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x86, pat: Preparatory changes in pat.c for bigger rbtree change
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Minor changes in pat.c to cleanup code and make it smoother to introduce
bigger rbtree only change in the following patch. The changes are cleaup
only and should not have any functional impact.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
LKML-Reference: <20100210195909.792781000@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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venkatesh.pallipadi@intel.com authored and H. Peter Anvin committed Feb 18, 2010
1 parent 17d9ddc commit be5a0c1
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Showing 2 changed files with 116 additions and 82 deletions.
170 changes: 88 additions & 82 deletions arch/x86/mm/pat.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,8 @@
#include <asm/pat.h>
#include <asm/io.h>

#include "pat_internal.h"

#ifdef CONFIG_X86_PAT
int __read_mostly pat_enabled = 1;

Expand All @@ -53,19 +55,15 @@ static inline void pat_disable(const char *reason)
#endif


static int debug_enable;
int pat_debug_enable;

static int __init pat_debug_setup(char *str)
{
debug_enable = 1;
pat_debug_enable = 1;
return 0;
}
__setup("debugpat", pat_debug_setup);

#define dprintk(fmt, arg...) \
do { if (debug_enable) printk(KERN_INFO fmt, ##arg); } while (0)


static u64 __read_mostly boot_pat_state;

enum {
Expand Down Expand Up @@ -132,17 +130,6 @@ void pat_init(void)

#undef PAT

static char *cattr_name(unsigned long flags)
{
switch (flags & _PAGE_CACHE_MASK) {
case _PAGE_CACHE_UC: return "uncached";
case _PAGE_CACHE_UC_MINUS: return "uncached-minus";
case _PAGE_CACHE_WB: return "write-back";
case _PAGE_CACHE_WC: return "write-combining";
default: return "broken";
}
}

/*
* The global memtype list keeps track of memory type for specific
* physical memory areas. Conflicting memory types in different
Expand All @@ -159,14 +146,6 @@ static char *cattr_name(unsigned long flags)
* memtype_lock protects both the linear list and rbtree.
*/

struct memtype {
u64 start;
u64 end;
unsigned long type;
struct list_head nd;
struct rb_node rb;
};

static struct rb_root memtype_rbroot = RB_ROOT;
static LIST_HEAD(memtype_list);
static DEFINE_SPINLOCK(memtype_lock); /* protects memtype list */
Expand Down Expand Up @@ -349,6 +328,64 @@ static int free_ram_pages_type(u64 start, u64 end)
return 0;
}

static int memtype_check_insert(struct memtype *new, unsigned long *new_type)
{
struct memtype *entry;
u64 start, end;
unsigned long actual_type;
struct list_head *where;
int err = 0;

start = new->start;
end = new->end;
actual_type = new->type;

/* Search for existing mapping that overlaps the current range */
where = NULL;
list_for_each_entry(entry, &memtype_list, nd) {
if (end <= entry->start) {
where = entry->nd.prev;
break;
} else if (start <= entry->start) { /* end > entry->start */
err = chk_conflict(new, entry, new_type);
if (!err) {
dprintk("Overlap at 0x%Lx-0x%Lx\n",
entry->start, entry->end);
where = entry->nd.prev;
}
break;
} else if (start < entry->end) { /* start > entry->start */
err = chk_conflict(new, entry, new_type);
if (!err) {
dprintk("Overlap at 0x%Lx-0x%Lx\n",
entry->start, entry->end);

/*
* Move to right position in the linked
* list to add this new entry
*/
list_for_each_entry_continue(entry,
&memtype_list, nd) {
if (start <= entry->start) {
where = entry->nd.prev;
break;
}
}
}
break;
}
}
if (!err) {
if (where)
list_add(&new->nd, where);
else
list_add_tail(&new->nd, &memtype_list);

memtype_rb_insert(&memtype_rbroot, new);
}
return err;
}

/*
* req_type typically has one of the:
* - _PAGE_CACHE_WB
Expand All @@ -364,9 +401,8 @@ static int free_ram_pages_type(u64 start, u64 end)
int reserve_memtype(u64 start, u64 end, unsigned long req_type,
unsigned long *new_type)
{
struct memtype *new, *entry;
struct memtype *new;
unsigned long actual_type;
struct list_head *where;
int is_range_ram;
int err = 0;

