[PATCH] x86_64 irq: Simplify assign_irq_vector's arguments.

Currently assign_irq_vector works mostly by side effect and returns
the results of it's changes to the caller.  Which makes for a lot of
arguments to pass/return and confusion as to what to do if you need
the status but you aren't calling assign_irq_vector.

This patch stops returning values from assign_irq_vector that can be
retrieved just as easily by examining irq_cfg, and modifies the
callers to retrive those values from irq_cfg when they need them.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
index dd6580c..79fa7b2 100644 (file)
--- a/arch/x86_64/kernel/io_apic.c
+++ b/arch/x86_64/kernel/io_apic.c
@@ -72,7 +72,7 @@ struct irq_cfg irq_cfg[NR_IRQS] __read_mostly = {
        [15] = { .domain = CPU_MASK_ALL, .vector = FIRST_EXTERNAL_VECTOR + 15 },
 };
 
-static int assign_irq_vector(int irq, cpumask_t mask, cpumask_t *result);
+static int assign_irq_vector(int irq, cpumask_t mask);
 
 #define __apicdebuginit  __init
 
@@ -262,19 +262,19 @@ static void __target_IO_APIC_irq(unsigned int irq, unsigned int dest, u8 vector)
 
 static void set_ioapic_affinity_irq(unsigned int irq, cpumask_t mask)
 {
+       struct irq_cfg *cfg = irq_cfg + irq;
        unsigned long flags;
        unsigned int dest;
        cpumask_t tmp;
-       int vector;
 
        cpus_and(tmp, mask, cpu_online_map);
        if (cpus_empty(tmp))
                return;
 
-       vector = assign_irq_vector(irq, mask, &tmp);
-       if (vector < 0)
+       if (assign_irq_vector(irq, mask))
                return;
 
+       cpus_and(tmp, cfg->domain, mask);
        dest = cpu_mask_to_apicid(tmp);
 
        /*
@@ -283,7 +283,7 @@ static void set_ioapic_affinity_irq(unsigned int irq, cpumask_t mask)
        dest = SET_APIC_LOGICAL_ID(dest);
 
        spin_lock_irqsave(&ioapic_lock, flags);
-       __target_IO_APIC_irq(irq, dest, vector);
+       __target_IO_APIC_irq(irq, dest, cfg->vector);
        irq_desc[irq].affinity = mask;
        spin_unlock_irqrestore(&ioapic_lock, flags);
 }
@@ -638,7 +638,7 @@ static int pin_2_irq(int idx, int apic, int pin)
        return irq;
 }
 
-static int __assign_irq_vector(int irq, cpumask_t mask, cpumask_t *result)
+static int __assign_irq_vector(int irq, cpumask_t mask)
 {
        /*
         * NOTE! The local APIC isn't very good at handling
@@ -653,7 +653,7 @@ static int __assign_irq_vector(int irq, cpumask_t mask, cpumask_t *result)
         */
        static int current_vector = FIRST_DEVICE_VECTOR, current_offset = 0;
        cpumask_t old_mask = CPU_MASK_NONE;
-       int old_vector = -1;
+       unsigned int old_vector;
        int cpu;
        struct irq_cfg *cfg;
 
@@ -663,12 +663,12 @@ static int __assign_irq_vector(int irq, cpumask_t mask, cpumask_t *result)
        /* Only try and allocate irqs on cpus that are present */
        cpus_and(mask, mask, cpu_online_map);
 
-       if (cfg->vector > 0)
-               old_vector = cfg->vector;
-       if (old_vector > 0) {
-               cpus_and(*result, cfg->domain, mask);
-               if (!cpus_empty(*result))
-                       return old_vector;
+       old_vector = cfg->vector;
+       if (old_vector) {
+               cpumask_t tmp;
+               cpus_and(tmp, cfg->domain, mask);
+               if (!cpus_empty(tmp))
+                       return 0;
                cpus_and(old_mask, cfg->domain, cpu_online_map);
        }
 
@@ -705,21 +705,20 @@ next:
                        per_cpu(vector_irq, new_cpu)[vector] = irq;
                cfg->vector = vector;
                cfg->domain = domain;
-               cpus_and(*result, domain, mask);
-               return vector;
+               return 0;
        }
        return -ENOSPC;
 }
 
-static int assign_irq_vector(int irq, cpumask_t mask, cpumask_t *result)
+static int assign_irq_vector(int irq, cpumask_t mask)
 {
-       int vector;
+       int err;
        unsigned long flags;
 
        spin_lock_irqsave(&vector_lock, flags);
-       vector = __assign_irq_vector(irq, mask, result);
+       err = __assign_irq_vector(irq, mask);
        spin_unlock_irqrestore(&vector_lock, flags);
-       return vector;
+       return err;
 }
 
 static void __clear_irq_vector(int irq)
@@ -780,22 +779,24 @@ static void ioapic_register_intr(int irq, unsigned long trigger)
 static void setup_IO_APIC_irq(int apic, int pin, unsigned int irq,
                              int trigger, int polarity)
 {
+       struct irq_cfg *cfg = irq_cfg + irq;
        struct IO_APIC_route_entry entry;
        cpumask_t mask;
-       int vector;
        unsigned long flags;
 
        if (!IO_APIC_IRQ(irq))
                return;
 
