[net-next-2.6.git] / mm / fadvise.c

/*
 * mm/fadvise.c
 *
 * Copyright (C) 2002, Linus Torvalds
 *
 * 11Jan2003	Andrew Morton
 *		Initial version.
 */

#include <linux/kernel.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/backing-dev.h>
#include <linux/pagevec.h>
#include <linux/fadvise.h>
#include <linux/writeback.h>
#include <linux/syscalls.h>

#include <asm/unistd.h>

/*
 * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
 * deactivate the pages and clear PG_Referenced.
 */
asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
{
	struct file *file = fget(fd);
	struct address_space *mapping;
	struct backing_dev_info *bdi;
	loff_t endbyte;			/* inclusive */
	pgoff_t start_index;
	pgoff_t end_index;
	unsigned long nrpages;
	int ret = 0;

	if (!file)
		return -EBADF;

	if (S_ISFIFO(file->f_path.dentry->d_inode->i_mode)) {
		ret = -ESPIPE;
		goto out;
	}

	mapping = file->f_mapping;
	if (!mapping || len < 0) {
		ret = -EINVAL;
		goto out;
	}

	if (mapping->a_ops->get_xip_mem) {
		switch (advice) {
		case POSIX_FADV_NORMAL:
		case POSIX_FADV_RANDOM:
		case POSIX_FADV_SEQUENTIAL:
		case POSIX_FADV_WILLNEED:
		case POSIX_FADV_NOREUSE:
		case POSIX_FADV_DONTNEED:
			/* no bad return value, but ignore advice */
			break;
		default:
			ret = -EINVAL;
		}
		goto out;
	}

	/* Careful about overflows. Len == 0 means "as much as possible" */
	endbyte = offset + len;
	if (!len || endbyte < len)
		endbyte = -1;
	else
		endbyte--;		/* inclusive */

	bdi = mapping->backing_dev_info;

	switch (advice) {
	case POSIX_FADV_NORMAL:
		file->f_ra.ra_pages = bdi->ra_pages;
		break;
	case POSIX_FADV_RANDOM:
		file->f_ra.ra_pages = 0;
		break;
	case POSIX_FADV_SEQUENTIAL:
		file->f_ra.ra_pages = bdi->ra_pages * 2;
		break;
	case POSIX_FADV_WILLNEED:
		if (!mapping->a_ops->readpage) {
			ret = -EINVAL;
			break;
		}

		/* First and last PARTIAL page! */
		start_index = offset >> PAGE_CACHE_SHIFT;
		end_index = endbyte >> PAGE_CACHE_SHIFT;

		/* Careful about overflow on the "+1" */
		nrpages = end_index - start_index + 1;
		if (!nrpages)
			nrpages = ~0UL;
		
		ret = force_page_cache_readahead(mapping, file,
				start_index,
				max_sane_readahead(nrpages));
		if (ret > 0)
			ret = 0;
		break;
	case POSIX_FADV_NOREUSE:
		break;
	case POSIX_FADV_DONTNEED:
		if (!bdi_write_congested(mapping->backing_dev_info))
			filemap_flush(mapping);

		/* First and last FULL page! */
		start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
		end_index = (endbyte >> PAGE_CACHE_SHIFT);

		if (end_index >= start_index)
			invalidate_mapping_pages(mapping, start_index,
						end_index);
		break;
	default:
		ret = -EINVAL;
	}
out:
	fput(file);
	return ret;
}

#ifdef __ARCH_WANT_SYS_FADVISE64

asmlinkage long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
{
	return sys_fadvise64_64(fd, offset, len, advice);
}

