[RFC PATCH] pci_request_irq (was [-mm patch] aic7xxx: check irq validity)

[Frederik Deweerdt <deweerdt@free.fr>]

Hi all,

I've tried to summarize the different proposals made by Jeff Garzik,
Matthew Wilcox and Arjan van de Ven in the "[-mm patch] aic7xxx: check
irq validity" thread. I've also added:
- some kerneldoc
- renamed valid_irq to is_irq_valid() 
- added pci_release_irq(). 

I'll send a follow-up patch showing the implied modifications for the
following - semi-randomly chosen :) - drivers: aic7xxx, aic79xx, tg3
and drm.

Regards,
Frederik

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index a544997..ae20a3a 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -15,6 +15,7 @@ #include <linux/init.h>
 #include <linux/pci.h>
 #include <linux/module.h>
 #include <linux/spinlock.h>
+#include <linux/interrupt.h>
 #include <linux/string.h>
 #include <asm/dma.h>	/* isa_dma_bridge_buggy */
 #include "pci.h"
@@ -810,6 +811,49 @@ err_out:
 }
 
 /**
+ * pci_request_irq - Reserve an IRQ for a PCI device
+ * @pdev: The PCI device whose irq is to be reserved
+ * handler: The interrupt handler function,
+ * pci_get_drvdata(pdev) shall be passed as an argument to that function
+ * @flags: The flags to be passed to request_irq()
+ * @name: The name of the device to be associated with the irq
+ *
+ * Returns 0 on success, or a negative value on error.  A warning
+ * message is also printed on failure.
+ */
+int pci_request_irq(struct pci_dev *pdev,
+		    irqreturn_t (*handler)(int, void *, struct pt_regs *),
+		    unsigned long flags, const char *name)
+{
+	int rc;
+	const char *actual_name = name;
+
+	rc = is_irq_valid(pdev->irq);
+	if (!rc) {
+		dev_printk(KERN_ERR, &pdev->dev, "invalid irq #%d\n", pdev->irq);
+		return -EINVAL;
+	}
+
+	if (!actual_name)
+		actual_name = pci_name(pdev);
+
+	return request_irq(pdev->irq, handler, flags | IRQF_SHARED,
+			   actual_name, pci_get_drvdata(pdev));
+}
+EXPORT_SYMBOL(pci_request_irq);
+
+/**
+ * pci_free_irq - releases the interrupt line reserved to the PCI
+ * device pointed by @pdev 
+ * @pdev: the PCI device whose interrupt is to be freed
+ */
+void pci_free_irq(struct pci_dev *pdev)
+{
+	free_irq(pdev->irq, pci_get_drvdata(pdev));
+}
+EXPORT_SYMBOL(pci_free_irq);
+
+/**
  * pci_set_master - enables bus-mastering for device dev
  * @dev: the PCI device to enable
  *
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 1f97e3d..c320b50 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -75,6 +75,13 @@ struct irqaction {
 	struct proc_dir_entry *dir;
 };
 
+#ifndef ARCH_VALIDATE_PCI_IRQ
+static inline int is_irq_valid(unsigned int irq)
+{
+	return irq ? 1 : 0;
+}
+#endif /* ARCH_VALIDATE_PCI_IRQ */
+
 extern irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs);
 extern int request_irq(unsigned int,
 		       irqreturn_t (*handler)(int, void *, struct pt_regs *),
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 5bc4659..5e0f07a 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -52,6 +52,7 @@ #include <linux/list.h>
 #include <linux/compiler.h>
 #include <linux/errno.h>
 #include <linux/device.h>
+#include <linux/interrupt.h>
 
 /* File state for mmap()s on /proc/bus/pci/X/Y */
 enum pci_mmap_state {
@@ -531,6 +532,11 @@ void pci_release_regions(struct pci_dev 
 int __must_check pci_request_region(struct pci_dev *, int, const char *);
 void pci_release_region(struct pci_dev *, int);
 
+int __must_check pci_request_irq(struct pci_dev *pdev,
+		    irqreturn_t (*handler)(int, void *, struct pt_regs *),
+		    unsigned long flags, const char *name);
+void pci_free_irq(struct pci_dev *pdev);
+
 /* drivers/pci/bus.c */
 int __must_check pci_bus_alloc_resource(struct pci_bus *bus,
 			struct resource *res, resource_size_t size,