x86: mpparse: clean up code by introducing a few helper functions

Impact: cleanup

Refactor the MP-table parsing code via the introduction of the
following helper functions:

  skip_entry()
  smp_reserve_bootmem()
  check_irq_src()
  check_slot()

To simplify the code flow and to reduce the size of the
following oversized functions: smp_read_mpc(), smp_scan_config().

There should be no impact to functionality.

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 120 insertions, 141 deletions

diff --git a/arch/x86/kernel/mpparse.c b/arch/x86/kernel/mpparse.c
index 47673e02ae58..58ddf6259afb 100644
--- a/arch/x86/kernel/mpparse.c
+++ b/arch/x86/kernel/mpparse.c
@@ -109,9 +109,6 @@ static void __init MP_bus_info(struct mpc_bus *m)
         } else
                 printk(KERN_WARNING "Unknown bustype %s - ignoring\n", str);
 }
-#endif
-
-#ifdef CONFIG_X86_IO_APIC
 
 static int bad_ioapic(unsigned long address)
 {
@@ -224,8 +221,12 @@ static void __init MP_intsrc_info(struct mpc_intsrc *m)
         if (++mp_irq_entries == MAX_IRQ_SOURCES)
                 panic("Max # of irq sources exceeded!!\n");
 }
+#else /* CONFIG_X86_IO_APIC */
+static inline void __init MP_bus_info(struct mpc_bus *m) {}
+static inline void __init MP_ioapic_info(struct mpc_ioapic *m) {}
+static inline void __init MP_intsrc_info(struct mpc_intsrc *m) {}
+#endif /* CONFIG_X86_IO_APIC */
 
-#endif
 
 static void __init MP_lintsrc_info(struct mpc_lintsrc *m)
 {
@@ -275,6 +276,12 @@ 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 +317,27 @@ 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");
@@ -689,6 +668,31 @@ void __init get_smp_config(void)
         __get_smp_config(0);
 }
 
+static void smp_reserve_bootmem(struct mpf_intel *mpf)
+{
+        unsigned long size = get_mpc_size(mpf->physptr);
+#ifdef CONFIG_X86_32
+        /*
+         * We cannot access to MPC table to compute table size yet,
+         * as only few megabytes from the bottom is mapped now.
+         * PC-9800's MPC table places on the very last of physical
+         * memory; so that simply reserving PAGE_SIZE from mpf->physptr
+         * yields BUG() in reserve_bootmem.
+         * also need to make sure physptr is below than max_low_pfn
+         * we don't need reserve the area above max_low_pfn
+         */
+        unsigned long end = max_low_pfn * PAGE_SIZE;
+
+        if (mpf->physptr < end) {
+                if (mpf->physptr + size > end)
+                        size = end - mpf->physptr;
+                reserve_bootmem_generic(mpf->physptr, size, BOOTMEM_DEFAULT);
+        }
+#else
+        reserve_bootmem_generic(mpf->physptr, size, BOOTMEM_DEFAULT);
+#endif
+}
+
 static int __init smp_scan_config(unsigned long base, unsigned long length,
                                   unsigned reserve)
 {
@@ -717,35 +721,9 @@ static int __init smp_scan_config(unsigned long base, unsigned long length,
                         if (!reserve)
                                 return 1;
                         reserve_bootmem_generic(virt_to_phys(mpf), sizeof(*mpf),
-                                        BOOTMEM_DEFAULT);
-                        if (mpf->physptr) {
-                                unsigned long size = get_mpc_size(mpf->physptr);
-#ifdef CONFIG_X86_32
-                                /*
-                                 * We cannot access to MPC table to compute
-                                 * table size yet, as only few megabytes from
-                                 * the bottom is mapped now.
-                                 * PC-9800's MPC table places on the very last
-                                 * of physical memory; so that simply reserving
-                                 * PAGE_SIZE from mpf->physptr yields BUG()
-                                 * in reserve_bootmem.
-                                 * also need to make sure physptr is below than
-                                 * max_low_pfn
-                                 * we don't need reserve the area above max_low_pfn
-                                 */
-                                unsigned long end = max_low_pfn * PAGE_SIZE;
-
-                                if (mpf->physptr < end) {
-                                        if (mpf->physptr + size > end)
-                                                size = end - mpf->physptr;
-                                        reserve_bootmem_generic(mpf->physptr, size,
-                                                        BOOTMEM_DEFAULT);
-                                }
-#else
-                                reserve_bootmem_generic(mpf->physptr, size,
                                                 BOOTMEM_DEFAULT);
-#endif
-                        }
+                        if (mpf->physptr)
+                                smp_reserve_bootmem(mpf);
 
