[PATCH][TRIVIAL] madvise() syscall: don't test arguments holding semaphore

[Andrey Panin <pazke@donpac.ru>]

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Hi,

madvise() system call checks its arguments holding current->mm->mmap_sem
semaphore. I know that madvise() shouldn't be perfomance critical, 
but fix it so obvious :) Patch against 2.6.1-rc

Best regards.

-- 
Andrey Panin		| Linux and UNIX system administrator
pazke@donpac.ru		| PGP key: wwwkeys.pgp.net

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diff -urN -X /usr/share/dontdiff linux-2.6.0-test3.vanilla/mm/madvise.c linux-2.6.0-test3/mm/madvise.c
--- linux-2.6.0-test3.vanilla/mm/madvise.c	2003-08-09 08:34:02.000000000 +0400
+++ linux-2.6.0-test3/mm/madvise.c	2004-01-01 16:51:58.000000000 +0300
@@ -166,20 +166,20 @@
 	unsigned long end;
 	struct vm_area_struct * vma;
 	int unmapped_error = 0;
-	int error = -EINVAL;
-
-	down_write(&current->mm->mmap_sem);
+	int error;
 
 	if (start & ~PAGE_MASK)
-		goto out;
+		return -EINVAL;
+
 	len = (len + ~PAGE_MASK) & PAGE_MASK;
 	end = start + len;
 	if (end < start)
-		goto out;
+		return -EINVAL;
 
-	error = 0;
 	if (end == start)
-		goto out;
+		return 0;
+
+	down_write(&current->mm->mmap_sem);
 
 	/*
 	 * If the interval [start,end) covers some unmapped address

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