[PATCH V2] include: linux: Regularise the use of FIELD_SIZEOF macro

[PATCH V2] include: linux: Regularise the use of FIELD_SIZEOF macro

[Shyam Saini]

Currently, there are 3 different macros, namely sizeof_field, SIZEOF_FIELD
and FIELD_SIZEOF which are used to calculate the size of a member of
structure, so to bring uniformity in entire kernel source tree lets use
FIELD_SIZEOF and replace all occurrences of other two macros with this.

For this purpose, redefine FIELD_SIZEOF in include/linux/stddef.h and
tools/testing/selftests/bpf/bpf_util.h and remove its defination from
include/linux/kernel.h

In favour of FIELD_SIZEOF, this patch also deprecates other two similar
macros sizeof_field and SIZEOF_FIELD.

For code compatibility reason, retain sizeof_field macro as a wrapper macro
to FIELD_SIZEOF

Signed-off-by: Shyam Saini <shyam.saini@amarulasolutions.com>
---
Changelog:

V1->V2
- Consolidate previous patch 1 and 2 into single patch
- For code compatibility reason, retain sizeof_field macro as a
  wrapper macro to FIELD_SIZEOF
 
 arch/arm64/include/asm/processor.h                 | 10 +++++-----
 arch/mips/cavium-octeon/executive/cvmx-bootmem.c   |  9 +--------
 drivers/gpu/drm/i915/gvt/scheduler.c               |  2 +-
 drivers/net/ethernet/mellanox/mlxsw/spectrum_fid.c |  4 ++--
 fs/befs/linuxvfs.c                                 |  2 +-
 fs/ext2/super.c                                    |  2 +-
 fs/ext4/super.c                                    |  2 +-
 fs/freevxfs/vxfs_super.c                           |  2 +-
 fs/orangefs/super.c                                |  2 +-
 fs/ufs/super.c                                     |  2 +-
 include/linux/kernel.h                             |  9 ---------
 include/linux/slab.h                               |  2 +-
 include/linux/stddef.h                             | 17 ++++++++++++++---
 kernel/fork.c                                      |  2 +-
 kernel/utsname.c                                   |  2 +-
 net/caif/caif_socket.c                             |  2 +-
 net/core/skbuff.c                                  |  2 +-
 net/ipv4/raw.c                                     |  2 +-
 net/ipv6/raw.c                                     |  2 +-
 net/sctp/socket.c                                  |  4 ++--
 tools/testing/selftests/bpf/bpf_util.h             | 22 +++++++++++++++++++---
 virt/kvm/kvm_main.c                                |  2 +-
 22 files changed, 58 insertions(+), 47 deletions(-)

diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index fcd0e691b1ea..ace906d887cc 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -164,13 +164,13 @@ static inline void arch_thread_struct_whitelist(unsigned long *offset,
 						unsigned long *size)
 {
 	/* Verify that there is no padding among the whitelisted fields: */
-	BUILD_BUG_ON(sizeof_field(struct thread_struct, uw) !=
-		     sizeof_field(struct thread_struct, uw.tp_value) +
-		     sizeof_field(struct thread_struct, uw.tp2_value) +
-		     sizeof_field(struct thread_struct, uw.fpsimd_state));
+	BUILD_BUG_ON(FIELD_SIZEOF(struct thread_struct, uw) !=
+		     FIELD_SIZEOF(struct thread_struct, uw.tp_value) +
+		     FIELD_SIZEOF(struct thread_struct, uw.tp2_value) +
+		     FIELD_SIZEOF(struct thread_struct, uw.fpsimd_state));
 
 	*offset = offsetof(struct thread_struct, uw);
-	*size = sizeof_field(struct thread_struct, uw);
+	*size = FIELD_SIZEOF(struct thread_struct, uw);
 }
 
 #ifdef CONFIG_COMPAT
diff --git a/arch/mips/cavium-octeon/executive/cvmx-bootmem.c b/arch/mips/cavium-octeon/executive/cvmx-bootmem.c
index ba8f82a29a81..44b506a14666 100644
--- a/arch/mips/cavium-octeon/executive/cvmx-bootmem.c
+++ b/arch/mips/cavium-octeon/executive/cvmx-bootmem.c
@@ -45,13 +45,6 @@ static struct cvmx_bootmem_desc *cvmx_bootmem_desc;
 /* See header file for descriptions of functions */
 
 /**
- * This macro returns the size of a member of a structure.
- * Logically it is the same as "sizeof(s::field)" in C++, but
- * C lacks the "::" operator.
- */
-#define SIZEOF_FIELD(s, field) sizeof(((s *)NULL)->field)
-
-/**
  * This macro returns a member of the
  * cvmx_bootmem_named_block_desc_t structure. These members can't
  * be directly addressed as they might be in memory not directly
@@ -65,7 +58,7 @@ static struct cvmx_bootmem_desc *cvmx_bootmem_desc;
 #define CVMX_BOOTMEM_NAMED_GET_FIELD(addr, field)			\
 	__cvmx_bootmem_desc_get(addr,					\
 		offsetof(struct cvmx_bootmem_named_block_desc, field),	\
-		SIZEOF_FIELD(struct cvmx_bootmem_named_block_desc, field))
+		FIELD_SIZEOF(struct cvmx_bootmem_named_block_desc, field))
 
 /**
  * This function is the implementation of the get macros defined
diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
index 0f919f0a43d4..820f95a52542 100644
--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -1243,7 +1243,7 @@ int intel_vgpu_setup_submission(struct intel_vgpu *vgpu)
 						  sizeof(struct intel_vgpu_workload), 0,
 						  SLAB_HWCACHE_ALIGN,
 						  offsetof(struct intel_vgpu_workload, rb_tail),
-						  sizeof_field(struct intel_vgpu_workload, rb_tail),
+						  FIELD_SIZEOF(struct intel_vgpu_workload, rb_tail),
 						  NULL);
 
 	if (!s->workloads) {
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_fid.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_fid.c
index 46baf3b44309..c0447bf07fbb 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_fid.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_fid.c
@@ -49,13 +49,13 @@ struct mlxsw_sp_fid_8021d {
 };
 
 static const struct rhashtable_params mlxsw_sp_fid_ht_params = {
-	.key_len = sizeof_field(struct mlxsw_sp_fid, fid_index),
+	.key_len = FIELD_SIZEOF(struct mlxsw_sp_fid, fid_index),
 	.key_offset = offsetof(struct mlxsw_sp_fid, fid_index),
 	.head_offset = offsetof(struct mlxsw_sp_fid, ht_node),
 };
 
 static const struct rhashtable_params mlxsw_sp_fid_vni_ht_params = {
-	.key_len = sizeof_field(struct mlxsw_sp_fid, vni),
+	.key_len = FIELD_SIZEOF(struct mlxsw_sp_fid, vni),
 	.key_offset = offsetof(struct mlxsw_sp_fid, vni),
 	.head_offset = offsetof(struct mlxsw_sp_fid, vni_ht_node),
 };
diff --git a/fs/befs/linuxvfs.c b/fs/befs/linuxvfs.c
index 462d096ff3e9..06ffd4829e2e 100644
--- a/fs/befs/linuxvfs.c
+++ b/fs/befs/linuxvfs.c
@@ -438,7 +438,7 @@ befs_init_inodecache(void)
 					SLAB_ACCOUNT),
 				offsetof(struct befs_inode_info,
 					i_data.symlink),
-				sizeof_field(struct befs_inode_info,
+				FIELD_SIZEOF(struct befs_inode_info,
 					i_data.symlink),
 				init_once);
 	if (befs_inode_cachep == NULL)
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 1d7ab73b1014..d9a6c81f4a47 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -220,7 +220,7 @@ static int __init init_inodecache(void)
 				(SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
 					SLAB_ACCOUNT),
 				offsetof(struct ext2_inode_info, i_data),
-				sizeof_field(struct ext2_inode_info, i_data),
+				FIELD_SIZEOF(struct ext2_inode_info, i_data),
 				init_once);
 	if (ext2_inode_cachep == NULL)
 		return -ENOMEM;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 4079605d437a..b1b5856248bd 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1148,7 +1148,7 @@ static int __init init_inodecache(void)
 				(SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
 					SLAB_ACCOUNT),
 				offsetof(struct ext4_inode_info, i_data),
-				sizeof_field(struct ext4_inode_info, i_data),
+				FIELD_SIZEOF(struct ext4_inode_info, i_data),
 				init_once);
 	if (ext4_inode_cachep == NULL)
 		return -ENOMEM;
diff --git a/fs/freevxfs/vxfs_super.c b/fs/freevxfs/vxfs_super.c
index a89f68c3cbed..ffd22f85bbe0 100644
--- a/fs/freevxfs/vxfs_super.c
+++ b/fs/freevxfs/vxfs_super.c
@@ -329,7 +329,7 @@ vxfs_init(void)
 			sizeof(struct vxfs_inode_info), 0,
 			SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
 			offsetof(struct vxfs_inode_info, vii_immed.vi_immed),
-			sizeof_field(struct vxfs_inode_info,
+			FIELD_SIZEOF(struct vxfs_inode_info,
 				vii_immed.vi_immed),
 			NULL);
 	if (!vxfs_inode_cachep)
diff --git a/fs/orangefs/super.c b/fs/orangefs/super.c
index ee5efdc35cc1..30f625059ad9 100644
--- a/fs/orangefs/super.c
+++ b/fs/orangefs/super.c
@@ -646,7 +646,7 @@ int orangefs_inode_cache_initialize(void)
 					ORANGEFS_CACHE_CREATE_FLAGS,
 					offsetof(struct orangefs_inode_s,
 						link_target),
-					sizeof_field(struct orangefs_inode_s,
+					FIELD_SIZEOF(struct orangefs_inode_s,
 						link_target),
 					orangefs_inode_cache_ctor);
 
diff --git a/fs/ufs/super.c b/fs/ufs/super.c
index 3d247c0d92aa..1e8bcd950f6d 100644
--- a/fs/ufs/super.c
+++ b/fs/ufs/super.c
@@ -1469,7 +1469,7 @@ static int __init init_inodecache(void)
 				(SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
 					SLAB_ACCOUNT),
 				offsetof(struct ufs_inode_info, i_u1.i_symlink),
-				sizeof_field(struct ufs_inode_info,
+				FIELD_SIZEOF(struct ufs_inode_info,
 					i_u1.i_symlink),
 				init_once);
 	if (ufs_inode_cachep == NULL)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 74b1ee9027f5..4672391cdb5b 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -79,15 +79,6 @@
  */
 #define round_down(x, y) ((x) & ~__round_mask(x, y))
 
