This patch drops the powerpc-specific irq_map table and replaces it with
directly using the irq_alloc_desc()/irq_free_desc() interfaces for allocating
and freeing irq_desc structures.

This patch is a preparation step for generalizing the powerpc-specific virq
infrastructure to become irq_domains.

As part of this change, the irq_big_lock is changed to a mutex from a raw
spinlock.  There is no longer any need to use a spin lock since the irq_desc
allocation code is now responsible for the critical section of finding
an unused range of irq numbers.

The radix lookup table is also changed to store the irq_data pointer instead
of the irq_map entry since the irq_map is removed.  This should end up being
functionally equivalent since only allocated irq_descs are ever added to the
radix tree.

Signed-off-by: Grant Likely <grant.lik...@secretlab.ca>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Milton Miller <milt...@bga.com>
---
 arch/powerpc/include/asm/irq.h |   27 -----
 arch/powerpc/kernel/irq.c      |  227 +++++++++++-----------------------------
 2 files changed, 59 insertions(+), 195 deletions(-)

diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h
index cb06b39..abdd7ef 100644
--- a/arch/powerpc/include/asm/irq.h
+++ b/arch/powerpc/include/asm/irq.h
@@ -191,33 +191,6 @@ extern unsigned int irq_linear_revmap(struct irq_domain 
*host,
                                      irq_hw_number_t hwirq);
 
 
-
-/**
- * irq_alloc_virt - Allocate virtual irq numbers
- * @host: host owning these new virtual irqs
- * @count: number of consecutive numbers to allocate
- * @hint: pass a hint number, the allocator will try to use a 1:1 mapping
- *
- * This is a low level function that is used internally by irq_create_mapping()
- * and that can be used by some irq controllers implementations for things
- * like allocating ranges of numbers for MSIs. The revmaps are left untouched.
- */
-extern unsigned int irq_alloc_virt(struct irq_domain *host,
-                                  unsigned int count,
-                                  unsigned int hint);
-
-/**
- * irq_free_virt - Free virtual irq numbers
- * @virq: virtual irq number of the first interrupt to free
- * @count: number of interrupts to free
- *
- * This function is the opposite of irq_alloc_virt. It will not clear reverse
- * maps, this should be done previously by unmap'ing the interrupt. In fact,
- * all interrupts covered by the range being freed should have been unmapped
- * prior to calling this.
- */
-extern void irq_free_virt(unsigned int virq, unsigned int count);
-
 /**
  * irq_early_init - Init irq remapping subsystem
  */
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 7305f2f..db5b545 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -491,38 +491,29 @@ void do_softirq(void)
  * IRQ controller and virtual interrupts
  */
 
-/* The main irq map itself is an array of NR_IRQ entries containing the
- * associate host and irq number. An entry with a host of NULL is free.
- * An entry can be allocated if it's free, the allocator always then sets
- * hwirq first to the host's invalid irq number and then fills ops.
- */
-struct irq_map_entry {
-       irq_hw_number_t hwirq;
-       struct irq_domain       *host;
-};
-
 static LIST_HEAD(irq_domain_list);
-static DEFINE_RAW_SPINLOCK(irq_big_lock);
+static DEFINE_MUTEX(irq_domain_mutex);
 static DEFINE_MUTEX(revmap_trees_mutex);
-static struct irq_map_entry irq_map[NR_IRQS];
 static unsigned int irq_virq_count = NR_IRQS;
 static struct irq_domain *irq_default_host;
 
 irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
 {
-       return irq_map[d->irq].hwirq;
+       return d->hwirq;
 }
 EXPORT_SYMBOL_GPL(irqd_to_hwirq);
 
 irq_hw_number_t virq_to_hw(unsigned int virq)
 {
-       return irq_map[virq].hwirq;
+       struct irq_data *irq_data = irq_get_irq_data(virq);
+       return WARN_ON(!irq_data) ? 0 : irq_data->hwirq;
 }
 EXPORT_SYMBOL_GPL(virq_to_hw);
 
 bool virq_is_host(unsigned int virq, struct irq_domain *host)
 {
-       return irq_map[virq].host == host;
+       struct irq_data *irq_data = irq_get_irq_data(virq);
+       return irq_data ? irq_data->domain == host : false;
 }
 EXPORT_SYMBOL_GPL(virq_is_host);
 
