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authorChris Mason <chris.mason@oracle.com>2010-04-22 21:59:15 -0400
committerAndy Grover <andy.grover@oracle.com>2010-09-08 18:12:28 -0700
commit764f2dd92f5cd308d1c4372b33fea2b265c093f5 (patch)
treef979329a2b5bfb0c92fc83e951d9ac7654c4ba78 /net/rds/ib_rdma.c
parentc83188dcd76b1f0c17c31b4bbd8de57c634b19f8 (diff)
downloadlinux-764f2dd92f5cd308d1c4372b33fea2b265c093f5.tar.bz2
rds: rcu-ize rds_ib_get_device()
rds_ib_get_device is called very often as we turn an ip address into a corresponding device structure. It currently take a global spinlock as it walks different lists to find active devices. This commit changes the lists over to RCU, which isn't very complex because they are not updated very often at all. Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'net/rds/ib_rdma.c')
-rw-r--r--net/rds/ib_rdma.c24
1 files changed, 16 insertions, 8 deletions
diff --git a/net/rds/ib_rdma.c b/net/rds/ib_rdma.c
index 242231f09464..7240e583ee58 100644
--- a/net/rds/ib_rdma.c
+++ b/net/rds/ib_rdma.c
@@ -32,6 +32,7 @@
*/
#include <linux/kernel.h>
#include <linux/slab.h>
+#include <linux/rculist.h>
#include "rds.h"
#include "ib.h"
@@ -83,14 +84,14 @@ static struct rds_ib_device *rds_ib_get_device(__be32 ipaddr)
struct rds_ib_ipaddr *i_ipaddr;
list_for_each_entry(rds_ibdev, &rds_ib_devices, list) {
- spin_lock_irq(&rds_ibdev->spinlock);
- list_for_each_entry(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
if (i_ipaddr->ipaddr == ipaddr) {
- spin_unlock_irq(&rds_ibdev->spinlock);
+ rcu_read_unlock();
return rds_ibdev;
}
}
- spin_unlock_irq(&rds_ibdev->spinlock);
+ rcu_read_unlock();
}
return NULL;
@@ -107,7 +108,7 @@ static int rds_ib_add_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
i_ipaddr->ipaddr = ipaddr;
spin_lock_irq(&rds_ibdev->spinlock);
- list_add_tail(&i_ipaddr->list, &rds_ibdev->ipaddr_list);
+ list_add_tail_rcu(&i_ipaddr->list, &rds_ibdev->ipaddr_list);
spin_unlock_irq(&rds_ibdev->spinlock);
return 0;
@@ -116,16 +117,23 @@ static int rds_ib_add_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
static void rds_ib_remove_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
{
struct rds_ib_ipaddr *i_ipaddr, *next;
+ struct rds_ib_ipaddr *to_free = NULL;
+
spin_lock_irq(&rds_ibdev->spinlock);
- list_for_each_entry_safe(i_ipaddr, next, &rds_ibdev->ipaddr_list, list) {
+ list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
if (i_ipaddr->ipaddr == ipaddr) {
- list_del(&i_ipaddr->list);
- kfree(i_ipaddr);
+ list_del_rcu(&i_ipaddr->list);
+ to_free = i_ipaddr;
break;
}
}
spin_unlock_irq(&rds_ibdev->spinlock);
+
+ if (to_free) {
+ synchronize_rcu();
+ kfree(to_free);
+ }
}
int rds_ib_update_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)