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authorNick Piggin <npiggin@suse.de>2007-10-16 01:24:56 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-16 09:42:54 -0700
commit5fe172370687e03cc6ba8dca990b75db18ff9bb3 (patch)
tree8ce000fee15fa9ccd4313018f7f9ab1ffbc8cdaa /mm
parentae37461c70bc8c8416cad1bab13a9898ed030aa1 (diff)
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mm: debug write deadlocks
Allow CONFIG_DEBUG_VM to switch off the prefaulting logic, to simulate the Makes the race much easier to hit. This is useful for demonstration and testing purposes, but is removed in a subsequent patch. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/filemap.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index f74d052..0c54fc9 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1878,6 +1878,7 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
if (maxlen > bytes)
maxlen = bytes;
+#ifndef CONFIG_DEBUG_VM
/*
* Bring in the user page that we will copy from _first_.
* Otherwise there's a nasty deadlock on copying from the
@@ -1885,6 +1886,7 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
* up-to-date.
*/
fault_in_pages_readable(buf, maxlen);
+#endif
page = __grab_cache_page(mapping,index,&cached_page,&lru_pvec);
if (!page) {