Staging: hv: vmbus: Properly deal with de-registering channel callback
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>
diff --git a/drivers/staging/hv/channel.c b/drivers/staging/hv/channel.c
index ac92c1f..b6f3d38 100644
--- a/drivers/staging/hv/channel.c
+++ b/drivers/staging/hv/channel.c
@@ -513,9 +513,12 @@
{
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 @@
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 @@
*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 @@
ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen,
(desc.offset8 << 3));
- spin_unlock_irqrestore(&channel->inbound_lock, flags);
return 0;
}
@@ -785,19 +782,15 @@
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 @@
*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 @@
/* 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);
diff --git a/drivers/staging/hv/connection.c b/drivers/staging/hv/connection.c
index 7a3ec75..6aab802 100644
--- a/drivers/staging/hv/connection.c
+++ b/drivers/staging/hv/connection.c
@@ -215,6 +215,7 @@
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 @@
*/
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);
}
/*
diff --git a/drivers/staging/hv/netvsc.c b/drivers/staging/hv/netvsc.c
index 9828f0b..e4cc40a 100644
--- a/drivers/staging/hv/netvsc.c
+++ b/drivers/staging/hv/netvsc.c
@@ -62,9 +62,7 @@
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 @@
net_device = NULL;
get_in_err:
- spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
return net_device;
}
diff --git a/drivers/staging/hv/storvsc_drv.c b/drivers/staging/hv/storvsc_drv.c
index d575bc9..3686d10 100644
--- a/drivers/staging/hv/storvsc_drv.c
+++ b/drivers/staging/hv/storvsc_drv.c
@@ -352,9 +352,7 @@
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 @@
stor_device = NULL;
get_in_err:
- spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
return stor_device;
}
