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Date: Thu, 30 Aug 2012 18:03:52 +0300
From: "Michael S. Tsirkin" <mst@...hat.com>
To: Vlad Yasevich <vyasevic@...hat.com>
Cc: netdev@...r.kernel.org
Subject: Re: [RFC PATCH bridge 5/5] bridge: Add sysfs interface to display
VLANS
On Thu, Aug 30, 2012 at 10:51:35AM -0400, Vlad Yasevich wrote:
> On 08/30/2012 10:44 AM, Michael S. Tsirkin wrote:
> >On Thu, Aug 30, 2012 at 10:36:34AM -0400, Vlad Yasevich wrote:
> >>On 08/30/2012 10:26 AM, Michael S. Tsirkin wrote:
> >>>On Thu, Aug 30, 2012 at 10:05:16AM -0400, Vlad Yasevich wrote:
> >>>>On 08/30/2012 08:27 AM, Michael S. Tsirkin wrote:
> >>>>>On Thu, Aug 23, 2012 at 03:29:55PM -0400, Vlad Yasevich wrote:
> >>>>>>Add a binary sysfs file that will dump out vlans currently configured on the
> >>>>>>port.
> >>
> >>I initially though of creating a sysfs object per vlan. That would
> >>have made it easy to see which vlans are configured without any
> >>tools.
> >>But that could result in a lot of objects being created, so I abandoned it.
> >>
> >>I did think about a text interface, but due to a page of output
> >>limitation, I didn't go that route. The reason is that if someone
> >>cats the file, they may not see all the vlans configured. So I
> >>decided on the binary interface, since a binary interface with a
> >>tool to read it could avoid the single page limitation.
> >>
> >>-vlad
> >
> >Maybe it's not needed in sysfs then - expose it to
> >brctl or whatever.
> >
>
> brctl uses sysfs for almost everything any more :)
>
> -vlad
How about a long string of 0 and 1's?
And a separate one for untagged vlans.
> >>>
> >>>
> >>>>>
> >>>>>>---
> >>>>>> include/linux/if_bridge.h | 1 +
> >>>>>> net/bridge/br_if.c | 34 ++++++++++++++++++++++++++++++++++
> >>>>>> net/bridge/br_private.h | 2 ++
> >>>>>> net/bridge/br_sysfs_if.c | 28 ++++++++++++++++++++++++++++
> >>>>>> 4 files changed, 65 insertions(+), 0 deletions(-)
> >>>>>>
> >>>>>>diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
> >>>>>>index ab750dd..d0f869b 100644
> >>>>>>--- a/include/linux/if_bridge.h
> >>>>>>+++ b/include/linux/if_bridge.h
> >>>>>>@@ -20,6 +20,7 @@
> >>>>>> #define SYSFS_BRIDGE_PORT_SUBDIR "brif"
> >>>>>> #define SYSFS_BRIDGE_PORT_ATTR "brport"
> >>>>>> #define SYSFS_BRIDGE_PORT_LINK "bridge"
> >>>>>>+#define SYSFS_BRIDGE_PORT_VLANS "vlans"
> >>>>>>
> >>>>>> #define BRCTL_VERSION 1
> >>>>>>
> >>>>>>diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
> >>>>>>index 90c1038..3963748 100644
> >>>>>>--- a/net/bridge/br_if.c
> >>>>>>+++ b/net/bridge/br_if.c
> >>>>>>@@ -510,6 +510,40 @@ int br_del_port_vlan(struct net_bridge_port *p, unsigned long vlan)
> >>>>>> return 0;
> >>>>>> }
> >>>>>>
> >>>>>>+size_t br_port_fill_vlans(struct net_bridge_port *p, char* buf,
> >>>>>>+ unsigned long max, unsigned long skip)
> >>>>>>+{
> >>>>>>+ unsigned long *map;
> >>>>>>+ unsigned short *vid = (unsigned short *)buf;
> >>>>>>+ unsigned short i;
> >>>>>>+ int num = 0;
> >>>>>>+
> >>>>>>+ if (skip > (VLAN_N_VID+1))
> >>>>>>+ return -EINVAL;
> >>>>>>+
> >>>>>>+ memset(buf, 0, max * sizeof(unsigned short));
> >>>>>
> >>>>>Isn't max is in bytes? why is this safe?
