Merge tag 'char-misc-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc updates from Greg KH:
 "Here is the "big" char/misc driver patchset for 4.13-rc1.

  Lots of stuff in here, a large thunderbolt update, w1 driver header
  reorg, the new mux driver subsystem, google firmware driver updates,
  and a raft of other smaller things. Full details in the shortlog.

  All of these have been in linux-next for a while with the only
  reported issue being a merge problem with this tree and the jc-docs
  tree in the w1 documentation area"

* tag 'char-misc-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (147 commits)
  misc: apds990x: Use sysfs_match_string() helper
  mei: drop unreachable code in mei_start
  mei: validate the message header only in first fragment.
  DocBook: w1: Update W1 file locations and names in DocBook
  mux: adg792a: always require I2C support
  nvmem: rockchip-efuse: add support for rk322x-efuse
  nvmem: core: add locking to nvmem_find_cell
  nvmem: core: Call put_device() in nvmem_unregister()
  nvmem: core: fix leaks on registration errors
  nvmem: correct Broadcom OTP controller driver writes
  w1: Add subsystem kernel public interface
  drivers/fsi: Add module license to core driver
  drivers/fsi: Use asynchronous slave mode
  drivers/fsi: Add hub master support
  drivers/fsi: Add SCOM FSI client device driver
  drivers/fsi/gpio: Add tracepoints for GPIO master
  drivers/fsi: Add GPIO based FSI master
  drivers/fsi: Document FSI master sysfs files in ABI
  drivers/fsi: Add error handling for slave
  drivers/fsi: Add tracepoints for low-level operations
  ...

1 files changed, 53 insertions, 16 deletions

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 735f9363f2e4..0fabd410efd9 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -428,7 +428,6 @@ void vmbus_free_channels(void)
 {
 	struct vmbus_channel *channel, *tmp;
 
-	mutex_lock(&vmbus_connection.channel_mutex);
 	list_for_each_entry_safe(channel, tmp, &vmbus_connection.chn_list,
 		listentry) {
 		/* hv_process_channel_removal() needs this */
@@ -436,7 +435,6 @@ void vmbus_free_channels(void)
 
 		vmbus_device_unregister(channel->device_obj);
 	}
-	mutex_unlock(&vmbus_connection.channel_mutex);
 }
 
 /*
@@ -483,8 +481,10 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel)
 			list_add_tail(&newchannel->sc_list, &channel->sc_list);
 			channel->num_sc++;
 			spin_unlock_irqrestore(&channel->lock, flags);
-		} else
+		} else {
+			atomic_dec(&vmbus_connection.offer_in_progress);
 			goto err_free_chan;
+		}
 	}
 
 	dev_type = hv_get_dev_type(newchannel);
@@ -511,6 +511,7 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel)
 	if (!fnew) {
 		if (channel->sc_creation_callback != NULL)
 			channel->sc_creation_callback(newchannel);
+		atomic_dec(&vmbus_connection.offer_in_progress);
 		return;
 	}
 
@@ -532,9 +533,7 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel)
 	 * binding which eventually invokes the device driver's AddDevice()
 	 * method.
 	 */
-	mutex_lock(&vmbus_connection.channel_mutex);
 	ret = vmbus_device_register(newchannel->device_obj);
-	mutex_unlock(&vmbus_connection.channel_mutex);
 
 	if (ret != 0) {
 		pr_err("unable to add child device object (relid %d)\n",
@@ -542,6 +541,8 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel)
 		kfree(newchannel->device_obj);
 		goto err_deq_chan;
 	}
+
+	atomic_dec(&vmbus_connection.offer_in_progress);
 	return;
 
 err_deq_chan:
@@ -797,6 +798,7 @@ static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 	newchannel = alloc_channel();
 	if (!newchannel) {
 		vmbus_release_relid(offer->child_relid);
+		atomic_dec(&vmbus_connection.offer_in_progress);
 		pr_err("Unable to allocate channel object\n");
 		return;
 	}
@@ -843,16 +845,38 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 
 	rescind = (struct vmbus_channel_rescind_offer *)hdr;
 
+	/*
+	 * The offer msg and the corresponding rescind msg
+	 * from the host are guranteed to be ordered -
+	 * offer comes in first and then the rescind.
+	 * Since we process these events in work elements,
+	 * and with preemption, we may end up processing
+	 * the events out of order. Given that we handle these
+	 * work elements on the same CPU, this is possible only
+	 * in the case of preemption. In any case wait here
+	 * until the offer processing has moved beyond the
+	 * point where the channel is discoverable.
+	 */
+
+	while (atomic_read(&vmbus_connection.offer_in_progress) != 0) {
+		/*
+		 * We wait here until any channel offer is currently
+		 * being processed.
+		 */
+		msleep(1);
+	}
+
 	mutex_lock(&vmbus_connection.channel_mutex);
 	channel = relid2channel(rescind->child_relid);
+	mutex_unlock(&vmbus_connection.channel_mutex);
 
 	if (channel == NULL) {
 		/*
-		 * This is very impossible, because in
-		 * vmbus_process_offer(), we have already invoked
-		 * vmbus_release_relid() on error.
+		 * We failed in processing the offer message;
+		 * we would have cleaned up the relid in that
+		 * failure path.
 		 */
-		goto out;
+		return;
 	}
 
 	spin_lock_irqsave(&channel->lock, flags);
@@ -864,7 +888,7 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 	if (channel->device_obj) {
 		if (channel->chn_rescind_callback) {
 			channel->chn_rescind_callback(channel);
-			goto out;
+			return;
 		}
 		/*
 		 * We will have to unregister this device from the
@@ -875,13 +899,26 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 			vmbus_device_unregister(channel->device_obj);
 			put_device(dev);
 		}
-	} else {
-		hv_process_channel_removal(channel,
-			channel->offermsg.child_relid);
 	}
-
-out:
-	mutex_unlock(&vmbus_connection.channel_mutex);
+	if (channel->primary_channel != NULL) {
+		/*
+		 * Sub-channel is being rescinded. Following is the channel
+		 * close sequence when initiated from the driveri (refer to
+		 * vmbus_close() for details):
+		 * 1. Close all sub-channels first
+		 * 2. Then close the primary channel.
+		 */
+		if (channel->state == CHANNEL_OPEN_STATE) {
+			/*
+			 * The channel is currently not open;
+			 * it is safe for us to cleanup the channel.
+			 */
+			mutex_lock(&vmbus_connection.channel_mutex);
+			hv_process_channel_removal(channel,
+						channel->offermsg.child_relid);
+			mutex_unlock(&vmbus_connection.channel_mutex);
+		}
+	}
 }
 
 void vmbus_hvsock_device_unregister(struct vmbus_channel *channel)