                         return 1;
                 }
@@ -848,7 +826,57 @@ static int  __init get_MP_intsrc_index(struct mpc_intsrc *m)
 #define SPARE_SLOT_NUM 20
 
 static struct mpc_intsrc __initdata *m_spare[SPARE_SLOT_NUM];
-#endif
+
+static void check_irq_src(struct mpc_intsrc *m, int *nr_m_spare)
+{
+        int i;
+
+        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;
+        }
+        if (!i) {
+                /* legacy, do nothing */
+                return;
+        }
+        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 += 1;
+        }
+}
+#else /* CONFIG_X86_IO_APIC */
+static inline void check_irq_src(struct mpc_intsrc *m, int *nr_m_spare) {}
+#endif /* CONFIG_X86_IO_APIC */
+
+static int check_slot(unsigned long mpc_new_phys, unsigned long mpc_new_length,
+                      int count)
+{
+        if (!mpc_new_phys) {
+                pr_info("No spare slots, try to append...take your risk, "
+                        "new mpc_length %x\n", count);
+        } else {
+                if (count <= mpc_new_length)
+                        pr_info("No spare slots, try to append..., "
+                                "new mpc_length %x\n", count);
+                else {
+                        pr_err("mpc_new_length %lx is too small\n",
+                                mpc_new_length);
+                        return -1;
+                }
+        }
+
+        return 0;
+}
 
 static int  __init replace_intsrc_all(struct mpc_table *mpc,
                                         unsigned long mpc_new_phys,
@@ -856,71 +884,30 @@ static int  __init replace_intsrc_all(struct mpc_table *mpc,
 {
 #ifdef CONFIG_X86_IO_APIC
         int i;
-        int nr_m_spare = 0;
 #endif
-
         int count = sizeof(*mpc);
+        int nr_m_spare = 0;
         unsigned char *mpt = ((unsigned char *)mpc) + count;
 
         printk(KERN_INFO "mpc_length %x\n", mpc->length);
         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;
-                        }
+                        check_irq_src((struct mpc_intsrc *)&mpt, &nr_m_spare);
+                        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");
@@ -950,16 +937,8 @@ static int  __init replace_intsrc_all(struct mpc_table *mpc,
                 } else {
                         struct mpc_intsrc *m = (struct mpc_intsrc *)mpt;
                         count += sizeof(struct mpc_intsrc);
-                        if (!mpc_new_phys) {
-                                printk(KERN_INFO "No spare slots, try to append...take your risk, new mpc_length %x\n", count);
-                        } else {
-                                if (count <= mpc_new_length)
-                                        printk(KERN_INFO "No spare slots, try to append..., new mpc_length %x\n", count);
-                                else {
-                                        printk(KERN_ERR "mpc_new_length %lx is too small\n", mpc_new_length);
-                                        goto out;
-                                }
-                        }
+                        if (!check_slot(mpc_new_phys, mpc_new_length, count))
+                                goto out;
                         assign_to_mpc_intsrc(&mp_irqs[i], m);
                         mpc->length = count;
                         mpt += sizeof(struct mpc_intsrc);