-/**
- * FIELD_SIZEOF - get the size of a struct's field
- * @t: the target struct
- * @f: the target struct's field
- * Return: the size of @f in the struct definition without having a
- * declared instance of @t.
- */
-#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
-
 #define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
 
 #define DIV_ROUND_DOWN_ULL(ll, d) \
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 9449b19c5f10..8bdfdd389b37 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -175,7 +175,7 @@ void memcg_destroy_kmem_caches(struct mem_cgroup *);
 			sizeof(struct __struct),			\
 			__alignof__(struct __struct), (__flags),	\
 			offsetof(struct __struct, __field),		\
-			sizeof_field(struct __struct, __field), NULL)
+			FIELD_SIZEOF(struct __struct, __field), NULL)
 
 /*
  * Common kmalloc functions provided by all allocators
diff --git a/include/linux/stddef.h b/include/linux/stddef.h
index 998a4ba28eba..a5960e2b4a8b 100644
--- a/include/linux/stddef.h
+++ b/include/linux/stddef.h
@@ -20,12 +20,23 @@ enum {
 #endif
 
 /**
- * sizeof_field(TYPE, MEMBER)
+ * FIELD_SIZEOF - get the size of a struct's field
+ * @t: the target struct
+ * @f: the target struct's field
+ * Return: the size of @f in the struct definition without having a
+ * declared instance of @t.
+ */
+#define FIELD_SIZEOF(t, f) (sizeof(((t *)0)->f))
+
+/*
+ * For code compatibility
  *
+ * sizeof_field(TYPE, MEMBER)
  * @TYPE: The structure containing the field of interest
  * @MEMBER: The field to return the size of
  */
-#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
+
+#define sizeof_field(TYPE, MEMBER) FIELD_SIZEOF(TYPE, MEMBER)
 
 /**
  * offsetofend(TYPE, MEMBER)
@@ -34,6 +45,6 @@ enum {
  * @MEMBER: The member within the structure to get the end offset of
  */
 #define offsetofend(TYPE, MEMBER) \
-	(offsetof(TYPE, MEMBER)	+ sizeof_field(TYPE, MEMBER))
+	(offsetof(TYPE, MEMBER)	+ FIELD_SIZEOF(TYPE, MEMBER))
 
 #endif
diff --git a/kernel/fork.c b/kernel/fork.c
index 75675b9bf6df..ef40b95bf82c 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2553,7 +2553,7 @@ void __init proc_caches_init(void)
 			mm_size, ARCH_MIN_MMSTRUCT_ALIGN,
 			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
 			offsetof(struct mm_struct, saved_auxv),
-			sizeof_field(struct mm_struct, saved_auxv),
+			FIELD_SIZEOF(struct mm_struct, saved_auxv),
 			NULL);
 	vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT);
 	mmap_init();
diff --git a/kernel/utsname.c b/kernel/utsname.c
index f0e491193009..28257c571553 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -174,6 +174,6 @@ void __init uts_ns_init(void)
 			"uts_namespace", sizeof(struct uts_namespace), 0,
 			SLAB_PANIC|SLAB_ACCOUNT,
 			offsetof(struct uts_namespace, name),
-			sizeof_field(struct uts_namespace, name),
+			FIELD_SIZEOF(struct uts_namespace, name),
 			NULL);
 }
diff --git a/net/caif/caif_socket.c b/net/caif/caif_socket.c
index 13ea920600ae..3306bbed77eb 100644
--- a/net/caif/caif_socket.c
+++ b/net/caif/caif_socket.c
@@ -1033,7 +1033,7 @@ static int caif_create(struct net *net, struct socket *sock, int protocol,
 		.owner = THIS_MODULE,
 		.obj_size = sizeof(struct caifsock),
 		.useroffset = offsetof(struct caifsock, conn_req.param),
-		.usersize = sizeof_field(struct caifsock, conn_req.param)
+		.usersize = FIELD_SIZEOF(struct caifsock, conn_req.param)
 	};
 
 	if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 47c1aa9ee045..816bea0c4a8e 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3983,7 +3983,7 @@ void __init skb_init(void)
 					      0,
 					      SLAB_HWCACHE_ALIGN|SLAB_PANIC,
 					      offsetof(struct sk_buff, cb),
-					      sizeof_field(struct sk_buff, cb),
+					      FIELD_SIZEOF(struct sk_buff, cb),
 					      NULL);
 	skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
 						sizeof(struct sk_buff_fclones),
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 0b8e06ca75d6..efa4c745f7b9 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -977,7 +977,7 @@ struct proto raw_prot = {
 	.unhash		   = raw_unhash_sk,
 	.obj_size	   = sizeof(struct raw_sock),
 	.useroffset	   = offsetof(struct raw_sock, filter),
-	.usersize	   = sizeof_field(struct raw_sock, filter),
+	.usersize	   = FIELD_SIZEOF(struct raw_sock, filter),
 	.h.raw_hash	   = &raw_v4_hashinfo,
 #ifdef CONFIG_COMPAT
 	.compat_setsockopt = compat_raw_setsockopt,
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 70693bc7ad9d..257c71e22d74 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -1292,7 +1292,7 @@ struct proto rawv6_prot = {
 	.unhash		   = raw_unhash_sk,
 	.obj_size	   = sizeof(struct raw6_sock),
 	.useroffset	   = offsetof(struct raw6_sock, filter),
-	.usersize	   = sizeof_field(struct raw6_sock, filter),
+	.usersize	   = FIELD_SIZEOF(struct raw6_sock, filter),
 	.h.raw_hash	   = &raw_v6_hashinfo,
 #ifdef CONFIG_COMPAT
 	.compat_setsockopt = compat_rawv6_setsockopt,
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 39ea0a37af09..6b648a6033b9 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -9377,7 +9377,7 @@ struct proto sctp_prot = {
 	.useroffset  =  offsetof(struct sctp_sock, subscribe),
 	.usersize    =  offsetof(struct sctp_sock, initmsg) -
 				offsetof(struct sctp_sock, subscribe) +
-				sizeof_field(struct sctp_sock, initmsg),
+				FIELD_SIZEOF(struct sctp_sock, initmsg),
 	.sysctl_mem  =  sysctl_sctp_mem,
 	.sysctl_rmem =  sysctl_sctp_rmem,
 	.sysctl_wmem =  sysctl_sctp_wmem,
@@ -9419,7 +9419,7 @@ struct proto sctpv6_prot = {
 	.useroffset	= offsetof(struct sctp6_sock, sctp.subscribe),
 	.usersize	= offsetof(struct sctp6_sock, sctp.initmsg) -
 				offsetof(struct sctp6_sock, sctp.subscribe) +
-				sizeof_field(struct sctp6_sock, sctp.initmsg),
+				FIELD_SIZEOF(struct sctp6_sock, sctp.initmsg),
 	.sysctl_mem	= sysctl_sctp_mem,
 	.sysctl_rmem	= sysctl_sctp_rmem,
 	.sysctl_wmem	= sysctl_sctp_wmem,
diff --git a/tools/testing/selftests/bpf/bpf_util.h b/tools/testing/selftests/bpf/bpf_util.h
index a29206ebbd13..571c35aac90f 100644
--- a/tools/testing/selftests/bpf/bpf_util.h
+++ b/tools/testing/selftests/bpf/bpf_util.h
@@ -58,13 +58,29 @@ static inline unsigned int bpf_num_possible_cpus(void)
 # define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
 #endif
 
-#ifndef sizeof_field
-#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
+/*
+ * FIELD_SIZEOF - get the size of a struct's field
+ * @t: the target struct
+ * @f: the target struct's field
+ * Return: the size of @f in the struct definition without having a
+ * declared instance of @t.
+ */
+#ifndef FIELD_SIZEOF
+#define FIELD_SIZEOF(t, f) (sizeof(((t *)0)->f))
 #endif
 
+/*
+ * For code compatibility
+ *
+ * sizeof_field(TYPE, MEMBER)
+ * @TYPE: The structure containing the field of interest
+ * @MEMBER: The field to return the size of
+ */
+#define sizeof_field(TYPE, MEMBER) FIELD_SIZEOF(TYPE, MEMBER)
+
 #ifndef offsetofend
 #define offsetofend(TYPE, MEMBER) \
-	(offsetof(TYPE, MEMBER)	+ sizeof_field(TYPE, MEMBER))
+	(offsetof(TYPE, MEMBER)	+ FIELD_SIZEOF(TYPE, MEMBER))
 #endif
 
 #endif /* __BPF_UTIL__ */
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index ca54b09adf5b..e43e3a26f6ab 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4275,7 +4275,7 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
 		kmem_cache_create_usercopy("kvm_vcpu", vcpu_size, vcpu_align,
 					   SLAB_ACCOUNT,
 					   offsetof(struct kvm_vcpu, arch),
-					   sizeof_field(struct kvm_vcpu, arch),
+					   FIELD_SIZEOF(struct kvm_vcpu, arch),
 					   NULL);
 	if (!kvm_vcpu_cache) {
 		r = -ENOMEM;
-- 
2.11.0

Re: [PATCH V2] include: linux: Regularise the use of FIELD_SIZEOF macro

[Kees Cook]

On Wed, Jun 12, 2019 at 01:08:36AM +0530, Shyam Saini wrote:
> In favour of FIELD_SIZEOF, this patch also deprecates other two similar
> macros sizeof_field and SIZEOF_FIELD.
> 
> For code compatibility reason, retain sizeof_field macro as a wrapper macro
> to FIELD_SIZEOF

Can you explain this part? First sentence says you want to remove
sizeof_field, and the second says you're keeping it? I thought the point
was to switch all of these to FIELD_SIZEOF()?

