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| author |   Andrea Parri (Microsoft) <parri.andrea@gmail.com> | 2020-06-17 18:46:39 +0200 |
|---|---|---|
| committer |   Wei Liu <wei.liu@kernel.org> | 2020-06-19 15:38:26 +0000 |
| commit | 3eb0ac869c66d73a034004b97b3a4abe1c5cb998 (patch) | |
| tree | 0ae6c8ec7eb477178ed0c43f5ecf26a8046f4a0a /drivers/hv | |
| parent | Drivers: hv: vmbus: Remove unnecessary channel->lock critical sections (sc_list readers) (diff) | |
| download | wireguard-linux-3eb0ac869c66d73a034004b97b3a4abe1c5cb998.tar.xz wireguard-linux-3eb0ac869c66d73a034004b97b3a4abe1c5cb998.zip | |
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>
Diffstat (limited to 'drivers/hv')
| -rw-r--r-- | drivers/hv/vmbus_drv.c | 7 |
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; } |