linux-kernel - Re: [PATCH] ext4: kunit: use dynamic inode allocation

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Date: Wed, 28 Feb 2024 09:10:23 +0800
From: Kemeng Shi <shikemeng@...weicloud.com>
To: Arnd Bergmann <arnd@...nel.org>, Theodore Ts'o <tytso@....edu>,
 Andreas Dilger <adilger.kernel@...ger.ca>
Cc: Arnd Bergmann <arnd@...db.de>,
 "Ritesh Harjani (IBM)" <ritesh.list@...il.com>, linux-ext4@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ext4: kunit: use dynamic inode allocation



on 2/28/2024 12:15 AM, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@...db.de>
> 
> Storing an inode structure on the stack pushes some functions over the warning
> limit for stack frame size:
> 
> In file included from fs/ext4/mballoc.c:7039:
> fs/ext4/mballoc-test.c:506:13: error: stack frame size (1032) exceeds limit (1024) in 'test_mark_diskspace_used' [-Werror,-Wframe-larger-than]
>   506 | static void test_mark_diskspace_used(struct kunit *test)
>       |             ^
> 
> Use kunit_kzalloc() for all inodes. There may be a better way to do it by
> preallocating the inode, which would result in a larger rework.
> 
> Fixes: 2b81493f8eb6 ("ext4: Add unit test for ext4_mb_mark_diskspace_used")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>  fs/ext4/mballoc-test.c | 27 +++++++++++++++++++++------
>  1 file changed, 21 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/ext4/mballoc-test.c b/fs/ext4/mballoc-test.c
> index 12d0b22cabe1..3b43301054b6 100644
> --- a/fs/ext4/mballoc-test.c
> +++ b/fs/ext4/mballoc-test.c
> @@ -332,14 +332,19 @@ static void mbt_kunit_exit(struct kunit *test)
>  static void test_new_blocks_simple(struct kunit *test)
>  {
>  	struct super_block *sb = (struct super_block *)test->priv;
> -	struct inode inode = { .i_sb = sb, };
> +	struct inode *inode;
>  	struct ext4_allocation_request ar;
>  	ext4_group_t i, goal_group = TEST_GOAL_GROUP;
>  	int err = 0;
>  	ext4_fsblk_t found;
>  	struct ext4_sb_info *sbi = EXT4_SB(sb);
>  
> -	ar.inode = &inode;
> +	inode = kunit_kzalloc(test, sizeof(*inode), GFP_KERNEL);
> +	if (!inode)
> +		return;
> +
> +	inode->i_sb = sb;
> +	ar.inode = inode;
>  
>  	/* get block at goal */
>  	ar.goal = ext4_group_first_block_no(sb, goal_group);
> @@ -441,15 +446,20 @@ test_free_blocks_simple_range(struct kunit *test, ext4_group_t goal_group,
>  {
>  	struct super_block *sb = (struct super_block *)test->priv;
>  	struct ext4_sb_info *sbi = EXT4_SB(sb);
> -	struct inode inode = { .i_sb = sb, };
> +	struct inode *inode;
>  	ext4_fsblk_t block;
>  
> +	inode = kunit_kzalloc(test, sizeof(*inode), GFP_KERNEL);
> +	if (!inode)
> +		return;
> +	inode->i_sb = sb;
> +
>  	if (len == 0)
>  		return;
>  
>  	block = ext4_group_first_block_no(sb, goal_group) +
>  		EXT4_C2B(sbi, start);
> -	ext4_free_blocks_simple(&inode, block, len);
> +	ext4_free_blocks_simple(inode, block, len);
>  	validate_free_blocks_simple(test, sb, goal_group, start, len);
>  	mbt_ctx_mark_used(sb, goal_group, 0, EXT4_CLUSTERS_PER_GROUP(sb));
>  }
> @@ -506,16 +516,21 @@ test_mark_diskspace_used_range(struct kunit *test,
>  static void test_mark_diskspace_used(struct kunit *test)
>  {
>  	struct super_block *sb = (struct super_block *)test->priv;
> -	struct inode inode = { .i_sb = sb, };
> +	struct inode *inode;
>  	struct ext4_allocation_context ac;
>  	struct test_range ranges[TEST_RANGE_COUNT];
>  	int i;
>  
>  	mbt_generate_test_ranges(sb, ranges, TEST_RANGE_COUNT);
>  
> +	inode = kunit_kzalloc(test, sizeof(*inode), GFP_KERNEL);
> +	if (!inode)
> +		return;
> +	inode->i_sb = sb;
> +
>  	ac.ac_status = AC_STATUS_FOUND;
>  	ac.ac_sb = sb;
> -	ac.ac_inode = &inode;
> +	ac.ac_inode = inode;
>  	for (i = 0; i < TEST_RANGE_COUNT; i++)
>  		test_mark_diskspace_used_range(test, &ac, ranges[i].start,
>  					       ranges[i].len);
> 
Thanks for the fix. Feel free to add:

Reviewed-by: Kemeng Shi <shikemeng@...weicloud.com>