-Kees

> 
> Signed-off-by: Shyam Saini <shyam.saini@amarulasolutions.com>
> ---
> Changelog:
> 
> V1->V2
> - Consolidate previous patch 1 and 2 into single patch
> - For code compatibility reason, retain sizeof_field macro as a
>   wrapper macro to FIELD_SIZEOF
>  
>  arch/arm64/include/asm/processor.h                 | 10 +++++-----
>  arch/mips/cavium-octeon/executive/cvmx-bootmem.c   |  9 +--------
>  drivers/gpu/drm/i915/gvt/scheduler.c               |  2 +-
>  drivers/net/ethernet/mellanox/mlxsw/spectrum_fid.c |  4 ++--
>  fs/befs/linuxvfs.c                                 |  2 +-
>  fs/ext2/super.c                                    |  2 +-
>  fs/ext4/super.c                                    |  2 +-
>  fs/freevxfs/vxfs_super.c                           |  2 +-
>  fs/orangefs/super.c                                |  2 +-
>  fs/ufs/super.c                                     |  2 +-
>  include/linux/kernel.h                             |  9 ---------
>  include/linux/slab.h                               |  2 +-
>  include/linux/stddef.h                             | 17 ++++++++++++++---
>  kernel/fork.c                                      |  2 +-
>  kernel/utsname.c                                   |  2 +-
>  net/caif/caif_socket.c                             |  2 +-
>  net/core/skbuff.c                                  |  2 +-
>  net/ipv4/raw.c                                     |  2 +-
>  net/ipv6/raw.c                                     |  2 +-
>  net/sctp/socket.c                                  |  4 ++--
>  tools/testing/selftests/bpf/bpf_util.h             | 22 +++++++++++++++++++---
>  virt/kvm/kvm_main.c                                |  2 +-
>  22 files changed, 58 insertions(+), 47 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
> index fcd0e691b1ea..ace906d887cc 100644
> --- a/arch/arm64/include/asm/processor.h
> +++ b/arch/arm64/include/asm/processor.h
> @@ -164,13 +164,13 @@ static inline void arch_thread_struct_whitelist(unsigned long *offset,
>  						unsigned long *size)
>  {
>  	/* Verify that there is no padding among the whitelisted fields: */
> -	BUILD_BUG_ON(sizeof_field(struct thread_struct, uw) !=
> -		     sizeof_field(struct thread_struct, uw.tp_value) +
> -		     sizeof_field(struct thread_struct, uw.tp2_value) +
> -		     sizeof_field(struct thread_struct, uw.fpsimd_state));
> +	BUILD_BUG_ON(FIELD_SIZEOF(struct thread_struct, uw) !=
> +		     FIELD_SIZEOF(struct thread_struct, uw.tp_value) +
> +		     FIELD_SIZEOF(struct thread_struct, uw.tp2_value) +
> +		     FIELD_SIZEOF(struct thread_struct, uw.fpsimd_state));
>  
>  	*offset = offsetof(struct thread_struct, uw);
> -	*size = sizeof_field(struct thread_struct, uw);
> +	*size = FIELD_SIZEOF(struct thread_struct, uw);
>  }
>  
>  #ifdef CONFIG_COMPAT
> diff --git a/arch/mips/cavium-octeon/executive/cvmx-bootmem.c b/arch/mips/cavium-octeon/executive/cvmx-bootmem.c
> index ba8f82a29a81..44b506a14666 100644
> --- a/arch/mips/cavium-octeon/executive/cvmx-bootmem.c
> +++ b/arch/mips/cavium-octeon/executive/cvmx-bootmem.c
> @@ -45,13 +45,6 @@ static struct cvmx_bootmem_desc *cvmx_bootmem_desc;
>  /* See header file for descriptions of functions */
>  
>  /**
> - * This macro returns the size of a member of a structure.
> - * Logically it is the same as "sizeof(s::field)" in C++, but
> - * C lacks the "::" operator.
> - */
> -#define SIZEOF_FIELD(s, field) sizeof(((s *)NULL)->field)
> -
> -/**
>   * This macro returns a member of the
>   * cvmx_bootmem_named_block_desc_t structure. These members can't
>   * be directly addressed as they might be in memory not directly
> @@ -65,7 +58,7 @@ static struct cvmx_bootmem_desc *cvmx_bootmem_desc;
>  #define CVMX_BOOTMEM_NAMED_GET_FIELD(addr, field)			\
>  	__cvmx_bootmem_desc_get(addr,					\
>  		offsetof(struct cvmx_bootmem_named_block_desc, field),	\
> -		SIZEOF_FIELD(struct cvmx_bootmem_named_block_desc, field))
> +		FIELD_SIZEOF(struct cvmx_bootmem_named_block_desc, field))
>  
>  /**
>   * This function is the implementation of the get macros defined
> diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
> index 0f919f0a43d4..820f95a52542 100644
> --- a/drivers/gpu/drm/i915/gvt/scheduler.c
> +++ b/drivers/gpu/drm/i915/gvt/scheduler.c
> @@ -1243,7 +1243,7 @@ int intel_vgpu_setup_submission(struct intel_vgpu *vgpu)
>  						  sizeof(struct intel_vgpu_workload), 0,
>  						  SLAB_HWCACHE_ALIGN,
>  						  offsetof(struct intel_vgpu_workload, rb_tail),
> -						  sizeof_field(struct intel_vgpu_workload, rb_tail),
> +						  FIELD_SIZEOF(struct intel_vgpu_workload, rb_tail),
>  						  NULL);
>  
>  	if (!s->workloads) {
> diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_fid.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_fid.c
> index 46baf3b44309..c0447bf07fbb 100644
> --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_fid.c
> +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_fid.c
> @@ -49,13 +49,13 @@ struct mlxsw_sp_fid_8021d {
>  };
>  
>  static const struct rhashtable_params mlxsw_sp_fid_ht_params = {
> -	.key_len = sizeof_field(struct mlxsw_sp_fid, fid_index),
> +	.key_len = FIELD_SIZEOF(struct mlxsw_sp_fid, fid_index),
>  	.key_offset = offsetof(struct mlxsw_sp_fid, fid_index),
>  	.head_offset = offsetof(struct mlxsw_sp_fid, ht_node),
>  };
>  
>  static const struct rhashtable_params mlxsw_sp_fid_vni_ht_params = {
> -	.key_len = sizeof_field(struct mlxsw_sp_fid, vni),
> +	.key_len = FIELD_SIZEOF(struct mlxsw_sp_fid, vni),
>  	.key_offset = offsetof(struct mlxsw_sp_fid, vni),
>  	.head_offset = offsetof(struct mlxsw_sp_fid, vni_ht_node),
>  };
> diff --git a/fs/befs/linuxvfs.c b/fs/befs/linuxvfs.c
> index 462d096ff3e9..06ffd4829e2e 100644
> --- a/fs/befs/linuxvfs.c
> +++ b/fs/befs/linuxvfs.c
> @@ -438,7 +438,7 @@ befs_init_inodecache(void)
>  					SLAB_ACCOUNT),
>  				offsetof(struct befs_inode_info,
>  					i_data.symlink),
> -				sizeof_field(struct befs_inode_info,
> +				FIELD_SIZEOF(struct befs_inode_info,
>  					i_data.symlink),
>  				init_once);
>  	if (befs_inode_cachep == NULL)
> diff --git a/fs/ext2/super.c b/fs/ext2/super.c
> index 1d7ab73b1014..d9a6c81f4a47 100644
> --- a/fs/ext2/super.c
> +++ b/fs/ext2/super.c
> @@ -220,7 +220,7 @@ static int __init init_inodecache(void)
>  				(SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
>  					SLAB_ACCOUNT),
>  				offsetof(struct ext2_inode_info, i_data),
> -				sizeof_field(struct ext2_inode_info, i_data),
> +				FIELD_SIZEOF(struct ext2_inode_info, i_data),
>  				init_once);
>  	if (ext2_inode_cachep == NULL)
>  		return -ENOMEM;
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 4079605d437a..b1b5856248bd 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -1148,7 +1148,7 @@ static int __init init_inodecache(void)
>  				(SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
>  					SLAB_ACCOUNT),
>  				offsetof(struct ext4_inode_info, i_data),
> -				sizeof_field(struct ext4_inode_info, i_data),
> +				FIELD_SIZEOF(struct ext4_inode_info, i_data),
>  				init_once);
>  	if (ext4_inode_cachep == NULL)
>  		return -ENOMEM;
> diff --git a/fs/freevxfs/vxfs_super.c b/fs/freevxfs/vxfs_super.c
> index a89f68c3cbed..ffd22f85bbe0 100644
> --- a/fs/freevxfs/vxfs_super.c
> +++ b/fs/freevxfs/vxfs_super.c
> @@ -329,7 +329,7 @@ vxfs_init(void)
>  			sizeof(struct vxfs_inode_info), 0,
>  			SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
>  			offsetof(struct vxfs_inode_info, vii_immed.vi_immed),
> -			sizeof_field(struct vxfs_inode_info,
> +			FIELD_SIZEOF(struct vxfs_inode_info,
>  				vii_immed.vi_immed),
>  			NULL);
>  	if (!vxfs_inode_cachep)
> diff --git a/fs/orangefs/super.c b/fs/orangefs/super.c
> index ee5efdc35cc1..30f625059ad9 100644
> --- a/fs/orangefs/super.c
> +++ b/fs/orangefs/super.c
> @@ -646,7 +646,7 @@ int orangefs_inode_cache_initialize(void)
>  					ORANGEFS_CACHE_CREATE_FLAGS,
>  					offsetof(struct orangefs_inode_s,
>  						link_target),
> -					sizeof_field(struct orangefs_inode_s,
> +					FIELD_SIZEOF(struct orangefs_inode_s,
>  						link_target),
>  					orangefs_inode_cache_ctor);
>  
> diff --git a/fs/ufs/super.c b/fs/ufs/super.c
> index 3d247c0d92aa..1e8bcd950f6d 100644
> --- a/fs/ufs/super.c
> +++ b/fs/ufs/super.c
> @@ -1469,7 +1469,7 @@ static int __init init_inodecache(void)
>  				(SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
>  					SLAB_ACCOUNT),
