Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / mm / msync.c

diff --git a/kernel/mm/msync.c b/kernel/mm/msync.c
new file mode 100644 (file)
index 0000000..bb04d53
--- /dev/null
+++ b/kernel/mm/msync.c
@@ -0,0 +1,107 @@
+/*
+ *     linux/mm/msync.c
+ *
+ * Copyright (C) 1994-1999  Linus Torvalds
+ */
+
+/*
+ * The msync() system call.
+ */
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/file.h>
+#include <linux/syscalls.h>
+#include <linux/sched.h>
+
+/*
+ * MS_SYNC syncs the entire file - including mappings.
+ *
+ * MS_ASYNC does not start I/O (it used to, up to 2.5.67).
+ * Nor does it marks the relevant pages dirty (it used to up to 2.6.17).
+ * Now it doesn't do anything, since dirty pages are properly tracked.
+ *
+ * The application may now run fsync() to
+ * write out the dirty pages and wait on the writeout and check the result.
+ * Or the application may run fadvise(FADV_DONTNEED) against the fd to start
+ * async writeout immediately.
+ * So by _not_ starting I/O in MS_ASYNC we provide complete flexibility to
+ * applications.
+ */
+SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
+{
+       unsigned long end;
+       struct mm_struct *mm = current->mm;
+       struct vm_area_struct *vma;
+       int unmapped_error = 0;
+       int error = -EINVAL;
+
+       if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
+               goto out;
+       if (start & ~PAGE_MASK)
+               goto out;
+       if ((flags & MS_ASYNC) && (flags & MS_SYNC))
+               goto out;
+       error = -ENOMEM;
+       len = (len + ~PAGE_MASK) & PAGE_MASK;
+       end = start + len;
+       if (end < start)
+               goto out;
+       error = 0;
+       if (end == start)
+               goto out;
+       /*
+        * If the interval [start,end) covers some unmapped address ranges,
+        * just ignore them, but return -ENOMEM at the end.
+        */
+       down_read(&mm->mmap_sem);
+       vma = find_vma(mm, start);
+       for (;;) {
+               struct file *file;
+               loff_t fstart, fend;
+
+               /* Still start < end. */
+               error = -ENOMEM;
+               if (!vma)
+                       goto out_unlock;
+               /* Here start < vma->vm_end. */
+               if (start < vma->vm_start) {
+                       start = vma->vm_start;
+                       if (start >= end)
+                               goto out_unlock;
+                       unmapped_error = -ENOMEM;
+               }
+               /* Here vma->vm_start <= start < vma->vm_end. */
+               if ((flags & MS_INVALIDATE) &&
+                               (vma->vm_flags & VM_LOCKED)) {
+                       error = -EBUSY;
+                       goto out_unlock;
+               }
+               file = vma->vm_file;
+               fstart = (start - vma->vm_start) +
+                        ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
+               fend = fstart + (min(end, vma->vm_end) - start) - 1;
+               start = vma->vm_end;
+               if ((flags & MS_SYNC) && file &&
+                               (vma->vm_flags & VM_SHARED)) {
+                       get_file(file);
+                       up_read(&mm->mmap_sem);
+                       error = vfs_fsync_range(file, fstart, fend, 1);
+                       fput(file);
+                       if (error || start >= end)
+                               goto out;
+                       down_read(&mm->mmap_sem);
+                       vma = find_vma(mm, start);
+               } else {
+                       if (start >= end) {
+                               error = 0;
+                               goto out_unlock;
+                       }
+                       vma = vma->vm_next;
+               }
+       }
+out_unlock:
+       up_read(&mm->mmap_sem);
+out:
+       return error ? : unmapped_error;
+}