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authorPavel Emelyanov <xemul@parallels.com>2013-06-11 14:41:24 +0400
committerDavid S. Miller <davem@davemloft.net>2013-06-12 15:07:21 -0700
commit274038f8c94c493e2977983e2aecb5f5f0778479 (patch)
tree59c639c040acb5af3eafe2a2eb7787c03dd5bfbf
parent7c0cadc69ca2ac8893aa162ee80d92a805840909 (diff)
tun: Report "persist" flag to userspace
The TUN_PERSIST flag is not reported at all -- both TUNGETIFF, and sysfs "flags" attribute skip one. Knowing whether a device is persistent or not is critical for checkpoint-restore, thus I propose to add the read-only IFF_PERSIST one for this. Setting this new IFF_PERSIST is hardly possible, as TUNSETIFF doesn't check for unknown flags being zero and thus there can be trash. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/tun.c3
-rw-r--r--include/uapi/linux/if_tun.h2
2 files changed, 5 insertions, 0 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 89776c59215..b90a73165d3 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1530,6 +1530,9 @@ static int tun_flags(struct tun_struct *tun)
if (tun->flags & TUN_TAP_MQ)
flags |= IFF_MULTI_QUEUE;
+ if (tun->flags & TUN_PERSIST)
+ flags |= IFF_PERSIST;
+
return flags;
}
diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h
index 2835b85fd46..82334f88967 100644
--- a/include/uapi/linux/if_tun.h
+++ b/include/uapi/linux/if_tun.h
@@ -68,6 +68,8 @@
#define IFF_MULTI_QUEUE 0x0100
#define IFF_ATTACH_QUEUE 0x0200
#define IFF_DETACH_QUEUE 0x0400
+/* read-only flag */
+#define IFF_PERSIST 0x0800
/* Features for GSO (TUNSETOFFLOAD). */
#define TUN_F_CSUM 0x01 /* You can hand me unchecksummed packets. */