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Staging: hv: vmbus: Properly deal with de-registering channel callback

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Ensure that we correctly handle racing invocations of the channel callback
when the channel is being closed. We do this using the channel's inbound_lock.
A side-effect of this strategy is that we avoid repeatedly picking up this lock
as we drain the inbound ring-buffer.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
K. Y. Srinivasan 2011-08-27 11:31:33 -07:00 committed by Greg Kroah-Hartman
parent 76c39d429d
commit dad76bf73f
4 changed files with 8 additions and 21 deletions
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20
drivers/staging/hv/channel.c
View file

@ -513,9 +513,12 @@ void vmbus_close(struct vmbus_channel *channel)
{
struct vmbus_channel_close_channel *msg;
int ret;
unsigned long flags;
/* Stop callback and cancel the timer asap */
spin_lock_irqsave(&channel->inbound_lock, flags);
channel->onchannel_callback = NULL;
spin_unlock_irqrestore(&channel->inbound_lock, flags);
/* Send a closing message */
@ -735,19 +738,15 @@ int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
u32 packetlen;
u32 userlen;
int ret;
unsigned long flags;
*buffer_actual_len = 0;
*requestid = 0;
spin_lock_irqsave(&channel->inbound_lock, flags);
ret = hv_ringbuffer_peek(&channel->inbound, &desc,
sizeof(struct vmpacket_descriptor));
if (ret != 0) {
spin_unlock_irqrestore(&channel->inbound_lock, flags);
if (ret != 0)
return 0;
}
packetlen = desc.len8 << 3;
userlen = packetlen - (desc.offset8 << 3);
@ -755,7 +754,6 @@ int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
*buffer_actual_len = userlen;
if (userlen > bufferlen) {
spin_unlock_irqrestore(&channel->inbound_lock, flags);
pr_err("Buffer too small - got %d needs %d\n",
bufferlen, userlen);
@ -768,7 +766,6 @@ int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen,
(desc.offset8 << 3));
spin_unlock_irqrestore(&channel->inbound_lock, flags);
return 0;
}
@ -785,19 +782,15 @@ int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
u32 packetlen;
u32 userlen;
int ret;
unsigned long flags;
*buffer_actual_len = 0;
*requestid = 0;
spin_lock_irqsave(&channel->inbound_lock, flags);
ret = hv_ringbuffer_peek(&channel->inbound, &desc,
sizeof(struct vmpacket_descriptor));
if (ret != 0) {
spin_unlock_irqrestore(&channel->inbound_lock, flags);
if (ret != 0)
return 0;
}
packetlen = desc.len8 << 3;
@ -806,8 +799,6 @@ int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
*buffer_actual_len = packetlen;
if (packetlen > bufferlen) {
spin_unlock_irqrestore(&channel->inbound_lock, flags);
pr_err("Buffer too small - needed %d bytes but "
"got space for only %d bytes\n",
packetlen, bufferlen);
@ -819,7 +810,6 @@ int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
/* Copy over the entire packet to the user buffer */
ret = hv_ringbuffer_read(&channel->inbound, buffer, packetlen, 0);
spin_unlock_irqrestore(&channel->inbound_lock, flags);
return 0;
}
EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);

3
drivers/staging/hv/connection.c
View file

@ -215,6 +215,7 @@ struct vmbus_channel *relid2channel(u32 relid)
static void process_chn_event(u32 relid)
{
struct vmbus_channel *channel;
unsigned long flags;
/*
* Find the channel based on this relid and invokes the
@ -222,11 +223,13 @@ static void process_chn_event(u32 relid)
*/
channel = relid2channel(relid);
spin_lock_irqsave(&channel->inbound_lock, flags);
if (channel && (channel->onchannel_callback != NULL)) {
channel->onchannel_callback(channel->channel_callback_context);
} else {
pr_err("channel not found for relid - %u\n", relid);
}
spin_unlock_irqrestore(&channel->inbound_lock, flags);
}
/*

3
drivers/staging/hv/netvsc.c
View file

@ -62,9 +62,7 @@ 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->channel->inbound_lock, flags);
net_device = device->ext;
if (!net_device)
@ -75,7 +73,6 @@ static struct netvsc_device *get_inbound_net_device(struct hv_device *device)
net_device = NULL;
get_in_err:
spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
return net_device;
}

3
drivers/staging/hv/storvsc_drv.c
View file

@ -352,9 +352,7 @@ static inline struct storvsc_device *get_in_stor_device(
struct hv_device *device)
{
struct storvsc_device *stor_device;
unsigned long flags;
spin_lock_irqsave(&device->channel->inbound_lock, flags);
stor_device = (struct storvsc_device *)device->ext;
if (!stor_device)
@ -370,7 +368,6 @@ static inline struct storvsc_device *get_in_stor_device(
stor_device = NULL;
get_in_err:
spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
return stor_device;
}