2002-03-22 05:25:52

by Christopher Yeoh

[permalink] [raw]
Subject: [PATCH] msync writing when MS_INVALIDATE set and memory locked


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
--
[email protected]
IBM OzLabs Linux Development Group
Canberra, Australia