trafgen: setup_shared_var: fix couple of things

1) Fix a couple of sparse warnings:
 trafgen.c:382:27: error: cannot size expression
 trafgen.c:391:33: error: cannot size expression
 trafgen.c:393:33: error: cannot size expression
 trafgen.c:401:25: error: cannot size expression
2) Use MAP_FAILED instead of (void *) -1
3) No need to cast to void * on mmap(2)
4) Use NULL instead of 0 as mmap(2)'s first argument

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/trafgen.c b/trafgen.c
index 3457bfd..726959b 100644
--- a/trafgen.c
+++ b/trafgen.c
@@ -376,10 +376,11 @@ static void apply_csum16(int csum_id)
 static struct cpu_stats *setup_shared_var(unsigned long cpus)
 {
 	int fd;
-	char zbuff[cpus * sizeof(struct cpu_stats)], file[256];
+	size_t len = cpus * sizeof(struct cpu_stats);
+	char zbuff[len], file[256];
 	struct cpu_stats *buff;
 
-	fmemset(zbuff, 0, sizeof(zbuff));
+	fmemset(zbuff, 0, len);
 	slprintf(file, sizeof(file), ".tmp_mmap.%u", (unsigned int) rand());
 
 	fd = creat(file, S_IRUSR | S_IWUSR);
@@ -390,9 +391,9 @@ static struct cpu_stats *setup_shared_var(unsigned long cpus)
 			   S_IRUSR | S_IWUSR);
 	write_or_die(fd, zbuff, sizeof(zbuff));
 
-	buff = (void *) mmap(0, sizeof(zbuff), PROT_READ | PROT_WRITE,
-			     MAP_SHARED, fd, 0);
-	if (buff == (void *) -1)
+	buff = mmap(NULL, sizeof(zbuff), PROT_READ | PROT_WRITE,
+		    MAP_SHARED, fd, 0);
+	if (buff == MAP_FAILED)
 		panic("Cannot setup shared variable!\n");
 
 	close(fd);