[PATCH 17/40] Staging: hv: netvsc: Use the newly introduced lock in accessing ext field
From: "K. Y. Srinivasan" <kys@microsoft.com>
Date: 2011-06-29 14:30:11
Also in:
lkml
Subsystem:
staging subsystem, the rest · Maintainers:
Greg Kroah-Hartman, Linus Torvalds
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@microsoft.com> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Abhishek Kane <redacted> Signed-off-by: Hank Janssen <redacted> --- 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; }
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1.7.4.1