/*
 *  linux/mmnommu/memory.c
 *
 *  Copyright (c) 2000-2005 SnapGear Inc., David McCullough <davidm@snapgear.com>
 *  Copyright (c) 2000 Lineo,Inc. David McCullough <davidm@lineo.com>
 */

#include <linux/config.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/iobuf.h>
#include <linux/pagemap.h>
#include <linux/module.h>
#include <asm/uaccess.h>
#include <asm/tlb.h>

void *high_memory;
mem_map_t * mem_map = NULL;
unsigned long max_mapnr;
unsigned long num_physpages;
unsigned long num_mappedpages;
unsigned long askedalloc, realalloc;

/*
 * Force in an entire range of pages from the current process's user VA,
 * and pin them in physical memory.  
 */

int map_user_kiobuf(int rw, struct kiobuf *iobuf, unsigned long va, size_t len)
{
	return(0);
}

/*
 * Mark all of the pages in a kiobuf as dirty 
 *
 * We need to be able to deal with short reads from disk: if an IO error
 * occurs, the number of bytes read into memory may be less than the
 * size of the kiobuf, so we have to stop marking pages dirty once the
 * requested byte count has been reached.
 *
 * Must be called from process context - set_page_dirty() takes VFS locks.
 */

void mark_dirty_kiobuf(struct kiobuf *iobuf, int bytes)
{
	int index, offset, remaining;
	struct page *page;
	
	index = iobuf->offset >> PAGE_SHIFT;
	offset = iobuf->offset & ~PAGE_MASK;
	remaining = bytes;
	if (remaining > iobuf->length)
		remaining = iobuf->length;
	
	while (remaining > 0 && index < iobuf->nr_pages) {
		page = iobuf->maplist[index];
		
		if (!PageReserved(page))
			set_page_dirty(page);

		remaining -= (PAGE_SIZE - offset);
		offset = 0;
		index++;
	}
}

/*
 * Unmap all of the pages referenced by a kiobuf.  We release the pages,
 * and unlock them if they were locked. 
 */

void unmap_kiobuf (struct kiobuf *iobuf) 
{
}


/*
 * Lock down all of the pages of a kiovec for IO.
 *
 * If any page is mapped twice in the kiovec, we return the error -EINVAL.
 *
 * The optional wait parameter causes the lock call to block until all
 * pages can be locked if set.  If wait==0, the lock operation is
 * aborted if any locked pages are found and -EAGAIN is returned.
 */

int lock_kiovec(int nr, struct kiobuf *iovec[], int wait)
{
	return 0;
}

/*
 * Unlock all of the pages of a kiovec after IO.
 */

int unlock_kiovec(int nr, struct kiobuf *iovec[])
{
	return 0;
}

/*
 * Handle all mappings that got truncated by a "truncate()"
 * system call.
 *
 * NOTE! We have to be ready to update the memory sharing
 * between the file and the memory map for a potential last
 * incomplete page.  Ugly, but necessary.
 */
int vmtruncate(struct inode * inode, loff_t offset)
{
	struct address_space *mapping = inode->i_mapping;
	unsigned long limit;

	if (inode->i_size < offset)
		goto do_expand;
	inode->i_size = offset;

	truncate_inode_pages(mapping, offset);
	goto out_truncate;

do_expand:
	limit = current->rlim[RLIMIT_FSIZE].rlim_cur;
	if (limit != RLIM_INFINITY && offset > limit)
		goto out_sig;
	if (offset > inode->i_sb->s_maxbytes)
		goto out;
	inode->i_size = offset;

out_truncate:
	if (inode->i_op && inode->i_op->truncate) {
		lock_kernel();
		inode->i_op->truncate(inode);
		unlock_kernel();
	}
	return 0;
out_sig:
	send_sig(SIGXFSZ, current, 0);
out:
	return -EFBIG;
}


/*  Note: this is only safe if the mm semaphore is held when called. */
int remap_page_range(unsigned long from, unsigned long phys_addr, unsigned long size, pgprot_t prot)
{
	return -EPERM;
}


/*
 *	The nommu dodgy version :-)
 */

int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
		unsigned long start, int len, int write, int force,
		struct page **pages, struct vm_area_struct **vmas)
{
	int i;
	static struct vm_area_struct dummy_vma;

	for (i = 0; i < len; i++) {
		if (pages) {
			pages[i] = virt_to_page(start);
			if (pages[i])
				page_cache_get(pages[i]);
		}
		if (vmas)
			vmas[i] = &dummy_vma;
		start += PAGE_SIZE;
	}
	return(i);
}

EXPORT_SYMBOL(get_user_pages);

struct page * vmalloc_to_page(void * vmalloc_addr)
{
	return(virt_to_page(vmalloc_addr));
}