[PATCH] aoe: improve allowed interfaces configuration

improve allowed interfaces configuration
Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff -uprN a/Documentation/aoe/aoe.txt b/Documentation/aoe/aoe.txt

Documentation/aoe/aoe.txt

@@ -33,6 +33,9 @@ USING DEVICE NODES
   "cat /dev/etherd/err" blocks, waiting for error diagnostic output,
   like any retransmitted packets.
 
+  The /dev/etherd/interfaces special file is obsoleted by the
+  aoe_iflist boot option and module option (and its sysfs entry
+  described in the next section).
   "echo eth2 eth4 > /dev/etherd/interfaces" tells the aoe driver to
   limit ATA over Ethernet traffic to eth2 and eth4.  AoE traffic from
   untrusted networks should be ignored as a matter of security.
@@ -89,3 +92,23 @@ USING SYSFS
       e4.7            eth1              up
       e4.8            eth1              up
       e4.9            eth1              up
+
+  Use /sys/module/aoe/parameters/aoe_iflist (or better, the driver
+  option discussed below) instead of /dev/etherd/interfaces to limit
+  AoE traffic to the network interfaces in the given
+  whitespace-separated list.  Unlike the old character device, the
+  sysfs entry can be read from as well as written to.
+
+  It's helpful to trigger discovery after setting the list of allowed
+  interfaces.  If your distro provides an aoe-discover script, you can
+  use that.  Otherwise, you can directly use the /dev/etherd/discover
+  file described above.
+
+DRIVER OPTIONS
+
+  There is a boot option for the built-in aoe driver and a
+  corresponding module parameter, aoe_iflist.  Without this option,
+  all network interfaces may be used for ATA over Ethernet.  Here is a
+  usage example for the module parameter.
+
+    modprobe aoe_iflist="eth1 eth3"

drivers/block/aoe/aoenet.c

@@ -7,6 +7,7 @@
 #include <linux/hdreg.h>
 #include <linux/blkdev.h>
 #include <linux/netdevice.h>
+#include <linux/moduleparam.h>
 #include "aoe.h"
 
 #define NECODES 5
@@ -26,6 +27,19 @@ enum {
 };
 
 static char aoe_iflist[IFLISTSZ];
+module_param_string(aoe_iflist, aoe_iflist, IFLISTSZ, 0600);
+MODULE_PARM_DESC(aoe_iflist, "aoe_iflist=\"dev1 [dev2 ...]\"\n");
+
+#ifndef MODULE
+static int __init aoe_iflist_setup(char *str)
+{
+	strncpy(aoe_iflist, str, IFLISTSZ);
+	aoe_iflist[IFLISTSZ - 1] = '\0';
+	return 1;
+}
+
+__setup("aoe_iflist=", aoe_iflist_setup);
+#endif
 
 int
 is_aoe_netif(struct net_device *ifp)
@@ -36,7 +50,8 @@ is_aoe_netif(struct net_device *ifp)
 	if (aoe_iflist[0] == '\0')
 		return 1;
 
-	for (p = aoe_iflist; *p; p = q + strspn(q, WHITESPACE)) {
+	p = aoe_iflist + strspn(aoe_iflist, WHITESPACE);
+	for (; *p; p = q + strspn(q, WHITESPACE)) {
 		q = p + strcspn(p, WHITESPACE);
 		if (q != p)
 			len = q - p;