Merge branch 'libbpf-include-path'

Toke Høiland-Jørgensen says:

====================
We are currently being somewhat inconsistent with the libbpf include paths,
which makes it difficult to move files from the kernel into an external
libbpf-using project without adjusting include paths.

Having the bpf/ subdir of $INCLUDEDIR in the include path has never been a
requirement for building against libbpf before, and indeed the libbpf pkg-config
file doesn't include it. So let's make all libbpf includes across the kernel
tree use the bpf/ prefix in their includes. Since bpftool skeleton generation
emits code with a libbpf include, this also ensures that those can be used in
existing external projects using the regular pkg-config include path.

This turns out to be a somewhat invasive change in the number of files touched;
however, the actual changes to files are fairly trivial (most of them are simply
made with 'sed'). The series is split to make the change for one tool subdir at
a time, while trying not to break the build along the way. It is structured like
this:

- Patch 1-3: Trivial fixes to Makefiles for issues I discovered while changing
  the include paths.

- Patch 4-8: Change the include directives to use the bpf/ prefix, and updates
  Makefiles to make sure tools/lib/ is part of the include path, but without
  removing tools/lib/bpf

- Patch 9-11: Remove tools/lib/bpf from include paths to make sure we don't
  inadvertently re-introduce includes without the bpf/ prefix.

Changelog:

v5:
  - Combine the libbpf build rules in selftests Makefile (using Andrii's
    suggestion for a make rule).
  - Re-use self-tests libbpf build for runqslower (new patch 10)
  - Formatting fixes

v4:
  - Move runqslower error on missing BTF into make rule
  - Make sure we don't always force a rebuild selftests
  - Rebase on latest bpf-next (dropping patch 11)

v3:
  - Don't add the kernel build dir to the runqslower Makefile, pass it in from
    selftests instead.
  - Use libbpf's 'make install_headers' in selftests instead of trying to
    generate bpf_helper_defs.h in-place (to also work on read-only filesystems).
  - Use a scratch builddir for both libbpf and bpftool when building in selftests.
  - Revert bpf_helpers.h to quoted include instead of angled include with a bpf/
    prefix.
  - Fix a few style nits from Andrii

v2:
  - Do a full cleanup of libbpf includes instead of just changing the
    bpf_helper_defs.h include.
====================

Acked-by: Andrii Nakryiko <andriin@fb.com>
Tested-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

20 files changed, 58 insertions, 54 deletions

diff --git a/tools/bpf/bpftool/Documentation/bpftool-gen.rst b/tools/bpf/bpftool/Documentation/bpftool-gen.rst
index 86a87da97d0b..94d91322895a 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-gen.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-gen.rst
@@ -196,7 +196,7 @@ and global variables.
   #define __EXAMPLE_SKEL_H__
 
   #include <stdlib.h>
-  #include <libbpf.h>
+  #include <bpf/libbpf.h>
 
   struct example {
   	struct bpf_object_skeleton *skeleton;
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index 39bc6f0f4f0b..c4e810335810 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -45,7 +45,7 @@ CFLAGS += -DPACKAGE='"bpftool"' -D__EXPORTED_HEADERS__ \
 	-I$(srctree)/kernel/bpf/ \
 	-I$(srctree)/tools/include \
 	-I$(srctree)/tools/include/uapi \
-	-I$(srctree)/tools/lib/bpf \
+	-I$(srctree)/tools/lib \
 	-I$(srctree)/tools/perf
 CFLAGS += -DBPFTOOL_VERSION='"$(BPFTOOL_VERSION)"'
 ifneq ($(EXTRA_CFLAGS),)
diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
index 60c75be0666d..4ba90d81b6a1 100644
--- a/tools/bpf/bpftool/btf.c
+++ b/tools/bpf/bpftool/btf.c
@@ -8,15 +8,15 @@
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
-#include <bpf.h>
-#include <libbpf.h>
+#include <bpf/bpf.h>
+#include <bpf/btf.h>
+#include <bpf/libbpf.h>
 #include <linux/btf.h>
 #include <linux/hashtable.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
 
-#include "btf.h"
 #include "json_writer.h"
 #include "main.h"
 
