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Subject[PATCH 22/40] Staging: hv: netvsc: Further cleanup reference counting of netvsc_device
Date

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Abhishek Kane <v-abkane@microsoft.com>
Signed-off-by: Hank Janssen <hjanssen@microsoft.com>
---
drivers/staging/hv/netvsc.c | 25 ++++++++++++++++---------
1 files changed, 16 insertions(+), 9 deletions(-)
diff --git a/drivers/staging/hv/netvsc.c b/drivers/staging/hv/netvsc.c
index 9ee264c..caca82e 100644
--- a/drivers/staging/hv/netvsc.c
+++ b/drivers/staging/hv/netvsc.c
@@ -40,8 +40,7 @@ static struct netvsc_device *alloc_net_device(struct hv_device *device)
if (!net_device)
return NULL;

- /* Set to 2 to allow both inbound and outbound traffic */
- net_device->refcnt = 2;
+ net_device->refcnt = 1;
net_device->drain_notify = false;
net_device->destroy = false;
init_waitqueue_head(&net_device->waiting_to_drain);
@@ -52,7 +51,6 @@ static struct netvsc_device *alloc_net_device(struct hv_device *device)
return net_device;
}

-/* Get the net device object iff exists and its refcount > 1 */
static struct netvsc_device *get_outbound_net_device(struct hv_device *device)
{
struct netvsc_device *net_device;
@@ -60,7 +58,7 @@ static struct netvsc_device *get_outbound_net_device(struct hv_device *device)

spin_lock_irqsave(&device->ext_lock, flags);
net_device = device->ext;
- if (net_device && (net_device->refcnt > 1) &&
+ if (net_device && (net_device->refcnt) &&
!net_device->destroy)
net_device->refcnt++;
else
@@ -70,7 +68,6 @@ static struct netvsc_device *get_outbound_net_device(struct hv_device *device)
return net_device;
}

-/* Get the net device object iff exists and its refcount > 0 */
static struct netvsc_device *get_inbound_net_device(struct hv_device *device)
{
struct netvsc_device *net_device;
@@ -78,11 +75,21 @@ static struct netvsc_device *get_inbound_net_device(struct hv_device *device)

spin_lock_irqsave(&device->ext_lock, flags);
net_device = device->ext;
- if (net_device && net_device->refcnt)
- net_device->refcnt++;
- else
- net_device = NULL;

+ if (!net_device)
+ goto cleanup;
+
+ /*
+ * If the device is being destroyed; allow incoming
+ * traffic only to cleanup outstanding requests.
+ */
+ if (net_device->destroy &&
+ (atomic_read(&net_device->num_outstanding_sends) == 0))
+ goto cleanup;
+
+ net_device->refcnt++;
+
+cleanup:
spin_unlock_irqrestore(&device->ext_lock, flags);
return net_device;
}
--
1.7.4.1


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