fs: verity: Added some more stuff trying to make it compilable.

Unfortunately I failed at this point:

fs/verity/open.c:202:2: error: implicit declaration of function 'arch_cmpxchg' [-Werror=implicit-function-declaration]
  if (cmpxchg_release(&inode->i_verity_info, NULL, vi) != NULL) {
  ^

Change-Id: I0c2c74fdcee0ecc8a3f93be472b52457322b66c7

fs/verity/fsverity_private.h

@@ -20,6 +20,56 @@
 
 struct ahash_request;
 
+/* Missing stuff BEGIN */
+#include <linux/kasan-checks.h>
+#include <linux/kcsan-checks.h>
+
+#ifndef arch_cmpxchg_relaxed
+#define arch_cmpxchg_acquire arch_cmpxchg
+#define arch_cmpxchg_release arch_cmpxchg
+#define arch_cmpxchg_relaxed arch_cmpxchg
+#else /* arch_cmpxchg_relaxed */
+
+#ifndef arch_cmpxchg_acquire
+#define arch_cmpxchg_acquire(...) \
+	__atomic_op_acquire(arch_cmpxchg, __VA_ARGS__)
+#endif
+
+#ifndef arch_cmpxchg_release
+#define arch_cmpxchg_release(...) \
+	__atomic_op_release(arch_cmpxchg, __VA_ARGS__)
+#endif
+
+#ifndef arch_cmpxchg
+#define arch_cmpxchg(...) \
+	__atomic_op_fence(arch_cmpxchg, __VA_ARGS__)
+#endif
+
+#endif /* arch_cmpxchg_relaxed */
+
+#define cmpxchg_release(ptr, ...) \
+({ \
+	typeof(ptr) __ai_ptr = (ptr); \
+	instrument_atomic_write(__ai_ptr, sizeof(*__ai_ptr)); \
+	arch_cmpxchg_release(__ai_ptr, __VA_ARGS__); \
+})
+
+/**
+ * instrument_atomic_write - instrument atomic write access
+ *
+ * Instrument an atomic write access. The instrumentation should be inserted
+ * before the actual write happens.
+ *
+ * @ptr address of access
+ * @size size of access
+ */
+static __always_inline void instrument_atomic_write(const volatile void *v, size_t size)
+{
+	kasan_check_write(v, size);
+	kcsan_check_atomic_write(v, size);
+}
+/* Missing stuff END */
+
 /*
  * Implementation limit: maximum depth of the Merkle tree.  For now 8 is plenty;
  * it's enough for over U64_MAX bytes of data using SHA-256 and 4K blocks.

include/linux/dcache.h

@@ -427,4 +427,16 @@ struct name_snapshot {
 void take_dentry_name_snapshot(struct name_snapshot *, struct dentry *);
 void release_dentry_name_snapshot(struct name_snapshot *);
 
+/**
+ * d_inode - Get the actual inode of this dentry
+ * @dentry: The dentry to query
+ *
+ * This is the helper normal filesystems should use to get at their own inodes
+ * in their own dentries and ignore the layering superimposed upon them.
+ */
+static inline struct inode *d_inode(const struct dentry *dentry)
+{
+	return dentry->d_inode;
+}
+
 #endif	/* __LINUX_DCACHE_H */

include/linux/kasan-checks.h

+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_KASAN_CHECKS_H
+#define _LINUX_KASAN_CHECKS_H
+
+#include <linux/types.h>
+
+/*
+ * The annotations present in this file are only relevant for the software
+ * KASAN modes that rely on compiler instrumentation, and will be optimized
+ * away for the hardware tag-based KASAN mode. Use kasan_check_byte() instead.
+ */
+
+/*
+ * __kasan_check_*: Always available when KASAN is enabled. This may be used
+ * even in compilation units that selectively disable KASAN, but must use KASAN
+ * to validate access to an address.   Never use these in header files!
+ */
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
+bool __kasan_check_read(const volatile void *p, unsigned int size);
+bool __kasan_check_write(const volatile void *p, unsigned int size);
+#else
+static inline bool __kasan_check_read(const volatile void *p, unsigned int size)
+{
+	return true;
+}
+static inline bool __kasan_check_write(const volatile void *p, unsigned int size)
+{
+	return true;
+}
+#endif
+
+/*
+ * kasan_check_*: Only available when the particular compilation unit has KASAN
+ * instrumentation enabled. May be used in header files.
+ */
+#ifdef __SANITIZE_ADDRESS__
+#define kasan_check_read __kasan_check_read
+#define kasan_check_write __kasan_check_write
+#else
+static inline bool kasan_check_read(const volatile void *p, unsigned int size)
+{
+	return true;
+}
+static inline bool kasan_check_write(const volatile void *p, unsigned int size)
+{
+	return true;
+}
+#endif
+
+#endif

