driver: tun: Use new macro SOCK_IOC_TYPE instead of literal number 0x89

The current codes use _IOC_TYPE(cmd) == 0x89 to check if the cmd is one
socket ioctl command like SIOCGIFHWADDR. But the literal number 0x89 may
confuse readers. So create one macro SOCK_IOC_TYPE to enhance the readability.

Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 3 insertions, 1 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 9142db847ee1..1588469844e7 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1985,7 +1985,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
         int le;
         int ret;
 
-        if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
+        if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == SOCK_IOC_TYPE) {
                 if (copy_from_user(&ifr, argp, ifreq_len))
                         return -EFAULT;
         } else {
diff --git a/include/uapi/linux/sockios.h b/include/uapi/linux/sockios.h
index 83cc54ce6081..79d029d25310 100644
--- a/include/uapi/linux/sockios.h
+++ b/include/uapi/linux/sockios.h
@@ -24,6 +24,8 @@
 #define SIOCINQ         FIONREAD
 #define SIOCOUTQ        TIOCOUTQ        /* output queue size (not sent + not acked) */
 
+#define SOCK_IOC_TYPE   0x89
+
 /* Routing table calls. */
 #define SIOCADDRT       0x890B          /* add routing table entry      */
 #define SIOCDELRT       0x890C          /* delete routing table entry   */