[PATCH 17/40] Staging: hv: netvsc: Use the newly introduced lock in accessing ext field
K. Y. Srinivasan
kys at microsoft.com
Wed Jun 29 14:39:14 UTC 2011
The current reference counting mechanism is broken; use the newly introduced
lock to access the net_device pointer in struct hv_device.
Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz at microsoft.com>
Signed-off-by: Abhishek Kane <v-abkane at microsoft.com>
Signed-off-by: Hank Janssen <hjanssen at microsoft.com>
---
drivers/staging/hv/netvsc.c | 24 ++++++++++++++++++++++--
1 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/hv/netvsc.c b/drivers/staging/hv/netvsc.c
index f03018c..531de63 100644
--- a/drivers/staging/hv/netvsc.c
+++ b/drivers/staging/hv/netvsc.c
@@ -56,12 +56,15 @@ static struct netvsc_device *alloc_net_device(struct hv_device *device)
static struct netvsc_device *get_outbound_net_device(struct hv_device *device)
{
struct netvsc_device *net_device;
+ unsigned long flags;
+ spin_lock_irqsave(&device->ext_lock, flags);
net_device = device->ext;
if (net_device && atomic_read(&net_device->refcnt) > 1)
atomic_inc(&net_device->refcnt);
else
net_device = NULL;
+ spin_unlock_irqrestore(&device->ext_lock, flags);
return net_device;
}
@@ -70,38 +73,50 @@ static struct netvsc_device *get_outbound_net_device(struct hv_device *device)
static struct netvsc_device *get_inbound_net_device(struct hv_device *device)
{
struct netvsc_device *net_device;
+ unsigned long flags;
+ spin_lock_irqsave(&device->ext_lock, flags);
net_device = device->ext;
if (net_device && atomic_read(&net_device->refcnt))
atomic_inc(&net_device->refcnt);
else
net_device = NULL;
+ spin_unlock_irqrestore(&device->ext_lock, flags);
return net_device;
}
static void put_net_device(struct hv_device *device)
{
struct netvsc_device *net_device;
+ unsigned long flags;
+
+ spin_lock_irqsave(&device->ext_lock, flags);
net_device = device->ext;
atomic_dec(&net_device->refcnt);
+ spin_unlock_irqrestore(&device->ext_lock, flags);
}
static struct netvsc_device *release_outbound_net_device(
struct hv_device *device)
{
struct netvsc_device *net_device;
+ unsigned long flags;
+ spin_lock_irqsave(&device->ext_lock, flags);
net_device = device->ext;
- if (net_device == NULL)
+ if (net_device == NULL) {
+ spin_unlock_irqrestore(&device->ext_lock, flags);
return NULL;
+ }
/* Busy wait until the ref drop to 2, then set it to 1 */
while (atomic_cmpxchg(&net_device->refcnt, 2, 1) != 2)
udelay(100);
+ spin_unlock_irqrestore(&device->ext_lock, flags);
return net_device;
}
@@ -109,16 +124,21 @@ static struct netvsc_device *release_inbound_net_device(
struct hv_device *device)
{
struct netvsc_device *net_device;
+ unsigned long flags;
+ spin_lock_irqsave(&device->ext_lock, flags);
net_device = device->ext;
- if (net_device == NULL)
+ if (net_device == NULL) {
+ spin_unlock_irqrestore(&device->ext_lock, flags);
return NULL;
+ }
/* Busy wait until the ref drop to 1, then set it to 0 */
while (atomic_cmpxchg(&net_device->refcnt, 1, 0) != 1)
udelay(100);
device->ext = NULL;
+ spin_unlock_irqrestore(&device->ext_lock, flags);
return net_device;
}
--
1.7.4.1
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