linux/fs/iomap/seek.c
Christoph Hellwig 49694d14ff iomap: remove the length variable in iomap_seek_hole
The length variable is rather pointless given that it can be trivially
deduced from offset and size.  Also the initial calculation can lead
to KASAN warnings.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Leizhen (ThunderTown) <thunder.leizhen@huawei.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2021-07-15 09:58:04 -07:00

103 lines
2.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2017 Red Hat, Inc.
* Copyright (c) 2018 Christoph Hellwig.
*/
#include <linux/module.h>
#include <linux/compiler.h>
#include <linux/fs.h>
#include <linux/iomap.h>
#include <linux/pagemap.h>
#include <linux/pagevec.h>
static loff_t
iomap_seek_hole_actor(struct inode *inode, loff_t start, loff_t length,
void *data, struct iomap *iomap, struct iomap *srcmap)
{
loff_t offset = start;
switch (iomap->type) {
case IOMAP_UNWRITTEN:
offset = mapping_seek_hole_data(inode->i_mapping, start,
start + length, SEEK_HOLE);
if (offset == start + length)
return length;
fallthrough;
case IOMAP_HOLE:
*(loff_t *)data = offset;
return 0;
default:
return length;
}
}
loff_t
iomap_seek_hole(struct inode *inode, loff_t offset, const struct iomap_ops *ops)
{
loff_t size = i_size_read(inode);
loff_t ret;
/* Nothing to be found before or beyond the end of the file. */
if (offset < 0 || offset >= size)
return -ENXIO;
while (offset < size) {
ret = iomap_apply(inode, offset, size - offset, IOMAP_REPORT,
ops, &offset, iomap_seek_hole_actor);
if (ret < 0)
return ret;
if (ret == 0)
break;
offset += ret;
}
return offset;
}
EXPORT_SYMBOL_GPL(iomap_seek_hole);
static loff_t
iomap_seek_data_actor(struct inode *inode, loff_t start, loff_t length,
void *data, struct iomap *iomap, struct iomap *srcmap)
{
loff_t offset = start;
switch (iomap->type) {
case IOMAP_HOLE:
return length;
case IOMAP_UNWRITTEN:
offset = mapping_seek_hole_data(inode->i_mapping, start,
start + length, SEEK_DATA);
if (offset < 0)
return length;
fallthrough;
default:
*(loff_t *)data = offset;
return 0;
}
}
loff_t
iomap_seek_data(struct inode *inode, loff_t offset, const struct iomap_ops *ops)
{
loff_t size = i_size_read(inode);
loff_t ret;
/* Nothing to be found before or beyond the end of the file. */
if (offset < 0 || offset >= size)
return -ENXIO;
while (offset < size) {
ret = iomap_apply(inode, offset, size - offset, IOMAP_REPORT,
ops, &offset, iomap_seek_data_actor);
if (ret < 0)
return ret;
if (ret == 0)
return offset;
offset += ret;
}
/* We've reached the end of the file without finding data */
return -ENXIO;
}
EXPORT_SYMBOL_GPL(iomap_seek_data);