Linus Torvalds: Create helper for mmap_sem write-lock check in do_brk()

ChangeSet 1.1575, 2005/01/12 11:17:44-02:00, [email protected]

	Linus Torvalds: Create helper for mmap_sem write-lock check in do_brk()



 mmap.c |   11 ++++++++++-
 1 files changed, 10 insertions(+), 1 deletion(-)


diff -Nru a/mm/mmap.c b/mm/mmap.c
--- a/mm/mmap.c	2005-01-13 05:05:12 -08:00
+++ b/mm/mmap.c	2005-01-13 05:05:12 -08:00
@@ -1031,6 +1031,15 @@
 	return ret;
 }
 
+
+static inline void verify_mmap_write_lock_held(struct mm_struct *mm)
+{
+	if (down_read_trylock(&mm->mmap_sem)) {
+		WARN_ON(1);
+		up_read(&mm->mmap_sem);
+	}
+}
+
 /*
  *  this is really a simplified "do_mmap".  it only handles
  *  anonymous maps.  eventually we may be able to do some
@@ -1064,7 +1073,7 @@
 	 * mm->mmap_sem is required to protect against another thread
 	 * changing the mappings while we sleep (on kmalloc for one).
 	 */
-	WARN_ON(down_read_trylock(&mm->mmap_sem));
+	verify_mmap_write_lock_held(&mm);
 
 	/*
 	 * Clear old maps.  this also does some error checking for us