x86, ioapic: Use ioapic_saved_data while enabling intr-remapping

Code flow for enabling interrupt-remapping was
allocating/freeing buffers for saving/restoring io-apic RTE's.
ioapic suspend/resume code uses boot time allocated
ioapic_saved_data that is a perfect match for reuse here.

This will remove the unnecessary allocation/free of the
temporary buffers during suspend/resume of interrupt-remapping
enabled platforms aswell as paving the way for further code
consolidation.

Tested-by: Daniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/20110518233157.574469296@sbsiddha-MOBL3.sc.intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 31 insertions, 97 deletions

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index f92a8e5d1e21..b961af86bfea 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1461,7 +1461,6 @@ int __init enable_IR(void)
 void __init enable_IR_x2apic(void)
 {
         unsigned long flags;
-        struct IO_APIC_route_entry **ioapic_entries;
         int ret, x2apic_enabled = 0;
         int dmar_table_init_ret;
 
@@ -1469,13 +1468,7 @@ void __init enable_IR_x2apic(void)
         if (dmar_table_init_ret && !x2apic_supported())
                 return;
 
-        ioapic_entries = alloc_ioapic_entries();
-        if (!ioapic_entries) {
-                pr_err("Allocate ioapic_entries failed\n");
-                goto out;
-        }
-
-        ret = save_IO_APIC_setup(ioapic_entries);
+        ret = save_ioapic_entries();
         if (ret) {
                 pr_info("Saving IO-APIC state failed: %d\n", ret);
                 goto out;
@@ -1483,7 +1476,7 @@ void __init enable_IR_x2apic(void)
 
         local_irq_save(flags);
         legacy_pic->mask_all();
-        mask_IO_APIC_setup(ioapic_entries);
+        mask_ioapic_entries();
 
         if (dmar_table_init_ret)
                 ret = 0;
@@ -1514,14 +1507,11 @@ void __init enable_IR_x2apic(void)
 
 nox2apic:
         if (!ret) /* IR enabling failed */
-                restore_IO_APIC_setup(ioapic_entries);
+                restore_ioapic_entries();
         legacy_pic->restore_mask();
         local_irq_restore(flags);
 
 out:
-        if (ioapic_entries)
-                free_ioapic_entries(ioapic_entries);
-
         if (x2apic_enabled)
                 return;
 
@@ -2095,28 +2085,20 @@ static void lapic_resume(void)
 {
         unsigned int l, h;
         unsigned long flags;
-        int maxlvt, ret;
-        struct IO_APIC_route_entry **ioapic_entries = NULL;
+        int maxlvt;
 
         if (!apic_pm_state.active)
                 return;
 
         local_irq_save(flags);
         if (intr_remapping_enabled) {
-                ioapic_entries = alloc_ioapic_entries();
-                if (!ioapic_entries) {
-                        WARN(1, "Alloc ioapic_entries in lapic resume failed.");
-                        goto restore;
-                }
-
-                ret = save_IO_APIC_setup(ioapic_entries);
-                if (ret) {
-                        WARN(1, "Saving IO-APIC state failed: %d\n", ret);
-                        free_ioapic_entries(ioapic_entries);
-                        goto restore;
-                }
-
-                mask_IO_APIC_setup(ioapic_entries);
+                /*
+                 * IO-APIC and PIC have their own resume routines.
+                 * We just mask them here to make sure the interrupt
+                 * subsystem is completely quiet while we enable x2apic
+                 * and interrupt-remapping.
+                 */
+                mask_ioapic_entries();
                 legacy_pic->mask_all();
         }
 
@@ -2159,13 +2141,9 @@ static void lapic_resume(void)
         apic_write(APIC_ESR, 0);
         apic_read(APIC_ESR);
 
-        if (intr_remapping_enabled) {
+        if (intr_remapping_enabled)
                 reenable_intr_remapping(x2apic_mode);
-                legacy_pic->restore_mask();
-                restore_IO_APIC_setup(ioapic_entries);
-                free_ioapic_entries(ioapic_entries);
-        }
-restore:
+
         local_irq_restore(flags);
 }
 
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 8e771d32ada1..08b794d07a52 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -101,7 +101,7 @@ int mp_irq_entries;
 static int nr_irqs_gsi = NR_IRQS_LEGACY;
 
