The patch titled
Add unitialized_var() macro for suppressing gcc warnings
has been removed from the -mm tree. Its filename was
add-unitialized_var-macro-for-suppressing-gcc-warnings.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: Add unitialized_var() macro for suppressing gcc warnings
From: Borislav Petkov <bbpetkov@xxxxxxxx>
Introduce a macro for suppressing gcc from generating a warning about a
probable uninitialized state of a variable.
Example:
- spinlock_t *ptl;
+ spinlock_t *uninitialized_var(ptl);
Not a happy solution, but those warnings are obnoxious.
- Using the usual pointlessly-set-it-to-zero approach wastes several
bytes of text.
- Using a macro means we can (hopefully) do something else if gcc changes
cause the `x = x' hack to stop working
- Using a macro means that people who are worried about hiding true bugs
can easily turn it off.
Signed-off-by: Borislav Petkov <bbpetkov@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/compiler-gcc3.h | 6 ++++++
include/linux/compiler-gcc4.h | 6 ++++++
include/linux/compiler-intel.h | 2 ++
mm/memory.c | 2 +-
4 files changed, 15 insertions(+), 1 deletion(-)
diff -puN include/linux/compiler-gcc3.h~add-unitialized_var-macro-for-suppressing-gcc-warnings include/linux/compiler-gcc3.h
--- a/include/linux/compiler-gcc3.h~add-unitialized_var-macro-for-suppressing-gcc-warnings
+++ a/include/linux/compiler-gcc3.h
@@ -13,4 +13,10 @@
#define __must_check __attribute__((warn_unused_result))
#endif
+/*
+ * A trick to suppress uninitialized variable warning without generating any
+ * code
+ */
+#define uninitialized_var(x) x = x
+
#define __always_inline inline __attribute__((always_inline))
diff -puN include/linux/compiler-gcc4.h~add-unitialized_var-macro-for-suppressing-gcc-warnings include/linux/compiler-gcc4.h
--- a/include/linux/compiler-gcc4.h~add-unitialized_var-macro-for-suppressing-gcc-warnings
+++ a/include/linux/compiler-gcc4.h
@@ -16,3 +16,9 @@
#define __must_check __attribute__((warn_unused_result))
#define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
#define __always_inline inline __attribute__((always_inline))
+
+/*
+ * A trick to suppress uninitialized variable warning without generating any
+ * code
+ */
+#define uninitialized_var(x) x = x
diff -puN include/linux/compiler-intel.h~add-unitialized_var-macro-for-suppressing-gcc-warnings include/linux/compiler-intel.h
--- a/include/linux/compiler-intel.h~add-unitialized_var-macro-for-suppressing-gcc-warnings
+++ a/include/linux/compiler-intel.h
@@ -22,3 +22,5 @@
(typeof(ptr)) (__ptr + (off)); })
#endif
+
+#define uninitialized_var(x) x
diff -puN mm/memory.c~add-unitialized_var-macro-for-suppressing-gcc-warnings mm/memory.c
--- a/mm/memory.c~add-unitialized_var-macro-for-suppressing-gcc-warnings
+++ a/mm/memory.c
@@ -1455,7 +1455,7 @@ static int apply_to_pte_range(struct mm_
pte_t *pte;
int err;
struct page *pmd_page;
- spinlock_t *ptl = ptl; /* Suppress gcc warning */
+ spinlock_t *uninitialized_var(ptl);
pte = (mm == &init_mm) ?
pte_alloc_kernel(pmd, addr) :
_
Patches currently in -mm which might be from bbpetkov@xxxxxxxx are
origin.patch
kernel-doc-handle-arrays-with-arithmetic-expressions-as.patch
generate-main-index-page-when-building-htmldocs.patch
kill-warnings-when-building-mandocs.patch
-
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