@@ -537,11 +528,10 @@ struct irq_domain *irq_alloc_host(struct device_node 
*of_node,
                                struct irq_domain_ops *ops,
                                irq_hw_number_t inval_irq)
 {
-       struct irq_domain *host;
+       struct irq_domain *host, *h;
        unsigned int size = sizeof(struct irq_domain);
        unsigned int i;
        unsigned int *rmap;
-       unsigned long flags;
 
        /* Allocate structure and revmap table if using linear mapping */
        if (revmap_type == IRQ_DOMAIN_MAP_LINEAR)
@@ -559,23 +549,20 @@ struct irq_domain *irq_alloc_host(struct device_node 
*of_node,
        if (host->ops->match == NULL)
                host->ops->match = default_irq_host_match;
 
-       raw_spin_lock_irqsave(&irq_big_lock, flags);
-
-       /* If it's a legacy controller, check for duplicates and
-        * mark it as allocated (we use irq 0 host pointer for that
-        */
+       mutex_lock(&irq_domain_mutex);
+       /* Make sure only one legacy controller can be created */
        if (revmap_type == IRQ_DOMAIN_MAP_LEGACY) {
-               if (irq_map[0].host != NULL) {
-                       raw_spin_unlock_irqrestore(&irq_big_lock, flags);
-                       of_node_put(host->of_node);
-                       kfree(host);
-                       return NULL;
+               list_for_each_entry(h, &irq_domain_list, link) {
+                       if (WARN_ON(h->revmap_type == IRQ_DOMAIN_MAP_LEGACY)) {
+                               mutex_unlock(&irq_domain_mutex);
+                               of_node_put(host->of_node);
+                               kfree(host);
+                               return NULL;
+                       }
                }
-               irq_map[0].host = host;
        }
-
        list_add(&host->link, &irq_domain_list);
-       raw_spin_unlock_irqrestore(&irq_big_lock, flags);
+       mutex_unlock(&irq_domain_mutex);
 
        /* Additional setups per revmap type */
        switch(revmap_type) {
@@ -584,10 +571,9 @@ struct irq_domain *irq_alloc_host(struct device_node 
*of_node,
                host->inval_irq = 0;
                /* setup us as the host for all legacy interrupts */
                for (i = 1; i < NUM_ISA_INTERRUPTS; i++) {
-                       irq_map[i].hwirq = i;
-                       smp_wmb();
-                       irq_map[i].host = host;
-                       smp_wmb();
+                       struct irq_data *irq_data = irq_get_irq_data(i);
+                       irq_data->hwirq = i;
+                       irq_data->domain = host;
 
                        /* Legacy flags are left to default at this point,
                         * one can then use irq_create_mapping() to
@@ -604,7 +590,6 @@ struct irq_domain *irq_alloc_host(struct device_node 
*of_node,
                for (i = 0; i < revmap_arg; i++)
                        rmap[i] = NO_IRQ;
                host->revmap_data.linear.size = revmap_arg;
-               smp_wmb();
                host->revmap_data.linear.revmap = rmap;
                break;
        case IRQ_DOMAIN_MAP_TREE:
@@ -622,20 +607,19 @@ struct irq_domain *irq_alloc_host(struct device_node 
*of_node,
 struct irq_domain *irq_find_host(struct device_node *node)
 {
        struct irq_domain *h, *found = NULL;
-       unsigned long flags;
 
