linux-kernel - Re: [PATCH 2/5] x86, MCA: Convert dont_log

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Date:	Wed, 17 Oct 2012 15:15:59 +0200
From:	Borislav Petkov <bp@...64.org>
To:	"Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>
Cc:	Tony Luck <tony.luck@...el.com>,
	Greg Kroah-Hartman <greg@...ah.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/5] x86, MCA: Convert dont_log_ce, banks and tolerant

On Wed, Oct 17, 2012 at 05:37:54PM +0530, Naveen N. Rao wrote:
> Nit: no need for the above? Only 2 references below and I think we
> can simply continue to use mca_cfg for uniformity. Ditto for the use
> of cfg further below.
> 
> >
> >-	mce_banks = kzalloc(banks * sizeof(struct mce_bank), GFP_KERNEL);
> >+	mce_banks = kzalloc(num_banks * sizeof(struct mce_bank), GFP_KERNEL);
> >  	if (!mce_banks)
> >  		return -ENOMEM;

For the simple reason that this line violates the 80 columns and I
didn't want to bring any uglification to the code by breaking the line
in two.

For the generated asm it doesn't matter - it is simply done for keeping
the code as readable as possible.

> >-	for (i = 0; i < banks; i++) {
> >+
> >+	for (i = 0; i < num_banks; i++) {
> >  		struct mce_bank *b = &mce_banks[i];
> >
> >  		b->ctl = -1ULL;
> >@@ -1401,7 +1405,7 @@ static int __cpuinit __mcheck_cpu_cap_init(void)
> >  	rdmsrl(MSR_IA32_MCG_CAP, cap);
> >
> >  	b = cap & MCG_BANKCNT_MASK;
> >-	if (!banks)
> >+	if (!mca_cfg.banks)
> >  		pr_info("CPU supports %d MCE banks\n", b);
> >
> >  	if (b > MAX_NR_BANKS) {
> >@@ -1411,8 +1415,9 @@ static int __cpuinit __mcheck_cpu_cap_init(void)
> >  	}
> >
> >  	/* Don't support asymmetric configurations today */
> >-	WARN_ON(banks != 0 && b != banks);
> >-	banks = b;
> >+	WARN_ON(mca_cfg.banks != 0 && b != mca_cfg.banks);
> >+	mca_cfg.banks = b;
> >+
> >  	if (!mce_banks) {
> >  		int err = __mcheck_cpu_mce_banks_init();
> >
> >@@ -1448,7 +1453,7 @@ static void __mcheck_cpu_init_generic(void)
> >  	if (cap & MCG_CTL_P)
> >  		wrmsr(MSR_IA32_MCG_CTL, 0xffffffff, 0xffffffff);
> >
> >-	for (i = 0; i < banks; i++) {
> >+	for (i = 0; i < mca_cfg.banks; i++) {
> >  		struct mce_bank *b = &mce_banks[i];
> >
> >  		if (!b->init)
> >@@ -1489,6 +1494,8 @@ static void quirk_sandybridge_ifu(int bank, struct mce *m, struct pt_regs *regs)
> >  /* Add per CPU specific workarounds here */
> >  static int __cpuinit __mcheck_cpu_apply_quirks(struct cpuinfo_x86 *c)
> >  {
> >+	struct mca_config *cfg = &mca_cfg;
> >+
> 
> Same as above. We could probably continue using mca_cfg for uniformity.

There are 13 mca_cfg references total in that function so having it
shorter with a declaration at the beginning of the function of what cfg
is, is better IMO.

[ … ]

> > __init mcheck_enable(char *str)
> >  {
> >+	struct mca_config *cfg = &mca_cfg;
> >+
> 
> Same as above.

Ditto, 8 refs here.

-- 
Regards/Gruss,
Boris.

Advanced Micro Devices GmbH
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