[PATCH] genirq: rename desc->handler to desc->chip

This patch-queue improves the generic IRQ layer to be truly generic, by adding
various abstractions and features to it, without impacting existing
functionality.

While the queue can be best described as "fix and improve everything in the
generic IRQ layer that we could think of", and thus it consists of many
smaller features and lots of cleanups, the one feature that stands out most is
the new 'irq chip' abstraction.

The irq-chip abstraction is about describing and coding and IRQ controller
driver by mapping its raw hardware capabilities [and quirks, if needed] in a
straightforward way, without having to think about "IRQ flow"
(level/edge/etc.) type of details.

This stands in contrast with the current 'irq-type' model of genirq
architectures, which 'mixes' raw hardware capabilities with 'flow' details.
The patchset supports both types of irq controller designs at once, and
converts i386 and x86_64 to the new irq-chip design.

As a bonus side-effect of the irq-chip approach, chained interrupt controllers
(master/slave PIC constructs, etc.) are now supported by design as well.

The end result of this patchset intends to be simpler architecture-level code
and more consolidation between architectures.

We reused many bits of code and many concepts from Russell King's ARM IRQ
layer, the merging of which was one of the motivations for this patchset.

This patch:

rename desc->handler to desc->chip.

Originally i did not want to do this, because it's a big patch.  But having
both "desc->handler", "desc->handle_irq" and "action->handler" caused a
large degree of confusion and made the code appear alot less clean than it
truly is.

I have also attempted a dual approach as well by introducing a
desc->chip alias - but that just wasnt robust enough and broke
frequently.

So lets get over with this quickly.  The conversion was done automatically
via scripts and converts all the code in the kernel.

This renaming patch is the first one amongst the patches, so that the
remaining patches can stay flexible and can be merged and split up
without having some big monolithic patch act as a merge barrier.

[akpm@osdl.org: build fix]
[akpm@osdl.org: another build fix]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 15 insertions, 13 deletions

diff --git a/arch/x86_64/kernel/i8259.c b/arch/x86_64/kernel/i8259.c
index 86b2c1e197aa..3dd1659427dc 100644
--- a/arch/x86_64/kernel/i8259.c
+++ b/arch/x86_64/kernel/i8259.c
@@ -235,7 +235,7 @@ void make_8259A_irq(unsigned int irq)
 {
         disable_irq_nosync(irq);
         io_apic_irqs &= ~(1<<irq);
-        irq_desc[irq].handler = &i8259A_irq_type;
+        irq_desc[irq].chip = &i8259A_irq_type;
         enable_irq(irq);
 }
 
@@ -468,12 +468,12 @@ void __init init_ISA_irqs (void)
                         /*
                          * 16 old-style INTA-cycle interrupts:
                          */
-                        irq_desc[i].handler = &i8259A_irq_type;
+                        irq_desc[i].chip = &i8259A_irq_type;
                 } else {
                         /*
                          * 'high' PCI IRQs filled in on demand
                          */
-                        irq_desc[i].handler = &no_irq_type;
+                        irq_desc[i].chip = &no_irq_type;
                 }
         }
 }
diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
index c768d8a036d0..88a8736eb8ce 100644
--- a/arch/x86_64/kernel/io_apic.c
+++ b/arch/x86_64/kernel/io_apic.c
@@ -876,15 +876,17 @@ static struct hw_interrupt_type ioapic_edge_type;
 #define IOAPIC_EDGE     0
 #define IOAPIC_LEVEL    1
 
-static inline void ioapic_register_intr(int irq, int vector, unsigned long trigger)
+static void ioapic_register_intr(int irq, int vector, unsigned long trigger)
 {
-        unsigned idx = use_pci_vector() && !platform_legacy_irq(irq) ? vector : irq;
+        unsigned idx;
+
+        idx = use_pci_vector() && !platform_legacy_irq(irq) ? vector : irq;
 
         if ((trigger == IOAPIC_AUTO && IO_APIC_irq_trigger(irq)) ||
                         trigger == IOAPIC_LEVEL)
-                irq_desc[idx].handler = &ioapic_level_type;
+                irq_desc[idx].chip = &ioapic_level_type;
         else
-                irq_desc[idx].handler = &ioapic_edge_type;
+                irq_desc[idx].chip = &ioapic_edge_type;
         set_intr_gate(vector, interrupt[idx]);
 }
 
@@ -986,7 +988,7 @@ static void __init setup_ExtINT_IRQ0_pin(unsigned int apic, unsigned int pin, in
          * The timer IRQ doesn't have to know that behind the
          * scene we have a 8259A-master in AEOI mode ...
          */
-        irq_desc[0].handler = &ioapic_edge_type;
+        irq_desc[0].chip = &ioapic_edge_type;
 
         /*
          * Add it to the IO-APIC irq-routing table:
@@ -1683,7 +1685,7 @@ static inline void init_IO_APIC_traps(void)
                                 make_8259A_irq(irq);
                         else
                                 /* Strange. Oh, well.. */
-                                irq_desc[irq].handler = &no_irq_type;
+                                irq_desc[irq].chip = &no_irq_type;
                 }
         }
 }
@@ -1900,7 +1902,7 @@ static inline void check_timer(void)
         apic_printk(APIC_VERBOSE, KERN_INFO "...trying to set up timer as Virtual Wire IRQ...");
 
         disable_8259A_irq(0);
-        irq_desc[0].handler = &lapic_irq_type;
+        irq_desc[0].chip = &lapic_irq_type;
         apic_write(APIC_LVT0, APIC_DM_FIXED | vector);  /* Fixed mode */
         enable_8259A_irq(0);
 
diff --git a/arch/x86_64/kernel/irq.c b/arch/x86_64/kernel/irq.c
index bfa82f52a5cc..0c2fb2c77bd0 100644
--- a/arch/x86_64/kernel/irq.c
+++ b/arch/x86_64/kernel/irq.c
@@ -79,7 +79,7 @@ int show_interrupts(struct seq_file *p, void *v)
                 for_each_online_cpu(j)
                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 #endif
-                seq_printf(p, " %14s", irq_desc[i].handler->typename);
+                seq_printf(p, " %14s", irq_desc[i].chip->typename);
 
                 seq_printf(p, "  %s", action->name);
                 for (action=action->next; action; action = action->next)
@@ -151,8 +151,8 @@ void fixup_irqs(cpumask_t map)
                         printk("Breaking affinity for irq %i\n", irq);
                         mask = map;
                 }
-                if (irq_desc[irq].handler->set_affinity)
-                        irq_desc[irq].handler->set_affinity(irq, mask);
+                if (irq_desc[irq].chip->set_affinity)
+                        irq_desc[irq].chip->set_affinity(irq, mask);
                 else if (irq_desc[irq].action && !(warned++))
                         printk("Cannot set affinity for irq %i\n", irq);
         }