        /* We might want to match the legacy controller last since
         * it might potentially be set to match all interrupts in
         * the absence of a device node. This isn't a problem so far
         * yet though...
         */
-       raw_spin_lock_irqsave(&irq_big_lock, flags);
+       mutex_lock(&irq_domain_mutex);
        list_for_each_entry(h, &irq_domain_list, link)
                if (h->ops->match(h, node)) {
                        found = h;
                        break;
                }
-       raw_spin_unlock_irqrestore(&irq_big_lock, flags);
+       mutex_unlock(&irq_domain_mutex);
        return found;
 }
 EXPORT_SYMBOL_GPL(irq_find_host);
@@ -659,33 +643,20 @@ void irq_set_virq_count(unsigned int count)
 static int irq_setup_virq(struct irq_domain *host, unsigned int virq,
                            irq_hw_number_t hwirq)
 {
-       int res;
-
-       res = irq_alloc_desc_at(virq, 0);
-       if (res != virq) {
-               pr_debug("irq: -> allocating desc failed\n");
-               goto error;
-       }
-
-       /* map it */
-       smp_wmb();
-       irq_map[virq].hwirq = hwirq;
-       smp_mb();
+       struct irq_data *irq_data = irq_get_irq_data(virq);
 
+       irq_data->hwirq = hwirq;
+       irq_data->domain = host;
        if (host->ops->map(host, virq, hwirq)) {
                pr_debug("irq: -> mapping failed, freeing\n");
-               goto errdesc;
+               irq_data->domain = NULL;
+               irq_data->hwirq = 0;
+               return -1;
        }
 
        irq_clear_status_flags(virq, IRQ_NOREQUEST);
 
        return 0;
-
-errdesc:
-       irq_free_descs(virq, 1);
-error:
-       irq_free_virt(virq, 1);
-       return -1;
 }
 
 unsigned int irq_create_direct_mapping(struct irq_domain *host)
@@ -698,7 +669,7 @@ unsigned int irq_create_direct_mapping(struct irq_domain 
*host)
        BUG_ON(host == NULL);
        WARN_ON(host->revmap_type != IRQ_DOMAIN_MAP_NOMAP);
 
-       virq = irq_alloc_virt(host, 1, 0);
+       virq = irq_alloc_desc(0);
        if (virq == NO_IRQ) {
                pr_debug("irq: create_direct virq allocation failed\n");
                return NO_IRQ;
@@ -706,8 +677,10 @@ unsigned int irq_create_direct_mapping(struct irq_domain 
*host)
 
        pr_debug("irq: create_direct obtained virq %d\n", virq);
 
-       if (irq_setup_virq(host, virq, virq))
+       if (irq_setup_virq(host, virq, virq)) {
+               irq_free_desc(virq);
                return NO_IRQ;
+       }
 
        return virq;
 }
@@ -747,15 +720,20 @@ unsigned int irq_create_mapping(struct irq_domain *host,
        } else {
                /* Allocate a virtual interrupt number */
                hint = hwirq % irq_virq_count;
-               virq = irq_alloc_virt(host, 1, hint);
+               virq = irq_alloc_desc_from(hint, 0);
+               if (!virq)
+                       virq = irq_alloc_desc(0);
                if (virq == NO_IRQ) {
                        pr_debug("irq: -> virq allocation failed\n");
                        return NO_IRQ;
                }
        }
 
-       if (irq_setup_virq(host, virq, hwirq))
+       if (irq_setup_virq(host, virq, hwirq)) {
+               if (host->revmap_type != IRQ_DOMAIN_MAP_LEGACY)
+                       irq_free_desc(virq);
                return NO_IRQ;
+       }
 
        pr_debug("irq: irq %lu on host %s mapped to virtual irq %u\n",
                hwirq, host->of_node ? host->of_node->full_name : "null", virq);
@@ -806,13 +784,14 @@ EXPORT_SYMBOL_GPL(irq_create_of_mapping);
 
 void irq_dispose_mapping(unsigned int virq)
 {
+       struct irq_data *irq_data = irq_get_irq_data(virq);
        struct irq_domain *host;
        irq_hw_number_t hwirq;
 
-       if (virq == NO_IRQ)
+       if (virq == NO_IRQ || !irq_data)
                return;
 
