AcoSail/kernel_optimize_test
8
0
Fork 0
forked from luck/tmp_suning_uos_patched
Code Pull Requests Activity

tap: convert a mutex to a spinlock

Browse Source 
We are not allowed to block on the RCU reader side, so can't
just hold the mutex as before. As a quick fix, convert it to
a spinlock.

Fixes: d9f1f61c08 ("tap: Extending tap device create/destroy APIs")
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Sainath Grandhi <sainath.grandhi@intel.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
WANG Cong 2017-07-10 10:05:50 -07:00 committed by David S. Miller
parent 6a146f3a58
commit ffa423fb32
1 changed files with 9 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
drivers/net/tap.c
View File

@ -106,7 +106,7 @@ struct major_info {
struct rcu_head rcu;
dev_t major;
struct idr minor_idr;
struct mutex minor_lock;
spinlock_t minor_lock;
const char *device_name;
struct list_head next;
};
@ -416,15 +416,15 @@ int tap_get_minor(dev_t major, struct tap_dev *tap)
goto unlock;
}
mutex_lock(&tap_major->minor_lock);
retval = idr_alloc(&tap_major->minor_idr, tap, 1, TAP_NUM_DEVS, GFP_KERNEL);
spin_lock(&tap_major->minor_lock);
retval = idr_alloc(&tap_major->minor_idr, tap, 1, TAP_NUM_DEVS, GFP_ATOMIC);
if (retval >= 0) {
tap->minor = retval;
} else if (retval == -ENOSPC) {
netdev_err(tap->dev, "Too many tap devices\n");
retval = -EINVAL;
}
mutex_unlock(&tap_major->minor_lock);
spin_unlock(&tap_major->minor_lock);
unlock:
rcu_read_unlock();
@ -442,12 +442,12 @@ void tap_free_minor(dev_t major, struct tap_dev *tap)
goto unlock;
}
mutex_lock(&tap_major->minor_lock);
spin_lock(&tap_major->minor_lock);
if (tap->minor) {
idr_remove(&tap_major->minor_idr, tap->minor);
tap->minor = 0;
}
mutex_unlock(&tap_major->minor_lock);
spin_unlock(&tap_major->minor_lock);
unlock:
rcu_read_unlock();
@ -467,13 +467,13 @@ static struct tap_dev *dev_get_by_tap_file(int major, int minor)
goto unlock;
}
mutex_lock(&tap_major->minor_lock);
spin_lock(&tap_major->minor_lock);
tap = idr_find(&tap_major->minor_idr, minor);
if (tap) {
dev = tap->dev;
dev_hold(dev);
}
mutex_unlock(&tap_major->minor_lock);
spin_unlock(&tap_major->minor_lock);
unlock:
rcu_read_unlock();
@ -1244,7 +1244,7 @@ static int tap_list_add(dev_t major, const char *device_name)
tap_major->major = MAJOR(major);
idr_init(&tap_major->minor_idr);
mutex_init(&tap_major->minor_lock);
spin_lock_init(&tap_major->minor_lock);
tap_major->device_name = device_name;