[GitHub/mt8127/android_kernel_alcatel_ttab.git] / mm / fadvise.c

/*
 * mm/fadvise.c
 *
 * Copyright (C) 2002, Linus Torvalds
 *
 * 11Jan2003	akpm@digeo.com
 *		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_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_page)
		/* no bad return value, but ignore advice */
		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:
	case POSIX_FADV_NOREUSE:
		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_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	*
	6	* 11Jan2003 akpm@digeo.com
	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
87ba81db VB	41	if (S_ISFIFO(file->f_dentry->d_inode->i_mode)) {
	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
fe77ba6f CO	52	if (mapping->a_ops->get_xip_page)
	53	/* no bad return value, but ignore advice */
	54	goto out;
	55
1da177e4 LT	56	/* Careful about overflows. Len == 0 means "as much as possible" */
	57	endbyte = offset + len;
	58	if (!len \|\| endbyte < len)
	59	endbyte = -1;
ebcf28e1 AM	60	else
ebcf28e1 AM	61	endbyte--; /* inclusive */
1da177e4 LT	62
	63	bdi = mapping->backing_dev_info;
	64
	65	switch (advice) {
	66	case POSIX_FADV_NORMAL:
	67	file->f_ra.ra_pages = bdi->ra_pages;
	68	break;
	69	case POSIX_FADV_RANDOM:
	70	file->f_ra.ra_pages = 0;
	71	break;
	72	case POSIX_FADV_SEQUENTIAL:
	73	file->f_ra.ra_pages = bdi->ra_pages * 2;
	74	break;
	75	case POSIX_FADV_WILLNEED:
	76	case POSIX_FADV_NOREUSE:
	77	if (!mapping->a_ops->readpage) {
	78	ret = -EINVAL;
	79	break;
	80	}
	81
	82	/* First and last PARTIAL page! */
	83	start_index = offset >> PAGE_CACHE_SHIFT;
ebcf28e1	84	end_index = endbyte >> PAGE_CACHE_SHIFT;
1da177e4 LT	85
	86	/* Careful about overflow on the "+1" */
	87	nrpages = end_index - start_index + 1;
	88	if (!nrpages)
	89	nrpages = ~0UL;
	90
	91	ret = force_page_cache_readahead(mapping, file,
	92	start_index,
	93	max_sane_readahead(nrpages));
	94	if (ret > 0)
	95	ret = 0;
	96	break;
	97	case POSIX_FADV_DONTNEED:
	98	if (!bdi_write_congested(mapping->backing_dev_info))
	99	filemap_flush(mapping);
	100
	101	/* First and last FULL page! */
ebcf28e1	102	start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
1da177e4 LT	103	end_index = (endbyte >> PAGE_CACHE_SHIFT);
1da177e4 LT	104
ebcf28e1 AM	105	if (end_index >= start_index)
	106	invalidate_mapping_pages(mapping, start_index,
	107	end_index);
	108	break;
1da177e4 LT	109	default:
	110	ret = -EINVAL;
	111	}
	112	out:
	113	fput(file);
	114	return ret;
	115	}
	116
	117	#ifdef __ARCH_WANT_SYS_FADVISE64
	118
	119	asmlinkage long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
	120	{
	121	return sys_fadvise64_64(fd, offset, len, advice);
	122	}
	123
	124	#endif