releases/5.5.17/driver-core-reevaluate-dev-links.need_for_probe-as-suppliers-are-added.patch

From 1745d299af5b373abad08fa29bff0d31dc6aff21 Mon Sep 17 00:00:00 2001
From: Saravana Kannan <saravanak@google.com>
Date: Fri, 21 Feb 2020 17:40:34 -0800
Subject: driver core: Reevaluate dev->links.need_for_probe as suppliers are added

From: Saravana Kannan <saravanak@google.com>

commit 1745d299af5b373abad08fa29bff0d31dc6aff21 upstream.

A previous patch 03324507e66c ("driver core: Allow
fwnode_operations.add_links to differentiate errors") forgot to update
all call sites to fwnode_operations.add_links. This patch fixes that.

Legend:
-> Denotes RHS is an optional/potential supplier for LHS
=> Denotes RHS is a mandatory supplier for LHS

Example:

Device A => Device X
Device A -> Device Y

Before this patch:
1. Device A is added.
2. Device A is marked as waiting for mandatory suppliers
3. Device X is added
4. Device A is left marked as waiting for mandatory suppliers

Step 4 is wrong since all mandatory suppliers of Device A have been
added.

After this patch:
1. Device A is added.
2. Device A is marked as waiting for mandatory suppliers
3. Device X is added
4. Device A is no longer considered as waiting for mandatory suppliers

This is the correct behavior.

Fixes: 03324507e66c ("driver core: Allow fwnode_operations.add_links to differentiate errors")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200222014038.180923-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/base/core.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -523,9 +523,13 @@ static void device_link_add_missing_supp
 
 	mutex_lock(&wfs_lock);
 	list_for_each_entry_safe(dev, tmp, &wait_for_suppliers,
-				 links.needs_suppliers)
-		if (!fwnode_call_int_op(dev->fwnode, add_links, dev))
+				 links.needs_suppliers) {
+		int ret = fwnode_call_int_op(dev->fwnode, add_links, dev);
+		if (!ret)
 			list_del_init(&dev->links.needs_suppliers);
+		else if (ret != -ENODEV)
+			dev->links.need_for_probe = false;
+	}
 	mutex_unlock(&wfs_lock);
 }