This patch fixes bug in macro radix_tree_for_each_contig(). If radix_tree_next_slot() sees NULL in next slot it returns NULL, but following radix_tree_next_chunk() switches iterating into next chunk. As result iterating becomes non-contiguous and breaks vfs "splice" and all its users.
Unified · Split
| @@ -368,8 +368,11 @@ radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags) · 367 unmodified lines | ||
| 368 | 368 | iter->index++; |
| 369 | 369 | if (likely(*slot)) |
| 370 | 370 | return slot; |
| 371 | − if (flags & RADIX_TREE_ITER_CONTIG) | |
| 371 | + if (flags & RADIX_TREE_ITER_CONTIG) { | |
| 372 | + /* forbid switching to the next chunk */ | |
| 373 | + iter->next_index = 0; | |
| 372 | 374 | break; |
| 375 | + } | |
| 373 | 376 | } |
| 374 | 377 | } |
| 375 | 378 | return NULL; |
| @@ -686,6 +686,9 @@ void **radix_tree_next_chunk(struct radix_tree_root *root, · 685 unmodified lines | ||
| 686 | 686 | * during iterating; it can be zero only at the beginning. |
| 687 | 687 | * And we cannot overflow iter->next_index in a single step, |
| 688 | 688 | * because RADIX_TREE_MAP_SHIFT < BITS_PER_LONG. |
| 689 | + * | |
| 690 | + * This condition also used by radix_tree_next_slot() to stop | |
| 691 | + * contiguous iterating, and forbid swithing to the next chunk. | |
| 689 | 692 | */ |
| 690 | 693 | index = iter->next_index; |
| 691 | 694 | if (!index && iter->index) |