linux/kernel/resource.c
KAMEZAWA Hiroyuki 0f04ab5efb [PATCH] memory hotadd fixes: change find_next_system_ram's return value manner
find_next_system_ram() returns valid memory range which meets requested area,
only used by memory-hot-add.

This function always rewrite requested resource even if returned area is not
fully fit in requested one.  And sometimes the returnd resource is larger than
requested area.  This annoyes the caller.  This patch changes the returned
value to fit in requested area.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Keith Mannthey <kmannth@gmail.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-08-06 08:57:48 -07:00

589 lines
12 KiB
C

/*
* linux/kernel/resource.c
*
* Copyright (C) 1999 Linus Torvalds
* Copyright (C) 1999 Martin Mares <mj@ucw.cz>
*
* Arbitrary resource management.
*/
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <asm/io.h>
struct resource ioport_resource = {
.name = "PCI IO",
.start = 0,
.end = IO_SPACE_LIMIT,
.flags = IORESOURCE_IO,
};
EXPORT_SYMBOL(ioport_resource);
struct resource iomem_resource = {
.name = "PCI mem",
.start = 0,
.end = -1,
.flags = IORESOURCE_MEM,
};
EXPORT_SYMBOL(iomem_resource);
static DEFINE_RWLOCK(resource_lock);
#ifdef CONFIG_PROC_FS
enum { MAX_IORES_LEVEL = 5 };
static void *r_next(struct seq_file *m, void *v, loff_t *pos)
{
struct resource *p = v;
(*pos)++;
if (p->child)
return p->child;
while (!p->sibling && p->parent)
p = p->parent;
return p->sibling;
}
static void *r_start(struct seq_file *m, loff_t *pos)
__acquires(resource_lock)
{
struct resource *p = m->private;
loff_t l = 0;
read_lock(&resource_lock);
for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
;
return p;
}
static void r_stop(struct seq_file *m, void *v)
__releases(resource_lock)
{
read_unlock(&resource_lock);
}
static int r_show(struct seq_file *m, void *v)
{
struct resource *root = m->private;
struct resource *r = v, *p;
int width = root->end < 0x10000 ? 4 : 8;
int depth;
for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
if (p->parent == root)
break;
seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
depth * 2, "",
width, (unsigned long long) r->start,
width, (unsigned long long) r->end,
r->name ? r->name : "<BAD>");
return 0;
}
static struct seq_operations resource_op = {
.start = r_start,
.next = r_next,
.stop = r_stop,
.show = r_show,
};
static int ioports_open(struct inode *inode, struct file *file)
{
int res = seq_open(file, &resource_op);
if (!res) {
struct seq_file *m = file->private_data;
m->private = &ioport_resource;
}
return res;
}
static int iomem_open(struct inode *inode, struct file *file)
{
int res = seq_open(file, &resource_op);
if (!res) {
struct seq_file *m = file->private_data;
m->private = &iomem_resource;
}
return res;
}
static struct file_operations proc_ioports_operations = {
.open = ioports_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static struct file_operations proc_iomem_operations = {
.open = iomem_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int __init ioresources_init(void)
{
struct proc_dir_entry *entry;
entry = create_proc_entry("ioports", 0, NULL);
if (entry)
entry->proc_fops = &proc_ioports_operations;
entry = create_proc_entry("iomem", 0, NULL);
if (entry)
entry->proc_fops = &proc_iomem_operations;
return 0;
}
__initcall(ioresources_init);
#endif /* CONFIG_PROC_FS */
/* Return the conflict entry if you can't request it */
static struct resource * __request_resource(struct resource *root, struct resource *new)
{
resource_size_t start = new->start;
resource_size_t end = new->end;
struct resource *tmp, **p;
if (end < start)
return root;
if (start < root->start)
return root;
if (end > root->end)
return root;
p = &root->child;
for (;;) {
tmp = *p;
if (!tmp || tmp->start > end) {
new->sibling = tmp;
*p = new;
new->parent = root;
return NULL;
}
p = &tmp->sibling;
if (tmp->end < start)
continue;
return tmp;
}
}
static int __release_resource(struct resource *old)
{
struct resource *tmp, **p;
p = &old->parent->child;
for (;;) {
tmp = *p;
if (!tmp)
break;
if (tmp == old) {
*p = tmp->sibling;
old->parent = NULL;
return 0;
}
p = &tmp->sibling;
}
return -EINVAL;
}
int request_resource(struct resource *root, struct resource *new)
{
struct resource *conflict;
write_lock(&resource_lock);
conflict = __request_resource(root, new);
write_unlock(&resource_lock);
return conflict ? -EBUSY : 0;
}
EXPORT_SYMBOL(request_resource);
struct resource *____request_resource(struct resource *root, struct resource *new)
{
struct resource *conflict;
write_lock(&resource_lock);
conflict = __request_resource(root, new);
write_unlock(&resource_lock);
return conflict;
}
EXPORT_SYMBOL(____request_resource);
int release_resource(struct resource *old)
{
int retval;
write_lock(&resource_lock);
retval = __release_resource(old);
write_unlock(&resource_lock);
return retval;
}
EXPORT_SYMBOL(release_resource);
#ifdef CONFIG_MEMORY_HOTPLUG
/*
* Finds the lowest memory reosurce exists within [res->start.res->end)
* the caller must specify res->start, res->end, res->flags.
