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Date: Mon, 16 Mar 2009 17:48:15 +0530
From: Jaswinder Singh Rajput <jaswinder@...nel.org>
To: Ingo Molnar <mingo@...e.hu>
Cc: x86 maintainers <x86@...nel.org>,
LKML <linux-kernel@...r.kernel.org>,
Thomas Gleixner <tglx@...utronix.de>,
"H. Peter Anvin" <hpa@...or.com>
Subject: Re: [git-pull -tip] x86: cleanup patches
On Sat, 2009-03-14 at 18:03 +0100, Ingo Molnar wrote:
> ----- Forwarded message from Ingo Molnar <mingo@...e.hu> -----
>
> Date: Fri, 2 Jan 2009 18:21:50 +0100
> From: Ingo Molnar <mingo@...e.hu>
> To: Jaswinder Singh Rajput <jaswinder@...radead.org>
> Subject: Re: [PATCH] x86: mpparse.c fix style problems
> Cc: Alan Cox <alan@...rguk.ukuu.org.uk>, x86 maintainers <x86@...nel.org>,
> LKML <linux-kernel@...r.kernel.org>
>
>
> * Jaswinder Singh Rajput <jaswinder@...radead.org> wrote:
>
> > Impact: cleanup, fix style problems, more readable
>
> > @@ -314,7 +314,9 @@ static int __init smp_read_mpc(struct mp_config_table *mpc, unsigned early)
> > return 1;
> >
> > if (mpc->mpc_oemptr && x86_quirks->smp_read_mpc_oem) {
> > - struct mp_config_oemtable *oem_table = (struct mp_config_oemtable *)(unsigned long)mpc->mpc_oemptr;
> > + struct mp_config_oemtable *oem_table;
> > + oem_table = (struct mp_config_oemtable *)
> > + (unsigned long)mpc->mpc_oemptr;
> > x86_quirks->smp_read_mpc_oem(oem_table, mpc->mpc_oemsize);
> > }
>
> i think it would be cleaner to rename all the the mpc->mpc_X fields to
> mpc->X - that alone would give 4 characters per usage site. (we already
> know that it's an 'mpc' entity - no need to duplicate that in the field
> too)
>
Already fixed earlier.
> likewise, mp_config_oemtable should be renamed to mpc_oemtable to make it
> all more compact.
>
> also, instead of:
>
> > + struct mp_config_oemtable *oem_table;
> > + oem_table = (struct mp_config_oemtable *)
> > + (unsigned long)mpc->mpc_oemptr;
>
> we can do this oneliner:
>
> > + struct mpc_oemtable oem_table = (void *)(long)mpc->mpc_oemptr;
>
Already fixed earlier.
> these types of printk string tweaks:
>
> > - printk(KERN_INFO "No spare slots, try to append...take your risk, new mpc_length %x\n", count);
> > + printk(KERN_INFO "No spare slots, try to append"
> > + "...take your risk, new mpc_length %x\n",
> > + count);
>
> do not actually improve the result - as they break the string in about 40
> columns - making grepping harder and making it less readable. So it's a
> step backwards.
>
> To solve the 80 columns wrap problem, the following could be and should be
> done instead.
>
> 1) get the type names right - they should be expressive but short - like a
> good Huffman encoding:
>
> See the mpc_ suggestion above, but there are more examples as well:
>
> struct mpc_config_processor *m =
> (struct mpc_config_processor *)mpt;
>
> mpc_config_processor should be renamed to mpc_cpu. The reason: the 'c' in
> MPC already means 'config' - no need to repeat that in the type name. Plus
> 'processor' is a lot longer than 'cpu' - so we try to use 'cpu' in all
> type names, as much as possible.
>
Already fixed earlier.
> 2) get the code flow granularity right. Use small but expressive
> functions, where each function does one well-defined thing that is easy
> to think about as one unit of activity.
>
> For example observe that replace_intsrc_all() is too big and not
> particularly well structured.
>
> furthermore, the whole function could be split up with a few helper
> functions. Most of the loops could be split up by doing something like:
>
> while (count < mpc->mpc_length) {
> switch (*mpt) {
>
> case MP_PROCESSOR:
> skip_entry(&mpt, &count, sizeof(struct mpc_cpu));
> continue;
>
> case MP_BUS:
> skip_entry(&mpt, &count, sizeof(struct mpc_bus));
> continue;
>
> [...]
