x86/boot/e820: Clean up __e820__update_table() et al

The __e820__update_table() function has various weirdly named variables,
such as 'pbios', 'biosmap' and 'pnr_map' which are pretty confusing
and actively misleading at times.

This weird naming found its way into other functions as well, such as
__append_e820_table() and append_e820_table().

Standardize the naming to make it all much easier to read:

	biosmap  ->  entries
	pbios    ->  entry
	nr_map   ->  nr_entries
        pnr_map  ->  nr_entries
	...

Also clean up the types used: entry indices routinely mixed u32 and int,
standardize on u32 thoughout.

Update the comments as well, while at it.

No change in functionality.

Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Jackson <pj@sgi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 61 insertions, 59 deletions

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 49823e0a7aea..7dc430c03acb 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -175,23 +175,23 @@ void __init e820__print_table(char *who)
 }
 
 /*
- * Sanitize the BIOS E820 map.
+ * Sanitize an E820 map.
  *
- * Some E820 responses include overlapping entries. The following
+ * Some E820 layouts include overlapping entries. The following
  * replaces the original E820 map with a new one, removing overlaps,
  * and resolving conflicting memory types in favor of highest
  * numbered type.
  *
- * The input parameter biosmap points to an array of 'struct
- * e820_entry' which on entry has elements in the range [0, *pnr_map)
- * valid, and which has space for up to max_nr_map entries.
+ * The input parameter 'entries' points to an array of 'struct
+ * e820_entry' which on entry has elements in the range [0, *nr_entries)
+ * valid, and which has space for up to max_nr_entries entries.
  * On return, the resulting sanitized E820 map entries will be in
- * overwritten in the same location, starting at biosmap.
+ * overwritten in the same location, starting at 'entries'.
  *
- * The integer pointed to by pnr_map must be valid on entry (the
- * current number of valid entries located at biosmap). If the
- * sanitizing succeeds the *pnr_map will be updated with the new
- * number of valid entries (something no more than max_nr_map).
+ * The integer pointed to by nr_entries must be valid on entry (the
+ * current number of valid entries located at 'entries'). If the
+ * sanitizing succeeds the *nr_entries will be updated with the new
+ * number of valid entries (something no more than max_nr_entries).
  *
  * The return value from e820__update_table() is zero if it
  * successfully 'sanitized' the map entries passed in, and is -1
@@ -236,8 +236,8 @@ void __init e820__print_table(char *who)
  *         ______________________4_
  */
 struct change_member {
-        /* Pointer to the original BIOS entry: */
-        struct e820_entry       *pbios;
+        /* Pointer to the original entry: */
+        struct e820_entry       *entry;
         /* Address for this change point: */
         unsigned long long      addr;
 };
@@ -256,33 +256,33 @@ static int __init cpcompare(const void *a, const void *b)
         if (ap->addr != bp->addr)
                 return ap->addr > bp->addr ? 1 : -1;
 
-        return (ap->addr != ap->pbios->addr) - (bp->addr != bp->pbios->addr);
+        return (ap->addr != ap->entry->addr) - (bp->addr != bp->entry->addr);
 }
 
-static int __init __e820__update_table(struct e820_entry *biosmap, int max_nr_map, u32 *pnr_map)
+static int __init __e820__update_table(struct e820_entry *entries, u32 max_nr_entries, u32 *nr_entries)
 {
         static struct change_member change_point_list[2*E820_MAX_ENTRIES] __initdata;
         static struct change_member *change_point[2*E820_MAX_ENTRIES] __initdata;
         static struct e820_entry *overlap_list[E820_MAX_ENTRIES] __initdata;
-        static struct e820_entry new_bios[E820_MAX_ENTRIES] __initdata;
+        static struct e820_entry new_entries[E820_MAX_ENTRIES] __initdata;
         enum e820_type current_type, last_type;
         unsigned long long last_addr;
-        int chgidx;
-        int overlap_entries;
-        int new_bios_entry;
-        int old_nr, new_nr, chg_nr;
-        int i;
+        u32 chgidx;
+        u32 overlap_entries;
+        u32 new_nr_entries;
+        u32 old_nr, new_nr, chg_nr;
+        u32 i;
 
         /* If there's only one memory region, don't bother: */
-        if (*pnr_map < 2)
+        if (*nr_entries < 2)
                 return -1;
 
-        old_nr = *pnr_map;
-        BUG_ON(old_nr > max_nr_map);
+        old_nr = *nr_entries;
+        BUG_ON(old_nr > max_nr_entries);
 
-        /* Bail out if we find any unreasonable addresses in the BIOS map: */
+        /* Bail out if we find any unreasonable addresses in the map: */
         for (i = 0; i < old_nr; i++) {
-                if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr)
+                if (entries[i].addr + entries[i].size < entries[i].addr)
                         return -1;
         }
 
@@ -296,11 +296,11 @@ static int __init __e820__update_table(struct e820_entry *biosmap, int max_nr_ma
          */
         chgidx = 0;
         for (i = 0; i < old_nr; i++)    {
-                if (biosmap[i].size != 0) {
-                        change_point[chgidx]->addr      = biosmap[i].addr;
-                        change_point[chgidx++]->pbios   = &biosmap[i];
-                        change_point[chgidx]->addr      = biosmap[i].addr + biosmap[i].size;
-                        change_point[chgidx++]->pbios   = &biosmap[i];
+                if (entries[i].size != 0) {
+                        change_point[chgidx]->addr      = entries[i].addr;
+                        change_point[chgidx++]->entry   = &entries[i];
+                        change_point[chgidx]->addr      = entries[i].addr + entries[i].size;
+                        change_point[chgidx++]->entry   = &entries[i];
                 }
         }
         chg_nr = chgidx;
@@ -308,22 +308,22 @@ static int __init __e820__update_table(struct e820_entry *biosmap, int max_nr_ma
         /* Sort change-point list by memory addresses (low -> high): */
         sort(change_point, chg_nr, sizeof(*change_point), cpcompare, NULL);
 