* If found, returns 0, res is overwritten, if not found, returns -1.
*/
int find_next_system_ram(struct resource *res)
{
resource_size_t start, end;
struct resource *p;
BUG_ON(!res);
start = res->start;
end = res->end;
read_lock(&resource_lock);
for (p = iomem_resource.child; p ; p = p->sibling) {
/* system ram is just marked as IORESOURCE_MEM */
if (p->flags != res->flags)
continue;
if (p->start > end) {
p = NULL;
break;
}
if (p->start >= start)
break;
}
read_unlock(&resource_lock);
if (!p)
return -1;
/* copy data */
if (res->start < p->start)
res->start = p->start;
if (res->end > p->end)
res->end = p->end;
return 0;
}
#endif
/*
* Find empty slot in the resource tree given range and alignment.
*/
static int find_resource(struct resource *root, struct resource *new,
resource_size_t size, resource_size_t min,
resource_size_t max, resource_size_t align,
void (*alignf)(void *, struct resource *,
resource_size_t, resource_size_t),
void *alignf_data)
{
struct resource *this = root->child;
new->start = root->start;
/*
* Skip past an allocated resource that starts at 0, since the assignment
* of this->start - 1 to new->end below would cause an underflow.
*/
if (this && this->start == 0) {
new->start = this->end + 1;
this = this->sibling;
}
for(;;) {
if (this)
new->end = this->start - 1;
else
new->end = root->end;
if (new->start < min)
new->start = min;
if (new->end > max)
new->end = max;
new->start = ALIGN(new->start, align);
if (alignf)
alignf(alignf_data, new, size, align);
if (new->start < new->end && new->end - new->start >= size - 1) {
new->end = new->start + size - 1;
return 0;
}
if (!this)
break;
new->start = this->end + 1;
this = this->sibling;
}
return -EBUSY;
}
/*
* Allocate empty slot in the resource tree given range and alignment.
*/
int allocate_resource(struct resource *root, struct resource *new,
resource_size_t size, resource_size_t min,
resource_size_t max, resource_size_t align,
void (*alignf)(void *, struct resource *,
resource_size_t, resource_size_t),
void *alignf_data)
{
int err;
write_lock(&resource_lock);
err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
if (err >= 0 && __request_resource(root, new))
err = -EBUSY;
write_unlock(&resource_lock);
return err;
}
EXPORT_SYMBOL(allocate_resource);
/**
* insert_resource - Inserts a resource in the resource tree
* @parent: parent of the new resource
* @new: new resource to insert
*
* Returns 0 on success, -EBUSY if the resource can't be inserted.