> case MP_INTSRC:
> parse_mpc_irq_entry(&mpt, &count);
> continue;
>
> default:
> ...
> goto out;
> }
>
> The whole thing is way more readable, and it's immediately obvious that
> the real work is done by MP_INTSRC - in a separate helper function. The
> skip_entry() helper function just skips over
>
Here is the patch for skip_entry, I cannot check this patch on my side,
so please check it and let me know the feedbacks:
>>From ff5a4d728b42af867dc8f6aef43107c7a015a5b4 Mon Sep 17 00:00:00 2001
From: Jaswinder Singh Rajput <jaswinderrajput@...il.com>
Date: Mon, 16 Mar 2009 17:06:49 +0530
Subject: [PATCH] x86: mpparse cleanup
Impact: cleanup
Introduced helper function skip_entry and check_irq_src
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@...il.com>
---
arch/x86/kernel/mpparse.c | 179 ++++++++++++++++++++-------------------------
1 files changed, 78 insertions(+), 101 deletions(-)
diff --git a/arch/x86/kernel/mpparse.c b/arch/x86/kernel/mpparse.c
index 47673e0..f1cf457 100644
--- a/arch/x86/kernel/mpparse.c
+++ b/arch/x86/kernel/mpparse.c
@@ -68,9 +68,9 @@ static void __init MP_processor_info(struct mpc_cpu *m)
generic_processor_info(apicid, m->apicver);
}
-#ifdef CONFIG_X86_IO_APIC
static void __init MP_bus_info(struct mpc_bus *m)
{
+#ifdef CONFIG_X86_IO_APIC
char str[7];
memcpy(str, m->bustype, 6);
str[6] = 0;
@@ -108,11 +108,10 @@ static void __init MP_bus_info(struct mpc_bus *m)
#endif
} else
printk(KERN_WARNING "Unknown bustype %s - ignoring\n", str);
+#endif /* CONFIG_X86_IO_APIC */
}
-#endif
#ifdef CONFIG_X86_IO_APIC
-
static int bad_ioapic(unsigned long address)
{
if (nr_ioapics >= MAX_IO_APICS) {
@@ -127,9 +126,11 @@ static int bad_ioapic(unsigned long address)
}
return 0;
}
+#endif /* CONFIG_X86_IO_APIC */
static void __init MP_ioapic_info(struct mpc_ioapic *m)
{
+#ifdef CONFIG_X86_IO_APIC
if (!(m->flags & MPC_APIC_USABLE))
return;
@@ -145,25 +146,32 @@ static void __init MP_ioapic_info(struct mpc_ioapic *m)
mp_ioapics[nr_ioapics].apicver = m->apicver;
mp_ioapics[nr_ioapics].flags = m->flags;
nr_ioapics++;
+#endif /* CONFIG_X86_IO_APIC */
}
static void print_MP_intsrc_info(struct mpc_intsrc *m)
{
+#ifdef CONFIG_X86_IO_APIC
apic_printk(APIC_VERBOSE, "Int: type %d, pol %d, trig %d, bus %02x,"
" IRQ %02x, APIC ID %x, APIC INT %02x\n",
m->irqtype, m->irqflag & 3, (m->irqflag >> 2) & 3, m->srcbus,
m->srcbusirq, m->dstapic, m->dstirq);
+#endif /* CONFIG_X86_IO_APIC */
}
static void __init print_mp_irq_info(struct mpc_intsrc *mp_irq)
{
+#ifdef CONFIG_X86_IO_APIC
apic_printk(APIC_VERBOSE, "Int: type %d, pol %d, trig %d, bus %02x,"
" IRQ %02x, APIC ID %x, APIC INT %02x\n",
mp_irq->irqtype, mp_irq->irqflag & 3,
(mp_irq->irqflag >> 2) & 3, mp_irq->srcbus,
mp_irq->srcbusirq, mp_irq->dstapic, mp_irq->dstirq);
+#endif /* CONFIG_X86_IO_APIC */
}
+#ifdef CONFIG_X86_IO_APIC
+
static void __init assign_to_mp_irq(struct mpc_intsrc *m,
struct mpc_intsrc *mp_irq)
{
@@ -275,6 +283,12 @@ static int __init smp_check_mpc(struct mpc_table *mpc, char *oem, char *str)
return 1;
}
