Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:
 "Various misc subsystems, before getting into the post-linux-next
  material.

  41 patches.

  Subsystems affected by this patch series: procfs, misc, core-kernel,
  lib, checkpatch, init, pipe, minix, fat, cgroups, kexec, kdump,
  taskstats, panic, kcov, resource, and ubsan"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (41 commits)
  Revert "ubsan, kcsan: Don't combine sanitizer with kcov on clang"
  kernel/resource: fix kfree() of bootmem memory again
  kcov: properly handle subsequent mmap calls
  kcov: split ioctl handling into locked and unlocked parts
  panic: move panic_print before kmsg dumpers
  panic: add option to dump all CPUs backtraces in panic_print
  docs: sysctl/kernel: add missing bit to panic_print
  taskstats: remove unneeded dead assignment
  kasan: no need to unset panic_on_warn in end_report()
  ubsan: no need to unset panic_on_warn in ubsan_epilogue()
  panic: unset panic_on_warn inside panic()
  docs: kdump: add scp example to write out the dump file
  docs: kdump: update description about sysfs file system support
  arm64: mm: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
  x86/setup: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
  riscv: mm: init: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
  kexec: make crashk_res, crashk_low_res and crash_notes symbols always visible
  cgroup: use irqsave in cgroup_rstat_flush_locked().
  fat: use pointer to simple type in put_user()
  minix: fix bug when opening a file with O_DIRECT
  ...

7 files changed, 25 insertions, 20 deletions

diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h
index 6093fa6db260..c9be1657f03d 100644
--- a/include/linux/bitfield.h
+++ b/include/linux/bitfield.h
@@ -19,6 +19,9 @@
  *
  * Example:
  *
+ *  #include <linux/bitfield.h>
+ *  #include <linux/bits.h>
+ *
  *  #define REG_FIELD_A  GENMASK(6, 0)
  *  #define REG_FIELD_B  BIT(7)
  *  #define REG_FIELD_C  GENMASK(15, 8)
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index 1bc760ba400c..1c2c33ae1b37 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -11,6 +11,7 @@
 # define BTF_TYPE_TAG(value) /* nothing */
 #endif
 
+/* sparse defines __CHECKER__; see Documentation/dev-tools/sparse.rst */
 #ifdef __CHECKER__
 /* address spaces */
 # define __kernel	__attribute__((address_space(0)))
@@ -144,8 +145,6 @@ struct ftrace_likely_data {
  */
 #define __naked			__attribute__((__naked__)) notrace
 
-#define __compiler_offsetof(a, b)	__builtin_offsetof(a, b)
-
 /*
  * Prefer gnu_inline, so that extern inline functions do not emit an
  * externally visible function. This makes extern inline behave as per gnu89
diff --git a/include/linux/init.h b/include/linux/init.h
index d82b4b2e1d25..baf0b29a7010 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -320,12 +320,19 @@ struct obs_kernel_param {
 		__aligned(__alignof__(struct obs_kernel_param))		\
 		= { __setup_str_##unique_id, fn, early }
 
+/*
+ * NOTE: __setup functions return values:
+ * @fn returns 1 (or non-zero) if the option argument is "handled"
+ * and returns 0 if the option argument is "not handled".
+ */
 #define __setup(str, fn)						\
 	__setup_param(str, fn, fn, 0)
 
 /*
- * NOTE: fn is as per module_param, not __setup!
- * Emits warning if fn returns non-zero.
+ * NOTE: @fn is as per module_param, not __setup!
+ * I.e., @fn returns 0 for no error or non-zero for error
+ * (possibly @fn returns a -errno value, but it does not matter).
+ * Emits warning if @fn returns non-zero.
  */
 #define early_param(str, fn)						\
 	__setup_param(str, fn, fn, 1)
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 0c994ae37729..58d1b58a971e 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -20,6 +20,12 @@
 
 #include <uapi/linux/kexec.h>
 
+/* Location of a reserved region to hold the crash kernel.
+ */
+extern struct resource crashk_res;
+extern struct resource crashk_low_res;
+extern note_buf_t __percpu *crash_notes;
+
 #ifdef CONFIG_KEXEC_CORE
 #include <linux/list.h>
 #include <linux/compat.h>
@@ -350,12 +356,6 @@ extern int kexec_load_disabled;
 #define KEXEC_FILE_FLAGS	(KEXEC_FILE_UNLOAD | KEXEC_FILE_ON_CRASH | \
 				 KEXEC_FILE_NO_INITRAMFS)
 
-/* Location of a reserved region to hold the crash kernel.
- */
-extern struct resource crashk_res;
-extern struct resource crashk_low_res;
-extern note_buf_t __percpu *crash_notes;
-
 /* flag to track if kexec reboot is in progress */
 extern bool kexec_in_progress;
 
diff --git a/include/linux/log2.h b/include/linux/log2.h
index df0b155c2141..9f30d087a128 100644
--- a/include/linux/log2.h
+++ b/include/linux/log2.h
@@ -18,7 +18,7 @@
  * - the arch is not required to handle n==0 if implementing the fallback
  */
 #ifndef CONFIG_ARCH_HAS_ILOG2_U32
-static inline __attribute__((const))
+static __always_inline __attribute__((const))
 int __ilog2_u32(u32 n)
 {
 	return fls(n) - 1;
@@ -26,7 +26,7 @@ int __ilog2_u32(u32 n)
 #endif
 
 #ifndef CONFIG_ARCH_HAS_ILOG2_U64
-static inline __attribute__((const))
+static __always_inline __attribute__((const))
 int __ilog2_u64(u64 n)
 {
 	return fls64(n) - 1;
diff --git a/include/linux/stddef.h b/include/linux/stddef.h
index ca507bd5f808..929d67710cc5 100644
--- a/include/linux/stddef.h
+++ b/include/linux/stddef.h
@@ -13,11 +13,7 @@ enum {
 };
 
 #undef offsetof
-#ifdef __compiler_offsetof
-#define offsetof(TYPE, MEMBER)	__compiler_offsetof(TYPE, MEMBER)
-#else
-#define offsetof(TYPE, MEMBER)	((size_t)&((TYPE *)0)->MEMBER)
-#endif
+#define offsetof(TYPE, MEMBER)	__builtin_offsetof(TYPE, MEMBER)
 
 /**
  * sizeof_field() - Report the size of a struct field in bytes
diff --git a/include/uapi/linux/types.h b/include/uapi/linux/types.h
index f6d2f83cbe29..c4dc597f3dcf 100644
--- a/include/uapi/linux/types.h
+++ b/include/uapi/linux/types.h
@@ -19,12 +19,12 @@
  * any application/library that wants linux/types.h.
  */
 
+/* sparse defines __CHECKER__; see Documentation/dev-tools/sparse.rst */
 #ifdef __CHECKER__
-#define __bitwise__ __attribute__((bitwise))
+#define __bitwise	__attribute__((bitwise))
 #else
-#define __bitwise__
+#define __bitwise
 #endif
-#define __bitwise __bitwise__
 
 typedef __u16 __bitwise __le16;
 typedef __u16 __bitwise __be16;