Commit 43d9bb42 authored by Harry Yoo's avatar Harry Yoo Committed by Vlastimil Babka
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ext4: specify the free pointer offset for ext4_inode_cache 



Convert ext4_inode_cache to use the kmem_cache_args interface and
specify a free pointer offset.

Since ext4_inode_cache uses a constructor, the free pointer would be
placed after the object to prevent overwriting fields used by the
constructor.

However, some fields such as ->i_flags are not used by the constructor
and can safely be repurposed for the free pointer.

Specify the free pointer offset at i_flags to reduce the object size.

Signed-off-by: default avatarHarry Yoo <harry.yoo@oracle.com>
Link: https://patch.msgid.link/20260113061845.159790-4-harry.yoo@oracle.com


Signed-off-by: default avatarVlastimil Babka <vbabka@suse.cz>
parent a13b68d7

fs/ext4/super.c

+13 −6
Original line number Diff line number Diff line
@@ -1491,12 +1491,19 @@ static void init_once(void *foo) 


static int __init init_inodecache(void)

{

	ext4_inode_cachep = kmem_cache_create_usercopy("ext4_inode_cache",

				sizeof(struct ext4_inode_info), 0,

				SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT,

				offsetof(struct ext4_inode_info, i_data),

				sizeof_field(struct ext4_inode_info, i_data),

				init_once);

	struct kmem_cache_args args = {

		.useroffset = offsetof(struct ext4_inode_info, i_data),

		.usersize = sizeof_field(struct ext4_inode_info, i_data),

		.use_freeptr_offset = true,

		.freeptr_offset = offsetof(struct ext4_inode_info, i_flags),

		.ctor = init_once,

	};



	ext4_inode_cachep = kmem_cache_create("ext4_inode_cache",

				sizeof(struct ext4_inode_info),

				&args,

				SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT);



	if (ext4_inode_cachep == NULL)

		return -ENOMEM;

	return 0;