Expand Down Expand Up @@ -423,42 +459,7 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,

spin_lock(&memtype_lock);

/* Search for existing mapping that overlaps the current range */
where = NULL;
list_for_each_entry(entry, &memtype_list, nd) {
if (end <= entry->start) {
where = entry->nd.prev;
break;
} else if (start <= entry->start) { /* end > entry->start */
err = chk_conflict(new, entry, new_type);
if (!err) {
dprintk("Overlap at 0x%Lx-0x%Lx\n",
entry->start, entry->end);
where = entry->nd.prev;
}
break;
} else if (start < entry->end) { /* start > entry->start */
err = chk_conflict(new, entry, new_type);
if (!err) {
dprintk("Overlap at 0x%Lx-0x%Lx\n",
entry->start, entry->end);

/*
* Move to right position in the linked
* list to add this new entry
*/
list_for_each_entry_continue(entry,
&memtype_list, nd) {
if (start <= entry->start) {
where = entry->nd.prev;
break;
}
}
}
break;
}
}

err = memtype_check_insert(new, new_type);
if (err) {
printk(KERN_INFO "reserve_memtype failed 0x%Lx-0x%Lx, "
"track %s, req %s\n",
Expand All @@ -469,13 +470,6 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
return err;
}

if (where)
list_add(&new->nd, where);
else
list_add_tail(&new->nd, &memtype_list);

memtype_rb_insert(&memtype_rbroot, new);

spin_unlock(&memtype_lock);

dprintk("reserve_memtype added 0x%Lx-0x%Lx, track %s, req %s, ret %s\n",
Expand Down Expand Up @@ -937,28 +931,40 @@ EXPORT_SYMBOL_GPL(pgprot_writecombine);
#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)

/* get Nth element of the linked list */
static struct memtype *memtype_get_idx(loff_t pos)
static int copy_memtype_nth_element(struct memtype *out, loff_t pos)
{
struct memtype *list_node, *print_entry;
struct memtype *list_node;
int i = 1;

print_entry = kmalloc(sizeof(struct memtype), GFP_KERNEL);
if (!print_entry)
return NULL;

spin_lock(&memtype_lock);
list_for_each_entry(list_node, &memtype_list, nd) {
if (pos == i) {
*print_entry = *list_node;
spin_unlock(&memtype_lock);
return print_entry;
*out = *list_node;
return 0;
}
++i;
}
return 1;
}

static struct memtype *memtype_get_idx(loff_t pos)
{
struct memtype *print_entry;
int ret;

print_entry = kzalloc(sizeof(struct memtype), GFP_KERNEL);
if (!print_entry)
return NULL;

spin_lock(&memtype_lock);
ret = copy_memtype_nth_element(print_entry, pos);
spin_unlock(&memtype_lock);
kfree(print_entry);

return NULL;
if (!ret) {
return print_entry;
} else {
kfree(print_entry);
return NULL;
}
}

static void *memtype_seq_start(struct seq_file *seq, loff_t *pos)
Expand Down
28 changes: 28 additions & 0 deletions arch/x86/mm/pat_internal.h
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,28 @@
#ifndef __PAT_INTERNAL_H_
#define __PAT_INTERNAL_H_

extern int pat_debug_enable;

#define dprintk(fmt, arg...) \
do { if (pat_debug_enable) printk(KERN_INFO fmt, ##arg); } while (0)

struct memtype {
u64 start;
u64 end;
unsigned long type;
struct list_head nd;
struct rb_node rb;
};

static inline char *cattr_name(unsigned long flags)
{
switch (flags & _PAGE_CACHE_MASK) {
case _PAGE_CACHE_UC: return "uncached";
case _PAGE_CACHE_UC_MINUS: return "uncached-minus";
case _PAGE_CACHE_WB: return "write-back";
case _PAGE_CACHE_WC: return "write-combining";
default: return "broken";
}
}

#endif /* __PAT_INTERNAL_H_ */

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