>  				offsetof(struct ufs_inode_info, i_u1.i_symlink),
> -				sizeof_field(struct ufs_inode_info,
> +				FIELD_SIZEOF(struct ufs_inode_info,
>  					i_u1.i_symlink),
>  				init_once);
>  	if (ufs_inode_cachep == NULL)
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index 74b1ee9027f5..4672391cdb5b 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -79,15 +79,6 @@
>   */
>  #define round_down(x, y) ((x) & ~__round_mask(x, y))
>  
> -/**
> - * FIELD_SIZEOF - get the size of a struct's field
> - * @t: the target struct
> - * @f: the target struct's field
> - * Return: the size of @f in the struct definition without having a
> - * declared instance of @t.
> - */
> -#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
> -
>  #define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
>  
>  #define DIV_ROUND_DOWN_ULL(ll, d) \
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index 9449b19c5f10..8bdfdd389b37 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -175,7 +175,7 @@ void memcg_destroy_kmem_caches(struct mem_cgroup *);
>  			sizeof(struct __struct),			\
>  			__alignof__(struct __struct), (__flags),	\
>  			offsetof(struct __struct, __field),		\
> -			sizeof_field(struct __struct, __field), NULL)
> +			FIELD_SIZEOF(struct __struct, __field), NULL)
>  
>  /*
>   * Common kmalloc functions provided by all allocators
> diff --git a/include/linux/stddef.h b/include/linux/stddef.h
> index 998a4ba28eba..a5960e2b4a8b 100644
> --- a/include/linux/stddef.h
> +++ b/include/linux/stddef.h
> @@ -20,12 +20,23 @@ enum {
>  #endif
>  
>  /**
> - * sizeof_field(TYPE, MEMBER)
> + * FIELD_SIZEOF - get the size of a struct's field
> + * @t: the target struct
> + * @f: the target struct's field
> + * Return: the size of @f in the struct definition without having a
> + * declared instance of @t.
> + */
> +#define FIELD_SIZEOF(t, f) (sizeof(((t *)0)->f))
> +
> +/*
> + * For code compatibility
>   *
> + * sizeof_field(TYPE, MEMBER)
>   * @TYPE: The structure containing the field of interest
>   * @MEMBER: The field to return the size of
>   */
> -#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
> +
> +#define sizeof_field(TYPE, MEMBER) FIELD_SIZEOF(TYPE, MEMBER)
>  
>  /**
>   * offsetofend(TYPE, MEMBER)
> @@ -34,6 +45,6 @@ enum {
>   * @MEMBER: The member within the structure to get the end offset of
>   */
>  #define offsetofend(TYPE, MEMBER) \
> -	(offsetof(TYPE, MEMBER)	+ sizeof_field(TYPE, MEMBER))
> +	(offsetof(TYPE, MEMBER)	+ FIELD_SIZEOF(TYPE, MEMBER))
>  
>  #endif
> diff --git a/kernel/fork.c b/kernel/fork.c
> index 75675b9bf6df..ef40b95bf82c 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -2553,7 +2553,7 @@ void __init proc_caches_init(void)
>  			mm_size, ARCH_MIN_MMSTRUCT_ALIGN,
>  			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
>  			offsetof(struct mm_struct, saved_auxv),
> -			sizeof_field(struct mm_struct, saved_auxv),
> +			FIELD_SIZEOF(struct mm_struct, saved_auxv),
>  			NULL);
>  	vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT);
>  	mmap_init();
> diff --git a/kernel/utsname.c b/kernel/utsname.c
> index f0e491193009..28257c571553 100644
> --- a/kernel/utsname.c
> +++ b/kernel/utsname.c
> @@ -174,6 +174,6 @@ void __init uts_ns_init(void)
>  			"uts_namespace", sizeof(struct uts_namespace), 0,
>  			SLAB_PANIC|SLAB_ACCOUNT,
>  			offsetof(struct uts_namespace, name),
> -			sizeof_field(struct uts_namespace, name),
> +			FIELD_SIZEOF(struct uts_namespace, name),
>  			NULL);
>  }
> diff --git a/net/caif/caif_socket.c b/net/caif/caif_socket.c
> index 13ea920600ae..3306bbed77eb 100644
> --- a/net/caif/caif_socket.c
> +++ b/net/caif/caif_socket.c
> @@ -1033,7 +1033,7 @@ static int caif_create(struct net *net, struct socket *sock, int protocol,
>  		.owner = THIS_MODULE,
>  		.obj_size = sizeof(struct caifsock),
>  		.useroffset = offsetof(struct caifsock, conn_req.param),
> -		.usersize = sizeof_field(struct caifsock, conn_req.param)
> +		.usersize = FIELD_SIZEOF(struct caifsock, conn_req.param)
>  	};
>  
>  	if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index 47c1aa9ee045..816bea0c4a8e 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -3983,7 +3983,7 @@ void __init skb_init(void)
>  					      0,
>  					      SLAB_HWCACHE_ALIGN|SLAB_PANIC,
>  					      offsetof(struct sk_buff, cb),
> -					      sizeof_field(struct sk_buff, cb),
> +					      FIELD_SIZEOF(struct sk_buff, cb),
>  					      NULL);
>  	skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
>  						sizeof(struct sk_buff_fclones),
> diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
> index 0b8e06ca75d6..efa4c745f7b9 100644
> --- a/net/ipv4/raw.c
> +++ b/net/ipv4/raw.c
> @@ -977,7 +977,7 @@ struct proto raw_prot = {
>  	.unhash		   = raw_unhash_sk,
>  	.obj_size	   = sizeof(struct raw_sock),
>  	.useroffset	   = offsetof(struct raw_sock, filter),
> -	.usersize	   = sizeof_field(struct raw_sock, filter),
> +	.usersize	   = FIELD_SIZEOF(struct raw_sock, filter),
>  	.h.raw_hash	   = &raw_v4_hashinfo,
>  #ifdef CONFIG_COMPAT
>  	.compat_setsockopt = compat_raw_setsockopt,
> diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
> index 70693bc7ad9d..257c71e22d74 100644
> --- a/net/ipv6/raw.c
> +++ b/net/ipv6/raw.c
> @@ -1292,7 +1292,7 @@ struct proto rawv6_prot = {
>  	.unhash		   = raw_unhash_sk,
>  	.obj_size	   = sizeof(struct raw6_sock),
>  	.useroffset	   = offsetof(struct raw6_sock, filter),
> -	.usersize	   = sizeof_field(struct raw6_sock, filter),
> +	.usersize	   = FIELD_SIZEOF(struct raw6_sock, filter),
>  	.h.raw_hash	   = &raw_v6_hashinfo,
>  #ifdef CONFIG_COMPAT
>  	.compat_setsockopt = compat_rawv6_setsockopt,
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 39ea0a37af09..6b648a6033b9 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -9377,7 +9377,7 @@ struct proto sctp_prot = {
>  	.useroffset  =  offsetof(struct sctp_sock, subscribe),
>  	.usersize    =  offsetof(struct sctp_sock, initmsg) -
>  				offsetof(struct sctp_sock, subscribe) +
> -				sizeof_field(struct sctp_sock, initmsg),
> +				FIELD_SIZEOF(struct sctp_sock, initmsg),
>  	.sysctl_mem  =  sysctl_sctp_mem,
>  	.sysctl_rmem =  sysctl_sctp_rmem,
>  	.sysctl_wmem =  sysctl_sctp_wmem,
> @@ -9419,7 +9419,7 @@ struct proto sctpv6_prot = {
>  	.useroffset	= offsetof(struct sctp6_sock, sctp.subscribe),
>  	.usersize	= offsetof(struct sctp6_sock, sctp.initmsg) -
>  				offsetof(struct sctp6_sock, sctp.subscribe) +
> -				sizeof_field(struct sctp6_sock, sctp.initmsg),
> +				FIELD_SIZEOF(struct sctp6_sock, sctp.initmsg),
>  	.sysctl_mem	= sysctl_sctp_mem,
>  	.sysctl_rmem	= sysctl_sctp_rmem,
>  	.sysctl_wmem	= sysctl_sctp_wmem,
> diff --git a/tools/testing/selftests/bpf/bpf_util.h b/tools/testing/selftests/bpf/bpf_util.h
> index a29206ebbd13..571c35aac90f 100644
> --- a/tools/testing/selftests/bpf/bpf_util.h
> +++ b/tools/testing/selftests/bpf/bpf_util.h
> @@ -58,13 +58,29 @@ static inline unsigned int bpf_num_possible_cpus(void)
>  # define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
>  #endif
>  
> -#ifndef sizeof_field
> -#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
> +/*
> + * FIELD_SIZEOF - get the size of a struct's field
> + * @t: the target struct
> + * @f: the target struct's field
> + * Return: the size of @f in the struct definition without having a
> + * declared instance of @t.
> + */
> +#ifndef FIELD_SIZEOF
> +#define FIELD_SIZEOF(t, f) (sizeof(((t *)0)->f))
>  #endif
>  
> +/*
> + * For code compatibility
> + *
> + * sizeof_field(TYPE, MEMBER)
> + * @TYPE: The structure containing the field of interest
> + * @MEMBER: The field to return the size of
> + */
> +#define sizeof_field(TYPE, MEMBER) FIELD_SIZEOF(TYPE, MEMBER)
> +
>  #ifndef offsetofend
>  #define offsetofend(TYPE, MEMBER) \
> -	(offsetof(TYPE, MEMBER)	+ sizeof_field(TYPE, MEMBER))
> +	(offsetof(TYPE, MEMBER)	+ FIELD_SIZEOF(TYPE, MEMBER))
>  #endif
>  
>  #endif /* __BPF_UTIL__ */
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index ca54b09adf5b..e43e3a26f6ab 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -4275,7 +4275,7 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
>  		kmem_cache_create_usercopy("kvm_vcpu", vcpu_size, vcpu_align,
>  					   SLAB_ACCOUNT,
>  					   offsetof(struct kvm_vcpu, arch),
> -					   sizeof_field(struct kvm_vcpu, arch),
> +					   FIELD_SIZEOF(struct kvm_vcpu, arch),
>  					   NULL);
>  	if (!kvm_vcpu_cache) {
>  		r = -ENOMEM;
> -- 
> 2.11.0
> 