include/linux/kcsan-checks.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * KCSAN access checks and modifiers. These can be used to explicitly check
+ * uninstrumented accesses, or change KCSAN checking behaviour of accesses.
+ *
+ * Copyright (C) 2019, Google LLC.
+ */
+
+#ifndef _LINUX_KCSAN_CHECKS_H
+#define _LINUX_KCSAN_CHECKS_H
+
+/* Note: Only include what is already included by compiler.h. */
+#include <linux/types.h>
+
+/* Access types -- if KCSAN_ACCESS_WRITE is not set, the access is a read. */
+#define KCSAN_ACCESS_WRITE	(1 << 0) /* Access is a write. */
+#define KCSAN_ACCESS_COMPOUND	(1 << 1) /* Compounded read-write instrumentation. */
+#define KCSAN_ACCESS_ATOMIC	(1 << 2) /* Access is atomic. */
+/* The following are special, and never due to compiler instrumentation. */
+#define KCSAN_ACCESS_ASSERT	(1 << 3) /* Access is an assertion. */
+#define KCSAN_ACCESS_SCOPED	(1 << 4) /* Access is a scoped access. */
+
+/*
+ * __kcsan_*: Always calls into the runtime when KCSAN is enabled. This may be used
+ * even in compilation units that selectively disable KCSAN, but must use KCSAN
+ * to validate access to an address. Never use these in header files!
+ */
+#ifdef CONFIG_KCSAN
+/**
+ * __kcsan_check_access - check generic access for races
+ *
+ * @ptr: address of access
+ * @size: size of access
+ * @type: access type modifier
+ */
+void __kcsan_check_access(const volatile void *ptr, size_t size, int type);
+
+/**
+ * kcsan_disable_current - disable KCSAN for the current context
+ *
+ * Supports nesting.
+ */
+void kcsan_disable_current(void);
+
+/**
+ * kcsan_enable_current - re-enable KCSAN for the current context
+ *
+ * Supports nesting.
+ */
+void kcsan_enable_current(void);
+void kcsan_enable_current_nowarn(void); /* Safe in uaccess regions. */
+
+/**
+ * kcsan_nestable_atomic_begin - begin nestable atomic region
+ *
+ * Accesses within the atomic region may appear to race with other accesses but
+ * should be considered atomic.
+ */
+void kcsan_nestable_atomic_begin(void);
+
+/**
+ * kcsan_nestable_atomic_end - end nestable atomic region
+ */
+void kcsan_nestable_atomic_end(void);
+
+/**
+ * kcsan_flat_atomic_begin - begin flat atomic region
+ *
+ * Accesses within the atomic region may appear to race with other accesses but
+ * should be considered atomic.
+ */
+void kcsan_flat_atomic_begin(void);
+
+/**
+ * kcsan_flat_atomic_end - end flat atomic region
+ */
+void kcsan_flat_atomic_end(void);
+
+/**
+ * kcsan_atomic_next - consider following accesses as atomic
+ *
+ * Force treating the next n memory accesses for the current context as atomic
+ * operations.
+ *
+ * @n: number of following memory accesses to treat as atomic.
+ */
+void kcsan_atomic_next(int n);
+
+/**
+ * kcsan_set_access_mask - set access mask
+ *
+ * Set the access mask for all accesses for the current context if non-zero.
+ * Only value changes to bits set in the mask will be reported.
+ *
+ * @mask: bitmask
+ */
+void kcsan_set_access_mask(unsigned long mask);
+
+/* Scoped access information. */
+struct kcsan_scoped_access {
+	struct list_head list;
+	const volatile void *ptr;
+	size_t size;
+	int type;
+};
+/*
+ * Automatically call kcsan_end_scoped_access() when kcsan_scoped_access goes
+ * out of scope; relies on attribute "cleanup", which is supported by all
+ * compilers that support KCSAN.
+ */
+#define __kcsan_cleanup_scoped                                                 \
+	__maybe_unused __attribute__((__cleanup__(kcsan_end_scoped_access)))
+
+/**
+ * kcsan_begin_scoped_access - begin scoped access
+ *
+ * Begin scoped access and initialize @sa, which will cause KCSAN to
+ * continuously check the memory range in the current thread until
+ * kcsan_end_scoped_access() is called for @sa.
+ *
+ * Scoped accesses are implemented by appending @sa to an internal list for the
+ * current execution context, and then checked on every call into the KCSAN
+ * runtime.
+ *
+ * @ptr: address of access
+ * @size: size of access
+ * @type: access type modifier
+ * @sa: struct kcsan_scoped_access to use for the scope of the access
+ */
+struct kcsan_scoped_access *
+kcsan_begin_scoped_access(const volatile void *ptr, size_t size, int type,
