[PATCH v2 2/3] selftests/mm: compaction_test: Fix incorrect write of zero to nr_hugepages

[Dev Jain <dev.jain@arm.com>]

Currently, the test tries to set nr_hugepages to zero, but that is not
actually done because the file offset is not reset after read(). Fix that
using lseek().

Fixes: bd67d5c15cc1 ("Test compaction of mlocked memory")
Cc: stable@vger.kernel.org
Signed-off-by: Dev Jain <dev.jain@arm.com>
---
 tools/testing/selftests/mm/compaction_test.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/testing/selftests/mm/compaction_test.c b/tools/testing/selftests/mm/compaction_test.c
index 0b249a06a60b..5e9bd1da9370 100644
--- a/tools/testing/selftests/mm/compaction_test.c
+++ b/tools/testing/selftests/mm/compaction_test.c
@@ -108,6 +108,8 @@ int check_compaction(unsigned long mem_free, unsigned long hugepage_size)
 		goto close_fd;
 	}
 
+	lseek(fd, 0, SEEK_SET);
+
 	/* Start with the initial condition of 0 huge pages*/
 	if (write(fd, "0", sizeof(char)) != sizeof(char)) {
 		ksft_print_msg("Failed to write 0 to /proc/sys/vm/nr_hugepages: %s\n",
-- 
2.34.1