-- 
Kees Cook

Re: [PATCH V2] include: linux: Regularise the use of FIELD_SIZEOF macro

[Shyam Saini]

Hi Kees,

Cc'ing William Kucharski,

> On Wed, Jun 12, 2019 at 01:08:36AM +0530, Shyam Saini wrote:
> > In favour of FIELD_SIZEOF, this patch also deprecates other two similar
> > macros sizeof_field and SIZEOF_FIELD.
> >
> > For code compatibility reason, retain sizeof_field macro as a wrapper macro
> > to FIELD_SIZEOF
>
> Can you explain this part? First sentence says you want to remove
> sizeof_field, and the second says you're keeping it? I thought the point
> was to switch all of these to FIELD_SIZEOF()?

Previously, William [1] suggested to retain sizeof_field as macro to
FIELD_SIZEOF
for code compatibility reason. I have removed all the usage of
sizeof_field apart from retained
wrapper macro definition.


[1] https://patchwork.ozlabs.org/patch/1085275/

Thanks,
Shyam

> >
> >  arch/arm64/include/asm/processor.h                 | 10 +++++-----
> >  arch/mips/cavium-octeon/executive/cvmx-bootmem.c   |  9 +--------
> >  drivers/gpu/drm/i915/gvt/scheduler.c               |  2 +-
> >  drivers/net/ethernet/mellanox/mlxsw/spectrum_fid.c |  4 ++--
> >  fs/befs/linuxvfs.c                                 |  2 +-
> >  fs/ext2/super.c                                    |  2 +-
> >  fs/ext4/super.c                                    |  2 +-
> >  fs/freevxfs/vxfs_super.c                           |  2 +-
> >  fs/orangefs/super.c                                |  2 +-
> >  fs/ufs/super.c                                     |  2 +-
> >  include/linux/kernel.h                             |  9 ---------
> >  include/linux/slab.h                               |  2 +-
> >  include/linux/stddef.h                             | 17 ++++++++++++++---
> >  kernel/fork.c                                      |  2 +-
> >  kernel/utsname.c                                   |  2 +-
> >  net/caif/caif_socket.c                             |  2 +-
> >  net/core/skbuff.c                                  |  2 +-
> >  net/ipv4/raw.c                                     |  2 +-
> >  net/ipv6/raw.c                                     |  2 +-
> >  net/sctp/socket.c                                  |  4 ++--
> >  tools/testing/selftests/bpf/bpf_util.h             | 22 +++++++++++++++++++---
> >  virt/kvm/kvm_main.c                                |  2 +-
> >  22 files changed, 58 insertions(+), 47 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
> > index fcd0e691b1ea..ace906d887cc 100644
> > --- a/arch/arm64/include/asm/processor.h
> > +++ b/arch/arm64/include/asm/processor.h
> > @@ -164,13 +164,13 @@ static inline void arch_thread_struct_whitelist(unsigned long *offset,
> >                                               unsigned long *size)
> >  {
> >       /* Verify that there is no padding among the whitelisted fields: */
> > -     BUILD_BUG_ON(sizeof_field(struct thread_struct, uw) !=
> > -                  sizeof_field(struct thread_struct, uw.tp_value) +
> > -                  sizeof_field(struct thread_struct, uw.tp2_value) +
> > -                  sizeof_field(struct thread_struct, uw.fpsimd_state));
> > +     BUILD_BUG_ON(FIELD_SIZEOF(struct thread_struct, uw) !=
> > +                  FIELD_SIZEOF(struct thread_struct, uw.tp_value) +
> > +                  FIELD_SIZEOF(struct thread_struct, uw.tp2_value) +
> > +                  FIELD_SIZEOF(struct thread_struct, uw.fpsimd_state));
> >
> >       *offset = offsetof(struct thread_struct, uw);
> > -     *size = sizeof_field(struct thread_struct, uw);
> > +     *size = FIELD_SIZEOF(struct thread_struct, uw);
> >  }
> >
> >  #ifdef CONFIG_COMPAT
> > diff --git a/arch/mips/cavium-octeon/executive/cvmx-bootmem.c b/arch/mips/cavium-octeon/executive/cvmx-bootmem.c
> > index ba8f82a29a81..44b506a14666 100644
> > --- a/arch/mips/cavium-octeon/executive/cvmx-bootmem.c
> > +++ b/arch/mips/cavium-octeon/executive/cvmx-bootmem.c
> > @@ -45,13 +45,6 @@ static struct cvmx_bootmem_desc *cvmx_bootmem_desc;
> >  /* See header file for descriptions of functions */
> >
> >  /**
> > - * This macro returns the size of a member of a structure.
> > - * Logically it is the same as "sizeof(s::field)" in C++, but
> > - * C lacks the "::" operator.
> > - */
> > -#define SIZEOF_FIELD(s, field) sizeof(((s *)NULL)->field)
> > -
> > -/**
> >   * This macro returns a member of the
> >   * cvmx_bootmem_named_block_desc_t structure. These members can't
> >   * be directly addressed as they might be in memory not directly
> > @@ -65,7 +58,7 @@ static struct cvmx_bootmem_desc *cvmx_bootmem_desc;
> >  #define CVMX_BOOTMEM_NAMED_GET_FIELD(addr, field)                    \
> >       __cvmx_bootmem_desc_get(addr,                                   \
> >               offsetof(struct cvmx_bootmem_named_block_desc, field),  \
> > -             SIZEOF_FIELD(struct cvmx_bootmem_named_block_desc, field))
> > +             FIELD_SIZEOF(struct cvmx_bootmem_named_block_desc, field))
> >
> >  /**
> >   * This function is the implementation of the get macros defined
> > diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
> > index 0f919f0a43d4..820f95a52542 100644
> > --- a/drivers/gpu/drm/i915/gvt/scheduler.c
> > +++ b/drivers/gpu/drm/i915/gvt/scheduler.c
> > @@ -1243,7 +1243,7 @@ int intel_vgpu_setup_submission(struct intel_vgpu *vgpu)
> >                                                 sizeof(struct intel_vgpu_workload), 0,
> >                                                 SLAB_HWCACHE_ALIGN,
> >                                                 offsetof(struct intel_vgpu_workload, rb_tail),
> > -                                               sizeof_field(struct intel_vgpu_workload, rb_tail),
> > +                                               FIELD_SIZEOF(struct intel_vgpu_workload, rb_tail),
> >                                                 NULL);
> >
> >       if (!s->workloads) {
> > diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_fid.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_fid.c
> > index 46baf3b44309..c0447bf07fbb 100644
> > --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_fid.c
> > +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_fid.c
> > @@ -49,13 +49,13 @@ struct mlxsw_sp_fid_8021d {
> >  };
> >
> >  static const struct rhashtable_params mlxsw_sp_fid_ht_params = {
> > -     .key_len = sizeof_field(struct mlxsw_sp_fid, fid_index),
> > +     .key_len = FIELD_SIZEOF(struct mlxsw_sp_fid, fid_index),
> >       .key_offset = offsetof(struct mlxsw_sp_fid, fid_index),
> >       .head_offset = offsetof(struct mlxsw_sp_fid, ht_node),
> >  };
> >
> >  static const struct rhashtable_params mlxsw_sp_fid_vni_ht_params = {
> > -     .key_len = sizeof_field(struct mlxsw_sp_fid, vni),
> > +     .key_len = FIELD_SIZEOF(struct mlxsw_sp_fid, vni),
> >       .key_offset = offsetof(struct mlxsw_sp_fid, vni),
> >       .head_offset = offsetof(struct mlxsw_sp_fid, vni_ht_node),
> >  };
> > diff --git a/fs/befs/linuxvfs.c b/fs/befs/linuxvfs.c
> > index 462d096ff3e9..06ffd4829e2e 100644
> > --- a/fs/befs/linuxvfs.c
> > +++ b/fs/befs/linuxvfs.c
> > @@ -438,7 +438,7 @@ befs_init_inodecache(void)
> >                                       SLAB_ACCOUNT),
> >                               offsetof(struct befs_inode_info,
> >                                       i_data.symlink),
> > -                             sizeof_field(struct befs_inode_info,
> > +                             FIELD_SIZEOF(struct befs_inode_info,
> >                                       i_data.symlink),
> >                               init_once);
> >       if (befs_inode_cachep == NULL)
> > diff --git a/fs/ext2/super.c b/fs/ext2/super.c
> > index 1d7ab73b1014..d9a6c81f4a47 100644
> > --- a/fs/ext2/super.c
> > +++ b/fs/ext2/super.c
> > @@ -220,7 +220,7 @@ static int __init init_inodecache(void)
> >                               (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
> >                                       SLAB_ACCOUNT),
> >                               offsetof(struct ext2_inode_info, i_data),
> > -                             sizeof_field(struct ext2_inode_info, i_data),
> > +                             FIELD_SIZEOF(struct ext2_inode_info, i_data),
> >                               init_once);
> >       if (ext2_inode_cachep == NULL)
> >               return -ENOMEM;
> > diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> > index 4079605d437a..b1b5856248bd 100644
> > --- a/fs/ext4/super.c
> > +++ b/fs/ext4/super.c
> > @@ -1148,7 +1148,7 @@ static int __init init_inodecache(void)
> >                               (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
> >                                       SLAB_ACCOUNT),
> >                               offsetof(struct ext4_inode_info, i_data),
> > -                             sizeof_field(struct ext4_inode_info, i_data),
> > +                             FIELD_SIZEOF(struct ext4_inode_info, i_data),
> >                               init_once);
> >       if (ext4_inode_cachep == NULL)
> >               return -ENOMEM;
> > diff --git a/fs/freevxfs/vxfs_super.c b/fs/freevxfs/vxfs_super.c
> > index a89f68c3cbed..ffd22f85bbe0 100644
> > --- a/fs/freevxfs/vxfs_super.c
> > +++ b/fs/freevxfs/vxfs_super.c
> > @@ -329,7 +329,7 @@ vxfs_init(void)
> >                       sizeof(struct vxfs_inode_info), 0,
> >                       SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
> >                       offsetof(struct vxfs_inode_info, vii_immed.vi_immed),
> > -                     sizeof_field(struct vxfs_inode_info,
> > +                     FIELD_SIZEOF(struct vxfs_inode_info,
> >                               vii_immed.vi_immed),
> >                       NULL);
> >       if (!vxfs_inode_cachep)
> > diff --git a/fs/orangefs/super.c b/fs/orangefs/super.c
> > index ee5efdc35cc1..30f625059ad9 100644
> > --- a/fs/orangefs/super.c
> > +++ b/fs/orangefs/super.c
> > @@ -646,7 +646,7 @@ int orangefs_inode_cache_initialize(void)
> >                                       ORANGEFS_CACHE_CREATE_FLAGS,
> >                                       offsetof(struct orangefs_inode_s,
> >                                               link_target),
> > -                                     sizeof_field(struct orangefs_inode_s,
> > +                                     FIELD_SIZEOF(struct orangefs_inode_s,
> >                                               link_target),
> >                                       orangefs_inode_cache_ctor);
> >
> > diff --git a/fs/ufs/super.c b/fs/ufs/super.c
> > index 3d247c0d92aa..1e8bcd950f6d 100644
> > --- a/fs/ufs/super.c
> > +++ b/fs/ufs/super.c
