Stephen Hemminger
2007-Apr-18 12:34 UTC
[Bridge] [PATCH] (6/11) bridge -- read forwarding table chunk at a time.
Change how the read of forwarding table works. Instead of copying
entries to user one at a time, use an intermediate kernel buffer and
do up to a page at a chunk.
This gets rid of some awkward code dealing with entries getting deleted
during the copy. And allows same function to be used by later sysfs
hook.
diff -Nru a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
--- a/net/bridge/br_fdb.c 2004-05-20 09:59:49 -07:00
+++ b/net/bridge/br_fdb.c 2004-05-20 09:59:49 -07:00
@@ -16,11 +16,10 @@
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/spinlock.h>
-#include <linux/if_bridge.h>
#include <linux/times.h>
+#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <asm/atomic.h>
-#include <asm/uaccess.h>
#include "br_private.h"
static kmem_cache_t *br_fdb_cache;
@@ -54,17 +53,6 @@
&& time_before_eq(fdb->ageing_timer + hold_time(br), jiffies);
}
-static inline void copy_fdb(struct __fdb_entry *ent,
- const struct net_bridge_fdb_entry *f)
-{
- memset(ent, 0, sizeof(struct __fdb_entry));
- memcpy(ent->mac_addr, f->addr.addr, ETH_ALEN);
- ent->port_no = f->dst?f->dst->port_no:0;
- ent->is_local = f->is_local;
- ent->ageing_timer_value = f->is_static ? 0
- : jiffies_to_clock_t(jiffies - f->ageing_timer);
-}
-
static __inline__ int br_mac_hash(const unsigned char *mac)
{
unsigned long x;
@@ -214,68 +202,48 @@
kmem_cache_free(br_fdb_cache, ent);
}
-int br_fdb_get_entries(struct net_bridge *br,
- unsigned char *_buf,
- int maxnum,
- int offset)
+/*
+ * Fill buffer with forwarding table records in
+ * the API format.
+ */
+int br_fdb_fillbuf(struct net_bridge *br, void *buf,
+ unsigned long maxnum, unsigned long skip)
{
- int i;
- int num;
- struct __fdb_entry *walk;
+ struct __fdb_entry *fe = buf;
+ int i, num = 0;
+ struct hlist_node *h;
+ struct net_bridge_fdb_entry *f;
- num = 0;
- walk = (struct __fdb_entry *)_buf;
+ memset(buf, 0, maxnum*sizeof(struct __fdb_entry));
read_lock_bh(&br->hash_lock);
- for (i=0;i<BR_HASH_SIZE;i++) {
- struct hlist_node *h;
-
- hlist_for_each(h, &br->hash[i]) {
- struct net_bridge_fdb_entry *f
- = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
- struct __fdb_entry ent;
-
+ for (i = 0; i < BR_HASH_SIZE; i++) {
+ hlist_for_each_entry(f, h, &br->hash[i], hlist) {
if (num >= maxnum)
goto out;
if (has_expired(br, f))
continue;
- if (offset) {
- offset--;
+ if (skip) {
+ --skip;
continue;
}
- copy_fdb(&ent, f);
-
- atomic_inc(&f->use_count);
- read_unlock_bh(&br->hash_lock);
-
- if (copy_to_user(walk, &ent, sizeof(struct __fdb_entry)))
- return -EFAULT;
-
- read_lock_bh(&br->hash_lock);
-
- /* entry was deleted during copy_to_user */
- if (atomic_dec_and_test(&f->use_count)) {
- kmem_cache_free(br_fdb_cache, f);
- num = -EAGAIN;
- goto out;
- }
-
- /* entry changed address hash while copying */
- if (br_mac_hash(f->addr.addr) != i) {
- num = -EAGAIN;
- goto out;
- }
-
- num++;
- walk++;
+ /* convert from internal format to API */
+ memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN);
+ fe->port_no = f->dst->port_no;
+ fe->is_local = f->is_local;
+ if (!f->is_static)
+ fe->ageing_timer_value = jiffies_to_clock_t(jiffies -
f->ageing_timer);
+ ++fe;
+ ++num;
}
}
out:
read_unlock_bh(&br->hash_lock);
+
return num;
}
diff -Nru a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c
--- a/net/bridge/br_ioctl.c 2004-05-20 09:59:49 -07:00
+++ b/net/bridge/br_ioctl.c 2004-05-20 09:59:49 -07:00
@@ -52,6 +52,39 @@
}
}
+/*
+ * Format up to a page worth of forwarding table entries
+ * userbuf -- where to copy result
+ * maxnum -- maximum number of entries desired
+ * (limited to a page for sanity)
+ * offset -- number of records to skip
+ */
+static int get_fdb_entries(struct net_bridge *br, void __user *userbuf,
+ unsigned long maxnum, unsigned long offset)
+{
+ int num;
+ void *buf;
+ size_t size = maxnum * sizeof(struct __fdb_entry);
+
+ if (size > PAGE_SIZE) {
+ size = PAGE_SIZE;
+ maxnum = PAGE_SIZE/sizeof(struct __fdb_entry);
+ }
+
+ buf = kmalloc(size, GFP_USER);
+ if (!buf)
+ return -ENOMEM;
+
+ num = br_fdb_fillbuf(br, buf, maxnum, offset);
+ if (num > 0) {
+ if (copy_to_user(userbuf, buf, num*sizeof(struct __fdb_entry)))
+ num = -EFAULT;
+ }
+ kfree(buf);
+
+ return num;
+}
+
int br_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
struct net_bridge *br = netdev_priv(dev);
@@ -270,7 +303,8 @@
}
case BRCTL_GET_FDB_ENTRIES:
- return br_fdb_get_entries(br, (void *)args[1], args[2], args[3]);
+ return get_fdb_entries(br, (void __user *)args[1],
+ args[2], args[3]);
}
return -EOPNOTSUPP;
diff -Nru a/net/bridge/br_private.h b/net/bridge/br_private.h
--- a/net/bridge/br_private.h 2004-05-20 09:59:49 -07:00
+++ b/net/bridge/br_private.h 2004-05-20 09:59:49 -07:00
@@ -135,10 +135,8 @@
extern struct net_bridge_fdb_entry *br_fdb_get(struct net_bridge *br,
unsigned char *addr);
extern void br_fdb_put(struct net_bridge_fdb_entry *ent);
-extern int br_fdb_get_entries(struct net_bridge *br,
- unsigned char *_buf,
- int maxnum,
- int offset);
+extern int br_fdb_fillbuf(struct net_bridge *br, void *buf,
+ unsigned long count, unsigned long off);
extern int br_fdb_insert(struct net_bridge *br,
struct net_bridge_port *source,
const unsigned char *addr,