[PATCH v2 2/2] perf: Fix version kernel tag

[John Garry <john.garry@huawei.com>]

Generating the version kernel tag relies on "git describe" command to get
the latest Linus kernel tag.

However, when working from clones of Linus' git we may not have the latest
tag. For example, when working on Arnaldo's acme.git, we can have this:
$git branch
perf/core
$head -n 5 ../../Makefile
head -n 5 ../../Makefile  | tail -n 4
VERSION = 5
PATCHLEVEL = 17
SUBLEVEL = 0
EXTRAVERSION = -rc3
$ git describe --abbrev=0 --match "v[0-9].[0-9]*"
v4.13-rc5

Indeed using tags is a problem as it relies on tags being pulled from
Linus' git (and pushed to the clone).

In commit a4147f0f9138 ("perf tools: Fix perf version generation"), Robert
introduced a change to use the kernelversion rule to generate the kernel
tag when no git tags are available. However, as mentioned above, the tag we
generate may be incorrect, so just always use kernelversion to get the tag
(apart from building perf out of tree).

Signed-off-by: John Garry <john.garry@huawei.com>
---
 tools/perf/util/PERF-VERSION-GEN | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/tools/perf/util/PERF-VERSION-GEN b/tools/perf/util/PERF-VERSION-GEN
index 59241ff342be..0ee5af529238 100755
--- a/tools/perf/util/PERF-VERSION-GEN
+++ b/tools/perf/util/PERF-VERSION-GEN
@@ -11,23 +11,18 @@ LF='
 '
 
 #
-# First check if there is a .git to get the version from git describe
-# otherwise try to get the version from the kernel Makefile
+# Always try first to get the version from the kernel Makefile
 #
 CID=
 TAG=
 if test -d ../../.git -o -f ../../.git
 then
-	TAG=$(git describe --abbrev=0 --match "v[0-9].[0-9]*" 2>/dev/null )
+	TAG=$(MAKEFLAGS= make -sC ../.. kernelversion)
 	CID=$(git log -1 --abbrev=12 --pretty=format:"%h" 2>/dev/null) && CID="-g$CID"
-elif test -f ../../PERF-VERSION-FILE
-then
+else
 	TAG=$(cut -d' ' -f3 ../../PERF-VERSION-FILE | sed -e 's/\"//g')
 fi
-if test -z "$TAG"
-then
-	TAG=$(MAKEFLAGS= make -sC ../.. kernelversion)
-fi
+
 VN="$TAG$CID"
 if test -n "$CID"
 then
-- 
2.26.2