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Revert "resources: support allocating space within a region from the top down"

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This reverts commit e7f8567db9.

Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Bjorn Helgaas 2010-12-16 10:38:41 -07:00 committed by Jesse Barnes
parent 6db45b76ea
commit c0f5ac5426
3 changed files with 4 additions and 100 deletions
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5
Documentation/kernel-parameters.txt
View file

@ -2175,11 +2175,6 @@ and is between 256 and 4096 characters. It is defined in the file
reset_devices [KNL] Force drivers to reset the underlying device
during initialization.
resource_alloc_from_bottom
Allocate new resources from the beginning of available
space, not the end. If you need to use this, please
report a bug.
resume= [SWSUSP]
Specify the partition device for software suspend

1
include/linux/ioport.h
View file

@ -112,7 +112,6 @@ struct resource_list {
/* PC/ISA/whatever - the normal PC address spaces: IO and memory */
extern struct resource ioport_resource;
extern struct resource iomem_resource;
extern int resource_alloc_from_bottom;
extern struct resource *request_resource_conflict(struct resource *root, struct resource *new);
extern int request_resource(struct resource *root, struct resource *new);

98
kernel/resource.c
View file

@ -40,23 +40,6 @@ EXPORT_SYMBOL(iomem_resource);
static DEFINE_RWLOCK(resource_lock);
/*
* By default, we allocate free space bottom-up. The architecture can request
* top-down by clearing this flag. The user can override the architecture's
* choice with the "resource_alloc_from_bottom" kernel boot option, but that
* should only be a debugging tool.
*/
int resource_alloc_from_bottom = 1;
static __init int setup_alloc_from_bottom(char *s)
{
printk(KERN_INFO
"resource: allocating from bottom-up; please report a bug\n");
resource_alloc_from_bottom = 1;
return 0;
}
early_param("resource_alloc_from_bottom", setup_alloc_from_bottom);
static void *r_next(struct seq_file *m, void *v, loff_t *pos)
{
struct resource *p = v;
@ -396,75 +379,8 @@ static bool resource_contains(struct resource *res1, struct resource *res2)
return res1->start <= res2->start && res1->end >= res2->end;
}
/*
* Find the resource before "child" in the sibling list of "root" children.
*/
static struct resource *find_sibling_prev(struct resource *root, struct resource *child)
{
struct resource *this;
for (this = root->child; this; this = this->sibling)
if (this->sibling == child)
return this;
return NULL;
}
/*
* Find empty slot in the resource tree given range and alignment.
* This version allocates from the end of the root resource first.
*/
static int find_resource_from_top(struct resource *root, struct resource *new,
resource_size_t size, resource_size_t min,
resource_size_t max, resource_size_t align,
resource_size_t (*alignf)(void *,
const struct resource *,
resource_size_t,
resource_size_t),
void *alignf_data)
{
struct resource *this;
struct resource tmp, avail, alloc;
tmp.start = root->end;
tmp.end = root->end;
this = find_sibling_prev(root, NULL);
for (;;) {
if (this) {
if (this->end < root->end)
tmp.start = this->end + 1;
} else
tmp.start = root->start;
resource_clip(&tmp, min, max);
/* Check for overflow after ALIGN() */
avail = *new;
avail.start = ALIGN(tmp.start, align);
avail.end = tmp.end;
if (avail.start >= tmp.start) {
alloc.start = alignf(alignf_data, &avail, size, align);
alloc.end = alloc.start + size - 1;
if (resource_contains(&avail, &alloc)) {
new->start = alloc.start;
new->end = alloc.end;
return 0;
}
}
if (!this || this->start == root->start)
break;
tmp.end = this->start - 1;
this = find_sibling_prev(root, this);
}
return -EBUSY;
}
/*
* Find empty slot in the resource tree given range and alignment.
* This version allocates from the beginning of the root resource first.
*/
static int find_resource(struct resource *root, struct resource *new,
resource_size_t size, resource_size_t min,
@ -480,15 +396,14 @@ static int find_resource(struct resource *root, struct resource *new,
tmp.start = root->start;
/*
* Skip past an allocated resource that starts at 0, since the
* assignment of this->start - 1 to tmp->end below would cause an
* underflow.
* Skip past an allocated resource that starts at 0, since the assignment
* of this->start - 1 to tmp->end below would cause an underflow.
*/
if (this && this->start == 0) {
tmp.start = this->end + 1;
this = this->sibling;
}
for (;;) {
for(;;) {
if (this)
tmp.end = this->start - 1;
else
@ -509,10 +424,8 @@ static int find_resource(struct resource *root, struct resource *new,
return 0;
}
}
if (!this)
break;
tmp.start = this->end + 1;
this = this->sibling;
}
@ -545,10 +458,7 @@ int allocate_resource(struct resource *root, struct resource *new,
alignf = simple_align_resource;
write_lock(&resource_lock);
if (resource_alloc_from_bottom)
err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
else
err = find_resource_from_top(root, new, size, min, max, align, alignf, alignf_data);
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);