> > @@ -1469,7 +1469,7 @@ static int __init init_inodecache(void)
> >                               (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
> >                                       SLAB_ACCOUNT),
> >                               offsetof(struct ufs_inode_info, i_u1.i_symlink),
> > -                             sizeof_field(struct ufs_inode_info,
> > +                             FIELD_SIZEOF(struct ufs_inode_info,
> >                                       i_u1.i_symlink),
> >                               init_once);
> >       if (ufs_inode_cachep == NULL)
> > diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> > index 74b1ee9027f5..4672391cdb5b 100644
> > --- a/include/linux/kernel.h
> > +++ b/include/linux/kernel.h
> > @@ -79,15 +79,6 @@
> >   */
> >  #define round_down(x, y) ((x) & ~__round_mask(x, y))
> >
> > -/**
> > - * FIELD_SIZEOF - get the size of a struct's field
> > - * @t: the target struct
> > - * @f: the target struct's field
> > - * Return: the size of @f in the struct definition without having a
> > - * declared instance of @t.
> > - */
> > -#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
> > -
> >  #define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
> >
> >  #define DIV_ROUND_DOWN_ULL(ll, d) \
> > diff --git a/include/linux/slab.h b/include/linux/slab.h
> > index 9449b19c5f10..8bdfdd389b37 100644
> > --- a/include/linux/slab.h
> > +++ b/include/linux/slab.h
> > @@ -175,7 +175,7 @@ void memcg_destroy_kmem_caches(struct mem_cgroup *);
> >                       sizeof(struct __struct),                        \
> >                       __alignof__(struct __struct), (__flags),        \
> >                       offsetof(struct __struct, __field),             \
> > -                     sizeof_field(struct __struct, __field), NULL)
> > +                     FIELD_SIZEOF(struct __struct, __field), NULL)
> >
> >  /*
> >   * Common kmalloc functions provided by all allocators
> > diff --git a/include/linux/stddef.h b/include/linux/stddef.h
> > index 998a4ba28eba..a5960e2b4a8b 100644
> > --- a/include/linux/stddef.h
> > +++ b/include/linux/stddef.h
> > @@ -20,12 +20,23 @@ enum {
> >  #endif
> >
> >  /**
> > - * sizeof_field(TYPE, MEMBER)
> > + * FIELD_SIZEOF - get the size of a struct's field
> > + * @t: the target struct
> > + * @f: the target struct's field
> > + * Return: the size of @f in the struct definition without having a
> > + * declared instance of @t.
> > + */
> > +#define FIELD_SIZEOF(t, f) (sizeof(((t *)0)->f))
> > +
> > +/*
> > + * For code compatibility
> >   *
> > + * sizeof_field(TYPE, MEMBER)
> >   * @TYPE: The structure containing the field of interest
> >   * @MEMBER: The field to return the size of
> >   */
> > -#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
> > +
> > +#define sizeof_field(TYPE, MEMBER) FIELD_SIZEOF(TYPE, MEMBER)
> >
> >  /**
> >   * offsetofend(TYPE, MEMBER)
> > @@ -34,6 +45,6 @@ enum {
> >   * @MEMBER: The member within the structure to get the end offset of
> >   */
> >  #define offsetofend(TYPE, MEMBER) \
> > -     (offsetof(TYPE, MEMBER) + sizeof_field(TYPE, MEMBER))
> > +     (offsetof(TYPE, MEMBER) + FIELD_SIZEOF(TYPE, MEMBER))
> >
> >  #endif
> > diff --git a/kernel/fork.c b/kernel/fork.c
> > index 75675b9bf6df..ef40b95bf82c 100644
> > --- a/kernel/fork.c
> > +++ b/kernel/fork.c
> > @@ -2553,7 +2553,7 @@ void __init proc_caches_init(void)
> >                       mm_size, ARCH_MIN_MMSTRUCT_ALIGN,
> >                       SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
> >                       offsetof(struct mm_struct, saved_auxv),
> > -                     sizeof_field(struct mm_struct, saved_auxv),
> > +                     FIELD_SIZEOF(struct mm_struct, saved_auxv),
> >                       NULL);
> >       vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT);
> >       mmap_init();
> > diff --git a/kernel/utsname.c b/kernel/utsname.c
> > index f0e491193009..28257c571553 100644
> > --- a/kernel/utsname.c
> > +++ b/kernel/utsname.c
> > @@ -174,6 +174,6 @@ void __init uts_ns_init(void)
> >                       "uts_namespace", sizeof(struct uts_namespace), 0,
> >                       SLAB_PANIC|SLAB_ACCOUNT,
> >                       offsetof(struct uts_namespace, name),
> > -                     sizeof_field(struct uts_namespace, name),
> > +                     FIELD_SIZEOF(struct uts_namespace, name),
> >                       NULL);
> >  }
> > diff --git a/net/caif/caif_socket.c b/net/caif/caif_socket.c
> > index 13ea920600ae..3306bbed77eb 100644
> > --- a/net/caif/caif_socket.c
> > +++ b/net/caif/caif_socket.c
> > @@ -1033,7 +1033,7 @@ static int caif_create(struct net *net, struct socket *sock, int protocol,
> >               .owner = THIS_MODULE,
> >               .obj_size = sizeof(struct caifsock),
> >               .useroffset = offsetof(struct caifsock, conn_req.param),
> > -             .usersize = sizeof_field(struct caifsock, conn_req.param)
> > +             .usersize = FIELD_SIZEOF(struct caifsock, conn_req.param)
> >       };
> >
> >       if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
> > diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> > index 47c1aa9ee045..816bea0c4a8e 100644
> > --- a/net/core/skbuff.c
> > +++ b/net/core/skbuff.c
> > @@ -3983,7 +3983,7 @@ void __init skb_init(void)
> >                                             0,
> >                                             SLAB_HWCACHE_ALIGN|SLAB_PANIC,
> >                                             offsetof(struct sk_buff, cb),
> > -                                           sizeof_field(struct sk_buff, cb),
> > +                                           FIELD_SIZEOF(struct sk_buff, cb),
> >                                             NULL);
> >       skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
> >                                               sizeof(struct sk_buff_fclones),
> > diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
> > index 0b8e06ca75d6..efa4c745f7b9 100644
> > --- a/net/ipv4/raw.c
> > +++ b/net/ipv4/raw.c
> > @@ -977,7 +977,7 @@ struct proto raw_prot = {
> >       .unhash            = raw_unhash_sk,
> >       .obj_size          = sizeof(struct raw_sock),
> >       .useroffset        = offsetof(struct raw_sock, filter),
> > -     .usersize          = sizeof_field(struct raw_sock, filter),
> > +     .usersize          = FIELD_SIZEOF(struct raw_sock, filter),
> >       .h.raw_hash        = &raw_v4_hashinfo,
> >  #ifdef CONFIG_COMPAT
> >       .compat_setsockopt = compat_raw_setsockopt,
> > diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
> > index 70693bc7ad9d..257c71e22d74 100644
> > --- a/net/ipv6/raw.c
> > +++ b/net/ipv6/raw.c
> > @@ -1292,7 +1292,7 @@ struct proto rawv6_prot = {
> >       .unhash            = raw_unhash_sk,
> >       .obj_size          = sizeof(struct raw6_sock),
> >       .useroffset        = offsetof(struct raw6_sock, filter),
> > -     .usersize          = sizeof_field(struct raw6_sock, filter),
> > +     .usersize          = FIELD_SIZEOF(struct raw6_sock, filter),
> >       .h.raw_hash        = &raw_v6_hashinfo,
> >  #ifdef CONFIG_COMPAT
> >       .compat_setsockopt = compat_rawv6_setsockopt,
> > diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> > index 39ea0a37af09..6b648a6033b9 100644
> > --- a/net/sctp/socket.c
> > +++ b/net/sctp/socket.c
> > @@ -9377,7 +9377,7 @@ struct proto sctp_prot = {
> >       .useroffset  =  offsetof(struct sctp_sock, subscribe),
> >       .usersize    =  offsetof(struct sctp_sock, initmsg) -
> >                               offsetof(struct sctp_sock, subscribe) +
> > -                             sizeof_field(struct sctp_sock, initmsg),
> > +                             FIELD_SIZEOF(struct sctp_sock, initmsg),
> >       .sysctl_mem  =  sysctl_sctp_mem,
> >       .sysctl_rmem =  sysctl_sctp_rmem,
> >       .sysctl_wmem =  sysctl_sctp_wmem,
> > @@ -9419,7 +9419,7 @@ struct proto sctpv6_prot = {
> >       .useroffset     = offsetof(struct sctp6_sock, sctp.subscribe),
> >       .usersize       = offsetof(struct sctp6_sock, sctp.initmsg) -
> >                               offsetof(struct sctp6_sock, sctp.subscribe) +
> > -                             sizeof_field(struct sctp6_sock, sctp.initmsg),
> > +                             FIELD_SIZEOF(struct sctp6_sock, sctp.initmsg),
> >       .sysctl_mem     = sysctl_sctp_mem,
> >       .sysctl_rmem    = sysctl_sctp_rmem,
> >       .sysctl_wmem    = sysctl_sctp_wmem,
> > diff --git a/tools/testing/selftests/bpf/bpf_util.h b/tools/testing/selftests/bpf/bpf_util.h
> > index a29206ebbd13..571c35aac90f 100644
> > --- a/tools/testing/selftests/bpf/bpf_util.h
> > +++ b/tools/testing/selftests/bpf/bpf_util.h
> > @@ -58,13 +58,29 @@ static inline unsigned int bpf_num_possible_cpus(void)
> >  # define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
> >  #endif
> >
> > -#ifndef sizeof_field
> > -#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
> > +/*
> > + * FIELD_SIZEOF - get the size of a struct's field
> > + * @t: the target struct
> > + * @f: the target struct's field
> > + * Return: the size of @f in the struct definition without having a
> > + * declared instance of @t.
> > + */
> > +#ifndef FIELD_SIZEOF
> > +#define FIELD_SIZEOF(t, f) (sizeof(((t *)0)->f))
> >  #endif
> >
> > +/*
> > + * For code compatibility
> > + *
> > + * sizeof_field(TYPE, MEMBER)
> > + * @TYPE: The structure containing the field of interest
> > + * @MEMBER: The field to return the size of
> > + */
> > +#define sizeof_field(TYPE, MEMBER) FIELD_SIZEOF(TYPE, MEMBER)
> > +
> >  #ifndef offsetofend
> >  #define offsetofend(TYPE, MEMBER) \
> > -     (offsetof(TYPE, MEMBER) + sizeof_field(TYPE, MEMBER))
> > +     (offsetof(TYPE, MEMBER) + FIELD_SIZEOF(TYPE, MEMBER))
> >  #endif
> >
> >  #endif /* __BPF_UTIL__ */
> > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> > index ca54b09adf5b..e43e3a26f6ab 100644
> > --- a/virt/kvm/kvm_main.c
> > +++ b/virt/kvm/kvm_main.c
> > @@ -4275,7 +4275,7 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
> >               kmem_cache_create_usercopy("kvm_vcpu", vcpu_size, vcpu_align,
> >                                          SLAB_ACCOUNT,
> >                                          offsetof(struct kvm_vcpu, arch),
> > -                                        sizeof_field(struct kvm_vcpu, arch),
> > +                                        FIELD_SIZEOF(struct kvm_vcpu, arch),
> >                                          NULL);
> >       if (!kvm_vcpu_cache) {
> >               r = -ENOMEM;
> > --
> > 2.11.0
> >
>
> --
> Kees Cook

