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Date: Fri, 14 Aug 2009 18:49:46 -0700
From: "Michael Chan" <mchan@...adcom.com>
To: davem@...emloft.net, James.Bottomley@...senPartnership.com,
michaelc@...wisc.edu
cc: netdev@...r.kernel.org, linux-scsi@...r.kernel.org
Subject: [PATCH 4/5] cnic: Fix locking in start/stop calls.
The slow path ulp_start and ulp_stop calls to the bnx2i driver
are sleepable calls and therefore should not be protected using
rcu_read_lock. Fix it by using mutex and setting a bit during
these calls. cnic_unregister_device() will now wait for the bit
to clear before completing the call.
Signed-off-by: Michael Chan <mchan@...adcom.com>
Reviewed-by: Benjamin Li <benli@...adcom.com>
---
drivers/net/cnic.c | 44 ++++++++++++++++++++++++++++----------------
drivers/net/cnic.h | 1 +
2 files changed, 29 insertions(+), 16 deletions(-)
diff --git a/drivers/net/cnic.c b/drivers/net/cnic.c
index 2db81f0..4ff618a 100644
--- a/drivers/net/cnic.c
+++ b/drivers/net/cnic.c
@@ -466,6 +466,7 @@ EXPORT_SYMBOL(cnic_register_driver);
static int cnic_unregister_device(struct cnic_dev *dev, int ulp_type)
{
struct cnic_local *cp = dev->cnic_priv;
+ int i = 0;
if (ulp_type >= MAX_CNIC_ULP_TYPE) {
printk(KERN_ERR PFX "cnic_unregister_device: Bad type %d\n",
@@ -486,6 +487,15 @@ static int cnic_unregister_device(struct cnic_dev *dev, int ulp_type)
synchronize_rcu();
+ while (test_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[ulp_type]) &&
+ i < 20) {
+ msleep(100);
+ i++;
+ }
+ if (test_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[ulp_type]))
+ printk(KERN_WARNING PFX "%s: Failed waiting for ULP up call"
+ " to complete.\n", dev->netdev->name);
+
return 0;
}
EXPORT_SYMBOL(cnic_unregister_driver);
@@ -1076,18 +1086,23 @@ static void cnic_ulp_stop(struct cnic_dev *dev)
if (cp->cnic_uinfo)
cnic_send_nlmsg(cp, ISCSI_KEVENT_IF_DOWN, NULL);
- rcu_read_lock();
for (if_type = 0; if_type < MAX_CNIC_ULP_TYPE; if_type++) {
struct cnic_ulp_ops *ulp_ops;
- ulp_ops = rcu_dereference(cp->ulp_ops[if_type]);
- if (!ulp_ops)
+ mutex_lock(&cnic_lock);
+ ulp_ops = cp->ulp_ops[if_type];
+ if (!ulp_ops) {
+ mutex_unlock(&cnic_lock);
continue;
+ }
+ set_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[if_type]);
+ mutex_unlock(&cnic_lock);
if (test_and_clear_bit(ULP_F_START, &cp->ulp_flags[if_type]))
ulp_ops->cnic_stop(cp->ulp_handle[if_type]);
+
+ clear_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[if_type]);
}
- rcu_read_unlock();
}
static void cnic_ulp_start(struct cnic_dev *dev)
@@ -1095,18 +1110,23 @@ static void cnic_ulp_start(struct cnic_dev *dev)
struct cnic_local *cp = dev->cnic_priv;
int if_type;
- rcu_read_lock();
for (if_type = 0; if_type < MAX_CNIC_ULP_TYPE; if_type++) {
struct cnic_ulp_ops *ulp_ops;
- ulp_ops = rcu_dereference(cp->ulp_ops[if_type]);
- if (!ulp_ops || !ulp_ops->cnic_start)
+ mutex_lock(&cnic_lock);
+ ulp_ops = cp->ulp_ops[if_type];
+ if (!ulp_ops || !ulp_ops->cnic_start) {
+ mutex_unlock(&cnic_lock);
continue;
+ }
+ set_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[if_type]);
+ mutex_unlock(&cnic_lock);
if (!test_and_set_bit(ULP_F_START, &cp->ulp_flags[if_type]))
ulp_ops->cnic_start(cp->ulp_handle[if_type]);
+
+ clear_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[if_type]);
}
- rcu_read_unlock();
}
static int cnic_ctl(void *data, struct cnic_ctl_info *info)
@@ -1116,22 +1136,18 @@ static int cnic_ctl(void *data, struct cnic_ctl_info *info)
switch (info->cmd) {
case CNIC_CTL_STOP_CMD:
cnic_hold(dev);
- mutex_lock(&cnic_lock);
cnic_ulp_stop(dev);
cnic_stop_hw(dev);
- mutex_unlock(&cnic_lock);
cnic_put(dev);
break;
case CNIC_CTL_START_CMD:
cnic_hold(dev);
- mutex_lock(&cnic_lock);
if (!cnic_start_hw(dev))
cnic_ulp_start(dev);
- mutex_unlock(&cnic_lock);
cnic_put(dev);
break;
default:
@@ -2667,10 +2683,8 @@ static int cnic_netdev_event(struct notifier_block *this, unsigned long event,
cnic_put(dev);
goto done;
}
- mutex_lock(&cnic_lock);
if (!cnic_start_hw(dev))
cnic_ulp_start(dev);
- mutex_unlock(&cnic_lock);
}
rcu_read_lock();
@@ -2689,10 +2703,8 @@ static int cnic_netdev_event(struct notifier_block *this, unsigned long event,
rcu_read_unlock();
if (event == NETDEV_GOING_DOWN) {
- mutex_lock(&cnic_lock);
cnic_ulp_stop(dev);
cnic_stop_hw(dev);
- mutex_unlock(&cnic_lock);
cnic_unregister_netdev(dev);
} else if (event == NETDEV_UNREGISTER) {
write_lock(&cnic_dev_lock);
diff --git a/drivers/net/cnic.h b/drivers/net/cnic.h
index 5192d4a..a94b302 100644
--- a/drivers/net/cnic.h
+++ b/drivers/net/cnic.h
@@ -176,6 +176,7 @@ struct cnic_local {
unsigned long ulp_flags[MAX_CNIC_ULP_TYPE];
#define ULP_F_INIT 0
#define ULP_F_START 1
+#define ULP_F_CALL_PENDING 2
struct cnic_ulp_ops *ulp_ops[MAX_CNIC_ULP_TYPE];
/* protected by ulp_lock */
--
1.5.6.GIT
--
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