@@ -532,7 +532,7 @@ static int do_dump(int argc, char **argv)
 		if (IS_ERR(btf)) {
 			err = PTR_ERR(btf);
 			btf = NULL;
-			p_err("failed to load BTF from %s: %s", 
+			p_err("failed to load BTF from %s: %s",
 			      *argv, strerror(err));
 			goto done;
 		}
diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
index d66131f69689..eb4a142016a0 100644
--- a/tools/bpf/bpftool/btf_dumper.c
+++ b/tools/bpf/bpftool/btf_dumper.c
@@ -8,8 +8,8 @@
 #include <linux/bitops.h>
 #include <linux/btf.h>
 #include <linux/err.h>
+#include <bpf/btf.h>
 
-#include "btf.h"
 #include "json_writer.h"
 #include "main.h"
 
diff --git a/tools/bpf/bpftool/cgroup.c b/tools/bpf/bpftool/cgroup.c
index 2f017caa678d..62c6a1d7cd18 100644
--- a/tools/bpf/bpftool/cgroup.c
+++ b/tools/bpf/bpftool/cgroup.c
@@ -14,7 +14,7 @@
 #include <sys/types.h>
 #include <unistd.h>
 
-#include <bpf.h>
+#include <bpf/bpf.h>
 
 #include "main.h"
 
diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index 88264abaa738..b75b8ec5469c 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -20,8 +20,8 @@
 #include <sys/stat.h>
 #include <sys/vfs.h>
 
-#include <bpf.h>
-#include <libbpf.h> /* libbpf_num_possible_cpus */
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h> /* libbpf_num_possible_cpus */
 
 #include "main.h"
 
diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
index 94735d968c34..446ba891f1e2 100644
--- a/tools/bpf/bpftool/feature.c
+++ b/tools/bpf/bpftool/feature.c
@@ -12,8 +12,8 @@
 #include <linux/filter.h>
 #include <linux/limits.h>
 
-#include <bpf.h>
-#include <libbpf.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
 #include <zlib.h>
 
 #include "main.h"
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index 7ce09a9a6999..f8113b3646f5 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -12,15 +12,15 @@
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
-#include <bpf.h>
-#include <libbpf.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/mman.h>
 #include <unistd.h>
+#include <bpf/btf.h>
 
-#include "btf.h"
-#include "libbpf_internal.h"
+#include "bpf/libbpf_internal.h"
 #include "json_writer.h"
 #include "main.h"
 
@@ -333,7 +333,7 @@ static int do_skeleton(int argc, char **argv)
 		#define %2$s						    \n\
 									    \n\
 		#include <stdlib.h>					    \n\
-		#include <libbpf.h>					    \n\
+		#include <bpf/libbpf.h>					    \n\
 									    \n\
 		struct %1$s {						    \n\
 			struct bpf_object_skeleton *skeleton;		    \n\
diff --git a/tools/bpf/bpftool/jit_disasm.c b/tools/bpf/bpftool/jit_disasm.c
index bfed711258ce..f7f5885aa3ba 100644
--- a/tools/bpf/bpftool/jit_disasm.c
+++ b/tools/bpf/bpftool/jit_disasm.c
@@ -24,7 +24,7 @@
 #include <dis-asm.h>
 #include <sys/stat.h>
 #include <limits.h>
-#include <libbpf.h>
+#include <bpf/libbpf.h>
 
 #include "json_writer.h"
 #include "main.h"
diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index 1fe91c558508..6d41bbfc6459 100644
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -9,8 +9,8 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include <bpf.h>
-#include <libbpf.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
 
 #include "main.h"
 
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 86f8ab0b7e63..e6c85680b34d 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -15,9 +15,9 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 
-#include <bpf.h>
+#include <bpf/bpf.h>
+#include <bpf/btf.h>
 
-#include "btf.h"
 #include "json_writer.h"
 #include "main.h"
 
diff --git a/tools/bpf/bpftool/map_perf_ring.c b/tools/bpf/bpftool/map_perf_ring.c
index 4c5531d1a450..d9b29c17fbb8 100644
--- a/tools/bpf/bpftool/map_perf_ring.c
+++ b/tools/bpf/bpftool/map_perf_ring.c
@@ -6,7 +6,7 @@
  */
 #include <errno.h>
 #include <fcntl.h>
-#include <libbpf.h>
+#include <bpf/libbpf.h>
 #include <poll.h>
 #include <signal.h>
 #include <stdbool.h>
@@ -21,7 +21,7 @@
 #include <sys/mman.h>
 #include <sys/syscall.h>
 
