genirq: Create irq_data

Low level chip functions need access to irq_desc->handler_data,
irq_desc->chip_data and irq_desc->msi_desc. We hand down the irq
number to the low level functions, so they need to lookup irq_desc.
With sparse irq this means a radix tree lookup.

We could hand down irq_desc itself, but low level chip functions have
no need to fiddle with it directly and we want to restrict access to
irq_desc further.

Preparatory patch for new chip functions.

Note, that the ugly anon union/struct is there to avoid a full tree
wide clean up for now. This is not going to last 3 years like __do_IRQ()

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20100927121841.645542300@linutronix.de>
Reviewed-by: H. Peter Anvin <hpa@zytor.com>
Reviewed-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 82 insertions, 47 deletions

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 06273a2a17e7..363c76ff82c8 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -84,6 +84,37 @@ struct proc_dir_entry;
 struct msi_desc;
 
 /**
+ * struct irq_data - per irq and irq chip data passed down to chip functions
+ * @irq:                interrupt number
+ * @node:               node index useful for balancing
+ * @chip:               low level interrupt hardware access
+ * @handler_data:       per-IRQ data for the irq_chip methods
+ * @chip_data:          platform-specific per-chip private data for the chip
+ *                      methods, to allow shared chip implementations
+ * @msi_desc:           MSI descriptor
+ * @affinity:           IRQ affinity on SMP
+ * @irq_2_iommu:        iommu with this irq
+ *
+ * The fields here need to overlay the ones in irq_desc until we
+ * cleaned up the direct references and switched everything over to
+ * irq_data.
+ */
+struct irq_data {
+        unsigned int            irq;
+        unsigned int            node;
+        struct irq_chip         *chip;
+        void                    *handler_data;
+        void                    *chip_data;
+        struct msi_desc         *msi_desc;
+#ifdef CONFIG_SMP
+        cpumask_var_t           affinity;
+#endif
+#ifdef CONFIG_INTR_REMAP
+        struct irq_2_iommu      *irq_2_iommu;
+#endif
+};
+
+/**
  * struct irq_chip - hardware interrupt chip descriptor
  *
  * @name:               name for /proc/interrupts
@@ -140,16 +171,10 @@ struct timer_rand_state;
 struct irq_2_iommu;
 /**
  * struct irq_desc - interrupt descriptor
- * @irq:                interrupt number for this descriptor
+ * @irq_data:           per irq and chip data passed down to chip functions
  * @timer_rand_state:   pointer to timer rand state struct
  * @kstat_irqs:         irq stats per cpu
- * @irq_2_iommu:        iommu with this irq
  * @handle_irq:         highlevel irq-events handler [if NULL, __do_IRQ()]
- * @chip:               low level interrupt hardware access
- * @msi_desc:           MSI descriptor
- * @handler_data:       per-IRQ data for the irq_chip methods
- * @chip_data:          platform-specific per-chip private data for the chip
- *                      methods, to allow shared chip implementations
  * @action:             the irq action chain
  * @status:             status information
  * @depth:              disable-depth, for nested irq_disable() calls
@@ -158,8 +183,6 @@ struct irq_2_iommu;
  * @last_unhandled:     aging timer for unhandled count
  * @irqs_unhandled:     stats field for spurious unhandled interrupts
  * @lock:               locking for SMP
- * @affinity:           IRQ affinity on SMP
- * @node:               node index useful for balancing
  * @pending_mask:       pending rebalanced interrupts
  * @threads_active:     number of irqaction threads currently running
  * @wait_for_threads:   wait queue for sync_irq to wait for threaded handlers
@@ -167,17 +190,32 @@ struct irq_2_iommu;
  * @name:               flow handler name for /proc/interrupts output
  */
 struct irq_desc {
-        unsigned int            irq;
-        struct timer_rand_state *timer_rand_state;
-        unsigned int            *kstat_irqs;
+
+        /*
+         * This union will go away, once we fixed the direct access to
+         * irq_desc all over the place. The direct fields are a 1:1
+         * overlay of irq_data.
+         */
+        union {
+                struct irq_data         irq_data;
+                struct {
+                        unsigned int            irq;
+                        unsigned int            node;
+                        struct irq_chip         *chip;
+                        void                    *handler_data;
+                        void                    *chip_data;
+                        struct msi_desc         *msi_desc;
+#ifdef CONFIG_SMP
+                        cpumask_var_t           affinity;
+#endif
 #ifdef CONFIG_INTR_REMAP
-        struct irq_2_iommu      *irq_2_iommu;
+                        struct irq_2_iommu      *irq_2_iommu;
 #endif
+                };
+        };
+        struct timer_rand_state *timer_rand_state;
+        unsigned int            *kstat_irqs;
         irq_flow_handler_t      handle_irq;
-        struct irq_chip         *chip;
-        struct msi_desc         *msi_desc;
-        void                    *handler_data;
-        void                    *chip_data;
         struct irqaction        *action;        /* IRQ action list */
         unsigned int            status;         /* IRQ status */
 