+static void skip_entry(unsigned char **ptr, int *count, int size)
+{
+ *ptr += size;
+ *count += size;
+}
+
static int __init smp_read_mpc(struct mpc_table *mpc, unsigned early)
{
char str[16];
@@ -310,55 +324,27 @@ static int __init smp_read_mpc(struct mpc_table *mpc, unsigned early)
while (count < mpc->length) {
switch (*mpt) {
case MP_PROCESSOR:
- {
- struct mpc_cpu *m = (struct mpc_cpu *)mpt;
- /* ACPI may have already provided this data */
- if (!acpi_lapic)
- MP_processor_info(m);
- mpt += sizeof(*m);
- count += sizeof(*m);
- break;
- }
+ /* ACPI may have already provided this data */
+ if (!acpi_lapic)
+ MP_processor_info((struct mpc_cpu *)&mpt);
+ skip_entry(&mpt, &count, sizeof(struct mpc_cpu));
+ break;
case MP_BUS:
- {
- struct mpc_bus *m = (struct mpc_bus *)mpt;
-#ifdef CONFIG_X86_IO_APIC
- MP_bus_info(m);
-#endif
- mpt += sizeof(*m);
- count += sizeof(*m);
- break;
- }
+ MP_bus_info((struct mpc_bus *)&mpt);
+ skip_entry(&mpt, &count, sizeof(struct mpc_bus));
+ break;
case MP_IOAPIC:
- {
-#ifdef CONFIG_X86_IO_APIC
- struct mpc_ioapic *m = (struct mpc_ioapic *)mpt;
- MP_ioapic_info(m);
-#endif
- mpt += sizeof(struct mpc_ioapic);
- count += sizeof(struct mpc_ioapic);
- break;
- }
+ MP_ioapic_info((struct mpc_ioapic *)&mpt);
+ skip_entry(&mpt, &count, sizeof(struct mpc_ioapic));
+ break;
case MP_INTSRC:
- {
-#ifdef CONFIG_X86_IO_APIC
- struct mpc_intsrc *m = (struct mpc_intsrc *)mpt;
-
- MP_intsrc_info(m);
-#endif
- mpt += sizeof(struct mpc_intsrc);
- count += sizeof(struct mpc_intsrc);
- break;
- }
+ MP_intsrc_info((struct mpc_intsrc *)&mpt);
+ skip_entry(&mpt, &count, sizeof(struct mpc_intsrc));
+ break;
case MP_LINTSRC:
- {
- struct mpc_lintsrc *m =
- (struct mpc_lintsrc *)mpt;
- MP_lintsrc_info(m);
- mpt += sizeof(*m);
- count += sizeof(*m);
- break;
- }
+ MP_lintsrc_info((struct mpc_lintsrc *)&mpt);
+ skip_entry(&mpt, &count, sizeof(struct mpc_lintsrc));
+ break;
default:
/* wrong mptable */
printk(KERN_ERR "Your mptable is wrong, contact your HW vendor!\n");
@@ -850,15 +836,46 @@ static int __init get_MP_intsrc_index(struct mpc_intsrc *m)
static struct mpc_intsrc __initdata *m_spare[SPARE_SLOT_NUM];
#endif
+static int check_irq_src(struct mpc_intsrc *m)
+{
+#ifdef CONFIG_X86_IO_APIC
+ int i, nr_m_spare = 0;
+
+ apic_printk(APIC_VERBOSE, "OLD ");
+ print_MP_intsrc_info(m);
+
+ i = get_MP_intsrc_index(m);
+ if (i > 0) {
+ assign_to_mpc_intsrc(&mp_irqs[i], m);
+ apic_printk(APIC_VERBOSE, "NEW ");
+ print_mp_irq_info(&mp_irqs[i]);
+ return 0;
+ }
+ if (!i) {
+ /* legacy, do nothing */
+ return 0;
+ }
+
+ /*
+ * not found (-1), or duplicated (-2)
+ * are invalid entries,
+ * we need to use the slot later
+ */
+ m_spare[nr_m_spare] = m;
+ nr_m_spare++;
+
+ return nr_m_spare;
+#endif /* CONFIG_X86_IO_APIC */
+}
+
static int __init replace_intsrc_all(struct mpc_table *mpc,
unsigned long mpc_new_phys,
unsigned long mpc_new_length)
{
#ifdef CONFIG_X86_IO_APIC
int i;
- int nr_m_spare = 0;
#endif
-
+ int nr_m_spare = 0;
int count = sizeof(*mpc);
unsigned char *mpt = ((unsigned char *)mpc) + count;