-       host = irq_map[virq].host;
+       host = irq_data->domain;
        if (WARN_ON(host == NULL))
                return;
 
@@ -834,7 +813,7 @@ void irq_dispose_mapping(unsigned int virq)
        smp_mb();
 
        /* Clear reverse map */
-       hwirq = irq_map[virq].hwirq;
+       hwirq = irq_data->hwirq;
        switch(host->revmap_type) {
        case IRQ_DOMAIN_MAP_LINEAR:
                if (hwirq < host->revmap_data.linear.size)
@@ -848,12 +827,9 @@ void irq_dispose_mapping(unsigned int virq)
        }
 
        /* Destroy map */
-       smp_mb();
-       irq_map[virq].hwirq = host->inval_irq;
+       irq_data->hwirq = host->inval_irq;
 
-       irq_free_descs(virq, 1);
-       /* Free it */
-       irq_free_virt(virq, 1);
+       irq_free_desc(virq);
 }
 EXPORT_SYMBOL_GPL(irq_dispose_mapping);
 
@@ -877,9 +853,9 @@ unsigned int irq_find_mapping(struct irq_domain *host,
        if (hint < NUM_ISA_INTERRUPTS)
                hint = NUM_ISA_INTERRUPTS;
        i = hint;
-       do  {
-               if (irq_map[i].host == host &&
-                   irq_map[i].hwirq == hwirq)
+       do {
+               struct irq_data *data = irq_get_irq_data(i);
+               if (data && (data->domain == host) && (data->hwirq == hwirq))
                        return i;
                i++;
                if (i >= irq_virq_count)
@@ -928,19 +904,17 @@ int irq_choose_cpu(const struct cpumask *mask)
 unsigned int irq_radix_revmap_lookup(struct irq_domain *host,
                                     irq_hw_number_t hwirq)
 {
-       struct irq_map_entry *ptr;
-       unsigned int virq;
+       struct irq_data *irq_data;
 
        if (WARN_ON_ONCE(host->revmap_type != IRQ_DOMAIN_MAP_TREE))
                return irq_find_mapping(host, hwirq);
 
        /*
-        * The ptr returned references the static global irq_map.
-        * but freeing an irq can delete nodes along the path to
+        * Freeing an irq can delete nodes along the path to
         * do the lookup via call_rcu.
         */
        rcu_read_lock();
-       ptr = radix_tree_lookup(&host->revmap_data.tree, hwirq);
+       irq_data = radix_tree_lookup(&host->revmap_data.tree, hwirq);
        rcu_read_unlock();
 
        /*
@@ -948,24 +922,20 @@ unsigned int irq_radix_revmap_lookup(struct irq_domain 
*host,
         * Else fallback to linear lookup - this should not happen in practice
         * as it means that we failed to insert the node in the radix tree.
         */
-       if (ptr)
-               virq = ptr - irq_map;
-       else
-               virq = irq_find_mapping(host, hwirq);
-
-       return virq;
+       return irq_data ? irq_data->irq : irq_find_mapping(host, hwirq);
 }
 
 void irq_radix_revmap_insert(struct irq_domain *host, unsigned int virq,
                             irq_hw_number_t hwirq)
 {
+       struct irq_data *irq_data = irq_get_irq_data(virq);
+
        if (WARN_ON(host->revmap_type != IRQ_DOMAIN_MAP_TREE))
                return;
 
        if (virq != NO_IRQ) {
                mutex_lock(&revmap_trees_mutex);
-               radix_tree_insert(&host->revmap_data.tree, hwirq,
-                                 &irq_map[virq]);
+               radix_tree_insert(&host->revmap_data.tree, hwirq, irq_data);
                mutex_unlock(&revmap_trees_mutex);
        }
 }
@@ -994,86 +964,6 @@ unsigned int irq_linear_revmap(struct irq_domain *host,
        return revmap[hwirq];
 }
 
