i386 pgd_index() doesn't parenthesize its arg

William Lee Irwin III
2003-01-17T05:42:37Z

pgd_index() doesn't parenthesize its argument. This is a bad idea for
macros, since it's legitimate to pass expressions to them that will
get misinterpreted given operator precedence and the shift.

vs. 2.5.59

-- wli

===== include/asm-i386/pgtable.h 1.22 vs edited =====
--- 1.22/include/asm-i386/pgtable.h Mon Nov 25 14:41:15 2002
+++ edited/include/asm-i386/pgtable.h Thu Jan 16 21:08:06 2003
@@ -242,7 +242,7 @@
((pmd_val(pmd) & (_PAGE_PSE|_PAGE_PRESENT)) == (_PAGE_PSE|_PAGE_PRESENT))

/* to find an entry in a page-table-directory. */
-#define pgd_index(address) ((address >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
+#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))

#define __pgd_offset(address) pgd_index(address)