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authorWANG Cong <xiyou.wangcong@gmail.com>2017-07-10 10:05:50 -0700
committerDavid S. Miller <davem@davemloft.net>2017-07-11 13:41:57 -0700
commitffa423fb3251f8737303ffc3b0659e86e501808e (patch)
tree0d93e56751fc63134f41f2bbb5e38963c6281aa4 /drivers/net/tap.c
parent6a146f3a5894b751cef16feb3d7903e45e3c445c (diff)
downloadlinux-ffa423fb3251f8737303ffc3b0659e86e501808e.tar.bz2
tap: convert a mutex to a spinlock
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: d9f1f61c0801 ("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>
Diffstat (limited to 'drivers/net/tap.c')
-rw-r--r--drivers/net/tap.c18
1 files changed, 9 insertions, 9 deletions
diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index 9af3239d6ad5..3570c7576993 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -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;