1 files changed, 92 insertions, 8 deletions

diff --git a/drivers/usb/usbip/stub_main.c b/drivers/usb/usbip/stub_main.c
index c31c8402a0c5..bf8a5feb0ee9 100644
--- a/drivers/usb/usbip/stub_main.c
+++ b/drivers/usb/usbip/stub_main.c
@@ -14,6 +14,7 @@
 #define DRIVER_DESC "USB/IP Host Driver"
 
 struct kmem_cache *stub_priv_cache;
+
 /*
  * busid_tables defines matching busids that usbip can grab. A user can change
  * dynamically what device is locally used and what device is exported to a
@@ -25,6 +26,8 @@ static spinlock_t busid_table_lock;
 
 static void init_busid_table(void)
 {
+	int i;
+
 	/*
 	 * This also sets the bus_table[i].status to
 	 * STUB_BUSID_OTHER, which is 0.
@@ -32,6 +35,9 @@ static void init_busid_table(void)
 	memset(busid_table, 0, sizeof(busid_table));
 
 	spin_lock_init(&busid_table_lock);
+
+	for (i = 0; i < MAX_BUSID; i++)
+		spin_lock_init(&busid_table[i].busid_lock);
 }
 
 /*
@@ -43,15 +49,20 @@ static int get_busid_idx(const char *busid)
 	int i;
 	int idx = -1;
 
-	for (i = 0; i < MAX_BUSID; i++)
+	for (i = 0; i < MAX_BUSID; i++) {
+		spin_lock(&busid_table[i].busid_lock);
 		if (busid_table[i].name[0])
 			if (!strncmp(busid_table[i].name, busid, BUSID_SIZE)) {
 				idx = i;
+				spin_unlock(&busid_table[i].busid_lock);
 				break;
 			}
+		spin_unlock(&busid_table[i].busid_lock);
+	}
 	return idx;
 }
 
+/* Returns holding busid_lock. Should call put_busid_priv() to unlock */
 struct bus_id_priv *get_busid_priv(const char *busid)
 {
 	int idx;
@@ -59,13 +70,22 @@ struct bus_id_priv *get_busid_priv(const char *busid)
 
 	spin_lock(&busid_table_lock);
 	idx = get_busid_idx(busid);
-	if (idx >= 0)
+	if (idx >= 0) {
 		bid = &(busid_table[idx]);
+		/* get busid_lock before returning */
+		spin_lock(&bid->busid_lock);
+	}
 	spin_unlock(&busid_table_lock);
 
 	return bid;
 }
 
+void put_busid_priv(struct bus_id_priv *bid)
+{
+	if (bid)
+		spin_unlock(&bid->busid_lock);
+}
+
 static int add_match_busid(char *busid)
 {
 	int i;
@@ -78,15 +98,19 @@ static int add_match_busid(char *busid)
 		goto out;
 	}
 
-	for (i = 0; i < MAX_BUSID; i++)
+	for (i = 0; i < MAX_BUSID; i++) {
+		spin_lock(&busid_table[i].busid_lock);
 		if (!busid_table[i].name[0]) {
 			strlcpy(busid_table[i].name, busid, BUSID_SIZE);
 			if ((busid_table[i].status != STUB_BUSID_ALLOC) &&
 			    (busid_table[i].status != STUB_BUSID_REMOV))
 				busid_table[i].status = STUB_BUSID_ADDED;
 			ret = 0;
+			spin_unlock(&busid_table[i].busid_lock);
 			break;
 		}
+		spin_unlock(&busid_table[i].busid_lock);
+	}
 
 out:
 	spin_unlock(&busid_table_lock);
@@ -107,6 +131,8 @@ int del_match_busid(char *busid)
 	/* found */
 	ret = 0;
 
+	spin_lock(&busid_table[idx].busid_lock);
+
 	if (busid_table[idx].status == STUB_BUSID_OTHER)
 		memset(busid_table[idx].name, 0, BUSID_SIZE);
 
