x86/PCI: MMCONFIG: manage pci_mmcfg_region as a list, not a table

This changes pci_mmcfg_region from a table to a list, to make it easier
to add and remove MMCONFIG regions for PCI host bridge hotplug.

Reviewed-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 41 insertions, 65 deletions

diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 6eeeac0d25f4..2709aa81801d 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -16,7 +16,6 @@
 #include <linux/sfi_acpi.h>
 #include <linux/bitmap.h>
 #include <linux/dmi.h>
-#include <linux/sort.h>
 #include <asm/e820.h>
 #include <asm/pci_x86.h>
 #include <asm/acpi.h>
@@ -26,53 +25,58 @@
 /* Indicate if the mmcfg resources have been placed into the resource table. */
 static int __initdata pci_mmcfg_resources_inserted;
 
+LIST_HEAD(pci_mmcfg_list);
+
 static __init void free_all_mmcfg(void)
 {
-        int i;
-        struct pci_mmcfg_region *cfg;
+        struct pci_mmcfg_region *cfg, *tmp;
 
         pci_mmcfg_arch_free();
-        for (i = 0; i < pci_mmcfg_config_num; i++) {
-                cfg = &pci_mmcfg_config[i];
+        list_for_each_entry_safe(cfg, tmp, &pci_mmcfg_list, list) {
                 if (cfg->res.parent)
                         release_resource(&cfg->res);
+                list_del(&cfg->list);
+                kfree(cfg);
         }
-        pci_mmcfg_config_num = 0;
-        kfree(pci_mmcfg_config);
-        pci_mmcfg_config = NULL;
+}
+
+static __init void list_add_sorted(struct pci_mmcfg_region *new)
+{
+        struct pci_mmcfg_region *cfg;
+
+        /* keep list sorted by segment and starting bus number */
+        list_for_each_entry(cfg, &pci_mmcfg_list, list) {
+                if (cfg->segment > new->segment ||
+                    (cfg->segment == new->segment &&
+                     cfg->start_bus >= new->start_bus)) {
+                        list_add_tail(&new->list, &cfg->list);
+                        return;
+                }
+        }
+        list_add_tail(&new->list, &pci_mmcfg_list);
 }
 
 static __init struct pci_mmcfg_region *pci_mmconfig_add(int segment, int start,
                                                         int end, u64 addr)
 {
         struct pci_mmcfg_region *new;
-        int new_num = pci_mmcfg_config_num + 1;
-        int i = pci_mmcfg_config_num;
         int num_buses;
         struct resource *res;
 
         if (addr == 0)
                 return NULL;
 
-        new = kzalloc(sizeof(pci_mmcfg_config[0]) * new_num, GFP_KERNEL);
+        new = kzalloc(sizeof(*new), GFP_KERNEL);
         if (!new)
                 return NULL;
 
-        if (pci_mmcfg_config) {
-                memcpy(new, pci_mmcfg_config,
-                         sizeof(pci_mmcfg_config[0]) * new_num);
-                kfree(pci_mmcfg_config);
-        }
-        pci_mmcfg_config = new;
-        pci_mmcfg_config_num++;
-
-        new = &pci_mmcfg_config[i];
-
         new->address = addr;
         new->segment = segment;
         new->start_bus = start;
         new->end_bus = end;
 
+        list_add_sorted(new);
+
         num_buses = end - start + 1;
         res = &new->res;
         res->start = addr + PCI_MMCFG_BUS_OFFSET(start);
@@ -82,7 +86,7 @@ static __init struct pci_mmcfg_region *pci_mmconfig_add(int segment, int start,
                  "PCI MMCONFIG %04x [bus %02x-%02x]", segment, start, end);
         res->name = new->name;
 
-        return &pci_mmcfg_config[i];
+        return new;
 }
 
 static const char __init *pci_mmcfg_e7520(void)
@@ -214,7 +218,7 @@ static const char __init *pci_mmcfg_nvidia_mcp55(void)
         /*
          * do check if amd fam10h already took over
          */
-        if (!acpi_disabled || pci_mmcfg_config_num || mcp55_checked)
+        if (!acpi_disabled || !list_empty(&pci_mmcfg_list) || mcp55_checked)
                 return NULL;
 
         mcp55_checked = true;
@@ -275,44 +279,26 @@ static struct pci_mmcfg_hostbridge_probe pci_mmcfg_probes[] __initdata = {
           0x0369, pci_mmcfg_nvidia_mcp55 },
 };
 