-#include <bpf.h>
+#include <bpf/bpf.h>
 #include <perf-sys.h>
 
 #include "main.h"
diff --git a/tools/bpf/bpftool/net.c b/tools/bpf/bpftool/net.c
index d93bee298e54..c5e3895b7c8b 100644
--- a/tools/bpf/bpftool/net.c
+++ b/tools/bpf/bpftool/net.c
@@ -7,7 +7,8 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#include <libbpf.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
 #include <net/if.h>
 #include <linux/if.h>
 #include <linux/rtnetlink.h>
@@ -16,9 +17,8 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
-#include <bpf.h>
-#include <nlattr.h>
-#include "libbpf_internal.h"
+#include "bpf/nlattr.h"
+#include "bpf/libbpf_internal.h"
 #include "main.h"
 #include "netlink_dumper.h"
 
diff --git a/tools/bpf/bpftool/netlink_dumper.c b/tools/bpf/bpftool/netlink_dumper.c
index 550a0f537eed..5f65140b003b 100644
--- a/tools/bpf/bpftool/netlink_dumper.c
+++ b/tools/bpf/bpftool/netlink_dumper.c
@@ -3,11 +3,11 @@
 
 #include <stdlib.h>
 #include <string.h>
-#include <libbpf.h>
+#include <bpf/libbpf.h>
 #include <linux/rtnetlink.h>
 #include <linux/tc_act/tc_bpf.h>
 
-#include <nlattr.h>
+#include "bpf/nlattr.h"
 #include "main.h"
 #include "netlink_dumper.h"
 
diff --git a/tools/bpf/bpftool/perf.c b/tools/bpf/bpftool/perf.c
index b2046f33e23f..3341aa14acda 100644
--- a/tools/bpf/bpftool/perf.c
+++ b/tools/bpf/bpftool/perf.c
@@ -13,7 +13,7 @@
 #include <unistd.h>
 #include <ftw.h>
 
-#include <bpf.h>
+#include <bpf/bpf.h>
 
 #include "main.h"
 
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 47a61ac42dc0..a3521deca869 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -17,9 +17,9 @@
 #include <linux/err.h>
 #include <linux/sizes.h>
 
-#include <bpf.h>
-#include <btf.h>
-#include <libbpf.h>
+#include <bpf/bpf.h>
+#include <bpf/btf.h>
+#include <bpf/libbpf.h>
 
 #include "cfg.h"
 #include "main.h"
diff --git a/tools/bpf/bpftool/xlated_dumper.c b/tools/bpf/bpftool/xlated_dumper.c
index 5b91ee65a080..8608cd68cdd0 100644
--- a/tools/bpf/bpftool/xlated_dumper.c
+++ b/tools/bpf/bpftool/xlated_dumper.c
@@ -7,7 +7,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
-#include <libbpf.h>
+#include <bpf/libbpf.h>
 
 #include "disasm.h"
 #include "json_writer.h"
diff --git a/tools/bpf/runqslower/Makefile b/tools/bpf/runqslower/Makefile
index cff2fbcd29a8..faf5418609ea 100644
--- a/tools/bpf/runqslower/Makefile
+++ b/tools/bpf/runqslower/Makefile
@@ -6,17 +6,16 @@ LLVM_STRIP := llvm-strip
 DEFAULT_BPFTOOL := $(OUTPUT)/sbin/bpftool
 BPFTOOL ?= $(DEFAULT_BPFTOOL)
 LIBBPF_SRC := $(abspath ../../lib/bpf)
+BPFOBJ := $(OUTPUT)/libbpf.a
+BPF_INCLUDE := $(OUTPUT)
+INCLUDES := -I$(BPF_INCLUDE) -I$(OUTPUT) -I$(abspath ../../lib)
 CFLAGS := -g -Wall
 
 # Try to detect best kernel BTF source
 KERNEL_REL := $(shell uname -r)
-ifneq ("$(wildcard /sys/kernel/btf/vmlinux)","")
-VMLINUX_BTF := /sys/kernel/btf/vmlinux
-else ifneq ("$(wildcard /boot/vmlinux-$(KERNEL_REL))","")
-VMLINUX_BTF := /boot/vmlinux-$(KERNEL_REL)
-else
-$(error "Can't detect kernel BTF, use VMLINUX_BTF to specify it explicitly")
-endif
+VMLINUX_BTF_PATHS := /sys/kernel/btf/vmlinux /boot/vmlinux-$(KERNEL_REL)
+VMLINUX_BTF_PATH := $(or $(VMLINUX_BTF),$(firstword			       \
+					  $(wildcard $(VMLINUX_BTF_PATHS))))
 
 abs_out := $(abspath $(OUTPUT))
 ifeq ($(V),1)
@@ -40,7 +39,7 @@ clean:
 	$(call msg,CLEAN)
 	$(Q)rm -rf $(OUTPUT) runqslower
 
