If the shm file is removed and a subsequent close, only release shm
object, but inode is leaked. Should decrease refcount to release inode
when unmapped, that matched with refcount increase when mapped.
Another fix that remove the shm file failed.
nsh> rm /var/shm/pts_mmap_1_2_5
nsh: rm: unlink failed: 6
Signed-off-by: fangxinyong <fangxinyong@xiaomi.com>
ea52220509