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, 38 insertions, 0 deletions

diff --git a/drivers/scsi/scsi_sysctl.c b/drivers/scsi/scsi_sysctl.c
new file mode 100644
index 000000000..055a03a83
--- /dev/null
+++ b/drivers/scsi/scsi_sysctl.c
@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2003 Christoph Hellwig.
+ */
+
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/sysctl.h>
+
+#include "scsi_logging.h"
+#include "scsi_priv.h"
+
+
+static const struct ctl_table scsi_table[] = {
+	{ .procname	= "logging_level",
+	  .data		= &scsi_logging_level,
+	  .maxlen	= sizeof(scsi_logging_level),
+	  .mode		= 0644,
+	  .proc_handler	= proc_dointvec_minmax,
+	  .extra1	= SYSCTL_ZERO,
+	  .extra2	= SYSCTL_INT_MAX },
+};
+
+static struct ctl_table_header *scsi_table_header;
+
+int __init scsi_init_sysctl(void)
+{
+	scsi_table_header = register_sysctl("dev/scsi", scsi_table);
+	if (!scsi_table_header)
+		return -ENOMEM;
+	return 0;
+}
+
+void scsi_exit_sysctl(void)
+{
+	unregister_sysctl_table(scsi_table_header);
+}