Re: [PATCH] mm/mmap: replace if (cond) BUG() with BUG_ON()

[Alex Shi <alex.shi@linux.alibaba.com>]

I'm very sorry, a typo here. the patch should be updated:

From ed4fa1c6d5bed5766c5f0c35af0c597855d7be06 Mon Sep 17 00:00:00 2001
From: Alex Shi <alex.shi@linux.alibaba.com>
Date: Fri, 11 Dec 2020 21:26:46 +0800
Subject: [PATCH] mm/mmap: replace if (cond) BUG() with BUG_ON()

coccinelle reports some warnings:
WARNING: Use BUG_ON instead of if condition followed by BUG.

It could be fixed by BUG_ON().

Reported-by: abaci@linux.alibaba.com
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/mmap.c | 22 ++++++++--------------
 1 file changed, 8 insertions(+), 14 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 8144fc3c5a78..107fa91bb59f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -712,9 +712,8 @@ static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
 	struct vm_area_struct *prev;
 	struct rb_node **rb_link, *rb_parent;
 
-	if (find_vma_links(mm, vma->vm_start, vma->vm_end,
-			   &prev, &rb_link, &rb_parent))
-		BUG();
+	BUG_ON(find_vma_links(mm, vma->vm_start, vma->vm_end,
+			   &prev, &rb_link, &rb_parent));
 	__vma_link(mm, vma, prev, rb_link, rb_parent);
 	mm->map_count++;
 }
@@ -3585,9 +3584,8 @@ static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
 		 * can't change from under us thanks to the
 		 * anon_vma->root->rwsem.
 		 */
-		if (__test_and_set_bit(0, (unsigned long *)
-				       &anon_vma->root->rb_root.rb_root.rb_node))
-			BUG();
+		BUG_ON(__test_and_set_bit(0, (unsigned long *)
+			&anon_vma->root->rb_root.rb_root.rb_node));
 	}
 }
 
@@ -3603,8 +3601,7 @@ static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
 		 * mm_all_locks_mutex, there may be other cpus
 		 * changing other bitflags in parallel to us.
 		 */
-		if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
-			BUG();
+		BUG_ON(test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags));
 		down_write_nest_lock(&mapping->i_mmap_rwsem, &mm->mmap_lock);
 	}
 }
@@ -3701,9 +3698,8 @@ static void vm_unlock_anon_vma(struct anon_vma *anon_vma)
 		 * can't change from under us until we release the
 		 * anon_vma->root->rwsem.
 		 */
-		if (!__test_and_clear_bit(0, (unsigned long *)
-					  &anon_vma->root->rb_root.rb_root.rb_node))
-			BUG();
+		BUG_ON(!__test_and_clear_bit(0, (unsigned long *)
+				&anon_vma->root->rb_root.rb_root.rb_node));
 		anon_vma_unlock_write(anon_vma);
 	}
 }
@@ -3716,9 +3712,7 @@ static void vm_unlock_mapping(struct address_space *mapping)
 		 * because we hold the mm_all_locks_mutex.
 		 */
 		i_mmap_unlock_write(mapping);
-		if (!test_and_clear_bit(AS_MM_ALL_LOCKS,
-					&mapping->flags))
-			BUG();
+		BUG_ON(!test_and_clear_bit(AS_MM_ALL_LOCKS, &mapping->flags));
 	}
 }
 
-- 
2.29.GIT