linux-kernel - Re: [PATCH] x86/mce: Do not overwrite MCi_STATUS in mce_no_way

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Message-ID: <20180621181808.GA20097@agluck-desk>
Date:   Thu, 21 Jun 2018 11:18:09 -0700
From:   "Luck, Tony" <tony.luck@...el.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86/mce: Do not overwrite MCi_STATUS in mce_no_way_out()

Counter proposal.  We don't need the temp mci_status because we exit the
loop early.  Nor the "ret" variable.


How does this look?

-Tony

---


diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index e4cf6ff1c2e1..0e30abccfe54 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -772,23 +772,23 @@ EXPORT_SYMBOL_GPL(machine_check_poll);
 static int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp,
 			  struct pt_regs *regs)
 {
-	int i, ret = 0;
+	int i;
 	char *tmp;
 
 	for (i = 0; i < mca_cfg.banks; i++) {
 		m->status = mce_rdmsrl(msr_ops.status(i));
-		if (m->status & MCI_STATUS_VAL) {
-			__set_bit(i, validp);
-			if (quirk_no_way_out)
-				quirk_no_way_out(i, m, regs);
-		}
+		if (!(m->status & MCI_STATUS_VAL))
+			continue;
+		__set_bit(i, validp);
+		if (quirk_no_way_out)
+			quirk_no_way_out(i, m, regs);
 
 		if (mce_severity(m, mca_cfg.tolerant, &tmp, true) >= MCE_PANIC_SEVERITY) {
 			*msg = tmp;
-			ret = 1;
+			return 1;
 		}
 	}
-	return ret;
+	return 0;
 }
 
 /*