[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>

1 files changed, 56 insertions, 53 deletions

diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
index dd6580c66f61..79fa7b2bbee4 100644
--- 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 */