-       vector = assign_irq_vector(irq, TARGET_CPUS, &mask);
-       if (vector < 0)
+       mask = TARGET_CPUS;
+       if (assign_irq_vector(irq, mask))
                return;
 
+       cpus_and(mask, cfg->domain, mask);
+
        apic_printk(APIC_VERBOSE,KERN_DEBUG
                    "IOAPIC[%d]: Set routing entry (%d-%d -> 0x%x -> "
                    "IRQ %d Mode:%i Active:%i)\n",
-                   apic, mp_ioapics[apic].mpc_apicid, pin, vector,
+                   apic, mp_ioapics[apic].mpc_apicid, pin, cfg->vector,
                    irq, trigger, polarity);
 
        /*
@@ -809,7 +810,7 @@ static void setup_IO_APIC_irq(int apic, int pin, unsigned int irq,
        entry.mask = 0;                         /* enable IRQ */
        entry.trigger = trigger;
        entry.polarity = polarity;
-       entry.vector = vector;
+       entry.vector = cfg->vector;
 
        /* Mask level triggered irqs.
         * Use IRQ_DELAYED_DISABLE for edge triggered irqs.
@@ -1558,15 +1559,14 @@ static inline void unlock_ExtINT_logic(void)
  */
 static inline void check_timer(void)
 {
+       struct irq_cfg *cfg = irq_cfg + 0;
        int apic1, pin1, apic2, pin2;
-       int vector;
-       cpumask_t mask;
 
        /*
         * get/set the timer IRQ vector:
         */
        disable_8259A_irq(0);
-       vector = assign_irq_vector(0, TARGET_CPUS, &mask);
+       assign_irq_vector(0, TARGET_CPUS);
 
        /*
         * Subtle, code in do_timer_interrupt() expects an AEOI
@@ -1586,7 +1586,7 @@ static inline void check_timer(void)
        apic2 = ioapic_i8259.apic;
 
        apic_printk(APIC_VERBOSE,KERN_INFO "..TIMER: vector=0x%02X apic1=%d pin1=%d apic2=%d pin2=%d\n",
-               vector, apic1, pin1, apic2, pin2);
+               cfg->vector, apic1, pin1, apic2, pin2);
 
        if (pin1 != -1) {
                /*
@@ -1617,7 +1617,7 @@ static inline void check_timer(void)
                /*
                 * legacy devices should be connected to IO APIC #0
                 */
-               setup_ExtINT_IRQ0_pin(apic2, pin2, vector);
+               setup_ExtINT_IRQ0_pin(apic2, pin2, cfg->vector);
                if (timer_irq_works()) {
                        apic_printk(APIC_VERBOSE," works.\n");
                        nmi_watchdog_default();
@@ -1642,14 +1642,14 @@ static inline void check_timer(void)
 
        disable_8259A_irq(0);
        irq_desc[0].chip = &lapic_irq_type;
-       apic_write(APIC_LVT0, APIC_DM_FIXED | vector);  /* Fixed mode */
+       apic_write(APIC_LVT0, APIC_DM_FIXED | cfg->vector);     /* Fixed mode */
        enable_8259A_irq(0);
 
        if (timer_irq_works()) {
                apic_printk(APIC_VERBOSE," works.\n");
                return;
        }
-       apic_write(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_FIXED | vector);
+       apic_write(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_FIXED | cfg->vector);
        apic_printk(APIC_VERBOSE," failed.\n");
 
        apic_printk(APIC_VERBOSE, KERN_INFO "...trying to set up timer as ExtINT IRQ...");
@@ -1796,9 +1796,7 @@ int create_irq(void)
        /* Allocate an unused irq */
        int irq;
        int new;
-       int vector = 0;
        unsigned long flags;
-       cpumask_t mask;
 
        irq = -ENOSPC;
        spin_lock_irqsave(&vector_lock, flags);
@@ -1807,8 +1805,7 @@ int create_irq(void)
                        continue;
                if (irq_cfg[new].vector != 0)
                        continue;
-               vector = __assign_irq_vector(new, TARGET_CPUS, &mask);
-               if (likely(vector > 0))
+               if (__assign_irq_vector(new, TARGET_CPUS) == 0)
                        irq = new;
                break;
        }
@@ -1837,12 +1834,15 @@ void destroy_irq(unsigned int irq)
 #ifdef CONFIG_PCI_MSI
 static int msi_compose_msg(struct pci_dev *pdev, unsigned int irq, struct msi_msg *msg)
 {
-       int vector;
+       struct irq_cfg *cfg = irq_cfg + irq;
+       int err;
        unsigned dest;
        cpumask_t tmp;
 
