selftests/net: use MAP_FAILED instead of (void *)-1 in tcp_mmap

mmap() is documented to return MAP_FAILED on error, but tcp_mmap.c
compares the return value against (void *)-1 and (unsigned char *)-1.

Replace these with the standard MAP_FAILED macro for better readability
and type safety.

Signed-off-by: longlong yan <yanlonglong@kylinos.cn>
Reviewed-by: Joe Damato <joe@dama.to>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260722015129.916-1-yanlonglong@kylinos.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions