The patch titled
compiler: define __attribute_unused__
has been added to the -mm tree. Its filename is
compiler-define-__attribute_unused__.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: compiler: define __attribute_unused__
From: David Rientjes <rientjes@xxxxxxxxxx>
For all supported versions of gcc (major version 3 and above), functions and
variables may be declared with __attribute__((unused)) to suppress warnings if
they are declared but unused.
This shouldn't be confused with functions being declared with
__attribute__((used)). This specifies that the function code shall still be
emitted even if it appears to be unreferenced, normally used if embedded in
inline assembly. For gcc 3.4 and later, unreferenced static variables and
functions are not emitted so this attribute is necessary to force variables
and functions to be output. Earlier versions of gcc can simply use
__attribute__((unused)) to suppress warnings about such variables: we do not
require any special classification to ensure they are emitted.
We introduce __attribute_unused__ for variables that should not produce a
compile warning if they can, due to preprocessor macros, go unreferenced.
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/compiler-gcc.h | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff -puN include/linux/compiler-gcc.h~compiler-define-__attribute_unused__ include/linux/compiler-gcc.h
--- a/include/linux/compiler-gcc.h~compiler-define-__attribute_unused__
+++ a/include/linux/compiler-gcc.h
@@ -40,3 +40,19 @@
#define noinline __attribute__((noinline))
#define __attribute_pure__ __attribute__((pure))
#define __attribute_const__ __attribute__((__const__))
+
+/*
+ * __attribute_unused__ shall be used for functions or variables to suppress
+ * warnings when they may be declared but, due to preprocessor macros,
+ * commenting, etc., go unreferenced.
+ *
+ * In contrast, __attribute_used__ shall be used only for functions. gcc <3.4
+ * emits code for static functions that are unreferenced and outputs a warning.
+ * __attribute_used__ will correctly suppress this warning. gcc >=3.4 does not
+ * emit code for static functions that are unreferenced (and thus there is no
+ * warning), but __attribute_used__ forces the function code to be output. Use
+ * __attribute_unused__ to suppress warnings about functions being unused or
+ * __attribute_used__ to ensure code is emitted when it is referenced only in
+ * inline assembly.
+ */
+#define __attribute_unused__ __attribute__((unused))
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
origin.patch
i386-add-ptep_test_and_clear_dirtyyoung.patch
i386-use-pte_update_defer-in-ptep_test_and_clear_dirtyyoung.patch
smaps-extract-pmd-walker-from-smaps-code.patch
smaps-add-pages-referenced-count-to-smaps.patch
smaps-add-clear_refs-file-to-clear-reference.patch
cpusets-allow-tif_memdie-threads-to-allocate-anywhere.patch
mm-fix-handling-of-panic_on_oom-when-cpusets-are-in-use.patch
oom-fix-constraint-deadlock.patch
wavefront-only-declare-isapnp-on-config_pnp.patch
git-cpufreq.patch
maps2-uninline-some-functions-in-the-page-walker.patch
maps2-eliminate-the-pmd_walker-struct-in-the-page-walker.patch
maps2-remove-vma-from-args-in-the-page-walker.patch
maps2-propagate-errors-from-callback-in-page-walker.patch
maps2-add-callbacks-for-each-level-to-page-walker.patch
maps2-move-the-page-walker-code-to-lib.patch
maps2-simplify-interdependence-of-proc-pid-maps-and-smaps.patch
maps2-move-clear_refs-code-to-task_mmuc.patch
maps2-regroup-task_mmu-by-interface.patch
maps2-make-proc-pid-smaps-optional-under-config_embedded.patch
maps2-make-proc-pid-clear_refs-option-under-config_embedded.patch
maps2-add-proc-pid-pagemap-interface.patch
maps2-add-proc-kpagemap-interface.patch
cpusets-allow-empty-cpusmems_allowed-to-be-set-for.patch
cpusets-allow-empty-cpusmems_allowed-to-be-set-for-fix.patch
compiler-define-__attribute_unused__.patch
i386-pci-type-may-be-unused.patch
sh-dma-use-__attribute_unused__.patch
scsi-fix-ambiguous-gdthtable-definition.patch
frv-gdb-use-__attribute_unused__.patch
i386-voyager-use-__attribute_unused__.patch
mips-excite-use-__attribute_unused__.patch
mips-tlbex-use-__attribute_unused__.patch
powerpc-ps3-use-__attribute_unused__.patch
i386-mmzone-use-__attribute_unused__.patch
-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