-       vector = assign_irq_vector(irq, TARGET_CPUS, &tmp);
-       if (vector >= 0) {
+       tmp = TARGET_CPUS;
+       err = assign_irq_vector(irq, tmp);
+       if (!err) {
+               cpus_and(tmp, cfg->domain, tmp);
                dest = cpu_mask_to_apicid(tmp);
 
                msg->address_hi = MSI_ADDR_BASE_HI;
@@ -1862,33 +1862,33 @@ static int msi_compose_msg(struct pci_dev *pdev, unsigned int irq, struct msi_ms
                        ((INT_DELIVERY_MODE != dest_LowestPrio) ?
                                MSI_DATA_DELIVERY_FIXED:
                                MSI_DATA_DELIVERY_LOWPRI) |
-                       MSI_DATA_VECTOR(vector);
+                       MSI_DATA_VECTOR(cfg->vector);
        }
-       return vector;
+       return err;
 }
 
 #ifdef CONFIG_SMP
 static void set_msi_irq_affinity(unsigned int irq, cpumask_t mask)
 {
+       struct irq_cfg *cfg = irq_cfg + irq;
        struct msi_msg msg;
        unsigned int dest;
        cpumask_t tmp;
-       int vector;
 
        cpus_and(tmp, mask, cpu_online_map);
        if (cpus_empty(tmp))
                return;
 
-       vector = assign_irq_vector(irq, mask, &tmp);
-       if (vector < 0)
+       if (assign_irq_vector(irq, mask))
                return;
 
+       cpus_and(tmp, cfg->domain, mask);
        dest = cpu_mask_to_apicid(tmp);
 
        read_msi_msg(irq, &msg);
 
        msg.data &= ~MSI_DATA_VECTOR_MASK;
-       msg.data |= MSI_DATA_VECTOR(vector);
+       msg.data |= MSI_DATA_VECTOR(cfg->vector);
        msg.address_lo &= ~MSI_ADDR_DEST_ID_MASK;
        msg.address_lo |= MSI_ADDR_DEST_ID(dest);
 
@@ -1964,21 +1964,21 @@ static void target_ht_irq(unsigned int irq, unsigned int dest, u8 vector)
 
 static void set_ht_irq_affinity(unsigned int irq, cpumask_t mask)
 {
+       struct irq_cfg *cfg = irq_cfg + irq;
        unsigned int dest;
        cpumask_t tmp;
-       int vector;
 
        cpus_and(tmp, mask, cpu_online_map);
        if (cpus_empty(tmp))
                return;
 
-       vector = assign_irq_vector(irq, mask, &tmp);
-       if (vector < 0)
+       if (assign_irq_vector(irq, mask))
                return;
 
+       cpus_and(tmp, cfg->domain, mask);
        dest = cpu_mask_to_apicid(tmp);
 
-       target_ht_irq(irq, dest, vector);
+       target_ht_irq(irq, dest, cfg->vector);
        irq_desc[irq].affinity = mask;
 }
 #endif
@@ -1996,14 +1996,17 @@ static struct irq_chip ht_irq_chip = {
 
 int arch_setup_ht_irq(unsigned int irq, struct pci_dev *dev)
 {
-       int vector;
+       struct irq_cfg *cfg = irq_cfg + irq;
+       int err;
        cpumask_t tmp;
 
-       vector = assign_irq_vector(irq, TARGET_CPUS, &tmp);
-       if (vector >= 0) {
+       tmp = TARGET_CPUS;
+       err = assign_irq_vector(irq, tmp);
+       if (!err) {
                struct ht_irq_msg msg;
                unsigned dest;
 
+               cpus_and(tmp, cfg->domain, tmp);
                dest = cpu_mask_to_apicid(tmp);
 
                msg.address_hi = HT_IRQ_HIGH_DEST_ID(dest);
@@ -2011,7 +2014,7 @@ int arch_setup_ht_irq(unsigned int irq, struct pci_dev *dev)
                msg.address_lo =
                        HT_IRQ_LOW_BASE |
                        HT_IRQ_LOW_DEST_ID(dest) |
-                       HT_IRQ_LOW_VECTOR(vector) |
+                       HT_IRQ_LOW_VECTOR(cfg->vector) |
                        ((INT_DEST_MODE == 0) ?
                                HT_IRQ_LOW_DM_PHYSICAL :
                                HT_IRQ_LOW_DM_LOGICAL) |
@@ -2026,7 +2029,7 @@ int arch_setup_ht_irq(unsigned int irq, struct pci_dev *dev)
                set_irq_chip_and_handler_name(irq, &ht_irq_chip,
                                              handle_edge_irq, "edge");
        }
-       return vector;
+       return err;
 }
 #endif /* CONFIG_HT_IRQ */