AcoSail/kernel_optimize_test
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cnic: Fix locking in init/exit calls.

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The slow path ulp_init and ulp_exit calls to the bnx2i driver
are sleepable calls and therefore should not be protected using
rcu_read_lock.  Fix it by using mutex and refcount during these
calls.  cnic_unregister_driver() will now wait for the refcount
to go to zero before completing the call.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Reviewed-by: Benjamin Li <benli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Michael Chan 2009-08-14 15:49:47 +00:00 committed by David S. Miller
parent 681dbd7107
commit 7fc1ece407
2 changed files with 40 additions and 9 deletions
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48
drivers/net/cnic.c
View File

@ -138,6 +138,16 @@ static struct cnic_dev *cnic_from_netdev(struct net_device *netdev)
return NULL;
}
static inline void ulp_get(struct cnic_ulp_ops *ulp_ops)
{
atomic_inc(&ulp_ops->ref_count);
}
static inline void ulp_put(struct cnic_ulp_ops *ulp_ops)
{
atomic_dec(&ulp_ops->ref_count);
}
static void cnic_ctx_wr(struct cnic_dev *dev, u32 cid_addr, u32 off, u32 val)
{
struct cnic_local *cp = dev->cnic_priv;
@ -358,6 +368,7 @@ int cnic_register_driver(int ulp_type, struct cnic_ulp_ops *ulp_ops)
}
read_unlock(&cnic_dev_lock);
atomic_set(&ulp_ops->ref_count, 0);
rcu_assign_pointer(cnic_ulp_tbl[ulp_type], ulp_ops);
mutex_unlock(&cnic_lock);
@ -379,6 +390,8 @@ int cnic_register_driver(int ulp_type, struct cnic_ulp_ops *ulp_ops)
int cnic_unregister_driver(int ulp_type)
{
struct cnic_dev *dev;
struct cnic_ulp_ops *ulp_ops;
int i = 0;
if (ulp_type >= MAX_CNIC_ULP_TYPE) {
printk(KERN_ERR PFX "cnic_unregister_driver: Bad type %d\n",
@ -386,7 +399,8 @@ int cnic_unregister_driver(int ulp_type)
return -EINVAL;
}
mutex_lock(&cnic_lock);
if (!cnic_ulp_tbl[ulp_type]) {
ulp_ops = cnic_ulp_tbl[ulp_type];
if (!ulp_ops) {
printk(KERN_ERR PFX "cnic_unregister_driver: Type %d has not "
"been registered\n", ulp_type);
goto out_unlock;
@ -411,6 +425,14 @@ int cnic_unregister_driver(int ulp_type)
mutex_unlock(&cnic_lock);
synchronize_rcu();
while ((atomic_read(&ulp_ops->ref_count) != 0) && (i < 20)) {
msleep(100);
i++;
}
if (atomic_read(&ulp_ops->ref_count) != 0)
printk(KERN_WARNING PFX "%s: Failed waiting for ref count to go"
" to zero.\n", dev->netdev->name);
return 0;
out_unlock:
@ -1161,19 +1183,23 @@ static void cnic_ulp_init(struct cnic_dev *dev)
int i;
struct cnic_local *cp = dev->cnic_priv;
rcu_read_lock();
for (i = 0; i < MAX_CNIC_ULP_TYPE_EXT; i++) {
struct cnic_ulp_ops *ulp_ops;
ulp_ops = rcu_dereference(cnic_ulp_tbl[i]);
if (!ulp_ops || !ulp_ops->cnic_init)
mutex_lock(&cnic_lock);
ulp_ops = cnic_ulp_tbl[i];
if (!ulp_ops || !ulp_ops->cnic_init) {
mutex_unlock(&cnic_lock);
continue;
}
ulp_get(ulp_ops);
mutex_unlock(&cnic_lock);
if (!test_and_set_bit(ULP_F_INIT, &cp->ulp_flags[i]))
ulp_ops->cnic_init(dev);
ulp_put(ulp_ops);
}
rcu_read_unlock();
}
static void cnic_ulp_exit(struct cnic_dev *dev)
@ -1181,19 +1207,23 @@ static void cnic_ulp_exit(struct cnic_dev *dev)
int i;
struct cnic_local *cp = dev->cnic_priv;
rcu_read_lock();
for (i = 0; i < MAX_CNIC_ULP_TYPE_EXT; i++) {
struct cnic_ulp_ops *ulp_ops;
ulp_ops = rcu_dereference(cnic_ulp_tbl[i]);
if (!ulp_ops || !ulp_ops->cnic_exit)
mutex_lock(&cnic_lock);
ulp_ops = cnic_ulp_tbl[i];
if (!ulp_ops || !ulp_ops->cnic_exit) {
mutex_unlock(&cnic_lock);
continue;
}
ulp_get(ulp_ops);
mutex_unlock(&cnic_lock);
if (test_and_clear_bit(ULP_F_INIT, &cp->ulp_flags[i]))
ulp_ops->cnic_exit(dev);
ulp_put(ulp_ops);
}
rcu_read_unlock();
}
static int cnic_cm_offload_pg(struct cnic_sock *csk)

1
drivers/net/cnic_if.h
View File

@ -290,6 +290,7 @@ struct cnic_ulp_ops {
void (*iscsi_nl_send_msg)(struct cnic_dev *dev, u32 msg_type,
char *data, u16 data_size);
struct module *owner;
atomic_t ref_count;
};
extern int cnic_register_driver(int ulp_type, struct cnic_ulp_ops *ulp_ops);