Commit 12d0dd8e authored by Andrea Parri (Microsoft)'s avatar Andrea Parri (Microsoft) Committed by Wei Liu
Browse files

Drivers: hv: vmbus: Remove unnecessary channel->lock critical sections (sc_list readers) 



Additions/deletions to/from sc_list (as well as modifications of
target_cpu(s)) are protected by channel_mutex, which hv_synic_cleanup()
and vmbus_bus_suspend() own for the duration of the channel->lock
critical section in question.

Signed-off-by: default avatarAndrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20200617164642.37393-5-parri.andrea@gmail.com


Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent 0a968209

drivers/hv/hv.c

+0 −3
Original line number Diff line number Diff line
@@ -241,7 +241,6 @@ int hv_synic_cleanup(unsigned int cpu) 
{

	struct vmbus_channel *channel, *sc;

	bool channel_found = false;

	unsigned long flags;



	/*

	 * Hyper-V does not provide a way to change the connect CPU once
@@ -263,14 +262,12 @@ int hv_synic_cleanup(unsigned int cpu) 
			channel_found = true;

			break;

		}

		spin_lock_irqsave(&channel->lock, flags);

		list_for_each_entry(sc, &channel->sc_list, sc_list) {

			if (sc->target_cpu == cpu) {

				channel_found = true;

				break;

			}

		}

		spin_unlock_irqrestore(&channel->lock, flags);

		if (channel_found)

			break;

	}

drivers/hv/vmbus_drv.c

+0 −3
Original line number Diff line number Diff line
@@ -2344,7 +2344,6 @@ acpi_walk_err: 
static int vmbus_bus_suspend(struct device *dev)

{

	struct vmbus_channel *channel, *sc;

	unsigned long flags;



	while (atomic_read(&vmbus_connection.offer_in_progress) != 0) {

		/*
@@ -2402,12 +2401,10 @@ static int vmbus_bus_suspend(struct device *dev) 
			continue;

		}



		spin_lock_irqsave(&channel->lock, flags);

		list_for_each_entry(sc, &channel->sc_list, sc_list) {

			pr_err("Sub-channel not deleted!\n");

			WARN_ON_ONCE(1);

		}

		spin_unlock_irqrestore(&channel->lock, flags);



		atomic_inc(&vmbus_connection.nr_chan_fixup_on_resume);

	}

CRA Git | Maintained and supported by SUSTech CRA and CCSE