+			  struct kcsan_scoped_access *sa);
+
+/**
+ * kcsan_end_scoped_access - end scoped access
+ *
+ * End a scoped access, which will stop KCSAN checking the memory range.
+ * Requires that kcsan_begin_scoped_access() was previously called once for @sa.
+ *
+ * @sa: a previously initialized struct kcsan_scoped_access
+ */
+void kcsan_end_scoped_access(struct kcsan_scoped_access *sa);
+
+
+#else /* CONFIG_KCSAN */
+
+static inline void __kcsan_check_access(const volatile void *ptr, size_t size,
+					int type) { }
+
+static inline void kcsan_disable_current(void)		{ }
+static inline void kcsan_enable_current(void)		{ }
+static inline void kcsan_enable_current_nowarn(void)	{ }
+static inline void kcsan_nestable_atomic_begin(void)	{ }
+static inline void kcsan_nestable_atomic_end(void)	{ }
+static inline void kcsan_flat_atomic_begin(void)	{ }
+static inline void kcsan_flat_atomic_end(void)		{ }
+static inline void kcsan_atomic_next(int n)		{ }
+static inline void kcsan_set_access_mask(unsigned long mask) { }
+
+struct kcsan_scoped_access { };
+#define __kcsan_cleanup_scoped __maybe_unused
+static inline struct kcsan_scoped_access *
+kcsan_begin_scoped_access(const volatile void *ptr, size_t size, int type,
+			  struct kcsan_scoped_access *sa) { return sa; }
+static inline void kcsan_end_scoped_access(struct kcsan_scoped_access *sa) { }
+
+#endif /* CONFIG_KCSAN */
+
+#ifdef __SANITIZE_THREAD__
+/*
+ * Only calls into the runtime when the particular compilation unit has KCSAN
+ * instrumentation enabled. May be used in header files.
+ */
+#define kcsan_check_access __kcsan_check_access
+
+/*
+ * Only use these to disable KCSAN for accesses in the current compilation unit;
+ * calls into libraries may still perform KCSAN checks.
+ */
+#define __kcsan_disable_current kcsan_disable_current
+#define __kcsan_enable_current kcsan_enable_current_nowarn
+#else
+static inline void kcsan_check_access(const volatile void *ptr, size_t size,
+				      int type) { }
+static inline void __kcsan_enable_current(void)  { }
+static inline void __kcsan_disable_current(void) { }
+#endif
+
+/**
+ * __kcsan_check_read - check regular read access for races
+ *
+ * @ptr: address of access
+ * @size: size of access
+ */
+#define __kcsan_check_read(ptr, size) __kcsan_check_access(ptr, size, 0)
+
+/**
+ * __kcsan_check_write - check regular write access for races
+ *
+ * @ptr: address of access
+ * @size: size of access
+ */
+#define __kcsan_check_write(ptr, size)                                         \
+	__kcsan_check_access(ptr, size, KCSAN_ACCESS_WRITE)
+
+/**
+ * __kcsan_check_read_write - check regular read-write access for races
+ *
+ * @ptr: address of access
+ * @size: size of access
+ */
+#define __kcsan_check_read_write(ptr, size)                                    \
+	__kcsan_check_access(ptr, size, KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE)
+
+/**
+ * kcsan_check_read - check regular read access for races
+ *
+ * @ptr: address of access
+ * @size: size of access
+ */
+#define kcsan_check_read(ptr, size) kcsan_check_access(ptr, size, 0)
+
+/**
+ * kcsan_check_write - check regular write access for races
+ *
+ * @ptr: address of access
+ * @size: size of access
+ */
+#define kcsan_check_write(ptr, size)                                           \
+	kcsan_check_access(ptr, size, KCSAN_ACCESS_WRITE)
+
+/**
+ * kcsan_check_read_write - check regular read-write access for races
+ *
+ * @ptr: address of access
+ * @size: size of access
+ */
+#define kcsan_check_read_write(ptr, size)                                      \
+	kcsan_check_access(ptr, size, KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE)
+
+/*
+ * Check for atomic accesses: if atomic accesses are not ignored, this simply
+ * aliases to kcsan_check_access(), otherwise becomes a no-op.
+ */
+#ifdef CONFIG_KCSAN_IGNORE_ATOMICS
+#define kcsan_check_atomic_read(...)		do { } while (0)
+#define kcsan_check_atomic_write(...)		do { } while (0)
+#define kcsan_check_atomic_read_write(...)	do { } while (0)
+#else
+#define kcsan_check_atomic_read(ptr, size)                                     \
+	kcsan_check_access(ptr, size, KCSAN_ACCESS_ATOMIC)