@@ -866,61 +883,21 @@ static int __init replace_intsrc_all(struct mpc_table *mpc,
while (count < mpc->length) {
switch (*mpt) {
case MP_PROCESSOR:
- {
- struct mpc_cpu *m = (struct mpc_cpu *)mpt;
- mpt += sizeof(*m);
- count += sizeof(*m);
- break;
- }
+ skip_entry(&mpt, &count, sizeof(struct mpc_cpu));
+ break;
case MP_BUS:
- {
- struct mpc_bus *m = (struct mpc_bus *)mpt;
- mpt += sizeof(*m);
- count += sizeof(*m);
- break;
- }
+ skip_entry(&mpt, &count, sizeof(struct mpc_bus));
+ break;
case MP_IOAPIC:
- {
- mpt += sizeof(struct mpc_ioapic);
- count += sizeof(struct mpc_ioapic);
- break;
- }
+ skip_entry(&mpt, &count, sizeof(struct mpc_ioapic));
+ break;
case MP_INTSRC:
- {
-#ifdef CONFIG_X86_IO_APIC
- struct mpc_intsrc *m = (struct mpc_intsrc *)mpt;
-
- apic_printk(APIC_VERBOSE, "OLD ");
- print_MP_intsrc_info(m);
- i = get_MP_intsrc_index(m);
- if (i > 0) {
- assign_to_mpc_intsrc(&mp_irqs[i], m);
- apic_printk(APIC_VERBOSE, "NEW ");
- print_mp_irq_info(&mp_irqs[i]);
- } else if (!i) {
- /* legacy, do nothing */
- } else if (nr_m_spare < SPARE_SLOT_NUM) {
- /*
- * not found (-1), or duplicated (-2)
- * are invalid entries,
- * we need to use the slot later
- */
- m_spare[nr_m_spare] = m;
- nr_m_spare++;
- }
-#endif
- mpt += sizeof(struct mpc_intsrc);
- count += sizeof(struct mpc_intsrc);
- break;
- }
+ nr_m_spare = check_irq_src((struct mpc_intsrc *)&mpt);
+ skip_entry(&mpt, &count, sizeof(struct mpc_intsrc));
+ break;
case MP_LINTSRC:
- {
- struct mpc_lintsrc *m =
- (struct mpc_lintsrc *)mpt;
- mpt += sizeof(*m);
- count += sizeof(*m);
- break;
- }
+ skip_entry(&mpt, &count, sizeof(struct mpc_lintsrc));
+ break;
default:
/* wrong mptable */
printk(KERN_ERR "Your mptable is wrong, contact your HW vendor!\n");
--
1.6.0.6
> 3) Get the details right. Look at the source code - should that code be
> done like that and does it look as compact as it could be?
>
> for example these bits:
>
> while (count < mpc->mpc_length) {
> switch (*mpt) {
> case MP_PROCESSOR:
> {
> struct mpc_config_processor *m =
> (struct mpc_config_processor *)mpt;
> mpt += sizeof(*m);
> count += sizeof(*m);
> break;
> }
> case MP_BUS:
>
> are _way_ too wasteful with tabs - and that is causing the 80 cols
> problems. (we'd fix this if we hadnt fixed it at step 2 already ;-)
>
> Or these bits:
>
> ---------------->
> static int __init replace_intsrc_all(struct mp_config_table *mpc,
> unsigned long mpc_new_phys,
> unsigned long mpc_new_length)
> {
> #ifdef CONFIG_X86_IO_APIC
> int i;
> int nr_m_spare = 0;
> #endif
>
> int count = sizeof(*mpc);
> unsigned char *mpt = ((unsigned char *)mpc) + count;
> <----------------
>
> are more readable as:
>
> ---------------->
> static int __init
> replace_intsrc_all(struct mpc_table *mpc,
> unsigned long mpc_new_phys,
> unsigned long mpc_new_length)
> {
> unsigned char *mpt = (void *)mpc;
> int count = 0;
>
> skip_entry(&mpt, &count, sizeof(struct mpc_table));
> <----------------
>
Already fixed earlier.
Thanks,
--
JSR
--
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