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, 78 insertions, 0 deletions

diff --git a/tools/testing/vsock/timeout.c b/tools/testing/vsock/timeout.c
new file mode 100644
index 000000000..1453d38e0
--- /dev/null
+++ b/tools/testing/vsock/timeout.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Timeout API for single-threaded programs that use blocking
+ * syscalls (read/write/send/recv/connect/accept).
+ *
+ * Copyright (C) 2017 Red Hat, Inc.
+ *
+ * Author: Stefan Hajnoczi <stefanha@redhat.com>
+ */
+
+/* Use the following pattern:
+ *
+ *   timeout_begin(TIMEOUT);
+ *   do {
+ *       ret = accept(...);
+ *       timeout_check("accept");
+ *   } while (ret < 0 && ret == EINTR);
+ *   timeout_end();
+ */
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <time.h>
+#include "timeout.h"
+
+static volatile bool timeout;
+
+/* SIGALRM handler function.  Do not use sleep(2), alarm(2), or
+ * setitimer(2) while using this API - they may interfere with each
+ * other.
+ *
+ * If you need to sleep, please use timeout_sleep() provided by this API.
+ */
+void sigalrm(int signo)
+{
+	timeout = true;
+}
+
+/* Start a timeout.  Call timeout_check() to verify that the timeout hasn't
+ * expired.  timeout_end() must be called to stop the timeout.  Timeouts cannot
+ * be nested.
+ */
+void timeout_begin(unsigned int seconds)
+{
+	alarm(seconds);
+}
+
+/* Exit with an error message if the timeout has expired */
+void timeout_check(const char *operation)
+{
+	if (timeout) {
+		fprintf(stderr, "%s timed out\n", operation);
+		exit(EXIT_FAILURE);
+	}
+}
+
+/* Stop a timeout */
+void timeout_end(void)
+{
+	alarm(0);
+	timeout = false;
+}
+
+/* Sleep in a timeout section.
+ *
+ * nanosleep(2) can be used with this API since POSIX.1 explicitly
+ * specifies that it does not interact with signals.
+ */
+int timeout_usleep(useconds_t usec)
+{
+	struct timespec ts = {
+		.tv_sec = usec / 1000000,
+		.tv_nsec = (usec % 1000000) * 1000,
+	};
+
+	return nanosleep(&ts, NULL);
+}