PCI: Add pci_irq_type() to query the allocated interrupt typegrafted

Add a helper that returns PCI_IRQ_MSIX, PCI_IRQ_MSI, or PCI_IRQ_INTX
based on the interrupt type the PCI core selected after
pci_alloc_irq_vectors().

Several drivers already open-code this check against pdev->msix_enabled
and pdev->msi_enabled, or even open code this helper [1].

A common helper avoids the duplication and keeps drivers from accessing
the bitfield directly (see also [2]).

Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Link: https://elixir.bootlin.com/linux/v7.1/source/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c#L196 [1]
Inspired-by: John Hubbard <jhubbard@nvidia.com>
Link: https://lore.kernel.org/all/DKKG2QM3YJYB.Z2H2B2UXJ75N@kernel.org/ [2]
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260813165234.620555-5-dakr@kernel.org
[ Add missing pci_irq_type() stub for CONFIG_PCI=n. ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/Documentation/rust/index.rst b/Documentation/rust/index.rst
new file mode 100644
index 000000000..b78ed0efa
--- /dev/null
+++ b/Documentation/rust/index.rst
@@ -0,0 +1,42 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Rust
+====
+
+Documentation related to Rust within the kernel. To start using Rust
+in the kernel, please read the quick-start.rst guide.
+
+
+Code documentation
+------------------
+
+Given a kernel configuration, the kernel may generate Rust code documentation,
+i.e. HTML rendered by the ``rustdoc`` tool.
+
+.. only:: rustdoc and html
+
+	This kernel documentation was built with `Rust code documentation
+	<rustdoc/kernel/index.html>`_.
+
+.. only:: not rustdoc and html
+
+	This kernel documentation was not built with Rust code documentation.
+
+A pregenerated version is provided at:
+
+	https://rust.docs.kernel.org
+
+Please see the :ref:`Code documentation <rust_code_documentation>` section for
+more details.
+
+.. toctree::
+    :maxdepth: 1
+
+    quick-start
+    general-information
+    coding-guidelines
+    arch-support
+    testing
+
+You can also find learning materials for Rust in its section in
+:doc:`../process/kernel-docs`.