + if (!f3) { + err = -ENOMEM; + goto error_put_f2; + } + + dma_fence_unwrap_for_each(fence, &iter, f3) { + if (fence == f1) { + f1 = NULL; + } else if (fence == f2) { + f2 = NULL; + } else { + pr_err("Unexpected fence!\n"); + err = -EINVAL; + } + } + + if (f1 || f2) { + pr_err("Not all fences seen!\n"); + err = -EINVAL; + } + + dma_fence_put(f3); +error_put_f2: + dma_fence_put(f2); +error_put_f1: + dma_fence_put(f1); + return err; +} + int dma_fence_unwrap(void) { static const struct subtest tests[] = { @@ -247,6 +293,7 @@ int dma_fence_unwrap(void) SUBTEST(unwrap_array), SUBTEST(unwrap_chain), SUBTEST(unwrap_chain_array), + SUBTEST(unwrap_merge), };
return subtests(tests, NULL); diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c index 0fe564539166..fe149d7e3ce2 100644 --- a/drivers/dma-buf/sync_file.c +++ b/drivers/dma-buf/sync_file.c @@ -146,50 +146,6 @@ char *sync_file_get_name(struct sync_file *sync_file, char *buf, int len) return buf; }
-static int sync_file_set_fence(struct sync_file *sync_file, - struct dma_fence **fences, int num_fences) -{ - struct dma_fence_array *array; - - /* - * The reference for the fences in the new sync_file and held - * in add_fence() during the merge procedure, so for num_fences == 1 - * we already own a new reference to the fence. For num_fence > 1 - * we own the reference of the dma_fence_array creation. - */ - - if (num_fences == 0) { - sync_file->fence = dma_fence_get_stub(); - kfree(fences); - - } else if (num_fences == 1) { - sync_file->fence = fences[0]; - kfree(fences); - - } else { - array = dma_fence_array_create(num_fences, fences, - dma_fence_context_alloc(1), - 1, false); - if (!array) - return -ENOMEM; - - sync_file->fence = &array->base; - } - - return 0; -} - -static void add_fence(struct dma_fence **fences, - int *i, struct dma_fence *fence) -{ - fences[*i] = fence; - - if (!dma_fence_is_signaled(fence)) { - dma_fence_get(fence); - (*i)++; - } -} - /** * sync_file_merge() - merge two sync_files * @name: name of new fence @@ -203,84 +159,21 @@ static void add_fence(struct dma_fence **fences, static struct sync_file *sync_file_merge(const char *name, struct sync_file *a, struct sync_file *b) { - struct dma_fence *a_fence, *b_fence, **fences; - struct dma_fence_unwrap a_iter, b_iter; - unsigned int index, num_fences; struct sync_file *sync_file; + struct dma_fence *fence;
sync_file = sync_file_alloc(); if (!sync_file) return NULL;
- num_fences = 0; - dma_fence_unwrap_for_each(a_fence, &a_iter, a->fence) - ++num_fences; - dma_fence_unwrap_for_each(b_fence, &b_iter, b->fence) - ++num_fences; - - if (num_fences > INT_MAX) - goto err_free_sync_file; - - fences = kcalloc(num_fences, sizeof(*fences), GFP_KERNEL); - if (!fences) - goto err_free_sync_file; - - /* - * We can't guarantee that fences in both a and b are ordered, but it is - * still quite likely. - * - * So attempt to order the fences as we pass over them and merge fences - * with the same context. - */ - - index = 0; - for (a_fence = dma_fence_unwrap_first(a->fence, &a_iter), - b_fence = dma_fence_unwrap_first(b->fence, &b_iter); - a_fence || b_fence; ) { - - if (!b_fence) { - add_fence(fences, &index, a_fence); - a_fence = dma_fence_unwrap_next(&a_iter); - - } else if (!a_fence) { - add_fence(fences, &index, b_fence); - b_fence = dma_fence_unwrap_next(&b_iter); - - } else if (a_fence->context < b_fence->context) { - add_fence(fences, &index, a_fence); - a_fence = dma_fence_unwrap_next(&a_iter); - - } else if (b_fence->context < a_fence->context) { - add_fence(fences, &index, b_fence); - b_fence = dma_fence_unwrap_next(&b_iter); - - } else if (__dma_fence_is_later(a_fence->seqno, b_fence->seqno, - a_fence->ops)) { - add_fence(fences, &index, a_fence); - a_fence = dma_fence_unwrap_next(&a_iter); - b_fence = dma_fence_unwrap_next(&b_iter); - - } else { - add_fence(fences, &index, b_fence); - a_fence = dma_fence_unwrap_next(&a_iter); - b_fence = dma_fence_unwrap_next(&b_iter); - } + fence = dma_fence_merge(a->fence, b->fence); + if (!fence) { + fput(sync_file->file); + return NULL; } - - if (sync_file_set_fence(sync_file, fences, index) < 0) - goto err_put_fences; - + sync_file->fence = fence; strlcpy(sync_file->user_name, name, sizeof(sync_file->user_name)); return sync_file; - -err_put_fences: - while (index) - dma_fence_put(fences[--index]); - kfree(fences); - -err_free_sync_file: - fput(sync_file->file); - return NULL; }
static int sync_file_release(struct inode *inode, struct file *file) diff --git a/include/linux/dma-fence-unwrap.h b/include/linux/dma-fence-unwrap.h index e7c219da4ed7..7c0fab318301 100644 --- a/include/linux/dma-fence-unwrap.h +++ b/include/linux/dma-fence-unwrap.h @@ -48,4 +48,28 @@ struct dma_fence *dma_fence_unwrap_next(struct dma_fence_unwrap *cursor); for (fence = dma_fence_unwrap_first(head, cursor); fence; \ fence = dma_fence_unwrap_next(cursor))
+struct dma_fence *__dma_fence_merge(unsigned int num_fences, + struct dma_fence **fences, + struct dma_fence_unwrap *cursors); + +/** + * dma_fence_merge - unwrap and merge fences + * + * All fences given as parameters are unwrapped and merged back together as flat + * dma_fence_array. Useful if multiple containers need to be merged together. + * + * Implemented as a macro to allocate the necessary arrays on the stack and + * account the stack frame size to the caller. + * + * Returns NULL on memory allocation failure, a dma_fence object representing + * all the given fences otherwise. + */ +#define dma_fence_merge(...) \ + ({ \ + struct dma_fence *__f[] = { __VA_ARGS__ }; \ + struct dma_fence_unwrap __c[ARRAY_SIZE(__f)]; \ + \ + __dma_fence_merge(ARRAY_SIZE(__f), __f, __c); \ + }) + #endif