+#define kcsan_check_atomic_write(ptr, size)                                    \
+	kcsan_check_access(ptr, size, KCSAN_ACCESS_ATOMIC | KCSAN_ACCESS_WRITE)
+#define kcsan_check_atomic_read_write(ptr, size)                               \
+	kcsan_check_access(ptr, size, KCSAN_ACCESS_ATOMIC | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_COMPOUND)
+#endif
+
+/**
+ * ASSERT_EXCLUSIVE_WRITER - assert no concurrent writes to @var
+ *
+ * Assert that there are no concurrent writes to @var; other readers are
+ * allowed. This assertion can be used to specify properties of concurrent code,
+ * where violation cannot be detected as a normal data race.
+ *
+ * For example, if we only have a single writer, but multiple concurrent
+ * readers, to avoid data races, all these accesses must be marked; even
+ * concurrent marked writes racing with the single writer are bugs.
+ * Unfortunately, due to being marked, they are no longer data races. For cases
+ * like these, we can use the macro as follows:
+ *
+ * .. code-block:: c
+ *
+ *	void writer(void) {
+ *		spin_lock(&update_foo_lock);
+ *		ASSERT_EXCLUSIVE_WRITER(shared_foo);
+ *		WRITE_ONCE(shared_foo, ...);
+ *		spin_unlock(&update_foo_lock);
+ *	}
+ *	void reader(void) {
+ *		// update_foo_lock does not need to be held!
+ *		... = READ_ONCE(shared_foo);
+ *	}
+ *
+ * Note: ASSERT_EXCLUSIVE_WRITER_SCOPED(), if applicable, performs more thorough
+ * checking if a clear scope where no concurrent writes are expected exists.
+ *
+ * @var: variable to assert on
+ */
+#define ASSERT_EXCLUSIVE_WRITER(var)                                           \
+	__kcsan_check_access(&(var), sizeof(var), KCSAN_ACCESS_ASSERT)
+
+/*
+ * Helper macros for implementation of for ASSERT_EXCLUSIVE_*_SCOPED(). @id is
+ * expected to be unique for the scope in which instances of kcsan_scoped_access
+ * are declared.
+ */
+#define __kcsan_scoped_name(c, suffix) __kcsan_scoped_##c##suffix
+#define __ASSERT_EXCLUSIVE_SCOPED(var, type, id)                               \
+	struct kcsan_scoped_access __kcsan_scoped_name(id, _)                  \
+		__kcsan_cleanup_scoped;                                        \
+	struct kcsan_scoped_access *__kcsan_scoped_name(id, _dummy_p)          \
+		__maybe_unused = kcsan_begin_scoped_access(                    \
+			&(var), sizeof(var), KCSAN_ACCESS_SCOPED | (type),     \
+			&__kcsan_scoped_name(id, _))
+
+/**
+ * ASSERT_EXCLUSIVE_WRITER_SCOPED - assert no concurrent writes to @var in scope
+ *
+ * Scoped variant of ASSERT_EXCLUSIVE_WRITER().
+ *
+ * Assert that there are no concurrent writes to @var for the duration of the
+ * scope in which it is introduced. This provides a better way to fully cover
+ * the enclosing scope, compared to multiple ASSERT_EXCLUSIVE_WRITER(), and
+ * increases the likelihood for KCSAN to detect racing accesses.
+ *
+ * For example, it allows finding race-condition bugs that only occur due to
+ * state changes within the scope itself:
+ *
+ * .. code-block:: c
+ *
+ *	void writer(void) {
+ *		spin_lock(&update_foo_lock);
+ *		{
+ *			ASSERT_EXCLUSIVE_WRITER_SCOPED(shared_foo);
+ *			WRITE_ONCE(shared_foo, 42);
+ *			...
+ *			// shared_foo should still be 42 here!
+ *		}
+ *		spin_unlock(&update_foo_lock);
+ *	}
+ *	void buggy(void) {
+ *		if (READ_ONCE(shared_foo) == 42)
+ *			WRITE_ONCE(shared_foo, 1); // bug!
+ *	}
+ *
+ * @var: variable to assert on
+ */
+#define ASSERT_EXCLUSIVE_WRITER_SCOPED(var)                                    \
+	__ASSERT_EXCLUSIVE_SCOPED(var, KCSAN_ACCESS_ASSERT, __COUNTER__)
+
+/**
+ * ASSERT_EXCLUSIVE_ACCESS - assert no concurrent accesses to @var
+ *
+ * Assert that there are no concurrent accesses to @var (no readers nor
+ * writers). This assertion can be used to specify properties of concurrent
+ * code, where violation cannot be detected as a normal data race.
+ *
+ * For example, where exclusive access is expected after determining no other
+ * users of an object are left, but the object is not actually freed. We can
+ * check that this property actually holds as follows:
+ *
+ * .. code-block:: c
+ *
+ *	if (refcount_dec_and_test(&obj->refcnt)) {
+ *		ASSERT_EXCLUSIVE_ACCESS(*obj);
+ *		do_some_cleanup(obj);
