From dad76bf73fc20b42d020fe5a93dbe4b4868e7681 Mon Sep 17 00:00:00 2001 From: "K. Y. Srinivasan" Date: Sat, 27 Aug 2011 11:31:33 -0700 Subject: [PATCH] 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 Signed-off-by: Haiyang Zhang Signed-off-by: Greg Kroah-Hartman --- drivers/staging/hv/channel.c | 20 +++++--------------- drivers/staging/hv/connection.c | 3 +++ drivers/staging/hv/netvsc.c | 3 --- drivers/staging/hv/storvsc_drv.c | 3 --- 4 files changed, 8 insertions(+), 21 deletions(-) diff --git a/drivers/staging/hv/channel.c b/drivers/staging/hv/channel.c index ac92c1f99261..b6f3d38a6dbb 100644 --- a/drivers/staging/hv/channel.c +++ b/drivers/staging/hv/channel.c @@ -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); diff --git a/drivers/staging/hv/connection.c b/drivers/staging/hv/connection.c index 7a3ec75bab18..6aab802ba99a 100644 --- a/drivers/staging/hv/connection.c +++ b/drivers/staging/hv/connection.c @@ -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); } /* diff --git a/drivers/staging/hv/netvsc.c b/drivers/staging/hv/netvsc.c index 9828f0b5960e..e4cc40a3bd86 100644 --- a/drivers/staging/hv/netvsc.c +++ b/drivers/staging/hv/netvsc.c @@ -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; } diff --git a/drivers/staging/hv/storvsc_drv.c b/drivers/staging/hv/storvsc_drv.c index d575bc92ffc4..3686d1048e31 100644 --- a/drivers/staging/hv/storvsc_drv.c +++ b/drivers/staging/hv/storvsc_drv.c @@ -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; } -- 2.34.1