*
* This function is equivalent of request_resource when no conflict
* happens. If a conflict happens, and the conflicting resources
* entirely fit within the range of the new resource, then the new
* resource is inserted and the conflicting resources become childs of
* the new resource. Otherwise the new resource becomes the child of
* the conflicting resource
*/
int insert_resource(struct resource *parent, struct resource *new)
{
int result;
struct resource *first, *next;
write_lock(&resource_lock);
begin:
result = 0;
first = __request_resource(parent, new);
if (!first)
goto out;
result = -EBUSY;
if (first == parent)
goto out;
/* Resource fully contained by the clashing resource? Recurse into it */
if (first->start <= new->start && first->end >= new->end) {
parent = first;
goto begin;
}
for (next = first; ; next = next->sibling) {
/* Partial overlap? Bad, and unfixable */
if (next->start < new->start || next->end > new->end)
goto out;
if (!next->sibling)
break;
if (next->sibling->start > new->end)
break;
}
result = 0;
new->parent = parent;
new->sibling = next->sibling;
new->child = first;
next->sibling = NULL;
for (next = first; next; next = next->sibling)
next->parent = new;
if (parent->child == first) {
parent->child = new;
} else {
next = parent->child;
while (next->sibling != first)
next = next->sibling;
next->sibling = new;
}
out:
write_unlock(&resource_lock);
return result;
}
/*
* Given an existing resource, change its start and size to match the
* arguments. Returns -EBUSY if it can't fit. Existing children of
* the resource are assumed to be immutable.
*/
int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
{
struct resource *tmp, *parent = res->parent;
resource_size_t end = start + size - 1;
int result = -EBUSY;
write_lock(&resource_lock);
if ((start < parent->start) || (end > parent->end))
goto out;
for (tmp = res->child; tmp; tmp = tmp->sibling) {
if ((tmp->start < start) || (tmp->end > end))
goto out;
}
if (res->sibling && (res->sibling->start <= end))
goto out;
tmp = parent->child;
if (tmp != res) {
while (tmp->sibling != res)
tmp = tmp->sibling;
if (start <= tmp->end)
goto out;
}
res->start = start;
res->end = end;
result = 0;
out:
write_unlock(&resource_lock);
return result;
}
EXPORT_SYMBOL(adjust_resource);
/*
* This is compatibility stuff for IO resources.
*
* Note how this, unlike the above, knows about
* the IO flag meanings (busy etc).
*
* Request-region creates a new busy region.
*
* Check-region returns non-zero if the area is already busy
*
* Release-region releases a matching busy region.
*/
struct resource * __request_region(struct resource *parent,
resource_size_t start, resource_size_t n,
const char *name)
{
struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
if (res) {
res->name = name;
res->start = start;
res->end = start + n - 1;
res->flags = IORESOURCE_BUSY;
write_lock(&resource_lock);
for (;;) {
struct resource *conflict;
conflict = __request_resource(parent, res);
if (!conflict)
break;
if (conflict != parent) {
parent = conflict;
if (!(conflict->flags & IORESOURCE_BUSY))
continue;
}
/* Uhhuh, that didn't work out.. */
kfree(res);
res = NULL;
break;
}
write_unlock(&resource_lock);
}
return res;
}
EXPORT_SYMBOL(__request_region);
int __check_region(struct resource *parent, resource_size_t start,
resource_size_t n)
{
struct resource * res;
res = __request_region(parent, start, n, "check-region");
if (!res)
return -EBUSY;
release_resource(res);
kfree(res);
return 0;
}
EXPORT_SYMBOL(__check_region);
void __release_region(struct resource *parent, resource_size_t start,
resource_size_t n)
{
struct resource **p;
resource_size_t end;
p = &parent->child;
end = start + n - 1;
write_lock(&resource_lock);
for (;;) {
struct resource *res = *p;
if (!res)
break;
if (res->start <= start && res->end >= end) {
if (!(res->flags & IORESOURCE_BUSY)) {
p = &res->child;
continue;
}
if (res->start != start || res->end != end)
break;
*p = res->sibling;
write_unlock(&resource_lock);
kfree(res);
return;
}
p = &res->sibling;
}
write_unlock(&resource_lock);
printk(KERN_WARNING "Trying to free nonexistent resource "
"<%016llx-%016llx>\n", (unsigned long long)start,
(unsigned long long)end);
}
EXPORT_SYMBOL(__release_region);
/*
* Called from init/main.c to reserve IO ports.
*/
#define MAXRESERVE 4
static int __init reserve_setup(char *str)
{
static int reserved;
static struct resource reserve[MAXRESERVE];
for (;;) {
int io_start, io_num;
int x = reserved;
if (get_option (&str, &io_start) != 2)
break;
if (get_option (&str, &io_num) == 0)
break;
if (x < MAXRESERVE) {
struct resource *res = reserve + x;
res->name = "reserved";
res->start = io_start;
res->end = io_start + io_num - 1;
res->flags = IORESOURCE_BUSY;
res->child = NULL;
if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
reserved = x+1;
}
}
return 1;
}
__setup("reserve=", reserve_setup);