[PATCH 08/20] thread: move thread bits accessors to separated file

Yury Norov
2017-06-19T15:49:51Z

They may be accessed from low-level code, so isolating is a measure to
avoid circular dependencies in header files.

The exact reason for circular dependency is WARN_ON() macro added in patch
edd63a27 "set_restore_sigmask() is never called without SIGPENDING (and
never should be)"

Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
---
include/linux/thread_bits.h | 63 +++++++++++++++++++++++++++++++++++++++++++
include/linux/thread_info.h | 65 +++++++++------------------------------------
2 files changed, 75 insertions(+), 53 deletions(-)
create mode 100644 include/linux/thread_bits.h

diff --git a/include/linux/thread_bits.h b/include/linux/thread_bits.h
new file mode 100644
index 000000000000..87354331bc7b
--- /dev/null
+++ b/include/linux/thread_bits.h
@@ -0,0 +1,63 @@
+/* thread_bits.h: common low-level thread bits accessors */
+
+#ifndef _LINUX_THREAD_BITS_H
+#define _LINUX_THREAD_BITS_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/bitops.h>
+#include <asm/thread_info.h>
+
+#ifdef CONFIG_THREAD_INFO_IN_TASK
+/*
+ * For CONFIG_THREAD_INFO_IN_TASK kernels we need <asm/current.h> for the
+ * definition of current, but for !CONFIG_THREAD_INFO_IN_TASK kernels,
+ * including <asm/current.h> can cause a circular dependency on some platforms.
+ */
+#include <asm/current.h>
+#define current_thread_info() ((struct thread_info *)current)
+#endif
+
+/*
+ * flag set/clear/test wrappers
+ * - pass TIF_xxxx constants to these functions
+ */
+
+static inline void set_ti_thread_flag(struct thread_info *ti, int flag)
+{
+ set_bit(flag, (unsigned long *)&ti->flags);
+}
+
+static inline void clear_ti_thread_flag(struct thread_info *ti, int flag)
+{
+ clear_bit(flag, (unsigned long *)&ti->flags);
+}
+
+static inline int test_and_set_ti_thread_flag(struct thread_info *ti, int flag)
+{
+ return test_and_set_bit(flag, (unsigned long *)&ti->flags);
+}
+
+static inline int test_and_clear_ti_thread_flag(struct thread_info *ti, int flag)
+{
+ return test_and_clear_bit(flag, (unsigned long *)&ti->flags);
+}
+
+static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
+{
+ return test_bit(flag, (unsigned long *)&ti->flags);
+}
+
+#define set_thread_flag(flag) \
+ set_ti_thread_flag(current_thread_info(), flag)
+#define clear_thread_flag(flag) \
+ clear_ti_thread_flag(current_thread_info(), flag)
+#define test_and_set_thread_flag(flag) \
+ test_and_set_ti_thread_flag(current_thread_info(), flag)
+#define test_and_clear_thread_flag(flag) \
+ test_and_clear_ti_thread_flag(current_thread_info(), flag)
+#define test_thread_flag(flag) \
+ test_ti_thread_flag(current_thread_info(), flag)
+
+#endif /* !__ASSEMBLY__ */
+#endif /* _LINUX_THREAD_BITS_H */
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index d7d3ea637dd0..c40a89357329 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -7,9 +7,21 @@
#ifndef _LINUX_THREAD_INFO_H
#define _LINUX_THREAD_INFO_H

+/*
+ * For per-arch arch_within_stack_frames() implementations, defined in
+ * asm/thread_info.h.
+ */
+enum {
+ BAD_STACK = -1,
+ NOT_STACK = 0,
+ GOOD_FRAME,
+ GOOD_STACK,
+};
+
#include <linux/types.h>
#include <linux/bug.h>
#include <linux/restart_block.h>
+#include <linux/thread_bits.h>

#ifdef CONFIG_THREAD_INFO_IN_TASK
/*
@@ -22,18 +34,6 @@
#endif

#include <linux/bitops.h>
-
-/*
- * For per-arch arch_within_stack_frames() implementations, defined in
- * asm/thread_info.h.
- */
-enum {
- BAD_STACK = -1,
- NOT_STACK = 0,
- GOOD_FRAME,
- GOOD_STACK,
-};
-
#include <asm/thread_info.h>

#ifdef __KERNEL__
@@ -45,47 +45,6 @@ enum {
# define THREADINFO_GFP (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK)
#endif

-/*
- * flag set/clear/test wrappers
- * - pass TIF_xxxx constants to these functions
- */
-
-static inline void set_ti_thread_flag(struct thread_info *ti, int flag)
-{
- set_bit(flag, (unsigned long *)&ti->flags);
-}
-
-static inline void clear_ti_thread_flag(struct thread_info *ti, int flag)
-{
- clear_bit(flag, (unsigned long *)&ti->flags);
-}
-
-static inline int test_and_set_ti_thread_flag(struct thread_info *ti, int flag)
-{
- return test_and_set_bit(flag, (unsigned long *)&ti->flags);
-}
-
-static inline int test_and_clear_ti_thread_flag(struct thread_info *ti, int flag)
-{
- return test_and_clear_bit(flag, (unsigned long *)&ti->flags);
-}
-
-static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
-{
- return test_bit(flag, (unsigned long *)&ti->flags);
-}
-
-#define set_thread_flag(flag) \
- set_ti_thread_flag(current_thread_info(), flag)
-#define clear_thread_flag(flag) \
- clear_ti_thread_flag(current_thread_info(), flag)
-#define test_and_set_thread_flag(flag) \
- test_and_set_ti_thread_flag(current_thread_info(), flag)
-#define test_and_clear_thread_flag(flag) \
- test_and_clear_ti_thread_flag(current_thread_info(), flag)
-#define test_thread_flag(flag) \
- test_ti_thread_flag(current_thread_info(), flag)
-
#define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED)

#ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES
--
2.11.0