From d5dcce0c414fcbfe4c2037b66ac69ea5f9b3f75c Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Thu, 22 Oct 2020 21:40:59 +0300 Subject: device property: Keep secondary firmware node secondary by type Behind primary and secondary we understand the type of the nodes which might define their ordering. However, if primary node gone, we can't maintain the ordering by definition of the linked list. Thus, by ordering secondary node becomes first in the list. But in this case the meaning of it is still secondary (or auxiliary). The type of the node is maintained by the secondary pointer in it: secondary pointer Meaning NULL or valid primary node ERR_PTR(-ENODEV) secondary node So, if by some reason we do the following sequence of calls set_primary_fwnode(dev, NULL); set_primary_fwnode(dev, primary); we should preserve secondary node. This concept is supported by the description of set_primary_fwnode() along with implementation of set_secondary_fwnode(). Hence, fix the commit c15e1bdda436 to follow this as well. Fixes: c15e1bdda436 ("device property: Fix the secondary firmware node handling in set_primary_fwnode()") Cc: Ferry Toth Signed-off-by: Andy Shevchenko Reviewed-by: Heikki Krogerus Tested-by: Ferry Toth Cc: 5.9+ # 5.9+ Signed-off-by: Rafael J. Wysocki --- drivers/base/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/base/core.c b/drivers/base/core.c index c852f16c111b..41feab679fa1 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -4278,7 +4278,7 @@ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode) } else { if (fwnode_is_primary(fn)) { dev->fwnode = fn->secondary; - fn->secondary = NULL; + fn->secondary = ERR_PTR(-ENODEV); } else { dev->fwnode = NULL; } -- cgit v1.2.3 From 99aed9227073fb34ce2880cbc7063e04185a65e1 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Thu, 22 Oct 2020 21:41:00 +0300 Subject: device property: Don't clear secondary pointer for shared primary firmware node It appears that firmware nodes can be shared between devices. In such case when a (child) device is about to be deleted, its firmware node may be shared and ACPI_COMPANION_SET(..., NULL) call for it breaks the secondary link of the shared primary firmware node. In order to prevent that, check, if the device has a parent and parent's firmware node is shared with its child, and avoid crashing the link. Fixes: c15e1bdda436 ("device property: Fix the secondary firmware node handling in set_primary_fwnode()") Reported-by: Ferry Toth Signed-off-by: Andy Shevchenko Reviewed-by: Heikki Krogerus Tested-by: Ferry Toth Cc: 5.9+ # 5.9+ Signed-off-by: Rafael J. Wysocki --- drivers/base/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/base/core.c b/drivers/base/core.c index 41feab679fa1..78114ddac755 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -4264,6 +4264,7 @@ static inline bool fwnode_is_primary(struct fwnode_handle *fwnode) */ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode) { + struct device *parent = dev->parent; struct fwnode_handle *fn = dev->fwnode; if (fwnode) { @@ -4278,7 +4279,8 @@ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode) } else { if (fwnode_is_primary(fn)) { dev->fwnode = fn->secondary; - fn->secondary = ERR_PTR(-ENODEV); + if (!(parent && fn == parent->fwnode)) + fn->secondary = ERR_PTR(-ENODEV); } else { dev->fwnode = NULL; } -- cgit v1.2.3