From: Jani Nikula <jani.nikula@intel.com>
To: linux-kernel@vger.kernel.org
Cc: jani.nikula@intel.com, intel-gfx@lists.freedesktop.org,
dri-devel@lists.freedesktop.org,
"David Gow" <davidgow@google.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Christian König" <christian.koenig@amd.com>
Subject: [Intel-gfx] [PATCH 2/4] log2: have is_power_of_2() support bigger types than unsigned long
Date: Thu, 30 Mar 2023 13:42:41 +0300 [thread overview]
Message-ID: <20230330104243.2120761-3-jani.nikula@intel.com> (raw)
In-Reply-To: <20230330104243.2120761-1-jani.nikula@intel.com>
is_power_of_2() does not work properly for e.g. u64 in 32-bit
builds. Choose an unsigned long long version if the argument is bigger
than unsigned long.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Gow <davidgow@google.com>
Link: https://lore.kernel.org/r/20230329065532.2122295-2-davidgow@google.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
include/linux/log2.h | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/include/linux/log2.h b/include/linux/log2.h
index 19e773116ae3..4027d1eecd7f 100644
--- a/include/linux/log2.h
+++ b/include/linux/log2.h
@@ -35,6 +35,18 @@ int __ilog2_u64(u64 n)
#define __IS_POWER_OF_2(n) ((n) != 0 && (((n) & ((n) - 1)) == 0))
+static inline __attribute__((const))
+bool __is_power_of_2_ull(unsigned long long n)
+{
+ return __IS_POWER_OF_2(n);
+}
+
+static inline __attribute__((const))
+bool __is_power_of_2(unsigned long n)
+{
+ return __IS_POWER_OF_2(n);
+}
+
/**
* is_power_of_2() - check if a value is a power of two
* @n: the value to check
@@ -43,11 +55,10 @@ int __ilog2_u64(u64 n)
* *not* considered a power of two.
* Return: true if @n is a power of 2, otherwise false.
*/
-static inline __attribute__((const))
-bool is_power_of_2(unsigned long n)
-{
- return __IS_POWER_OF_2(n);
-}
+#define is_power_of_2(n) \
+ __builtin_choose_expr(sizeof(n) > sizeof(unsigned long), \
+ __is_power_of_2_ull(n), \
+ __is_power_of_2(n))
/**
* __roundup_pow_of_two() - round up to nearest power of two
--
2.39.2
next prev parent reply other threads:[~2023-03-30 10:43 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-30 10:42 [Intel-gfx] [PATCH 0/4] log2: make is_power_of_2() more generic Jani Nikula
2023-03-30 10:42 ` [Intel-gfx] [PATCH 1/4] log2: add helper __IS_POWER_OF_2() Jani Nikula
2023-03-30 10:42 ` Jani Nikula [this message]
2023-03-30 10:42 ` [Intel-gfx] [PATCH 3/4] log2: allow use of is_power_of_2() in constant expressions Jani Nikula
2023-03-30 10:42 ` [Intel-gfx] [PATCH 4/4] drm/i915/reg: use is_power_of_2() from log2.h Jani Nikula
2023-03-30 10:59 ` [Intel-gfx] [PATCH 0/4] log2: make is_power_of_2() more generic Christian König
2023-03-30 11:10 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for " Patchwork
2023-03-30 11:10 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork
2023-03-30 11:23 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2023-03-30 19:50 ` [Intel-gfx] [PATCH 0/4] " Andrew Morton
2023-03-30 21:53 ` David Laight
2023-03-30 22:18 ` Andrew Morton
2023-03-31 7:33 ` David Laight
2023-03-31 8:31 ` Jani Nikula
2023-04-05 15:27 ` Steven Price
2024-04-12 10:01 ` Jani Nikula
2023-03-31 5:58 ` [Intel-gfx] ✓ Fi.CI.IGT: success for " Patchwork
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