> >>>>>
> >>>>>>+
> >>>>>>+ rcu_read_lock();
> >>>>>>+ map = rcu_dereference(p->vlan_map);
> >>>>>>+ if (!map)
> >>>>>>+ goto out;
> >>>>>>+
> >>>>>>+ for (i = skip + 1; i < VLAN_N_VID + 1; i++) {
> >>>>>
> >>>>>Isn't skip in bytes too? Why do you compare it to i which is
> >>>>>in dwords?
> >>>>>
> >>>>>>+ if (test_bit(i, map)) {
> >>>>>>+ if (num > max)
> >>>>>>+ goto out;
> >>>>>>+
> >>>>>>+ *vid = i-1;
> >>>>>>+ vid++;
> >>>>>>+ num++;
> >>>>>>+ }
> >>>>>>+ }
> >>>>>>+out:
> >>>>>>+ rcu_read_unlock();
> >>>>>>+
> >>>>>>+ return num*sizeof(unsigned short);
> >>>>>>+}
> >>>>>>+
> >>>>>> void __net_exit br_net_exit(struct net *net)
> >>>>>> {
> >>>>>> struct net_device *dev;
> >>>>>>diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
> >>>>>>index 5639c1c..cf95cd7 100644
> >>>>>>--- a/net/bridge/br_private.h
> >>>>>>+++ b/net/bridge/br_private.h
> >>>>>>@@ -404,6 +404,8 @@ extern netdev_features_t br_features_recompute(struct net_bridge *br,
> >>>>>> netdev_features_t features);
> >>>>>> extern int br_set_port_vlan(struct net_bridge_port *p, unsigned long vid);
> >>>>>> extern int br_del_port_vlan(struct net_bridge_port *p, unsigned long vid);
> >>>>>>+extern size_t br_port_fill_vlans(struct net_bridge_port *p, char *buf,
> >>>>>>+ unsigned long max, unsigned long skip);
> >>>>>>
> >>>>>> /* br_input.c */
> >>>>>> extern int br_handle_frame_finish(struct sk_buff *skb);
> >>>>>>diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c
> >>>>>>index 13b36bd..a81e2ef 100644
> >>>>>>--- a/net/bridge/br_sysfs_if.c
> >>>>>>+++ b/net/bridge/br_sysfs_if.c
> >>>>>>@@ -234,6 +234,29 @@ const struct sysfs_ops brport_sysfs_ops = {
> >>>>>> };
> >>>>>>
> >>>>>> /*
> >>>>>>+ * Export the vlan table for a given port as a binary file.
> >>>>>>+ * The records are unsgined shorts.
> >>>>>>+ *
> >>>>>>+ * Returns the number of bytes read.
> >>>>>>+ */
> >>>>>>+static ssize_t brport_vlans_read(struct file *filp, struct kobject *kobj,
> >>>>>>+ struct bin_attribute *bin_attr,
> >>>>>>+ char *buf, loff_t off, size_t count)
> >>>>>>+{
> >>>>>>+ struct net_bridge_port *p = to_brport(kobj);
> >>>>>>+
> >>>>>>+ return br_port_fill_vlans(p, buf,
> >>>>>>+ count/sizeof(unsigned short),
> >>>>>>+ off/sizeof(unsigned short));
> >>>>>>+}
> >>>>>>+
> >>>>>>+static struct bin_attribute port_vlans = {
> >>>>>>+ .attr = { .name = SYSFS_BRIDGE_PORT_VLANS,
> >>>>>>+ .mode = S_IRUGO, },
> >>>>>>+ .read = brport_vlans_read,
> >>>>>>+};
> >>>>>>+
> >>>>>>+/*
> >>>>>> * Add sysfs entries to ethernet device added to a bridge.
> >>>>>> * Creates a brport subdirectory with bridge attributes.
> >>>>>> * Puts symlink in bridge's brif subdirectory
> >>>>>>@@ -255,6 +278,11 @@ int br_sysfs_addif(struct net_bridge_port *p)
> >>>>>> return err;
> >>>>>> }
> >>>>>>
> >>>>>>+ err = sysfs_create_bin_file(&p->kobj, &port_vlans);
> >>>>>>+ if (err) {
> >>>>>>+ return err;
> >>>>>>+ }
> >>>>>>+
> >>>>>> strlcpy(p->sysfs_name, p->dev->name, IFNAMSIZ);
> >>>>>> return sysfs_create_link(br->ifobj, &p->kobj, p->sysfs_name);
> >>>>>> }
> >>>>>>--
> >>>>>>1.7.7.6
> >>>>>>
> >>>>>>--
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