#endif
Commit	Line	Data
1da177e4 LT	1	/*
	2	* mm/fadvise.c
	3	*
	4	* Copyright (C) 2002, Linus Torvalds
	5	*
e1f8e874	6	* 11Jan2003 Andrew Morton
1da177e4 LT	7	* Initial version.
	8	*/
	9
	10	#include <linux/kernel.h>
	11	#include <linux/file.h>
	12	#include <linux/fs.h>
	13	#include <linux/mm.h>
	14	#include <linux/pagemap.h>
	15	#include <linux/backing-dev.h>
	16	#include <linux/pagevec.h>
	17	#include <linux/fadvise.h>
ebcf28e1	18	#include <linux/writeback.h>
1da177e4 LT	19	#include <linux/syscalls.h>
	20
	21	#include <asm/unistd.h>
	22
	23	/*
	24	* POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
	25	* deactivate the pages and clear PG_Referenced.
	26	*/
	27	asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
	28	{
	29	struct file *file = fget(fd);
	30	struct address_space *mapping;
	31	struct backing_dev_info *bdi;
ebcf28e1	32	loff_t endbyte; /* inclusive */
1da177e4 LT	33	pgoff_t start_index;
	34	pgoff_t end_index;
	35	unsigned long nrpages;
	36	int ret = 0;
	37
	38	if (!file)
	39	return -EBADF;
	40
d3ac7f89	41	if (S_ISFIFO(file->f_path.dentry->d_inode->i_mode)) {
87ba81db VB	42	ret = -ESPIPE;
	43	goto out;
	44	}
	45
1da177e4 LT	46	mapping = file->f_mapping;
	47	if (!mapping \|\| len < 0) {
	48	ret = -EINVAL;
	49	goto out;
	50	}
	51
70688e4d	52	if (mapping->a_ops->get_xip_mem) {
b5beb1ca MY	53	switch (advice) {
	54	case POSIX_FADV_NORMAL:
	55	case POSIX_FADV_RANDOM:
	56	case POSIX_FADV_SEQUENTIAL:
	57	case POSIX_FADV_WILLNEED:
	58	case POSIX_FADV_NOREUSE:
	59	case POSIX_FADV_DONTNEED:
	60	/* no bad return value, but ignore advice */
	61	break;
	62	default:
	63	ret = -EINVAL;
	64	}
fe77ba6f	65	goto out;
b5beb1ca	66	}
fe77ba6f	67
1da177e4 LT	68	/* Careful about overflows. Len == 0 means "as much as possible" */
	69	endbyte = offset + len;
	70	if (!len \|\| endbyte < len)
	71	endbyte = -1;
ebcf28e1 AM	72	else
ebcf28e1 AM	73	endbyte--; /* inclusive */
1da177e4 LT	74
	75	bdi = mapping->backing_dev_info;
	76
	77	switch (advice) {
	78	case POSIX_FADV_NORMAL:
	79	file->f_ra.ra_pages = bdi->ra_pages;
	80	break;
	81	case POSIX_FADV_RANDOM:
	82	file->f_ra.ra_pages = 0;
	83	break;
	84	case POSIX_FADV_SEQUENTIAL:
	85	file->f_ra.ra_pages = bdi->ra_pages * 2;
	86	break;
	87	case POSIX_FADV_WILLNEED:
1da177e4 LT	88	if (!mapping->a_ops->readpage) {
	89	ret = -EINVAL;
	90	break;
	91	}
	92
	93	/* First and last PARTIAL page! */
	94	start_index = offset >> PAGE_CACHE_SHIFT;
ebcf28e1	95	end_index = endbyte >> PAGE_CACHE_SHIFT;
1da177e4 LT	96
	97	/* Careful about overflow on the "+1" */
	98	nrpages = end_index - start_index + 1;
	99	if (!nrpages)
	100	nrpages = ~0UL;
	101
	102	ret = force_page_cache_readahead(mapping, file,
	103	start_index,
	104	max_sane_readahead(nrpages));
	105	if (ret > 0)
	106	ret = 0;
	107	break;
60c371bc AM	108	case POSIX_FADV_NOREUSE:
60c371bc AM	109	break;
1da177e4 LT	110	case POSIX_FADV_DONTNEED:
	111	if (!bdi_write_congested(mapping->backing_dev_info))
	112	filemap_flush(mapping);
	113
	114	/* First and last FULL page! */
ebcf28e1	115	start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
1da177e4 LT	116	end_index = (endbyte >> PAGE_CACHE_SHIFT);
1da177e4 LT	117
ebcf28e1 AM	118	if (end_index >= start_index)
	119	invalidate_mapping_pages(mapping, start_index,
	120	end_index);
	121	break;
1da177e4 LT	122	default:
	123	ret = -EINVAL;
	124	}
	125	out:
	126	fput(file);
	127	return ret;
	128	}
	129
	130	#ifdef __ARCH_WANT_SYS_FADVISE64
	131
	132	asmlinkage long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
	133	{
	134	return sys_fadvise64_64(fd, offset, len, advice);
	135	}
	136
	137	#endif