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authorAndrea Parri (Microsoft) <parri.andrea@gmail.com>2020-06-17 19:46:39 +0300
committerWei Liu <wei.liu@kernel.org>2020-06-19 18:38:26 +0300
commit3eb0ac869c66d73a034004b97b3a4abe1c5cb998 (patch)
tree0ae6c8ec7eb477178ed0c43f5ecf26a8046f4a0a
parent12d0dd8e728e785e6fb81f5232280678bc69d8dc (diff)
downloadlinux-3eb0ac869c66d73a034004b97b3a4abe1c5cb998.tar.xz
Drivers: hv: vmbus: Use channel_mutex in channel_vp_mapping_show()
The primitive currently uses channel->lock to protect the loop over sc_list w.r.t. list additions/deletions but it doesn't protect the target_cpu(s) loads w.r.t. a concurrent target_cpu_store(): while the data races on target_cpu are hardly of any concern here, replace the channel->lock critical section with a channel_mutex critical section and extend the latter to include the loads of target_cpu; this same pattern is also used in hv_synic_cleanup(). Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Link: https://lore.kernel.org/r/20200617164642.37393-6-parri.andrea@gmail.com Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>
-rw-r--r--drivers/hv/vmbus_drv.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 48446422b108..6afff04d9cc0 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -507,18 +507,17 @@ static ssize_t channel_vp_mapping_show(struct device *dev,
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct vmbus_channel *channel = hv_dev->channel, *cur_sc;
- unsigned long flags;
int buf_size = PAGE_SIZE, n_written, tot_written;
struct list_head *cur;
if (!channel)
return -ENODEV;
+ mutex_lock(&vmbus_connection.channel_mutex);
+
tot_written = snprintf(buf, buf_size, "%u:%u\n",
channel->offermsg.child_relid, channel->target_cpu);
- spin_lock_irqsave(&channel->lock, flags);
-
list_for_each(cur, &channel->sc_list) {
if (tot_written >= buf_size - 1)
break;
@@ -532,7 +531,7 @@ static ssize_t channel_vp_mapping_show(struct device *dev,
tot_written += n_written;
}
- spin_unlock_irqrestore(&channel->lock, flags);
+ mutex_unlock(&vmbus_connection.channel_mutex);
return tot_written;
}