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[net-next,v2] tools: ynl: improve the direct-include header guard logic

Message ID 20230621231719.2728928-1-kuba@kernel.org (mailing list archive)
State Accepted
Commit 0c3d6fd4b89c1a6393283249cdd0bd484ad8f2e5
Delegated to: Netdev Maintainers
Headers show
Series [net-next,v2] tools: ynl: improve the direct-include header guard logic | expand

Checks

Context Check Description
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 8 this patch: 8
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang success Errors and warnings before: 8 this patch: 8
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 8 this patch: 8
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 26 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Jakub Kicinski June 21, 2023, 11:17 p.m. UTC 
Przemek suggests that I shouldn't accuse GCC of witchcraft,
there is a simpler explanation for why we need manual define.

scripts/headers_install.sh modifies the guard, removing _UAPI.
That's why including a kernel header from the tree and from
/usr leads to duplicate definitions.

This also solves the mystery of why I needed to include
the header conditionally. I had the wrong guards for most
cases but ethtool.

Suggested-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
v2:
 - drop the HASH variable, too
v1: https://lore.kernel.org/all/20230616031252.2306420-1-kuba@kernel.org/
---
 tools/net/ynl/Makefile.deps | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org June 23, 2023, 2:50 a.m. UTC | #1 
Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Wed, 21 Jun 2023 16:17:19 -0700 you wrote:
> Przemek suggests that I shouldn't accuse GCC of witchcraft,
> there is a simpler explanation for why we need manual define.
> 
> scripts/headers_install.sh modifies the guard, removing _UAPI.
> That's why including a kernel header from the tree and from
> /usr leads to duplicate definitions.
> 
> [...]

Here is the summary with links:
  - [net-next,v2] tools: ynl: improve the direct-include header guard logic
    https://git.kernel.org/netdev/net-next/c/0c3d6fd4b89c

You are awesome, thank you!
diff mbox series

Patch

diff --git a/tools/net/ynl/Makefile.deps b/tools/net/ynl/Makefile.deps
index 524fc4bb586b..f842bc66b967 100644
--- a/tools/net/ynl/Makefile.deps
+++ b/tools/net/ynl/Makefile.deps
@@ -9,20 +9,12 @@ 
 
 UAPI_PATH:=../../../../include/uapi/
 
-# If the header does not exist at all in the system path - let the
-# compiler fall back to the kernel header via -Idirafter.
-# GCC seems to ignore header guard if the header is different, so we need
-# to specify the -D$(hdr_guard).
-# And we need to define HASH indirectly because GNU Make 4.2 wants it escaped
-# and Gnu Make 4.4 wants it without escaping.
+# scripts/headers_install.sh strips "_UAPI" from header guards so we
+# need the explicit -D matching what's in /usr, to avoid multiple definitions.
 
-HASH := \#
+get_hdr_inc=-D$(1) -include $(UAPI_PATH)/linux/$(2)
 
-get_hdr_inc=$(if $(shell echo "$(HASH)include <linux/$(2)>" | \
-			 cpp >>/dev/null 2>/dev/null && echo yes),\
-		-D$(1) -include $(UAPI_PATH)/linux/$(2))
-
-CFLAGS_devlink:=$(call get_hdr_inc,_UAPI_LINUX_DEVLINK_H_,devlink.h)
+CFLAGS_devlink:=$(call get_hdr_inc,_LINUX_DEVLINK_H_,devlink.h)
 CFLAGS_ethtool:=$(call get_hdr_inc,_LINUX_ETHTOOL_NETLINK_H_,ethtool_netlink.h)
-CFLAGS_handshake:=$(call get_hdr_inc,_UAPI_LINUX_HANDSHAKE_H,handshake.h)
-CFLAGS_netdev:=$(call get_hdr_inc,_UAPI_LINUX_NETDEV_H,netdev.h)
+CFLAGS_handshake:=$(call get_hdr_inc,_LINUX_HANDSHAKE_H,handshake.h)
+CFLAGS_netdev:=$(call get_hdr_inc,_LINUX_NETDEV_H,netdev.h)