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

This reverts commit e7f8567db9a7f6b3151b0b275e245c1cef0d9c70.

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>

3 files changed, 4 insertions, 100 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index cdd2a6e8a3b7..8b61c9360999 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 d377ea815d45..b22790268b64 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 9fad33efd0db..560659f7baef 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);