-static int __init cmp_mmcfg(const void *x1, const void *x2)
-{
-        const struct pci_mmcfg_region *m1 = x1;
-        const struct pci_mmcfg_region *m2 = x2;
-        int start1, start2;
-
-        start1 = m1->start_bus;
-        start2 = m2->start_bus;
-
-        return start1 - start2;
-}
-
 static void __init pci_mmcfg_check_end_bus_number(void)
 {
-        int i;
         struct pci_mmcfg_region *cfg, *cfgx;
 
-        /* sort them at first */
-        sort(pci_mmcfg_config, pci_mmcfg_config_num,
-                 sizeof(pci_mmcfg_config[0]), cmp_mmcfg, NULL);
-
         /* last one*/
-        if (pci_mmcfg_config_num > 0) {
-                i = pci_mmcfg_config_num - 1;
-                cfg = &pci_mmcfg_config[i];
+        cfg = list_entry(pci_mmcfg_list.prev, typeof(*cfg), list);
+        if (cfg)
                 if (cfg->end_bus < cfg->start_bus)
                         cfg->end_bus = 255;
-        }
 
-        /* don't overlap please */
-        for (i = 0; i < pci_mmcfg_config_num - 1; i++) {
-                cfg = &pci_mmcfg_config[i];
-                cfgx = &pci_mmcfg_config[i+1];
+        if (list_is_singular(&pci_mmcfg_list))
+                return;
 
+        /* don't overlap please */
+        list_for_each_entry(cfg, &pci_mmcfg_list, list) {
                 if (cfg->end_bus < cfg->start_bus)
                         cfg->end_bus = 255;
 
-                if (cfg->end_bus >= cfgx->start_bus)
+                cfgx = list_entry(cfg->list.next, typeof(*cfg), list);
+                if (cfg != cfgx && cfg->end_bus >= cfgx->start_bus)
                         cfg->end_bus = cfgx->start_bus - 1;
         }
 }
@@ -350,18 +336,15 @@ static int __init pci_mmcfg_check_hostbridge(void)
         /* some end_bus_number is crazy, fix it */
         pci_mmcfg_check_end_bus_number();
 
-        return pci_mmcfg_config_num != 0;
+        return !list_empty(&pci_mmcfg_list);
 }
 
 static void __init pci_mmcfg_insert_resources(void)
 {
-        int i;
         struct pci_mmcfg_region *cfg;
 
-        for (i = 0; i < pci_mmcfg_config_num; i++) {
-                cfg = &pci_mmcfg_config[i];
+        list_for_each_entry(cfg, &pci_mmcfg_list, list)
                 insert_resource(&iomem_resource, &cfg->res);
-        }
 
         /* Mark that the resources have been inserted. */
         pci_mmcfg_resources_inserted = 1;
@@ -482,18 +465,15 @@ static void __init pci_mmcfg_reject_broken(int early)
         struct pci_mmcfg_region *cfg;
         int i;
 
-        if (pci_mmcfg_config_num == 0)
-                return;
-
-        for (i = 0; i < pci_mmcfg_config_num; i++) {
+        list_for_each_entry(cfg, &pci_mmcfg_list, list) {
                 int valid = 0;
 
-                cfg = &pci_mmcfg_config[i];
                 printk(KERN_NOTICE "PCI: MCFG configuration %d: base %lx "
                        "segment %hu buses %u - %u\n",
                        i, (unsigned long)cfg->address, cfg->segment,
                        (unsigned int)cfg->start_bus,
                        (unsigned int)cfg->end_bus);
+                i++;
 
                 if (!early && !acpi_disabled)
                         valid = is_mmconf_reserved(is_acpi_reserved, i, cfg, 0);
@@ -524,10 +504,6 @@ reject:
 
 static int __initdata known_bridge;
 
-/* The physical address of the MMCONFIG aperture.  Set from ACPI tables. */
-struct pci_mmcfg_region *pci_mmcfg_config;
-int pci_mmcfg_config_num;
-
 static int __init acpi_mcfg_check_entry(struct acpi_table_mcfg *mcfg,
                                         struct acpi_mcfg_allocation *cfg)
 {
@@ -620,7 +596,7 @@ static void __init __pci_mmcfg_init(int early)
 
         pci_mmcfg_reject_broken(early);
 
-        if (pci_mmcfg_config_num == 0)
+        if (list_empty(&pci_mmcfg_list))
                 return;
 
         if (pci_mmcfg_arch_init())
@@ -652,7 +628,7 @@ static int __init pci_mmcfg_late_insert_resources(void)
          */
         if ((pci_mmcfg_resources_inserted == 1) ||
             (pci_probe & PCI_PROBE_MMCONF) == 0 ||
-            (pci_mmcfg_config_num == 0))
+            list_empty(&pci_mmcfg_list))
                 return 1;
 
         /*