[PATCH v1 3/3] driver core: fw_devlink: Improve logs for cycle detection

From: Saravana Kannan
Date: Fri Feb 02 2024 - 04:27:16 EST


The links in a cycle are not all logged in a consistent manner or not
logged at all. Make them consistent 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>
---
drivers/base/core.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index e3d666461835..084d9648e254 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;
}
@@ -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: depends on %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);
}
--
2.43.0.594.gd9cf4e227d-goog