Re: [PATCH V2] include: linux: Regularise the use of FIELD_SIZEOF macro

[Andrew Morton]

On Wed, 12 Jun 2019 01:08:36 +0530 Shyam Saini <shyam.saini@amarulasolutions.com> wrote:

> Currently, there are 3 different macros, namely sizeof_field, SIZEOF_FIELD
> and FIELD_SIZEOF which are used to calculate the size of a member of
> structure, so to bring uniformity in entire kernel source tree lets use
> FIELD_SIZEOF and replace all occurrences of other two macros with this.
> 
> For this purpose, redefine FIELD_SIZEOF in include/linux/stddef.h and
> tools/testing/selftests/bpf/bpf_util.h and remove its defination from
> include/linux/kernel.h
> 
> In favour of FIELD_SIZEOF, this patch also deprecates other two similar
> macros sizeof_field and SIZEOF_FIELD.
> 
> For code compatibility reason, retain sizeof_field macro as a wrapper macro
> to FIELD_SIZEOF

As Alexey has pointed out, C structs and unions don't have fields -
they have members.  So this is an opportunity to switch everything to
a new member_sizeof().

What do people think of that and how does this impact the patch footprint?

Re: [PATCH V2] include: linux: Regularise the use of FIELD_SIZEOF macro

[Andreas Dilger]

[-- Attachment #1: Type: text/plain, Size: 1974 bytes --]

On Jun 11, 2019, at 2:48 PM, Andrew Morton <akpm@linux-foundation.org> wrote:
> 
> On Wed, 12 Jun 2019 01:08:36 +0530 Shyam Saini <shyam.saini@amarulasolutions.com> wrote:
> 
>> Currently, there are 3 different macros, namely sizeof_field, SIZEOF_FIELD
>> and FIELD_SIZEOF which are used to calculate the size of a member of
>> structure, so to bring uniformity in entire kernel source tree lets use
>> FIELD_SIZEOF and replace all occurrences of other two macros with this.
>> 
>> For this purpose, redefine FIELD_SIZEOF in include/linux/stddef.h and
>> tools/testing/selftests/bpf/bpf_util.h and remove its defination from
>> include/linux/kernel.h
>> 
>> In favour of FIELD_SIZEOF, this patch also deprecates other two similar
>> macros sizeof_field and SIZEOF_FIELD.
>> 
>> For code compatibility reason, retain sizeof_field macro as a wrapper macro
>> to FIELD_SIZEOF
> 
> As Alexey has pointed out, C structs and unions don't have fields -
> they have members.  So this is an opportunity to switch everything to
> a new member_sizeof().
> 
> What do people think of that and how does this impact the patch footprint?

I did a check, and FIELD_SIZEOF() is used about 350x, while sizeof_field()
is about 30x, and SIZEOF_FIELD() is only about 5x.

That said, I'm much more in favour of "sizeof_field()" or "sizeof_member()"
than FIELD_SIZEOF().  Not only does that better match "offsetof()", with
which it is closely related, but is also closer to the original "sizeof()".

Since this is a rather trivial change, it can be split into a number of
patches to get approval/landing via subsystem maintainers, and there is no
huge urgency to remove the original macros until the users are gone.  It
would make sense to remove SIZEOF_FIELD() and sizeof_field() quickly so
they don't gain more users, and the remaining FIELD_SIZEOF() users can be
whittled away as the patches come through the maintainer trees.

Cheers, Andreas






[-- Attachment #2: Message signed with OpenPGP --]
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Re: [PATCH V2] include: linux: Regularise the use of FIELD_SIZEOF macro

[Andrew Morton]

On Tue, 11 Jun 2019 15:00:10 -0600 Andreas Dilger <adilger@dilger.ca> wrote:

> >> to FIELD_SIZEOF
> > 
> > As Alexey has pointed out, C structs and unions don't have fields -
> > they have members.  So this is an opportunity to switch everything to
> > a new member_sizeof().
> > 
> > What do people think of that and how does this impact the patch footprint?
> 
> I did a check, and FIELD_SIZEOF() is used about 350x, while sizeof_field()
> is about 30x, and SIZEOF_FIELD() is only about 5x.

Erk.  Sorry, I should have grepped.

> That said, I'm much more in favour of "sizeof_field()" or "sizeof_member()"
> than FIELD_SIZEOF().  Not only does that better match "offsetof()", with
> which it is closely related, but is also closer to the original "sizeof()".
> 
> Since this is a rather trivial change, it can be split into a number of
> patches to get approval/landing via subsystem maintainers, and there is no
> huge urgency to remove the original macros until the users are gone.  It
> would make sense to remove SIZEOF_FIELD() and sizeof_field() quickly so
> they don't gain more users, and the remaining FIELD_SIZEOF() users can be
> whittled away as the patches come through the maintainer trees.

In that case I'd say let's live with FIELD_SIZEOF() and remove
sizeof_field() and SIZEOF_FIELD().

I'm a bit surprised that the FIELD_SIZEOF() definition ends up in
stddef.h rather than in kernel.h where such things are normally
defined.  Why is that?

