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#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/slab.h>
#include "vmregion.h"
/*
* VM region handling support.
*
* This should become something generic, handling VM region allocations for
* vmalloc and similar (ioremap, module space, etc).
*
* I envisage vmalloc()'s supporting vm_struct becoming:
*
* struct vm_struct {
* struct vmregion region;
* unsigned long flags;
* struct page **pages;
* unsigned int nr_pages;
* unsigned long phys_addr;
* };
*
* get_vm_area() would then call vmregion_alloc with an appropriate
* struct vmregion head (eg):
*
* struct vmregion vmalloc_head = {
* .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list),
* .vm_start = VMALLOC_START,
* .vm_end = VMALLOC_END,
* };
*
* However, vmalloc_head.vm_start is variable (typically, it is dependent on
* the amount of RAM found at boot time.) I would imagine that get_vm_area()
* would have to initialise this each time prior to calling vmregion_alloc().
*/
struct arm_vmregion *
arm_vmregion_alloc(struct arm_vmregion_head *head, size_t size, gfp_t gfp)
{
unsigned long addr = head->vm_start, end = head->vm_end - size;
unsigned long flags;
struct arm_vmregion *c, *new;
if (head->vm_end - head->vm_start < size) {
printk(KERN_WARNING "%s: allocation too big (requested %#x)\n",
__func__, size);
goto out;
}
new = kmalloc(sizeof(struct arm_vmregion), gfp);
if (!new)
goto out;
spin_lock_irqsave(&head->vm_lock, flags);
list_for_each_entry(c, &head->vm_list, vm_list) {
if ((addr + size) < addr)
goto nospc;
if ((addr + size) <= c->vm_start)
goto found;
addr = c->vm_end;
if (addr > end)
goto nospc;
}
found:
/*
* Insert this entry _before_ the one we found.
*/
list_add_tail(&new->vm_list, &c->vm_list);
new->vm_start = addr;
new->vm_end = addr + size;
new->vm_active = 1;
spin_unlock_irqrestore(&head->vm_lock, flags);
return new;
nospc:
spin_unlock_irqrestore(&head->vm_lock, flags);
kfree(new);
out:
return NULL;
}
static struct arm_vmregion *__arm_vmregion_find(struct arm_vmregion_head *head, unsigned long addr)
{
struct arm_vmregion *c;
list_for_each_entry(c, &head->vm_list, vm_list) {
if (c->vm_active && c->vm_start == addr)
goto out;
}
c = NULL;
out:
return c;
}
struct arm_vmregion *arm_vmregion_find(struct arm_vmregion_head *head, unsigned long addr)
{
struct arm_vmregion *c;
unsigned long flags;
spin_lock_irqsave(&head->vm_lock, flags);
c = __arm_vmregion_find(head, addr);
spin_unlock_irqrestore(&head->vm_lock, flags);
return c;
}
struct arm_vmregion *arm_vmregion_find_remove(struct arm_vmregion_head *head, unsigned long addr)
{
struct arm_vmregion *c;
unsigned long flags;
spin_lock_irqsave(&head->vm_lock, flags);
c = __arm_vmregion_find(head, addr);
if (c)
c->vm_active = 0;
spin_unlock_irqrestore(&head->vm_lock, flags);
return c;
}
void arm_vmregion_free(struct arm_vmregion_head *head, struct arm_vmregion *c)
{
unsigned long flags;
spin_lock_irqsave(&head->vm_lock, flags);
list_del(&c->vm_list);
spin_unlock_irqrestore(&head->vm_lock, flags);
kfree(c);
}
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