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, 53 insertions, 0 deletions

diff --git a/include/net/dsfield.h b/include/net/dsfield.h
new file mode 100644
index 000000000..a59a57ffc
--- /dev/null
+++ b/include/net/dsfield.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* include/net/dsfield.h - Manipulation of the Differentiated Services field */
+
+/* Written 1998-2000 by Werner Almesberger, EPFL ICA */
+
+
+#ifndef __NET_DSFIELD_H
+#define __NET_DSFIELD_H
+
+#include <linux/types.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <asm/byteorder.h>
+
+
+static inline __u8 ipv4_get_dsfield(const struct iphdr *iph)
+{
+	return iph->tos;
+}
+
+
+static inline __u8 ipv6_get_dsfield(const struct ipv6hdr *ipv6h)
+{
+	return ntohs(*(__force const __be16 *)ipv6h) >> 4;
+}
+
+
+static inline void ipv4_change_dsfield(struct iphdr *iph,__u8 mask,
+    __u8 value)
+{
+        __u32 check = ntohs((__force __be16)iph->check);
+	__u8 dsfield;
+
+	dsfield = (iph->tos & mask) | value;
+	check += iph->tos;
+	if ((check+1) >> 16) check = (check+1) & 0xffff;
+	check -= dsfield;
+	check += check >> 16; /* adjust carry */
+	iph->check = (__force __sum16)htons(check);
+	iph->tos = dsfield;
+}
+
+
+static inline void ipv6_change_dsfield(struct ipv6hdr *ipv6h,__u8 mask,
+    __u8 value)
+{
+	__be16 *p = (__force __be16 *)ipv6h;
+
+	*p = (*p & htons((((u16)mask << 4) | 0xf00f))) | htons((u16)value << 4);
+}
+
+
+#endif