ksm: break cow once unshared

[safe/jmp/linux-2.6] / mm / mprotect.c

diff --git a/mm/mprotect.c b/mm/mprotect.c
index d0f6e7c..8bc969d 100644 (file)
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -23,6 +23,7 @@
 #include <linux/swapops.h>
 #include <linux/mmu_notifier.h>
 #include <linux/migrate.h>
+#include <linux/perf_event.h>
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 #include <asm/cacheflush.h>
@@ -151,10 +152,11 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
        /*
         * If we make a private mapping writable we increase our commit;
         * but (without finer accounting) cannot reduce our commit if we
-        * make it unwritable again.
+        * make it unwritable again. hugetlb mapping were accounted for
+        * even if read-only so there is no need to account for them here
         */
        if (newflags & VM_WRITE) {
-               if (!(oldflags & (VM_ACCOUNT|VM_WRITE|
+               if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
                                                VM_SHARED|VM_NORESERVE))) {
                        charged = nrpages;
                        if (security_vm_enough_memory(charged))
@@ -217,8 +219,8 @@ fail:
        return error;
 }
 
-asmlinkage long
-sys_mprotect(unsigned long start, size_t len, unsigned long prot)
+SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
+               unsigned long, prot)
 {
        unsigned long vm_flags, nstart, end, tmp, reqprot;
        struct vm_area_struct *vma, *prev;
@@ -298,6 +300,7 @@ sys_mprotect(unsigned long start, size_t len, unsigned long prot)
                error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
                if (error)
                        goto out;
+               perf_event_mmap(vma);
                nstart = tmp;
 
                if (nstart < prev->vm_end)