在 2023/4/26 00:08, Liam R. Howlett 写道:
* Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx> [230425 07:05]:Let mtree_alloc_range() and mtree_alloc_rrange() use mas_empty_area() and mas_empty_area_rev() respectively for allocation to reduce code redundancy. And after doing this, we don't need to maintain two logically identical codes to improve maintainability. In fact, mtree_alloc_range/rrange() has some bugs. For example, when dealing with min equals to max (mas_empty_area/area_rev() has been fixed), the allocation will fail. There are still some other bugs in it, I saw it with my naked eyes, but I didn't test it, for example: When mtree_alloc_range()->mas_alloc()->mas_awalk(), we set mas.index = min, mas.last = max - size. However, mas_awalk() requires mas.index = min, mas.last = max, which may lead to allocation failures.Please don't re-state code in your commit messages. Try to focus on what you did, and not why. ie: Aligned mtree_alloc_range() to use the same internal function as mas_empty_area().Right now no users are using these two functions so the bug won't trigger, but this might trigger in the future. Also use mas_store_gfp() instead of mas_fill_gap() as I don't see any difference between them.Yeah, evolution of the code converged on the same design. Thanks for seeing this.After doing this, we no longer need the three functions mas_fill_gap(), mas_alloc(), and mas_rev_alloc().Let's just drop mtree_alloc_range() and mtree_alloc_rrange() and whatever else you found here. They were planned to simplify the mmap code allocations, but since there would need to be arch involvement (coloring, etc) and alignment, etc; it is better to leave this job to the mm code itself.
Ok, I will remove some useless functions here.But mtree_alloc_range() and mtree_alloc_rrange() really don't need to be reserved? Because I don't know if there will be users using it in other scenarios in the future.
Thank you for all your suggestions on this patch set, I will update them.
Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx> --- lib/maple_tree.c | 45 ++++++++++++--------------------------------- 1 file changed, 12 insertions(+), 33 deletions(-) diff --git a/lib/maple_tree.c b/lib/maple_tree.c index aa55c914818a0..294d4c8668323 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -6362,32 +6362,20 @@ int mtree_alloc_range(struct maple_tree *mt, unsigned long *startp, { int ret = 0;- MA_STATE(mas, mt, min, max - size);+ MA_STATE(mas, mt, 0, 0); if (!mt_is_alloc(mt)) return -EINVAL;if (WARN_ON_ONCE(mt_is_reserved(entry)))return -EINVAL;- if (min > max)- return -EINVAL; - - if (max < size) - return -EINVAL; - - if (!size) - return -EINVAL; - mtree_lock(mt); -retry: - mas.offset = 0; - mas.index = min; - mas.last = max - size; - ret = mas_alloc(&mas, entry, size, startp); - if (mas_nomem(&mas, gfp)) - goto retry; - + ret = mas_empty_area(&mas, min, max, size); + if (!ret) + ret = mas_store_gfp(&mas, entry, gfp); mtree_unlock(mt); + if (!ret) + *startp = mas.index; return ret; } EXPORT_SYMBOL(mtree_alloc_range); @@ -6398,29 +6386,20 @@ int mtree_alloc_rrange(struct maple_tree *mt, unsigned long *startp, { int ret = 0;- MA_STATE(mas, mt, min, max - size);+ MA_STATE(mas, mt, 0, 0); if (!mt_is_alloc(mt)) return -EINVAL;if (WARN_ON_ONCE(mt_is_reserved(entry)))return -EINVAL;- if (min >= max)- return -EINVAL; - - if (max < size - 1) - return -EINVAL; - - if (!size) - return -EINVAL; - mtree_lock(mt); -retry: - ret = mas_rev_alloc(&mas, min, max, entry, size, startp); - if (mas_nomem(&mas, gfp)) - goto retry; - + ret = mas_empty_area_rev(&mas, min, max, size); + if (!ret) + ret = mas_store_gfp(&mas, entry, gfp); mtree_unlock(mt); + if (!ret) + *startp = mas.index; return ret; } EXPORT_SYMBOL(mtree_alloc_rrange); -- 2.20.1
