[PATCH] msync writing when MS_INVALIDATE set and memory locked

From: Christopher Yeoh (cyeoh@samba.org)
Date: Fri Mar 22 2002 - 00:16:34 EST


For msync, SUSv2 states that it will fail if:

"[EBUSY] Some or all of the addresses in the range starting at addr
and continuing for len bytes are locked, and MS_INVALIDATE is
specified."

This check isn't being done. The following patch (against 2.4.19pre4)
adds the correct behaviour:

--- linux-2.4.18/mm/filemap.c~ Thu Mar 21 16:04:48 2002
+++ linux-2.4.18/mm/filemap.c Fri Mar 22 15:48:40 2002
@@ -2205,6 +2205,9 @@
         int ret = 0;
         struct file * file = vma->vm_file;
 
+ if ( (flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED) )
+ return -EBUSY;
+
         if (file && (vma->vm_flags & VM_SHARED)) {
                 ret = filemap_sync(vma, start, end-start, flags);
 
Chris

-- 
cyeoh@au.ibm.com
IBM OzLabs Linux Development Group
Canberra, Australia
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