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Subject[PATCH 14/18] mm, hugetlb: clean-up error handling in hugetlb_cow()
Date
Current code include 'Caller expects lock to be held' in every error path.
We can clean-up it as we do error handling in one place.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 255bd9e..683fd38 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2516,6 +2516,7 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
struct hstate *h = hstate_vma(vma);
struct page *old_page, *new_page;
int use_reserve, outside_reserve = 0;
+ int ret = 0;
unsigned long mmun_start; /* For mmu_notifiers */
unsigned long mmun_end; /* For mmu_notifiers */

@@ -2537,11 +2538,8 @@ retry_avoidcopy:

use_reserve = vma_has_reserves(h, vma, address);
if (use_reserve == -ENOMEM) {
- page_cache_release(old_page);
-
- /* Caller expects lock to be held */
- spin_lock(&mm->page_table_lock);
- return VM_FAULT_OOM;
+ ret = VM_FAULT_OOM;
+ goto out_old_page;
}

/*
@@ -2588,9 +2586,8 @@ retry_avoidcopy:
WARN_ON_ONCE(1);
}

- /* Caller expects lock to be held */
- spin_lock(&mm->page_table_lock);
- return VM_FAULT_SIGBUS;
+ ret = VM_FAULT_SIGBUS;
+ goto out_lock;
}

/*
@@ -2598,11 +2595,8 @@ retry_avoidcopy:
* anon_vma prepared.
*/
if (unlikely(anon_vma_prepare(vma))) {
- page_cache_release(new_page);
- page_cache_release(old_page);
- /* Caller expects lock to be held */
- spin_lock(&mm->page_table_lock);
- return VM_FAULT_OOM;
+ ret = VM_FAULT_OOM;
+ goto out_new_page;
}

copy_user_huge_page(new_page, old_page, address, vma,
@@ -2630,12 +2624,15 @@ retry_avoidcopy:
}
spin_unlock(&mm->page_table_lock);
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
+
+out_new_page:
page_cache_release(new_page);
+out_old_page:
page_cache_release(old_page);
-
+out_lock:
/* Caller expects lock to be held */
spin_lock(&mm->page_table_lock);
- return 0;
+ return ret;
}

/* Return the pagecache page at a given address within a VMA */
--
1.7.9.5


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