-        /* Create a new BIOS memory map, removing overlaps: */
+        /* Create a new memory map, removing overlaps: */
         overlap_entries = 0;     /* Number of entries in the overlap table */
-        new_bios_entry = 0;      /* Index for creating new bios map entries */
+        new_nr_entries = 0;      /* Index for creating new map entries */
         last_type = 0;           /* Start with undefined memory type */
         last_addr = 0;           /* Start with 0 as last starting address */
 
-        /* Loop through change-points, determining effect on the new BIOS map: */
+        /* Loop through change-points, determining effect on the new map: */
         for (chgidx = 0; chgidx < chg_nr; chgidx++) {
-                /* Keep track of all overlapping BIOS entries */
-                if (change_point[chgidx]->addr == change_point[chgidx]->pbios->addr) {
+                /* Keep track of all overlapping entries */
+                if (change_point[chgidx]->addr == change_point[chgidx]->entry->addr) {
                         /* Add map entry to overlap list (> 1 entry implies an overlap) */
-                        overlap_list[overlap_entries++] = change_point[chgidx]->pbios;
+                        overlap_list[overlap_entries++] = change_point[chgidx]->entry;
                 } else {
                         /* Remove entry from list (order independent, so swap with last): */
                         for (i = 0; i < overlap_entries; i++) {
-                                if (overlap_list[i] == change_point[chgidx]->pbios)
+                                if (overlap_list[i] == change_point[chgidx]->entry)
                                         overlap_list[i] = overlap_list[overlap_entries-1];
                         }
                         overlap_entries--;
@@ -339,31 +339,31 @@ static int __init __e820__update_table(struct e820_entry *biosmap, int max_nr_ma
                                 current_type = overlap_list[i]->type;
                 }
 
-                /* Continue building up new BIOS map based on this information: */
+                /* Continue building up new map based on this information: */
                 if (current_type != last_type || current_type == E820_TYPE_PRAM) {
                         if (last_type != 0)      {
-                                new_bios[new_bios_entry].size = change_point[chgidx]->addr - last_addr;
+                                new_entries[new_nr_entries].size = change_point[chgidx]->addr - last_addr;
                                 /* Move forward only if the new size was non-zero: */
-                                if (new_bios[new_bios_entry].size != 0)
-                                        /* No more space left for new BIOS entries? */
-                                        if (++new_bios_entry >= max_nr_map)
+                                if (new_entries[new_nr_entries].size != 0)
+                                        /* No more space left for new entries? */
+                                        if (++new_nr_entries >= max_nr_entries)
                                                 break;
                         }
                         if (current_type != 0)  {
-                                new_bios[new_bios_entry].addr = change_point[chgidx]->addr;
-                                new_bios[new_bios_entry].type = current_type;
+                                new_entries[new_nr_entries].addr = change_point[chgidx]->addr;
+                                new_entries[new_nr_entries].type = current_type;
                                 last_addr = change_point[chgidx]->addr;
                         }
                         last_type = current_type;
                 }
         }
 
-        /* Retain count for new BIOS entries: */
-        new_nr = new_bios_entry;
+        /* Retain count for the new entries: */
+        new_nr = new_nr_entries;
 
-        /* Copy new BIOS mapping into the original location: */
-        memcpy(biosmap, new_bios, new_nr*sizeof(*biosmap));
-        *pnr_map = new_nr;
+        /* Copy the new entries into the original location: */
+        memcpy(entries, new_entries, new_nr*sizeof(*entries));
+        *nr_entries = new_nr;
 
         return 0;
 }
@@ -373,13 +373,15 @@ int __init e820__update_table(struct e820_table *table)
         return __e820__update_table(table->entries, ARRAY_SIZE(table->entries), &table->nr_entries);
 }
 
-static int __init __append_e820_table(struct e820_entry *biosmap, int nr_map)
+static int __init __append_e820_table(struct e820_entry *entries, u32 nr_entries)
 {
-        while (nr_map) {
-                u64 start = biosmap->addr;
-                u64 size = biosmap->size;
+        struct e820_entry *entry = entries;
+
+        while (nr_entries) {
+                u64 start = entry->addr;
+                u64 size = entry->size;
                 u64 end = start + size - 1;
-                u32 type = biosmap->type;
+                u32 type = entry->type;
 
                 /* Ignore the entry on 64-bit overflow: */
                 if (start > end && likely(size))
@@ -387,8 +389,8 @@ static int __init __append_e820_table(struct e820_entry *biosmap, int nr_map)
 
                 e820__range_add(start, size, type);
 
-                biosmap++;
-                nr_map--;
+                entry++;
+                nr_entries--;
         }
         return 0;
 }
@@ -402,13 +404,13 @@ static int __init __append_e820_table(struct e820_entry *biosmap, int nr_map)
  * will have given us a memory map that we can use to properly
  * set up memory.  If we aren't, we'll fake a memory map.
  */
-static int __init append_e820_table(struct e820_entry *biosmap, int nr_map)
+static int __init append_e820_table(struct e820_entry *entries, u32 nr_entries)
 {
         /* Only one memory region (or negative)? Ignore it */
-        if (nr_map < 2)
+        if (nr_entries < 2)
                 return -1;
 
-        return __append_e820_table(biosmap, nr_map);
+        return __append_e820_table(entries, nr_entries);
 }
 
 static u64 __init