1 files changed, 24 insertions, 12 deletions

diff --git a/arch/um/sys-i386/ldt.c b/arch/um/sys-i386/ldt.c
index 5db7737df0ff..4a8b4202ef9e 100644
--- a/arch/um/sys-i386/ldt.c
+++ b/arch/um/sys-i386/ldt.c
@@ -7,6 +7,7 @@
 #include "linux/slab.h"
 #include "linux/types.h"
 #include "linux/errno.h"
+#include "linux/spinlock.h"
 #include "asm/uaccess.h"
 #include "asm/smp.h"
 #include "asm/ldt.h"
@@ -386,23 +387,33 @@ static long do_modify_ldt_skas(int func, void __user *ptr,
         return ret;
 }
 
-short dummy_list[9] = {0, -1};
-short * host_ldt_entries = NULL;
+static DEFINE_SPINLOCK(host_ldt_lock);
+static short dummy_list[9] = {0, -1};
+static short * host_ldt_entries = NULL;
 
-void ldt_get_host_info(void)
+static void ldt_get_host_info(void)
 {
         long ret;
-        struct ldt_entry * ldt;
+        struct ldt_entry * ldt, *tmp;
         int i, size, k, order;
 
+        spin_lock(&host_ldt_lock);
+
+        if(host_ldt_entries != NULL){
+                spin_unlock(&host_ldt_lock);
+                return;
+        }
         host_ldt_entries = dummy_list+1;
 
+        spin_unlock(&host_ldt_lock);
+
         for(i = LDT_PAGES_MAX-1, order=0; i; i>>=1, order++);
 
         ldt = (struct ldt_entry *)
               __get_free_pages(GFP_KERNEL|__GFP_ZERO, order);
         if(ldt == NULL) {
-                printk("ldt_get_host_info: couldn't allocate buffer for host ldt\n");
+                printk("ldt_get_host_info: couldn't allocate buffer for host "
+                       "ldt\n");
                 return;
         }
 
@@ -426,11 +437,13 @@ void ldt_get_host_info(void)
                 host_ldt_entries = dummy_list;
         else {
                 size = (size + 1) * sizeof(dummy_list[0]);
-                host_ldt_entries = kmalloc(size, GFP_KERNEL);
-                if(host_ldt_entries == NULL) {
-                        printk("ldt_get_host_info: couldn't allocate host ldt list\n");
+                tmp = kmalloc(size, GFP_KERNEL);
+                if(tmp == NULL) {
+                        printk("ldt_get_host_info: couldn't allocate host ldt "
+                               "list\n");
                         goto out_free;
                 }
+                host_ldt_entries = tmp;
         }
 
         for(i=0, k=0; i<ret/LDT_ENTRY_SIZE; i++){
@@ -480,8 +493,7 @@ long init_new_ldt(struct mmu_context_skas * new_mm,
                          * inherited from the host. All ldt-entries found
                          * will be reset in the following loop
                          */
-                        if(host_ldt_entries == NULL)
-                                ldt_get_host_info();
+                        ldt_get_host_info();
                         for(num_p=host_ldt_entries; *num_p != -1; num_p++){
                                 desc.entry_number = *num_p;
                                 err = write_ldt_entry(&new_mm->id, 1, &desc,
@@ -560,6 +572,6 @@ void free_ldt(struct mmu_context_skas * mm)
 
 int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount)
 {
-        return(CHOOSE_MODE_PROC(do_modify_ldt_tt, do_modify_ldt_skas, func,
-                                ptr, bytecount));
+        return CHOOSE_MODE_PROC(do_modify_ldt_tt, do_modify_ldt_skas, func,
+                                ptr, bytecount);
 }