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>
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@ -513,9 +513,12 @@ void vmbus_close(struct vmbus_channel *channel)
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{
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struct vmbus_channel_close_channel *msg;
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int ret;
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unsigned long flags;
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/* Stop callback and cancel the timer asap */
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spin_lock_irqsave(&channel->inbound_lock, flags);
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channel->onchannel_callback = NULL;
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spin_unlock_irqrestore(&channel->inbound_lock, flags);
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/* Send a closing message */
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@ -735,19 +738,15 @@ int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
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u32 packetlen;
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u32 userlen;
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int ret;
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unsigned long flags;
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*buffer_actual_len = 0;
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*requestid = 0;
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spin_lock_irqsave(&channel->inbound_lock, flags);
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ret = hv_ringbuffer_peek(&channel->inbound, &desc,
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sizeof(struct vmpacket_descriptor));
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if (ret != 0) {
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spin_unlock_irqrestore(&channel->inbound_lock, flags);
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if (ret != 0)
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return 0;
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}
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packetlen = desc.len8 << 3;
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userlen = packetlen - (desc.offset8 << 3);
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@ -755,7 +754,6 @@ int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
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*buffer_actual_len = userlen;
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if (userlen > bufferlen) {
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spin_unlock_irqrestore(&channel->inbound_lock, flags);
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pr_err("Buffer too small - got %d needs %d\n",
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bufferlen, userlen);
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@ -768,7 +766,6 @@ int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
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ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen,
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(desc.offset8 << 3));
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spin_unlock_irqrestore(&channel->inbound_lock, flags);
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return 0;
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}
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@ -785,19 +782,15 @@ int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
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u32 packetlen;
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u32 userlen;
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int ret;
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unsigned long flags;
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*buffer_actual_len = 0;
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*requestid = 0;
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spin_lock_irqsave(&channel->inbound_lock, flags);
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ret = hv_ringbuffer_peek(&channel->inbound, &desc,
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sizeof(struct vmpacket_descriptor));
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if (ret != 0) {
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spin_unlock_irqrestore(&channel->inbound_lock, flags);
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if (ret != 0)
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return 0;
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}
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packetlen = desc.len8 << 3;
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@ -806,8 +799,6 @@ int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
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*buffer_actual_len = packetlen;
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if (packetlen > bufferlen) {
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spin_unlock_irqrestore(&channel->inbound_lock, flags);
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pr_err("Buffer too small - needed %d bytes but "
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"got space for only %d bytes\n",
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packetlen, bufferlen);
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@ -819,7 +810,6 @@ int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
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/* Copy over the entire packet to the user buffer */
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ret = hv_ringbuffer_read(&channel->inbound, buffer, packetlen, 0);
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spin_unlock_irqrestore(&channel->inbound_lock, flags);
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return 0;
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}
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EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);
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@ -215,6 +215,7 @@ struct vmbus_channel *relid2channel(u32 relid)
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static void process_chn_event(u32 relid)
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{
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struct vmbus_channel *channel;
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unsigned long flags;
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/*
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* Find the channel based on this relid and invokes the
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@ -222,11 +223,13 @@ static void process_chn_event(u32 relid)
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*/
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channel = relid2channel(relid);
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spin_lock_irqsave(&channel->inbound_lock, flags);
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if (channel && (channel->onchannel_callback != NULL)) {
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channel->onchannel_callback(channel->channel_callback_context);
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} else {
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pr_err("channel not found for relid - %u\n", relid);
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}
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spin_unlock_irqrestore(&channel->inbound_lock, flags);
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}
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/*
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@ -62,9 +62,7 @@ static struct netvsc_device *get_outbound_net_device(struct hv_device *device)
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static struct netvsc_device *get_inbound_net_device(struct hv_device *device)
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{
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struct netvsc_device *net_device;
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unsigned long flags;
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spin_lock_irqsave(&device->channel->inbound_lock, flags);
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net_device = device->ext;
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if (!net_device)
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@ -75,7 +73,6 @@ static struct netvsc_device *get_inbound_net_device(struct hv_device *device)
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net_device = NULL;
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get_in_err:
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spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
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return net_device;
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}
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@ -352,9 +352,7 @@ static inline struct storvsc_device *get_in_stor_device(
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struct hv_device *device)
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{
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struct storvsc_device *stor_device;
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unsigned long flags;
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spin_lock_irqsave(&device->channel->inbound_lock, flags);
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stor_device = (struct storvsc_device *)device->ext;
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if (!stor_device)
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@ -370,7 +368,6 @@ static inline struct storvsc_device *get_in_stor_device(
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stor_device = NULL;
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get_in_err:
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spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
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return stor_device;
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}
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