[PATCH v2] samples/bpf: Add a workaround for asm_inline

[KP Singh]

From: KP Singh <kpsingh@xxxxxxxxxx>

This was added in:

  commit eb111869301e ("compiler-types.h: add asm_inline definition")

and breaks samples/bpf as clang does not support asm __inline.

Co-developed-by: Florent Revest <revest@xxxxxxxxxx>
Signed-off-by: Florent Revest <revest@xxxxxxxxxx>
Signed-off-by: KP Singh <kpsingh@xxxxxxxxxx>
---

Changes since v1:

- Dropped the rename from asm_workaround.h to asm_goto_workaround.h
- Dropped the fix for task_fd_query_user.c as it is updated in
  https://lore.kernel.org/bpf/20191001112249.27341-1-bjorn.topel@xxxxxxxxx/

 samples/bpf/asm_goto_workaround.h | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/samples/bpf/asm_goto_workaround.h b/samples/bpf/asm_goto_workaround.h
index 7409722727ca..7048bb3594d6 100644
--- a/samples/bpf/asm_goto_workaround.h
+++ b/samples/bpf/asm_goto_workaround.h
@@ -3,7 +3,8 @@
 #ifndef __ASM_GOTO_WORKAROUND_H
 #define __ASM_GOTO_WORKAROUND_H
 
-/* this will bring in asm_volatile_goto macro definition
+/*
+ * This will bring in asm_volatile_goto and asm_inline macro definitions
  * if enabled by compiler and config options.
  */
 #include <linux/types.h>
@@ -13,5 +14,15 @@
 #define asm_volatile_goto(x...) asm volatile("invalid use of asm_volatile_goto")
 #endif
 
+/*
+ * asm_inline is defined as asm __inline in "include/linux/compiler_types.h"
+ * if supported by the kernel's CC (i.e CONFIG_CC_HAS_ASM_INLINE) which is not
+ * supported by CLANG.
+ */
+#ifdef asm_inline
+#undef asm_inline
+#define asm_inline asm
+#endif
+
 #define volatile(x...) volatile("")
 #endif
-- 
2.20.1