[PATCH 091/117] Staging: hv: netvsc: Use the newly introduced lock in accessing ext field

K. Y. Srinivasan
Fri, 15 Jul 2011 17:47:19 -0000

Use the newly introduced lock in accessing ext field.

Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz at microsoft.com>
---
 drivers/staging/hv/netvsc.c |   33 ++++++++++++++++++++++++++++++---
 1 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/hv/netvsc.c b/drivers/staging/hv/netvsc.c
index 67cf7fb..c38c669 100644
--- a/drivers/staging/hv/netvsc.c
+++ b/drivers/staging/hv/netvsc.c
@@ -54,12 +54,15 @@ 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;
 }
@@ -68,33 +71,46 @@ 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;
+	}
+
+	spin_unlock_irqrestore(&device->ext_lock, flags);

 	/* Busy wait until the ref drop to 2, then set it to 1 */
 	while (atomic_cmpxchg(&net_device->refcnt, 2, 1) != 2)
@@ -107,16 +123,23 @@ 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;
+	}

+	spin_unlock_irqrestore(&device->ext_lock, flags);
 	/* Busy wait until the ref drop to 1, then set it to 0 */
 	while (atomic_cmpxchg(&net_device->refcnt, 1, 0) != 1)
 		udelay(100);

+	spin_lock_irqsave(&device->ext_lock, flags);
 	device->ext = NULL;
+	spin_unlock_irqrestore(&device->ext_lock, flags);
 	return net_device;
 }

@@ -397,6 +420,8 @@ int netvsc_device_remove(struct hv_device *device)
 {
 	struct netvsc_device *net_device;
 	struct hv_netvsc_packet *netvsc_packet, *pos;
+	unsigned long flags;
+

 	/* Stop outbound traffic ie sends and receives completions */
 	net_device = release_outbound_net_device(device);
@@ -404,8 +429,10 @@ int netvsc_device_remove(struct hv_device *device)
 		dev_err(&device->device, "No net device present!!");
 		return -ENODEV;
 	}
-
+	spin_lock_irqsave(&device->ext_lock, flags);
 	net_device->destroy = true;
+	spin_unlock_irqrestore(&device->ext_lock, flags);
+

 	/* Wait for all send completions */
 	while (atomic_read(&net_device->num_outstanding_sends)) {
--
1.7.4.1