[PATCH 1/4] rust: pci: make Vendor::from_raw() public

[Maurice Hieronymus]

Vendor::from_raw() is currently pub(super), so a Vendor can only be
obtained through the named constants generated from the PCI_VENDOR_ID_*
defines in <linux/pci_ids.h>. A driver therefore cannot match a device
whose vendor ID has no symbolic name.

Such devices exist. QEMU's "edu" educational device and the legacy
qemu/Bochs stdvga both use vendor ID 0x1234, which is not registered in
pci_ids.h. Per the policy stated at the top of that header, IDs are only
added there when shared between multiple drivers; a single-driver ID is
expected to be open-coded in the driver instead. C drivers already do
this -- see drivers/gpu/drm/tiny/bochs.c, which matches with a bare
".vendor = 0x1234".

The Rust abstraction has no equivalent escape hatch: there is no public
way to express an unregistered vendor. Make Vendor::from_raw() public (and
const, so it can be used in the const device-ID tables built by
pci_device_table!) so that drivers can construct a Vendor from a raw ID,
matching what C drivers can already do.

Signed-off-by: Maurice Hieronymus <mhi@xxxxxxxxxxx>
---
 rust/kernel/pci/id.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rust/kernel/pci/id.rs b/rust/kernel/pci/id.rs
index 50005d176561..bd3cf17fd8de 100644
--- a/rust/kernel/pci/id.rs
+++ b/rust/kernel/pci/id.rs
@@ -156,7 +156,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 impl Vendor {
     /// Create a Vendor from a raw 16-bit vendor ID.
     #[inline]
-    pub(super) fn from_raw(vendor_id: u16) -> Self {
+    pub const fn from_raw(vendor_id: u16) -> Self {
         Self(vendor_id)
     }
 

-- 
2.51.2