driver core: fw_devlink: Improve logs for cycle detection

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@google.com>
Tested-by: Xu Yang <xu.yang_2@nxp.com>
Link: https://lore.kernel.org/r/20240202095636.868578-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/base/core.c b/drivers/base/core.c
index e3d666461835b6bb82fdb698a81d0dcd3e093c1b..9828da9b933cb7511756d15ec8be2ebbd14f9e44 100644 (file)
--- 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;
 }
@@ -1945,6 +1945,7 @@ static bool __fw_devlink_relax_cycles(struct device *con,
 
        /* Termination condition. */
        if (sup_dev == con) {
+               pr_debug("----- cycle: start -----\n");
                ret = true;
                goto out;
        }
@@ -1976,8 +1977,11 @@ 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;
@@ -1993,6 +1997,8 @@ 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;
@@ -2072,6 +2078,7 @@ 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);
                }