Re: [PATCH V2] include: linux: Regularise the use of FIELD_SIZEOF macro

[Shyam Saini]

Hi Andrew,

>
> On Tue, 11 Jun 2019 15:00:10 -0600 Andreas Dilger <adilger@dilger.ca> wrote:
>
> > >> to FIELD_SIZEOF
> > >
> > > As Alexey has pointed out, C structs and unions don't have fields -
> > > they have members.  So this is an opportunity to switch everything to
> > > a new member_sizeof().
> > >
> > > What do people think of that and how does this impact the patch footprint?
> >
> > I did a check, and FIELD_SIZEOF() is used about 350x, while sizeof_field()
> > is about 30x, and SIZEOF_FIELD() is only about 5x.
>
> Erk.  Sorry, I should have grepped.
>
> > That said, I'm much more in favour of "sizeof_field()" or "sizeof_member()"
> > than FIELD_SIZEOF().  Not only does that better match "offsetof()", with
> > which it is closely related, but is also closer to the original "sizeof()".
> >
> > Since this is a rather trivial change, it can be split into a number of
> > patches to get approval/landing via subsystem maintainers, and there is no
> > huge urgency to remove the original macros until the users are gone.  It
> > would make sense to remove SIZEOF_FIELD() and sizeof_field() quickly so
> > they don't gain more users, and the remaining FIELD_SIZEOF() users can be
> > whittled away as the patches come through the maintainer trees.
>
> In that case I'd say let's live with FIELD_SIZEOF() and remove
> sizeof_field() and SIZEOF_FIELD().
>
> I'm a bit surprised that the FIELD_SIZEOF() definition ends up in
> stddef.h rather than in kernel.h where such things are normally
> defined.  Why is that?

Thanks for pointing out this, I was not aware if this is a convention.
Anyway, I'll keep FIELD_SIZEOF definition in kernel.h in next version.

Re: [PATCH V2] include: linux: Regularise the use of FIELD_SIZEOF macro

[Andreas Dilger]

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On Jun 11, 2019, at 3:09 PM, Andrew Morton <akpm@linux-foundation.org> wrote:
> 
> On Tue, 11 Jun 2019 15:00:10 -0600 Andreas Dilger <adilger@dilger.ca> wrote:
> 
>>>> to FIELD_SIZEOF
>>> 
>>> As Alexey has pointed out, C structs and unions don't have fields -
>>> they have members.  So this is an opportunity to switch everything to
>>> a new member_sizeof().
>>> 
>>> What do people think of that and how does this impact the patch footprint?
>> 
>> I did a check, and FIELD_SIZEOF() is used about 350x, while sizeof_field()
>> is about 30x, and SIZEOF_FIELD() is only about 5x.
> 
> Erk.  Sorry, I should have grepped.
> 
>> That said, I'm much more in favour of "sizeof_field()" or "sizeof_member()"
>> than FIELD_SIZEOF().  Not only does that better match "offsetof()", with
>> which it is closely related, but is also closer to the original "sizeof()".
>> 
>> Since this is a rather trivial change, it can be split into a number of
>> patches to get approval/landing via subsystem maintainers, and there is no
>> huge urgency to remove the original macros until the users are gone.  It
>> would make sense to remove SIZEOF_FIELD() and sizeof_field() quickly so
>> they don't gain more users, and the remaining FIELD_SIZEOF() users can be
>> whittled away as the patches come through the maintainer trees.
> 
> In that case I'd say let's live with FIELD_SIZEOF() and remove
> sizeof_field() and SIZEOF_FIELD().

The real question is whether we want to live with a sub-standard macro for
the next 20 years rather than taking the opportunity to clean it up now?

> I'm a bit surprised that the FIELD_SIZEOF() definition ends up in
> stddef.h rather than in kernel.h where such things are normally
> defined.  Why is that?

Cheers, Andreas






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Re: [PATCH V2] include: linux: Regularise the use of FIELD_SIZEOF macro

[Alexey Dobriyan]

On Tue, Jun 11, 2019 at 03:00:10PM -0600, Andreas Dilger wrote:
> On Jun 11, 2019, at 2:48 PM, Andrew Morton <akpm@linux-foundation.org> wrote:
> > 
> > On Wed, 12 Jun 2019 01:08:36 +0530 Shyam Saini <shyam.saini@amarulasolutions.com> wrote:

> I did a check, and FIELD_SIZEOF() is used about 350x, while sizeof_field()
> is about 30x, and SIZEOF_FIELD() is only about 5x.
> 
> That said, I'm much more in favour of "sizeof_field()" or "sizeof_member()"
> than FIELD_SIZEOF().  Not only does that better match "offsetof()", with
> which it is closely related, but is also closer to the original "sizeof()".
> 
> Since this is a rather trivial change, it can be split into a number of
> patches to get approval/landing via subsystem maintainers, and there is no
> huge urgency to remove the original macros until the users are gone.  It
> would make sense to remove SIZEOF_FIELD() and sizeof_field() quickly so
> they don't gain more users, and the remaining FIELD_SIZEOF() users can be
> whittled away as the patches come through the maintainer trees.

The signature should be

	sizeof_member(T, m)

it is proper English,
it is lowercase, so is easier to type,
it uses standard term (member, not field),
it blends in with standard "sizeof" operator,

Re: [PATCH V2] include: linux: Regularise the use of FIELD_SIZEOF macro

[Joe Perches]

On Sat, 2019-06-29 at 17:25 +0300, Alexey Dobriyan wrote:
> On Tue, Jun 11, 2019 at 03:00:10PM -0600, Andreas Dilger wrote:
> > On Jun 11, 2019, at 2:48 PM, Andrew Morton <akpm@linux-foundation.org> wrote:
> > > On Wed, 12 Jun 2019 01:08:36 +0530 Shyam Saini <shyam.saini@amarulasolutions.com> wrote:
> > I did a check, and FIELD_SIZEOF() is used about 350x, while sizeof_field()
> > is about 30x, and SIZEOF_FIELD() is only about 5x.
> > 
> > That said, I'm much more in favour of "sizeof_field()" or "sizeof_member()"
> > than FIELD_SIZEOF().  Not only does that better match "offsetof()", with
> > which it is closely related, but is also closer to the original "sizeof()".
> > 
> > Since this is a rather trivial change, it can be split into a number of
> > patches to get approval/landing via subsystem maintainers, and there is no
> > huge urgency to remove the original macros until the users are gone.  It
> > would make sense to remove SIZEOF_FIELD() and sizeof_field() quickly so
> > they don't gain more users, and the remaining FIELD_SIZEOF() users can be
> > whittled away as the patches come through the maintainer trees.
> 
> The signature should be
> 
> 	sizeof_member(T, m)
> 
> it is proper English,
> it is lowercase, so is easier to type,
> it uses standard term (member, not field),
> it blends in with standard "sizeof" operator,

yes please.

Also, a simple script conversion applied
immediately after an rc1 might be easiest
rather than individual patches.

Re: [PATCH V2] include: linux: Regularise the use of FIELD_SIZEOF macro

[Kees Cook]

On Sat, Jun 29, 2019 at 09:45:10AM -0700, Joe Perches wrote:
> On Sat, 2019-06-29 at 17:25 +0300, Alexey Dobriyan wrote:
> > On Tue, Jun 11, 2019 at 03:00:10PM -0600, Andreas Dilger wrote:
> > > On Jun 11, 2019, at 2:48 PM, Andrew Morton <akpm@linux-foundation.org> wrote:
> > > > On Wed, 12 Jun 2019 01:08:36 +0530 Shyam Saini <shyam.saini@amarulasolutions.com> wrote:
> > > I did a check, and FIELD_SIZEOF() is used about 350x, while sizeof_field()
> > > is about 30x, and SIZEOF_FIELD() is only about 5x.
> > > 
> > > That said, I'm much more in favour of "sizeof_field()" or "sizeof_member()"
> > > than FIELD_SIZEOF().  Not only does that better match "offsetof()", with
> > > which it is closely related, but is also closer to the original "sizeof()".
> > > 
> > > Since this is a rather trivial change, it can be split into a number of
> > > patches to get approval/landing via subsystem maintainers, and there is no
> > > huge urgency to remove the original macros until the users are gone.  It
> > > would make sense to remove SIZEOF_FIELD() and sizeof_field() quickly so
> > > they don't gain more users, and the remaining FIELD_SIZEOF() users can be
> > > whittled away as the patches come through the maintainer trees.
> > 
> > The signature should be
> > 
> > 	sizeof_member(T, m)
> > 
> > it is proper English,
> > it is lowercase, so is easier to type,
> > it uses standard term (member, not field),
> > it blends in with standard "sizeof" operator,
> 
> yes please.
> 
> Also, a simple script conversion applied
> immediately after an rc1 might be easiest
> rather than individual patches.

This seems reasonable to me. I think the patch steps would be:

1) implement sizeof_member(T, m) as a stand-alone macro
2) do a scripted replacement of all identical macros.
3) remove all the identical macros.

Step 2 can be a patch that includes the script used to do the
replacement. That way Linus can choose to just run the script instead of
taking the patch.

-- 
Kees Cook

Re: [PATCH V2] include: linux: Regularise the use of FIELD_SIZEOF macro

[Alexei Starovoitov]

On Tue, Jun 11, 2019 at 5:00 PM Shyam Saini
<shyam.saini@amarulasolutions.com> wrote:
>
> Currently, there are 3 different macros, namely sizeof_field, SIZEOF_FIELD
> and FIELD_SIZEOF which are used to calculate the size of a member of
> structure, so to bring uniformity in entire kernel source tree lets use
> FIELD_SIZEOF and replace all occurrences of other two macros with this.
>
> For this purpose, redefine FIELD_SIZEOF in include/linux/stddef.h and
> tools/testing/selftests/bpf/bpf_util.h and remove its defination from
> include/linux/kernel.h

please dont. bpf_util.h is a user space header.
Please leave it as-is.