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min/max: remove sparse warnings when they're nested

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Currently, when min/max are nested within themselves, sparse will warn:

    warning: symbol '_min1' shadows an earlier one
    originally declared here
    warning: symbol '_min1' shadows an earlier one
    originally declared here
    warning: symbol '_min2' shadows an earlier one
    originally declared here

This also immediately happens when min3() or max3() are used.

Since sparse implements __COUNTER__, we can use __UNIQUE_ID() to
generate unique variable names, avoiding this.

Link: http://lkml.kernel.org/r/1471519773-29882-1-git-send-email-johannes@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Johannes Berg 2016-10-07 17:02:42 -07:00 committed by Linus Torvalds
parent 53aeee7a86
commit 589a9785ee
1 changed files with 26 additions and 18 deletions
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44
include/linux/kernel.h
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@ -733,17 +733,25 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
* strict type-checking.. See the
* "unnecessary" pointer comparison.
*/
#define min(x, y) ({ \
typeof(x) _min1 = (x); \
typeof(y) _min2 = (y); \
(void) (&_min1 == &_min2); \
_min1 < _min2 ? _min1 : _min2; })
#define __min(t1, t2, min1, min2, x, y) ({ \
t1 min1 = (x); \
t2 min2 = (y); \
(void) (&min1 == &min2); \
min1 < min2 ? min1 : min2; })
#define min(x, y) \
__min(typeof(x), typeof(y), \
__UNIQUE_ID(min1_), __UNIQUE_ID(min2_), \
x, y)
#define max(x, y) ({ \
typeof(x) _max1 = (x); \
typeof(y) _max2 = (y); \
(void) (&_max1 == &_max2); \
_max1 > _max2 ? _max1 : _max2; })
#define __max(t1, t2, max1, max2, x, y) ({ \
t1 max1 = (x); \
t2 max2 = (y); \
(void) (&max1 == &max2); \
max1 > max2 ? max1 : max2; })
#define max(x, y) \
__max(typeof(x), typeof(y), \
__UNIQUE_ID(max1_), __UNIQUE_ID(max2_), \
x, y)
#define min3(x, y, z) min((typeof(x))min(x, y), z)
#define max3(x, y, z) max((typeof(x))max(x, y), z)
@ -775,15 +783,15 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
*
* Or not use min/max/clamp at all, of course.
*/
#define min_t(type, x, y) ({ \
type __min1 = (x); \
type __min2 = (y); \
__min1 < __min2 ? __min1: __min2; })
#define min_t(type, x, y) \
__min(type, type, \
__UNIQUE_ID(min1_), __UNIQUE_ID(min2_), \
x, y)
#define max_t(type, x, y) ({ \
type __max1 = (x); \
type __max2 = (y); \
__max1 > __max2 ? __max1: __max2; })
#define max_t(type, x, y) \
__max(type, type, \
__UNIQUE_ID(min1_), __UNIQUE_ID(min2_), \
x, y)
/**
* clamp_t - return a value clamped to a given range using a given type