Commit 5eeaf1f18973 (cpufreq: Fix build error on some platforms that
use cpufreq_for_each_*) moved function cpufreq_next_valid() to a public
header. Warnings are now generated when objects including that header
are built with -Wsign-compare (as an out-of-tree module might be):
.../include/linux/cpufreq.h: In function ‘cpufreq_next_valid’:
.../include/linux/cpufreq.h:519:27: warning: comparison between signed
and unsigned integer expressions [-Wsign-compare]
while ((*pos)->frequency != CPUFREQ_TABLE_END)
^
.../include/linux/cpufreq.h:520:25: warning: comparison between signed
and unsigned integer expressions [-Wsign-compare]
if ((*pos)->frequency != CPUFREQ_ENTRY_INVALID)
^
Constants CPUFREQ_ENTRY_INVALID and CPUFREQ_TABLE_END are signed, but
are used with unsigned member 'frequency' of cpufreq_frequency_table.
Update the macro definitions to be explicitly unsigned to match their
use.
This also corrects potentially wrong behavior of clk_rate_table_iter()
if unsigned long is wider than usigned int.
Signed-off-by: Brian W Hart <ha...@linux.vnet.ibm.com>
---
These macros are fairly broadly used in the kernel so I was bit leery
of changing them, but after inspection I think it's fine. I found 102
uses of the macros, of which:
99 are uses with cpufreq_frequency_table.frequency (95) or with local
variables of the same type as frequency (4). These should be just
fine with this change--we're just making explicit a conversion that
was previously implicit.
2 are uses with a local variable of different type (unsigned long) than
'frequency' (in drivers/sh/clk/core.c). One of these uses is safe;
the other (in clk_rate_table_iter()) is broken if unsigned long
is wider than unsigned int. As a side-effect, this patch corrects
the potential misbehavior there.
1 is a use in macro cpufreq_for_each_entry() with what _should_ be the
frequency member of a cpufreq_frequency_table, provided the caller it
well-behaved. There are 18 callers of this macro; all are well-behaved.
So these should also be safe.
include/linux/cpufreq.h | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index ec4112d..8f8ae95 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -482,8 +482,8 @@ extern struct cpufreq_governor cpufreq_gov_conservative;
*********************************************************************/
/* Special Values of .frequency field */
-#define CPUFREQ_ENTRY_INVALID ~0
-#define CPUFREQ_TABLE_END ~1
+#define CPUFREQ_ENTRY_INVALID ~0u
+#define CPUFREQ_TABLE_END ~1u
/* Special Values of .flags field */
#define CPUFREQ_BOOST_FREQ (1 << 0)
--
1.7.1
--
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