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Subject[PATCH 5/9] Revert "resources: support allocating space within a region from the top down"
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This reverts commit e7f8567db9a7f6b3151b0b275e245c1cef0d9c70.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
---
Documentation/kernel-parameters.txt | 5 --
include/linux/ioport.h | 1
kernel/resource.c | 98 +----------------------------------
3 files changed, 4 insertions(+), 100 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index cdd2a6e..8b61c93 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -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

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index d377ea8..b227902 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -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);
diff --git a/kernel/resource.c b/kernel/resource.c
index 9fad33e..560659f 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -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;
@@ -397,74 +380,7 @@ static bool resource_contains(struct resource *res1, struct resource *res2)
}

/*
- * 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);


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