@@ -114,6 +140,7 @@ int del_match_busid(char *busid)
 	    (busid_table[idx].status != STUB_BUSID_ADDED))
 		busid_table[idx].status = STUB_BUSID_REMOV;
 
+	spin_unlock(&busid_table[idx].busid_lock);
 out:
 	spin_unlock(&busid_table_lock);
 
@@ -126,9 +153,12 @@ static ssize_t match_busid_show(struct device_driver *drv, char *buf)
 	char *out = buf;
 
 	spin_lock(&busid_table_lock);
-	for (i = 0; i < MAX_BUSID; i++)
+	for (i = 0; i < MAX_BUSID; i++) {
+		spin_lock(&busid_table[i].busid_lock);
 		if (busid_table[i].name[0])
 			out += sprintf(out, "%s ", busid_table[i].name);
+		spin_unlock(&busid_table[i].busid_lock);
+	}
 	spin_unlock(&busid_table_lock);
 	out += sprintf(out, "\n");
 
@@ -169,6 +199,51 @@ static ssize_t match_busid_store(struct device_driver *dev, const char *buf,
 }
 static DRIVER_ATTR_RW(match_busid);
 
+static int do_rebind(char *busid, struct bus_id_priv *busid_priv)
+{
+	int ret;
+
+	/* device_attach() callers should hold parent lock for USB */
+	if (busid_priv->udev->dev.parent)
+		device_lock(busid_priv->udev->dev.parent);
+	ret = device_attach(&busid_priv->udev->dev);
+	if (busid_priv->udev->dev.parent)
+		device_unlock(busid_priv->udev->dev.parent);
+	if (ret < 0) {
+		dev_err(&busid_priv->udev->dev, "rebind failed\n");
+		return ret;
+	}
+	return 0;
+}
+
+static void stub_device_rebind(void)
+{
+#if IS_MODULE(CONFIG_USBIP_HOST)
+	struct bus_id_priv *busid_priv;
+	int i;
+
+	/* update status to STUB_BUSID_OTHER so probe ignores the device */
+	spin_lock(&busid_table_lock);
+	for (i = 0; i < MAX_BUSID; i++) {
+		if (busid_table[i].name[0] &&
+		    busid_table[i].shutdown_busid) {
+			busid_priv = &(busid_table[i]);
+			busid_priv->status = STUB_BUSID_OTHER;
+		}
+	}
+	spin_unlock(&busid_table_lock);
+
+	/* now run rebind - no need to hold locks. driver files are removed */
+	for (i = 0; i < MAX_BUSID; i++) {
+		if (busid_table[i].name[0] &&
+		    busid_table[i].shutdown_busid) {
+			busid_priv = &(busid_table[i]);
+			do_rebind(busid_table[i].name, busid_priv);
+		}
+	}
+#endif
+}
+
 static ssize_t rebind_store(struct device_driver *dev, const char *buf,
 				 size_t count)
 {
@@ -186,11 +261,17 @@ static ssize_t rebind_store(struct device_driver *dev, const char *buf,
 	if (!bid)
 		return -ENODEV;
 
-	ret = device_attach(&bid->udev->dev);
-	if (ret < 0) {
-		dev_err(&bid->udev->dev, "rebind failed\n");
+	/* mark the device for deletion so probe ignores it during rescan */
+	bid->status = STUB_BUSID_OTHER;
+	/* release the busid lock */
+	put_busid_priv(bid);
+
+	ret = do_rebind((char *) buf, bid);
+	if (ret < 0)
 		return ret;
-	}
+
+	/* delete device from busid_table */
+	del_match_busid((char *) buf);
 
 	return count;
 }
@@ -312,6 +393,9 @@ static void __exit usbip_host_exit(void)
 	 */
 	usb_deregister_device_driver(&stub_driver);
 
+	/* initiate scan to attach devices */
+	stub_device_rebind();
+
 	kmem_cache_destroy(stub_priv_cache);
 }