+ *		release_for_reuse(obj);
+ *	}
+ *
+ * Note:
+ *
+ * 1. ASSERT_EXCLUSIVE_ACCESS_SCOPED(), if applicable, performs more thorough
+ *    checking if a clear scope where no concurrent accesses are expected exists.
+ *
+ * 2. For cases where the object is freed, `KASAN <kasan.html>`_ is a better
+ *    fit to detect use-after-free bugs.
+ *
+ * @var: variable to assert on
+ */
+#define ASSERT_EXCLUSIVE_ACCESS(var)                                           \
+	__kcsan_check_access(&(var), sizeof(var), KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT)
+
+/**
+ * ASSERT_EXCLUSIVE_ACCESS_SCOPED - assert no concurrent accesses to @var in scope
+ *
+ * Scoped variant of ASSERT_EXCLUSIVE_ACCESS().
+ *
+ * Assert that there are no concurrent accesses to @var (no readers nor writers)
+ * for the entire duration of the scope in which it is introduced. This provides
+ * a better way to fully cover the enclosing scope, compared to multiple
+ * ASSERT_EXCLUSIVE_ACCESS(), and increases the likelihood for KCSAN to detect
+ * racing accesses.
+ *
+ * @var: variable to assert on
+ */
+#define ASSERT_EXCLUSIVE_ACCESS_SCOPED(var)                                    \
+	__ASSERT_EXCLUSIVE_SCOPED(var, KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT, __COUNTER__)
+
+/**
+ * ASSERT_EXCLUSIVE_BITS - assert no concurrent writes to subset of bits in @var
+ *
+ * Bit-granular variant of ASSERT_EXCLUSIVE_WRITER().
+ *
+ * Assert that there are no concurrent writes to a subset of bits in @var;
+ * concurrent readers are permitted. This assertion captures more detailed
+ * bit-level properties, compared to the other (word granularity) assertions.
+ * Only the bits set in @mask are checked for concurrent modifications, while
+ * ignoring the remaining bits, i.e. concurrent writes (or reads) to ~mask bits
+ * are ignored.
+ *
+ * Use this for variables, where some bits must not be modified concurrently,
+ * yet other bits are expected to be modified concurrently.
+ *
+ * For example, variables where, after initialization, some bits are read-only,
+ * but other bits may still be modified concurrently. A reader may wish to
+ * assert that this is true as follows:
+ *
+ * .. code-block:: c
+ *
+ *	ASSERT_EXCLUSIVE_BITS(flags, READ_ONLY_MASK);
+ *	foo = (READ_ONCE(flags) & READ_ONLY_MASK) >> READ_ONLY_SHIFT;
+ *
+ * Note: The access that immediately follows ASSERT_EXCLUSIVE_BITS() is assumed
+ * to access the masked bits only, and KCSAN optimistically assumes it is
+ * therefore safe, even in the presence of data races, and marking it with
+ * READ_ONCE() is optional from KCSAN's point-of-view. We caution, however, that
+ * it may still be advisable to do so, since we cannot reason about all compiler
+ * optimizations when it comes to bit manipulations (on the reader and writer
+ * side). If you are sure nothing can go wrong, we can write the above simply
+ * as:
+ *
+ * .. code-block:: c
+ *
+ *	ASSERT_EXCLUSIVE_BITS(flags, READ_ONLY_MASK);
+ *	foo = (flags & READ_ONLY_MASK) >> READ_ONLY_SHIFT;
+ *
+ * Another example, where this may be used, is when certain bits of @var may
+ * only be modified when holding the appropriate lock, but other bits may still
+ * be modified concurrently. Writers, where other bits may change concurrently,
+ * could use the assertion as follows:
+ *
+ * .. code-block:: c
+ *
+ *	spin_lock(&foo_lock);
+ *	ASSERT_EXCLUSIVE_BITS(flags, FOO_MASK);
+ *	old_flags = flags;
+ *	new_flags = (old_flags & ~FOO_MASK) | (new_foo << FOO_SHIFT);
+ *	if (cmpxchg(&flags, old_flags, new_flags) != old_flags) { ... }
+ *	spin_unlock(&foo_lock);
+ *
+ * @var: variable to assert on
+ * @mask: only check for modifications to bits set in @mask
+ */
+#define ASSERT_EXCLUSIVE_BITS(var, mask)                                       \
+	do {                                                                   \
+		kcsan_set_access_mask(mask);                                   \
+		__kcsan_check_access(&(var), sizeof(var), KCSAN_ACCESS_ASSERT);\
+		kcsan_set_access_mask(0);                                      \
+		kcsan_atomic_next(1);                                          \
+	} while (0)
+
+#endif /* _LINUX_KCSAN_CHECKS_H */

