Pinging for visibility
-Anish
________________________________________
From: Anish Bhatt [anish@xxxxxxxxxxx]
Sent: Monday, September 15, 2014 5:44 PM
To: linux-scsi@xxxxxxxxxxxxxxx
Cc: JBottomley@xxxxxxxxxxxxx; hch@xxxxxxxxxxxxx; Karen Xie; Manoj Malviya; Anish Bhatt
Subject: [PATCH scsi] cxgb4i : Avoid holding mutex in interrupt context
cxgbi_inet6addr_handler() can be called in interrupt context, so use rcu
protected list while finding netdev
Applies on top of core-for-3.18
Signed-off-by: Anish Bhatt <anish@xxxxxxxxxxx>
Signed-off-by: Karen Xie <kxie@xxxxxxxxxxx>
Fixes: fc8d0590d914 ("libcxgbi: Add ipv6 api to driver")
Fixes: 759a0cc5a3e1 ("cxgb4i: Add ipv6 code to driver, call into libcxgbi ipv6
api")
---
drivers/scsi/cxgbi/cxgb4i/cxgb4i.c | 2 +-
drivers/scsi/cxgbi/libcxgbi.c | 57 ++++++++++++++++++++++++++++++++++----
drivers/scsi/cxgbi/libcxgbi.h | 3 ++
3 files changed, 55 insertions(+), 7 deletions(-)
diff --git a/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c b/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c
index 79788a1..02e69e7 100644
--- a/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c
+++ b/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c
@@ -1647,7 +1647,7 @@ static int cxgbi_inet6addr_handler(struct notifier_block *this,
if (event_dev->priv_flags & IFF_802_1Q_VLAN)
event_dev = vlan_dev_real_dev(event_dev);
- cdev = cxgbi_device_find_by_netdev(event_dev, NULL);
+ cdev = cxgbi_device_find_by_netdev_rcu(event_dev, NULL);
if (!cdev)
return ret;
diff --git a/drivers/scsi/cxgbi/libcxgbi.c b/drivers/scsi/cxgbi/libcxgbi.c
index d65df6d..addd1dd 100644
--- a/drivers/scsi/cxgbi/libcxgbi.c
+++ b/drivers/scsi/cxgbi/libcxgbi.c
@@ -57,6 +57,9 @@ MODULE_PARM_DESC(dbg_level, "libiscsi debug level (default=0)");
static LIST_HEAD(cdev_list);
static DEFINE_MUTEX(cdev_mutex);
+static LIST_HEAD(cdev_rcu_list);
+static DEFINE_SPINLOCK(cdev_rcu_lock);
+
int cxgbi_device_portmap_create(struct cxgbi_device *cdev, unsigned int base,
unsigned int max_conn)
{
@@ -142,6 +145,10 @@ struct cxgbi_device *cxgbi_device_register(unsigned int extra,
list_add_tail(&cdev->list_head, &cdev_list);
mutex_unlock(&cdev_mutex);
+ spin_lock(&cdev_rcu_lock);
+ list_add_tail_rcu(&cdev->rcu_node, &cdev_rcu_list);
+ spin_unlock(&cdev_rcu_lock);
+
log_debug(1 << CXGBI_DBG_DEV,
"cdev 0x%p, p# %u.\n", cdev, nports);
return cdev;
@@ -153,9 +160,16 @@ void cxgbi_device_unregister(struct cxgbi_device *cdev)
log_debug(1 << CXGBI_DBG_DEV,
"cdev 0x%p, p# %u,%s.\n",
cdev, cdev->nports, cdev->nports ? cdev->ports[0]->name : "");
+
mutex_lock(&cdev_mutex);
list_del(&cdev->list_head);
mutex_unlock(&cdev_mutex);
+
+ spin_lock(&cdev_rcu_lock);
+ list_del_rcu(&cdev->rcu_node);
+ spin_unlock(&cdev_rcu_lock);
+ synchronize_rcu();
+
cxgbi_device_destroy(cdev);
}
EXPORT_SYMBOL_GPL(cxgbi_device_unregister);
@@ -167,12 +181,9 @@ void cxgbi_device_unregister_all(unsigned int flag)
mutex_lock(&cdev_mutex);
list_for_each_entry_safe(cdev, tmp, &cdev_list, list_head) {
if ((cdev->flags & flag) == flag) {
- log_debug(1 << CXGBI_DBG_DEV,
- "cdev 0x%p, p# %u,%s.\n",
- cdev, cdev->nports, cdev->nports ?
