[Xen-changelog] [xen-unstable] IRQ: Introduce old_vector to irq_cfg

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
# Date 1315231764 -3600
# Node ID 7f357e1ef60adf1e43fad97d58721cc2c5309c42
# Parent  9fa77d26a813867ad4c1ac4a78216f27c39f952b
IRQ: Introduce old_vector to irq_cfg

Introduce old_vector to irq_cfg with the same principle as
old_cpu_mask.  This removes a brute force loop from
__clear_irq_vector(), and paves the way to correct bitrotten logic
elsewhere in the irq code.

Signed-off-by Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---


diff -r 9fa77d26a813 -r 7f357e1ef60a xen/arch/x86/io_apic.c
--- a/xen/arch/x86/io_apic.c    Mon Sep 05 15:08:38 2011 +0100
+++ b/xen/arch/x86/io_apic.c    Mon Sep 05 15:09:24 2011 +0100
@@ -488,11 +488,16 @@
         __get_cpu_var(vector_irq)[vector] = -1;
         cfg->move_cleanup_count--;
 
-        if ( cfg->move_cleanup_count == 0 
-             &&  cfg->used_vectors )
+        if ( cfg->move_cleanup_count == 0 )
         {
-            ASSERT(test_bit(vector, cfg->used_vectors));
-            clear_bit(vector, cfg->used_vectors);
+            cfg->old_vector = IRQ_VECTOR_UNASSIGNED;
+            cpus_clear(cfg->old_cpu_mask);
+
+            if ( cfg->used_vectors )
+            {
+                ASSERT(test_bit(vector, cfg->used_vectors));
+                clear_bit(vector, cfg->used_vectors);
+            }
         }
 unlock:
         spin_unlock(&desc->lock);
diff -r 9fa77d26a813 -r 7f357e1ef60a xen/arch/x86/irq.c
--- a/xen/arch/x86/irq.c        Mon Sep 05 15:08:38 2011 +0100
+++ b/xen/arch/x86/irq.c        Mon Sep 05 15:09:24 2011 +0100
@@ -43,8 +43,6 @@
 u8 __read_mostly *irq_vector;
 struct irq_desc __read_mostly *irq_desc = NULL;
 
-#define IRQ_VECTOR_UNASSIGNED (0)
-
 static DECLARE_BITMAP(used_vectors, NR_VECTORS);
 
 struct irq_cfg __read_mostly *irq_cfg = NULL;
@@ -235,15 +233,9 @@
 
     cpus_and(tmp_mask, cfg->old_cpu_mask, cpu_online_map);
     for_each_cpu_mask(cpu, tmp_mask) {
-        for (vector = FIRST_DYNAMIC_VECTOR; vector <= LAST_DYNAMIC_VECTOR;
-                                vector++) {
-            if (per_cpu(vector_irq, cpu)[vector] != irq)
-                continue;
-            TRACE_3D(TRC_HW_IRQ_MOVE_FINISH,
-                     irq, vector, cpu);
-            per_cpu(vector_irq, cpu)[vector] = -1;
-             break;
-        }
+        ASSERT( per_cpu(vector_irq, cpu)[cfg->old_vector] == irq );
+        TRACE_3D(TRC_HW_IRQ_MOVE_FINISH, irq, vector, cpu);
+        per_cpu(vector_irq, cpu)[cfg->old_vector] = -1;
      }
 
     if ( cfg->used_vectors )
@@ -253,6 +245,8 @@
     }
 
     cfg->move_in_progress = 0;
+    cfg->old_vector = IRQ_VECTOR_UNASSIGNED;
+    cpus_clear(cfg->old_cpu_mask);
 }
 
 void clear_irq_vector(int irq)
@@ -303,6 +297,7 @@
 static void __init init_one_irq_cfg(struct irq_cfg *cfg)
 {
     cfg->vector = IRQ_VECTOR_UNASSIGNED;
+    cfg->old_vector = IRQ_VECTOR_UNASSIGNED;
     cpus_clear(cfg->cpu_mask);
     cpus_clear(cfg->old_cpu_mask);
     cfg->used_vectors = NULL;
@@ -491,6 +486,7 @@
         if (old_vector) {
             cfg->move_in_progress = 1;
             cpus_copy(cfg->old_cpu_mask, cfg->cpu_mask);
+            cfg->old_vector = cfg->vector;
         }
         trace_irq_mask(TRC_HW_IRQ_ASSIGN_VECTOR, irq, vector, &tmp_mask);
         for_each_cpu_mask(new_cpu, tmp_mask)
diff -r 9fa77d26a813 -r 7f357e1ef60a xen/include/asm-x86/irq.h
--- a/xen/include/asm-x86/irq.h Mon Sep 05 15:08:38 2011 +0100
+++ b/xen/include/asm-x86/irq.h Mon Sep 05 15:09:24 2011 +0100
@@ -28,7 +28,8 @@
 } vmask_t;
 
 struct irq_cfg {
-        int  vector;
+        s16 vector;                  /* vector itself is only 8 bits, */
+        s16 old_vector;              /* but we use -1 for unassigned  */
         cpumask_t cpu_mask;
         cpumask_t old_cpu_mask;
         unsigned move_cleanup_count;
@@ -41,6 +42,8 @@
 #define IRQ_UNUSED      (0)
 #define IRQ_USED        (1)
 
+#define IRQ_VECTOR_UNASSIGNED (-1)
+
 extern struct irq_cfg *irq_cfg;
 
 typedef int vector_irq_t[NR_VECTORS];

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