 /*
- * Saved I/O APIC state during suspend/resume.
+ * Saved I/O APIC state during suspend/resume, or while enabling intr-remap.
 */
 static struct IO_APIC_route_entry *ioapic_saved_data[MAX_IO_APICS];
 
@@ -628,74 +628,43 @@ static int __init ioapic_pirq_setup(char *str)
 __setup("pirq=", ioapic_pirq_setup);
 #endif /* CONFIG_X86_32 */
 
-struct IO_APIC_route_entry **alloc_ioapic_entries(void)
-{
-        int apic;
-        struct IO_APIC_route_entry **ioapic_entries;
-
-        ioapic_entries = kzalloc(sizeof(*ioapic_entries) * nr_ioapics,
-                                GFP_ATOMIC);
-        if (!ioapic_entries)
-                return 0;
-
-        for (apic = 0; apic < nr_ioapics; apic++) {
-                ioapic_entries[apic] =
-                        kzalloc(sizeof(struct IO_APIC_route_entry) *
-                                nr_ioapic_registers[apic], GFP_ATOMIC);
-                if (!ioapic_entries[apic])
-                        goto nomem;
-        }
-
-        return ioapic_entries;
-
-nomem:
-        while (--apic >= 0)
-                kfree(ioapic_entries[apic]);
-        kfree(ioapic_entries);
-
-        return 0;
-}
-
 /*
  * Saves all the IO-APIC RTE's
  */
-int save_IO_APIC_setup(struct IO_APIC_route_entry **ioapic_entries)
+int save_ioapic_entries(void)
 {
         int apic, pin;
-
-        if (!ioapic_entries)
-                return -ENOMEM;
+        int err = 0;
 
         for (apic = 0; apic < nr_ioapics; apic++) {
-                if (!ioapic_entries[apic])
-                        return -ENOMEM;
+                if (!ioapic_saved_data[apic]) {
+                        err = -ENOMEM;
+                        continue;
+                }
 
                 for (pin = 0; pin < nr_ioapic_registers[apic]; pin++)
-                        ioapic_entries[apic][pin] =
+                        ioapic_saved_data[apic][pin] =
                                 ioapic_read_entry(apic, pin);
         }
 
-        return 0;
+        return err;
 }
 
 /*
  * Mask all IO APIC entries.
  */
-void mask_IO_APIC_setup(struct IO_APIC_route_entry **ioapic_entries)
+void mask_ioapic_entries(void)
 {
         int apic, pin;
 
-        if (!ioapic_entries)
-                return;
-
         for (apic = 0; apic < nr_ioapics; apic++) {
-                if (!ioapic_entries[apic])
-                        break;
+                if (!ioapic_saved_data[apic])
+                        continue;
 
                 for (pin = 0; pin < nr_ioapic_registers[apic]; pin++) {
                         struct IO_APIC_route_entry entry;
 
-                        entry = ioapic_entries[apic][pin];
+                        entry = ioapic_saved_data[apic][pin];
                         if (!entry.mask) {
                                 entry.mask = 1;
                                 ioapic_write_entry(apic, pin, entry);
@@ -705,36 +674,23 @@ void mask_IO_APIC_setup(struct IO_APIC_route_entry **ioapic_entries)
 }
 
 /*
- * Restore IO APIC entries which was saved in ioapic_entries.
+ * Restore IO APIC entries which was saved in ioapic_saved_data
  */
-int restore_IO_APIC_setup(struct IO_APIC_route_entry **ioapic_entries)
+int restore_ioapic_entries(void)
 {
         int apic, pin;
 
-        if (!ioapic_entries)
-                return -ENOMEM;
-
         for (apic = 0; apic < nr_ioapics; apic++) {
-                if (!ioapic_entries[apic])
-                        return -ENOMEM;
+                if (!ioapic_saved_data[apic])
+                        continue;
 
                 for (pin = 0; pin < nr_ioapic_registers[apic]; pin++)
                         ioapic_write_entry(apic, pin,
-                                        ioapic_entries[apic][pin]);
+                                           ioapic_saved_data[apic][pin]);
         }
         return 0;
 }
 
-void free_ioapic_entries(struct IO_APIC_route_entry **ioapic_entries)
-{
-        int apic;
-
-        for (apic = 0; apic < nr_ioapics; apic++)
-                kfree(ioapic_entries[apic]);
-
-        kfree(ioapic_entries);
-}
-
 /*
  * Find the IRQ entry number of a certain pin.
  */