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of/irq: Stop the MSI walk at the first msi-parent

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of_check_msi_parent() returns -EINVAL both when the msi-parent names a
controller other than the one the caller filters on and when #msi-cells
isn't 0, so of_msi_xlate() can't tell the two apart and carries on up
the hierarchy. An ancestor's msi-map then maps the device onto a
controller its own node didn't name.

Hand the parsed specifier back to of_msi_xlate(), which owns the
reference as it already does on the msi-map path, and end the walk at
any node that declares an msi-parent.

Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/all/20260904074800.875391F00A3F@smtp.kernel.org/
Suggested-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Link: https://lore.kernel.org/all/apqnaNmeuUjfC8Ng@red-moon/
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Link: https://patch.msgid.link/20260907112944.313618-3-fuad.tabba@linux.dev
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
This commit is contained in:
Fuad Tabba 2026-09-07 12:29:44 +01:00 committed by Rob Herring (Arm)
parent cbe0f79dca
commit 833aaa4790
1 changed files with 22 additions and 17 deletions
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39
drivers/of/irq.c
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@ -765,34 +765,27 @@ void __init of_irq_init(const struct of_device_id *matches)
}
}
static int of_check_msi_parent(struct device_node *dev_node, struct device_node **msi_node)
static int of_check_msi_parent(struct device_node *dev_node, struct device_node **msi_node,
struct of_phandle_args *msi_spec)
{
struct of_phandle_args msi_spec;
int ret;
/*
* An msi-parent phandle with a missing or == 0 #msi-cells
* property identifies a 1:1 ID translation mapping.
*
* Set the msi controller node if the firmware matches this
* condition.
* @msi_spec keeps a reference to the target node whenever the
* phandle parses, -EINVAL included, and the caller releases it.
*/
ret = of_parse_phandle_with_optional_args(dev_node, "msi-parent", "#msi-cells",
0, &msi_spec);
0, msi_spec);
if (ret)
return ret;
if ((*msi_node && *msi_node != msi_spec.np) || msi_spec.args_count != 0)
ret = -EINVAL;
if ((*msi_node && *msi_node != msi_spec->np) || msi_spec->args_count != 0)
return -EINVAL;
if (!ret && !*msi_node) {
/* Return with a node reference held */
*msi_node = msi_spec.np;
return 0;
}
of_node_put(msi_spec.np);
return ret;
return 0;
}
/**
@ -806,7 +799,9 @@ static int of_check_msi_parent(struct device_node *dev_node, struct device_node
* @id_in: Device ID.
*
* Walk up the device hierarchy looking for devices with a "msi-map"
* or "msi-parent" property. If found, apply the mapping to @id_in.
* or "msi-parent" property. If found, apply the mapping to @id_in. With
* @msi_np non-NULL, a device declaring an msi-parent ends the walk, usable
* or not.
*
* Returns: The mapped MSI id.
*/
@ -821,6 +816,7 @@ u32 of_msi_xlate(struct device *dev, struct device_node **msi_np, u32 id_in)
*/
for (parent_dev = dev; parent_dev; parent_dev = parent_dev->parent) {
struct of_phandle_args msi_spec = {};
int ret;
if (!of_map_msi_id(parent_dev->of_node, id_in, msi_np, &msi_spec)) {
if (msi_spec.np) {
@ -835,8 +831,17 @@ u32 of_msi_xlate(struct device *dev, struct device_node **msi_np, u32 id_in)
break;
}
/* -ENODEV: msi-map absent → check for msi-parent */
if (msi_np && !of_check_msi_parent(parent_dev->of_node, msi_np))
if (!msi_np)
continue;
ret = of_check_msi_parent(parent_dev->of_node, msi_np, &msi_spec);
if (msi_spec.np) {
/* A declared msi-parent names the controller, usable or not */
if (!ret && !*msi_np)
*msi_np = of_node_get(msi_spec.np);
of_node_put(msi_spec.np);
break;
}
}
return id_out;
}