| Message ID | 20200417165442.1856-3-nsaenzjulienne@suse.de |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | of: property: fw_devlink misc fixes | expand |
| Context | Check | Description |
|---|---|---|
| robh/checkpatch | warning | "total: 0 errors, 1 warnings, 26 lines checked" |
On Fri, Apr 17, 2020 at 9:54 AM Nicolas Saenz Julienne <nsaenzjulienne@suse.de> wrote: > > When creating a consumer/supplier relationship between two devices, > make sure the supplier node is actually active. Otherwise this will > create a link relationship that will never be fulfilled. This, in the > worst case scenario, will hang the system during boot. > > Note that, in practice, the fact that a device-tree represented > consumer/supplier relationship isn't fulfilled will not prevent devices > from successfully probing. > > Fixes: a3e1d1a7f5fc ("of: property: Add functional dependency link from DT bindings") > Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> > > --- > > Changes since v1: > - Move availability check into the compatible search routine and bail > if device node disabled > > drivers/of/property.c | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > diff --git a/drivers/of/property.c b/drivers/of/property.c > index dc034eb45defd..14b6266dd054b 100644 > --- a/drivers/of/property.c > +++ b/drivers/of/property.c > @@ -1045,8 +1045,25 @@ static int of_link_to_phandle(struct device *dev, struct device_node *sup_np, > * Find the device node that contains the supplier phandle. It may be > * @sup_np or it may be an ancestor of @sup_np. > */ > - while (sup_np && !of_find_property(sup_np, "compatible", NULL)) > + while (sup_np) { > + > + /* > + * Don't allow linking a device node as consumer of a disabled > + * node. > + */ Minor nit: I'd just say "Don't allow linking to a disabled supplier". > + if (!of_device_is_available(sup_np)) { > + dev_dbg(dev, "Not linking to %pOFP - Not available\n", > + sup_np); > + of_node_put(sup_np); > + return -ENODEV; > + } This if block looks very similar to the one right after the loop. Maybe there's a nice way to combine it? If you replace this if block with this, it'll end up with the same result. if (!of_device_is_available(sup_np)) { of_node_put(sup_np); sup_np = NULL; } of_get_next_parent() handles a NULL input properly. So that won't be a problem. And "No device" is a valid statement for both cases I think. > + > + if (of_find_property(sup_np, "compatible", NULL)) > + break; > + > sup_np = of_get_next_parent(sup_np); > + } > + > if (!sup_np) { > dev_dbg(dev, "Not linking to %pOFP - No device\n", tmp_np); > return -ENODEV; However, not against this patch as is if Rob/Frank like it as is. -Saravana
On Fri, 2020-04-17 at 14:08 -0700, Saravana Kannan wrote: > On Fri, Apr 17, 2020 at 9:54 AM Nicolas Saenz Julienne > <nsaenzjulienne@suse.de> wrote: > > When creating a consumer/supplier relationship between two devices, > > make sure the supplier node is actually active. Otherwise this will > > create a link relationship that will never be fulfilled. This, in the > > worst case scenario, will hang the system during boot. > > > > Note that, in practice, the fact that a device-tree represented > > consumer/supplier relationship isn't fulfilled will not prevent devices > > from successfully probing. > > > > Fixes: a3e1d1a7f5fc ("of: property: Add functional dependency link from DT > > bindings") > > Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> > > > > --- > > > > Changes since v1: > > - Move availability check into the compatible search routine and bail > > if device node disabled > > > > drivers/of/property.c | 19 ++++++++++++++++++- > > 1 file changed, 18 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/of/property.c b/drivers/of/property.c > > index dc034eb45defd..14b6266dd054b 100644 > > --- a/drivers/of/property.c > > +++ b/drivers/of/property.c > > @@ -1045,8 +1045,25 @@ static int of_link_to_phandle(struct device *dev, > > struct device_node *sup_np, > > * Find the device node that contains the supplier phandle. It may > > be > > * @sup_np or it may be an ancestor of @sup_np. > > */ > > - while (sup_np && !of_find_property(sup_np, "compatible", NULL)) > > + while (sup_np) { > > + > > + /* > > + * Don't allow linking a device node as consumer of a > > disabled > > + * node. > > + */ > > Minor nit: I'd just say "Don't allow linking to a disabled supplier". > > > + if (!of_device_is_available(sup_np)) { > > + dev_dbg(dev, "Not linking to %pOFP - Not > > available\n", > > + sup_np); > > + of_node_put(sup_np); > > + return -ENODEV; > > + } > > This if block looks very similar to the one right after the loop. > Maybe there's a nice way to combine it? > > If you replace this if block with this, it'll end up with the same result. > if (!of_device_is_available(sup_np)) { > of_node_put(sup_np); > sup_np = NULL; > } > > of_get_next_parent() handles a NULL input properly. So that won't be a > problem. And "No device" is a valid statement for both cases I think. > > > + > > + if (of_find_property(sup_np, "compatible", NULL)) > > + break; > > + > > sup_np = of_get_next_parent(sup_np); > > + } > > + > > if (!sup_np) { > > dev_dbg(dev, "Not linking to %pOFP - No device\n", tmp_np); > > return -ENODEV; > > However, not against this patch as is if Rob/Frank like it as is. Agree with your suggestions, I'll send an v3. Regards, Nicolas
diff --git a/drivers/of/property.c b/drivers/of/property.c index dc034eb45defd..14b6266dd054b 100644 --- a/drivers/of/property.c +++ b/drivers/of/property.c @@ -1045,8 +1045,25 @@ static int of_link_to_phandle(struct device *dev, struct device_node *sup_np, * Find the device node that contains the supplier phandle. It may be * @sup_np or it may be an ancestor of @sup_np. */ - while (sup_np && !of_find_property(sup_np, "compatible", NULL)) + while (sup_np) { + + /* + * Don't allow linking a device node as consumer of a disabled + * node. + */ + if (!of_device_is_available(sup_np)) { + dev_dbg(dev, "Not linking to %pOFP - Not available\n", + sup_np); + of_node_put(sup_np); + return -ENODEV; + } + + if (of_find_property(sup_np, "compatible", NULL)) + break; + sup_np = of_get_next_parent(sup_np); + } + if (!sup_np) { dev_dbg(dev, "Not linking to %pOFP - No device\n", tmp_np); return -ENODEV;
When creating a consumer/supplier relationship between two devices, make sure the supplier node is actually active. Otherwise this will create a link relationship that will never be fulfilled. This, in the worst case scenario, will hang the system during boot. Note that, in practice, the fact that a device-tree represented consumer/supplier relationship isn't fulfilled will not prevent devices from successfully probing. Fixes: a3e1d1a7f5fc ("of: property: Add functional dependency link from DT bindings") Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> --- Changes since v1: - Move availability check into the compatible search routine and bail if device node disabled drivers/of/property.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-)