-$(OUTPUT)/runqslower: $(OUTPUT)/runqslower.o $(OUTPUT)/libbpf.a
+$(OUTPUT)/runqslower: $(OUTPUT)/runqslower.o $(BPFOBJ)
 	$(call msg,BINARY,$@)
 	$(Q)$(CC) $(CFLAGS) -lelf -lz $^ -o $@
 
@@ -53,27 +52,32 @@ $(OUTPUT)/%.skel.h: $(OUTPUT)/%.bpf.o | $(BPFTOOL)
 	$(call msg,GEN-SKEL,$@)
 	$(Q)$(BPFTOOL) gen skeleton $< > $@
 
-$(OUTPUT)/%.bpf.o: %.bpf.c $(OUTPUT)/libbpf.a | $(OUTPUT)
+$(OUTPUT)/%.bpf.o: %.bpf.c $(BPFOBJ) | $(OUTPUT)
 	$(call msg,BPF,$@)
-	$(Q)$(CLANG) -g -O2 -target bpf -I$(OUTPUT) -I$(LIBBPF_SRC)	      \
+	$(Q)$(CLANG) -g -O2 -target bpf $(INCLUDES)			      \
 		 -c $(filter %.c,$^) -o $@ &&				      \
 	$(LLVM_STRIP) -g $@
 
 $(OUTPUT)/%.o: %.c | $(OUTPUT)
 	$(call msg,CC,$@)
-	$(Q)$(CC) $(CFLAGS) -I$(LIBBPF_SRC) -I$(OUTPUT) -c $(filter %.c,$^) -o $@
+	$(Q)$(CC) $(CFLAGS) $(INCLUDES) -c $(filter %.c,$^) -o $@
 
 $(OUTPUT):
 	$(call msg,MKDIR,$@)
 	$(Q)mkdir -p $(OUTPUT)
 
-$(OUTPUT)/vmlinux.h: $(VMLINUX_BTF) | $(OUTPUT) $(BPFTOOL)
+$(OUTPUT)/vmlinux.h: $(VMLINUX_BTF_PATH) | $(OUTPUT) $(BPFTOOL)
 	$(call msg,GEN,$@)
-	$(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@
-
-$(OUTPUT)/libbpf.a: | $(OUTPUT)
+	$(Q)if [ ! -e "$(VMLINUX_BTF_PATH)" ] ; then \
+		echo "Couldn't find kernel BTF; set VMLINUX_BTF to"	       \
+			"specify its location." >&2;			       \
+		exit 1;\
+	fi
+	$(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF_PATH) format c > $@
+
+$(BPFOBJ): | $(OUTPUT)
 	$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC)			       \
-		    OUTPUT=$(abs_out)/ $(abs_out)/libbpf.a
+		    OUTPUT=$(abspath $(dir $@))/ $(abspath $@)
 
 $(DEFAULT_BPFTOOL):
 	$(Q)$(MAKE) $(submake_extras) -C ../bpftool			      \
diff --git a/tools/bpf/runqslower/runqslower.bpf.c b/tools/bpf/runqslower/runqslower.bpf.c
index 623cce4d37f5..48a39f72fadf 100644
--- a/tools/bpf/runqslower/runqslower.bpf.c
+++ b/tools/bpf/runqslower/runqslower.bpf.c
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 // Copyright (c) 2019 Facebook
 #include "vmlinux.h"
-#include <bpf_helpers.h>
+#include <bpf/bpf_helpers.h>
 #include "runqslower.h"
 
 #define TASK_RUNNING 0
diff --git a/tools/bpf/runqslower/runqslower.c b/tools/bpf/runqslower/runqslower.c
index 996f0e2c560e..d89715844952 100644
--- a/tools/bpf/runqslower/runqslower.c
+++ b/tools/bpf/runqslower/runqslower.c
@@ -6,8 +6,8 @@
 #include <string.h>
 #include <sys/resource.h>
 #include <time.h>
-#include <libbpf.h>
-#include <bpf.h>
+#include <bpf/libbpf.h>
+#include <bpf/bpf.h>
 #include "runqslower.h"
 #include "runqslower.skel.h"