Patch "driver core: fw_devlink: Improve logs for cycle detection" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    driver core: fw_devlink: Improve logs for cycle detection

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     driver-core-fw_devlink-improve-logs-for-cycle-detect.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 6a716baa913705f983ed10a53b944a57994d0378
Author: Saravana Kannan <saravanak@xxxxxxxxxx>
Date:   Fri Feb 2 01:56:35 2024 -0800

    driver core: fw_devlink: Improve logs for cycle detection
    
    [ Upstream commit 6e7ad1aebb4fc9fed0217dd50ef6e58a53f17d81 ]
    
    The links in a cycle are not all logged in a consistent manner or not
    logged at all. Make them consistent by adding a "cycle:" string and log all
    the link in the cycles (even the child ==> parent dependency) so that it's
    easier to debug cycle detection code. Also, mark the start and end of a
    cycle so it's easy to tell when multiple cycles are logged back to back.
    
    Signed-off-by: Saravana Kannan <saravanak@xxxxxxxxxx>
    Tested-by: Xu Yang <xu.yang_2@xxxxxxx>
    Link: https://lore.kernel.org/r/20240202095636.868578-4-saravanak@xxxxxxxxxx
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
    Stable-dep-of: bac3b10b78e5 ("driver core: fw_devlink: Stop trying to optimize cycle detection logic")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/base/core.c b/drivers/base/core.c
index c9fb3243e353e..499904f1ba6b3 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -125,7 +125,7 @@ static void __fwnode_link_del(struct fwnode_link *link)
  */
 static void __fwnode_link_cycle(struct fwnode_link *link)
 {
-	pr_debug("%pfwf: Relaxing link with %pfwf\n",
+	pr_debug("%pfwf: cycle: depends on %pfwf\n",
 		 link->consumer, link->supplier);
 	link->flags |= FWLINK_FLAG_CYCLE;
 }
@@ -1959,6 +1959,7 @@ static bool __fw_devlink_relax_cycles(struct device *con,
 
 	/* Termination condition. */
 	if (sup_dev == con) {
+		pr_debug("----- cycle: start -----\n");
 		ret = true;
 		goto out;
 	}
@@ -1990,8 +1991,11 @@ static bool __fw_devlink_relax_cycles(struct device *con,
 	else
 		par_dev = fwnode_get_next_parent_dev(sup_handle);
 
-	if (par_dev && __fw_devlink_relax_cycles(con, par_dev->fwnode))
+	if (par_dev && __fw_devlink_relax_cycles(con, par_dev->fwnode)) {
+		pr_debug("%pfwf: cycle: child of %pfwf\n", sup_handle,
+			 par_dev->fwnode);
 		ret = true;
+	}
 
 	if (!sup_dev)
 		goto out;
@@ -2007,6 +2011,8 @@ static bool __fw_devlink_relax_cycles(struct device *con,
 
 		if (__fw_devlink_relax_cycles(con,
 					      dev_link->supplier->fwnode)) {
+			pr_debug("%pfwf: cycle: depends on %pfwf\n", sup_handle,
+				 dev_link->supplier->fwnode);
 			fw_devlink_relax_link(dev_link);
 			dev_link->flags |= DL_FLAG_CYCLE;
 			ret = true;
@@ -2086,6 +2092,7 @@ static int fw_devlink_create_devlink(struct device *con,
 		if (__fw_devlink_relax_cycles(con, sup_handle)) {
 			__fwnode_link_cycle(link);
 			flags = fw_devlink_get_flags(link->flags);
+			pr_debug("----- cycle: end -----\n");
 			dev_info(con, "Fixed dependency cycle(s) with %pfwf\n",
 				 sup_handle);
 		}