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From: Borislav Petkov <bp@alien8.de>
To: Babu Moger <babu.moger@amd.com>
Cc: kernel test robot <lkp@intel.com>,
	llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	Reinette Chatre <reinette.chatre@intel.com>
Subject: [PATCH] x86/resctrl: Fix a silly -Wunused-but-set-variable warning
Date: Tue, 24 Jan 2023 19:13:08 +0100	[thread overview]
Message-ID: <Y9AftBkWXcFflHbm@zn.tnic> (raw)
In-Reply-To: <Y8/XoT23HVXHSY73@zn.tnic>

From: "Borislav Petkov (AMD)" <bp@alien8.de>

clang correctly complains

  arch/x86/kernel/cpu/resctrl/rdtgroup.c:1456:6: warning: variable \
     'h' set but not used [-Wunused-but-set-variable]
          u32 h;
              ^

but it can't know whether this use is innocuous or really a problem.
There's a reason why those warning switches are behind a W=1 and not
enabled by default - yes, one needs to do:

  make W=1 CC=clang HOSTCC=clang arch/x86/kernel/cpu/resctrl/

with clang 14 in order to trigger it.

I would normally not take a silly fix like that but this one is simple
and doesn't make the code uglier so...

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/202301242015.kbzkVteJ-lkp@intel.com
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 5990589f8a21..e2c1599d1b37 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1453,17 +1453,17 @@ static void mon_event_config_read(void *info)
 {
 	struct mon_config_info *mon_info = info;
 	unsigned int index;
-	u32 h;
+	u64 msrval;
 
 	index = mon_event_config_index_get(mon_info->evtid);
 	if (index == INVALID_CONFIG_INDEX) {
 		pr_warn_once("Invalid event id %d\n", mon_info->evtid);
 		return;
 	}
-	rdmsr(MSR_IA32_EVT_CFG_BASE + index, mon_info->mon_config, h);
+	rdmsrl(MSR_IA32_EVT_CFG_BASE + index, msrval);
 
 	/* Report only the valid event configuration bits */
-	mon_info->mon_config &= MAX_EVT_CONFIG_BITS;
+	mon_info->mon_config = msrval & MAX_EVT_CONFIG_BITS;
 }
 
 static void mondata_config_read(struct rdt_domain *d, struct mon_config_info *mon_info)
-- 
2.35.1

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  reply	other threads:[~2023-01-24 18:13 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-24 12:37 [tip:x86/cache 9/13] arch/x86/kernel/cpu/resctrl/rdtgroup.c:1456:6: warning: variable 'h' set but not used kernel test robot
2023-01-24 13:05 ` Borislav Petkov
2023-01-24 18:13   ` Borislav Petkov [this message]
2023-01-24 18:30     ` [PATCH] x86/resctrl: Fix a silly -Wunused-but-set-variable warning Reinette Chatre
2023-01-24 18:44     ` Moger, Babu
2023-02-09  3:06   ` [tip:x86/cache 9/13] arch/x86/kernel/cpu/resctrl/rdtgroup.c:1456:6: warning: variable 'h' set but not used Philip Li
2023-02-09  9:53     ` Borislav Petkov
2023-02-10  3:15       ` Philip Li
2023-02-10 21:49         ` Borislav Petkov

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