include/linux/slab.h

@@ -108,6 +108,11 @@ struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
 struct kmem_cache *
 kmem_cache_create_memcg(struct mem_cgroup *, const char *, size_t, size_t,
 			unsigned long, void (*)(void *), struct kmem_cache *);
+struct kmem_cache *kmem_cache_create_usercopy(const char *name,
+			unsigned int size, unsigned int align,
+			slab_flags_t flags,
+			unsigned int useroffset, unsigned int usersize,
+			void (*ctor)(void *));
 void kmem_cache_destroy(struct kmem_cache *);
 int kmem_cache_shrink(struct kmem_cache *);
 void kmem_cache_free(struct kmem_cache *, void *);
@@ -124,6 +129,17 @@ void kmem_cache_free(struct kmem_cache *, void *);
 		sizeof(struct __struct), __alignof__(struct __struct),\
 		(__flags), NULL)
 
+/*
+ * To whitelist a single field for copying to/from usercopy, use this
+ * macro instead for KMEM_CACHE() above.
+ */
+#define KMEM_CACHE_USERCOPY(__struct, __flags, __field)			\
+		kmem_cache_create_usercopy(#__struct,			\
+			sizeof(struct __struct),			\
+			__alignof__(struct __struct), (__flags),	\
+			offsetof(struct __struct, __field),		\
+			sizeof_field(struct __struct, __field), NULL)
+
 /*
  * Common kmalloc functions provided by all allocators
  */

include/linux/stddef.h

+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LINUX_STDDEF_H
 #define _LINUX_STDDEF_H
 
@@ -18,6 +19,14 @@ enum {
 #define offsetof(TYPE, MEMBER)	((size_t)&((TYPE *)0)->MEMBER)
 #endif
 
+/**
+ * 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))
+
 /**
  * offsetofend(TYPE, MEMBER)
  *
@@ -25,6 +34,6 @@ enum {
  * @MEMBER: The member within the structure to get the end offset of
  */
 #define offsetofend(TYPE, MEMBER) \
-	(offsetof(TYP