-unsigned int irq_alloc_virt(struct irq_domain *host,
-                           unsigned int count,
-                           unsigned int hint)
-{
-       unsigned long flags;
-       unsigned int i, j, found = NO_IRQ;
-
-       if (count == 0 || count > (irq_virq_count - NUM_ISA_INTERRUPTS))
-               return NO_IRQ;
-
-       raw_spin_lock_irqsave(&irq_big_lock, flags);
-
-       /* Use hint for 1 interrupt if any */
-       if (count == 1 && hint >= NUM_ISA_INTERRUPTS &&
-           hint < irq_virq_count && irq_map[hint].host == NULL) {
-               found = hint;
-               goto hint_found;
-       }
-
-       /* Look for count consecutive numbers in the allocatable
-        * (non-legacy) space
-        */
-       for (i = NUM_ISA_INTERRUPTS, j = 0; i < irq_virq_count; i++) {
-               if (irq_map[i].host != NULL)
-                       j = 0;
-               else
-                       j++;
-
-               if (j == count) {
-                       found = i - count + 1;
-                       break;
-               }
-       }
-       if (found == NO_IRQ) {
-               raw_spin_unlock_irqrestore(&irq_big_lock, flags);
-               return NO_IRQ;
-       }
- hint_found:
-       for (i = found; i < (found + count); i++) {
-               irq_map[i].hwirq = host->inval_irq;
-               smp_wmb();
-               irq_map[i].host = host;
-       }
-       raw_spin_unlock_irqrestore(&irq_big_lock, flags);
-       return found;
-}
-
-void irq_free_virt(unsigned int virq, unsigned int count)
-{
-       unsigned long flags;
-       unsigned int i;
-
-       WARN_ON (virq < NUM_ISA_INTERRUPTS);
-       WARN_ON (count == 0 || (virq + count) > irq_virq_count);
-
-       if (virq < NUM_ISA_INTERRUPTS) {
-               if (virq + count < NUM_ISA_INTERRUPTS)
-                       return;
-               count  =- NUM_ISA_INTERRUPTS - virq;
-               virq = NUM_ISA_INTERRUPTS;
-       }
-
-       if (count > irq_virq_count || virq > irq_virq_count - count) {
-               if (virq > irq_virq_count)
-                       return;
-               count = irq_virq_count - virq;
-       }
-
-       raw_spin_lock_irqsave(&irq_big_lock, flags);
-       for (i = virq; i < (virq + count); i++) {
-               struct irq_domain *host;
-
-               host = irq_map[i].host;
-               irq_map[i].hwirq = host->inval_irq;
-               smp_wmb();
-               irq_map[i].host = NULL;
-       }
-       raw_spin_unlock_irqrestore(&irq_big_lock, flags);
-}
-
 int arch_early_irq_init(void)
 {
        return 0;
@@ -1100,10 +990,11 @@ static int virq_debug_show(struct seq_file *m, void 
*private)
                raw_spin_lock_irqsave(&desc->lock, flags);
 
                if (desc->action && desc->action->handler) {
+                       struct irq_data *irq_data = irq_desc_get_data(desc);
                        struct irq_chip *chip;
 
                        seq_printf(m, "%5d  ", i);
-                       seq_printf(m, "0x%05lx  ", irq_map[i].hwirq);
+                       seq_printf(m, "0x%05lx  ", irq_data->hwirq);
 
                        chip = irq_desc_get_chip(desc);
                        if (chip && chip->name)
@@ -1115,8 +1006,8 @@ static int virq_debug_show(struct seq_file *m, void 
*private)
                        data = irq_desc_get_chip_data(desc);
                        seq_printf(m, "0x%16p  ", data);
 
-                       if (irq_map[i].host && irq_map[i].host->of_node)
-                               p = irq_map[i].host->of_node->full_name;
+                       if (irq_data->domain.of_node)
+                               p = irq_data->domain.of_node->full_name;
                        else
                                p = none;
                        seq_printf(m, "%s\n", p);
-- 
1.7.5.4

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