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

K. Y. Srinivasan
2011-07-15T17:38:09Z

Use the newly introduced lock in accessing ext field.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@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