@@ -188,9 +226,7 @@ struct irq_desc {
         unsigned int            irqs_unhandled;
         raw_spinlock_t          lock;
 #ifdef CONFIG_SMP
-        cpumask_var_t           affinity;
         const struct cpumask    *affinity_hint;
-        unsigned int            node;
 #ifdef CONFIG_GENERIC_PENDING_IRQ
         cpumask_var_t           pending_mask;
 #endif
@@ -406,15 +442,15 @@ extern int set_irq_chip_data(unsigned int irq, void *data);
 extern int set_irq_type(unsigned int irq, unsigned int type);
 extern int set_irq_msi(unsigned int irq, struct msi_desc *entry);
 
-#define get_irq_chip(irq)       (irq_to_desc(irq)->chip)
-#define get_irq_chip_data(irq)  (irq_to_desc(irq)->chip_data)
-#define get_irq_data(irq)       (irq_to_desc(irq)->handler_data)
-#define get_irq_msi(irq)        (irq_to_desc(irq)->msi_desc)
+#define get_irq_chip(irq)       (irq_to_desc(irq)->irq_data.chip)
+#define get_irq_chip_data(irq)  (irq_to_desc(irq)->irq_data.chip_data)
+#define get_irq_data(irq)       (irq_to_desc(irq)->irq_data.handler_data)
+#define get_irq_msi(irq)        (irq_to_desc(irq)->irq_data.msi_desc)
 
-#define get_irq_desc_chip(desc)         ((desc)->chip)
-#define get_irq_desc_chip_data(desc)    ((desc)->chip_data)
-#define get_irq_desc_data(desc)         ((desc)->handler_data)
-#define get_irq_desc_msi(desc)          ((desc)->msi_desc)
+#define get_irq_desc_chip(desc)         ((desc)->irq_data.chip)
+#define get_irq_desc_chip_data(desc)    ((desc)->irq_data.chip_data)
+#define get_irq_desc_data(desc)         ((desc)->irq_data.handler_data)
+#define get_irq_desc_msi(desc)          ((desc)->irq_data.msi_desc)
 
 #endif /* CONFIG_GENERIC_HARDIRQS */
 
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 27e5c6911223..099d4fc368c3 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -75,12 +75,10 @@ EXPORT_SYMBOL_GPL(nr_irqs);
 #ifdef CONFIG_SPARSE_IRQ
 
 static struct irq_desc irq_desc_init = {
-        .irq        = -1,
-        .status     = IRQ_DISABLED,
-        .chip       = &no_irq_chip,
-        .handle_irq = handle_bad_irq,
-        .depth      = 1,
-        .lock       = __RAW_SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
+        .status         = IRQ_DISABLED,
+        .handle_irq     = handle_bad_irq,
+        .depth          = 1,
+        .lock           = __RAW_SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
 };
 
 void __ref init_kstat_irqs(struct irq_desc *desc, int node, int nr)
@@ -105,7 +103,7 @@ static void init_one_irq_desc(int irq, struct irq_desc *desc, int node)
         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
 
         raw_spin_lock_init(&desc->lock);
-        desc->irq = irq;
+        desc->irq_data.irq = irq;
 #ifdef CONFIG_SMP
         desc->node = node;
 #endif
@@ -151,12 +149,10 @@ void replace_irq_desc(unsigned int irq, struct irq_desc *desc)
 
 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
         [0 ... NR_IRQS_LEGACY-1] = {
-                .irq        = -1,
-                .status     = IRQ_DISABLED,
-                .chip       = &no_irq_chip,
-                .handle_irq = handle_bad_irq,
-                .depth      = 1,
-                .lock       = __RAW_SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
+                .status         = IRQ_DISABLED,
+                .handle_irq     = handle_bad_irq,
+                .depth          = 1,
+                .lock           = __RAW_SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
         }
 };
 
@@ -183,8 +179,11 @@ int __init early_irq_init(void)
         kstat_irqs_legacy = kzalloc_node(NR_IRQS_LEGACY * nr_cpu_ids *
                                           sizeof(int), GFP_NOWAIT, node);
 
+        irq_desc_init.irq_data.chip = &no_irq_chip;
+
         for (i = 0; i < legacy_count; i++) {
-                desc[i].irq = i;
+                desc[i].irq_data.irq = i;
+                desc[i].irq_data.chip = &no_irq_chip;
 #ifdef CONFIG_SMP
                 desc[i].node = node;
 #endif
@@ -241,11 +240,10 @@ out_unlock:
 
 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
         [0 ... NR_IRQS-1] = {
-                .status = IRQ_DISABLED,
-                .chip = &no_irq_chip,
-                .handle_irq = handle_bad_irq,
-                .depth = 1,
-                .lock = __RAW_SPIN_LOCK_UNLOCKED(irq_desc->lock),
+                .status         = IRQ_DISABLED,
+                .handle_irq     = handle_bad_irq,
+                .depth          = 1,
+                .lock           = __RAW_SPIN_LOCK_UNLOCKED(irq_desc->lock),
         }
 };
 
@@ -264,7 +262,8 @@ int __init early_irq_init(void)
         count = ARRAY_SIZE(irq_desc);
 
         for (i = 0; i < count; i++) {
-                desc[i].irq = i;
+                desc[i].irq_data.irq = i;
+                desc[i].irq_data.chip = &no_irq_chip;
                 alloc_desc_masks(&desc[i], 0, true);
                 init_desc_masks(&desc[i]);
                 desc[i].kstat_irqs = kstat_irqs_all[i];