- cdev->ports[0]->name : "");
- list_del(&cdev->list_head);
- cxgbi_device_destroy(cdev);
+ mutex_unlock(&cdev_mutex);
+ cxgbi_device_unregister(cdev);
+ mutex_lock(&cdev_mutex);
}
}
mutex_unlock(&cdev_mutex);
@@ -191,6 +202,7 @@ struct cxgbi_device *cxgbi_device_find_by_lldev(void *lldev)
}
}
mutex_unlock(&cdev_mutex);
+
log_debug(1 << CXGBI_DBG_DEV,
"lldev 0x%p, NO match found.\n", lldev);
return NULL;
@@ -230,6 +242,39 @@ struct cxgbi_device *cxgbi_device_find_by_netdev(struct net_device *ndev,
}
EXPORT_SYMBOL_GPL(cxgbi_device_find_by_netdev);
+struct cxgbi_device *cxgbi_device_find_by_netdev_rcu(struct net_device *ndev,
+ int *port)
+{
+ struct net_device *vdev = NULL;
+ struct cxgbi_device *cdev;
+ int i;
+
+ if (ndev->priv_flags & IFF_802_1Q_VLAN) {
+ vdev = ndev;
+ ndev = vlan_dev_real_dev(ndev);
+ pr_info("vlan dev %s -> %s.\n", vdev->name, ndev->name);
+ }
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(cdev, &cdev_rcu_list, rcu_node) {
+ for (i = 0; i < cdev->nports; i++) {
+ if (ndev == cdev->ports[i]) {
+ cdev->hbas[i]->vdev = vdev;
+ rcu_read_unlock();
+ if (port)
+ *port = i;
+ return cdev;
+ }
+ }
+ }
+ rcu_read_unlock();
+
+ log_debug(1 << CXGBI_DBG_DEV,
+ "ndev 0x%p, %s, NO match found.\n", ndev, ndev->name);
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(cxgbi_device_find_by_netdev_rcu);
+
static struct cxgbi_device *cxgbi_device_find_by_mac(struct net_device *ndev,
int *port)
{
diff --git a/drivers/scsi/cxgbi/libcxgbi.h b/drivers/scsi/cxgbi/libcxgbi.h
index b3e6e75..1d98fad 100644
--- a/drivers/scsi/cxgbi/libcxgbi.h
+++ b/drivers/scsi/cxgbi/libcxgbi.h
@@ -527,6 +527,7 @@ struct cxgbi_ports_map {
#define CXGBI_FLAG_IPV4_SET 0x10
struct cxgbi_device {
struct list_head list_head;
+ struct list_head rcu_node;
unsigned int flags;
struct net_device **ports;
void *lldev;
@@ -709,6 +710,8 @@ void cxgbi_device_unregister(struct cxgbi_device *);
void cxgbi_device_unregister_all(unsigned int flag);
struct cxgbi_device *cxgbi_device_find_by_lldev(void *);
struct cxgbi_device *cxgbi_device_find_by_netdev(struct net_device *, int *);
+struct cxgbi_device *cxgbi_device_find_by_netdev_rcu(struct net_device *,
+ int *);
int cxgbi_hbas_add(struct cxgbi_device *, u64, unsigned int,
struct scsi_host_template *,
struct scsi_transport_template *);
--
2.1.0
--
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