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authorSaravana Kannan <saravanak@google.com>2020-05-26 15:09:27 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-05-27 12:20:47 +0200
commit8c3e315d4296421cd26b3300ee0ac117f0877f20 (patch)
treec3336561c4a2f22b629cd9762019473e485e34c5 /drivers/base
parentc2c076166b5880eabe068ce1cab30bf6edeeea1a (diff)
downloadlinux-8c3e315d4296421cd26b3300ee0ac117f0877f20.tar.bz2
driver core: Update device link status correctly for SYNC_STATE_ONLY links
When SYNC_STATE_ONLY support was added in commit 05ef983e0d65 ("driver core: Add device link support for SYNC_STATE_ONLY flag"), SYNC_STATE_ONLY links were treated similar to STATELESS links in terms of not blocking consumer probe if the supplier hasn't probed yet. That caused a SYNC_STATE_ONLY device link's status to not get updated. Since SYNC_STATE_ONLY device link is no longer useful once the consumer probes, commit 21c27f06587d ("driver core: Fix SYNC_STATE_ONLY device link implementation") addresses the status update issue by deleting the SYNC_STATE_ONLY device link instead of complicating the status update code. However, there are still some cases where we need to update the status of a SYNC_STATE_ONLY device link. This is because a SYNC_STATE_ONLY device link can later get converted into a normal MANAGED device link when a normal MANAGED device link is created between a supplier and consumer that already have a SYNC_STATE_ONLY device link between them. If a SYNC_STATE_ONLY device link's status isn't maintained correctly till it's converted to a normal MANAGED device link, then the normal MANAGED device link will end up with a wrong link status. This can cause a warning stack trace[1] when the consumer device probes successfully. This commit fixes the SYNC_STATE_ONLY device link status update issue where it wouldn't transition correctly from DL_STATE_DORMANT or DL_STATE_AVAILABLE to DL_STATE_CONSUMER_PROBE. It also resets the status back to DL_STATE_DORMANT or DL_STATE_AVAILABLE if the consumer probe fails. [1] - https://lore.kernel.org/lkml/20200522204120.3b3c9ed6@apollo/ Fixes: 05ef983e0d65 ("driver core: Add device link support for SYNC_STATE_ONLY flag") Fixes: 21c27f06587d ("driver core: Fix SYNC_STATE_ONLY device link implementation") Reported-by: Michael Walle <michael@walle.cc> Tested-by: Michael Walle <michael@walle.cc> Signed-off-by: Saravana Kannan <saravanak@google.com> Reviewed-by: Rafael J. Wysocki <rrafael.j.wysocki@intel.com> Link: https://lore.kernel.org/r/20200526220928.49939-1-saravanak@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/core.c34
1 files changed, 26 insertions, 8 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 791b7530599f..9a76dd44cb37 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -646,9 +646,17 @@ static void device_links_missing_supplier(struct device *dev)
{
struct device_link *link;
- list_for_each_entry(link, &dev->links.suppliers, c_node)
- if (link->status == DL_STATE_CONSUMER_PROBE)
+ list_for_each_entry(link, &dev->links.suppliers, c_node) {
+ if (link->status != DL_STATE_CONSUMER_PROBE)
+ continue;
+
+ if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
+ } else {
+ WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
+ WRITE_ONCE(link->status, DL_STATE_DORMANT);
+ }
+ }
}
/**
@@ -687,11 +695,11 @@ int device_links_check_suppliers(struct device *dev)
device_links_write_lock();
list_for_each_entry(link, &dev->links.suppliers, c_node) {
- if (!(link->flags & DL_FLAG_MANAGED) ||
- link->flags & DL_FLAG_SYNC_STATE_ONLY)
+ if (!(link->flags & DL_FLAG_MANAGED))
continue;
- if (link->status != DL_STATE_AVAILABLE) {
+ if (link->status != DL_STATE_AVAILABLE &&
+ !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
device_links_missing_supplier(dev);
ret = -EPROBE_DEFER;
break;
@@ -952,11 +960,21 @@ static void __device_links_no_driver(struct device *dev)
if (!(link->flags & DL_FLAG_MANAGED))
continue;
- if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
+ if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
device_link_drop_managed(link);
- else if (link->status == DL_STATE_CONSUMER_PROBE ||
- link->status == DL_STATE_ACTIVE)
+ continue;
+ }
+
+ if (link->status != DL_STATE_CONSUMER_PROBE &&
+ link->status != DL_STATE_ACTIVE)
+ continue;
+
+ if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
+ } else {
+ WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
+ WRITE_ONCE(link->status, DL_STATE_DORMANT);
+ }
}
dev->links.status = DL_DEV_NO_DRIVER;