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-rw-r--r--mm/mlock.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/mm/mlock.c b/mm/mlock.c
index 1ada366..3035a56 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -667,3 +667,48 @@ void user_shm_unlock(size_t size, struct user_struct *user)
spin_unlock(&shmlock_user_lock);
free_uid(user);
}
+
+void *alloc_locked_buffer(size_t size)
+{
+ unsigned long rlim, vm, pgsz;
+ void *buffer = NULL;
+
+ pgsz = PAGE_ALIGN(size) >> PAGE_SHIFT;
+
+ down_write(&current->mm->mmap_sem);
+
+ rlim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
+ vm = current->mm->total_vm + pgsz;
+ if (rlim < vm)
+ goto out;
+
+ rlim = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
+ vm = current->mm->locked_vm + pgsz;
+ if (rlim < vm)
+ goto out;
+
+ buffer = kzalloc(size, GFP_KERNEL);
+ if (!buffer)
+ goto out;
+
+ current->mm->total_vm += pgsz;
+ current->mm->locked_vm += pgsz;
+
+ out:
+ up_write(&current->mm->mmap_sem);
+ return buffer;
+}
+
+void free_locked_buffer(void *buffer, size_t size)
+{
+ unsigned long pgsz = PAGE_ALIGN(size) >> PAGE_SHIFT;
+
+ down_write(&current->mm->mmap_sem);
+
+ current->mm->total_vm -= pgsz;
+ current->mm->locked_vm -= pgsz;
+
+ up_write(&current->mm->mmap_sem);
+
+ kfree(buffer);
+}
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