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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2024-2025 Christoph Hellwig.
*/
#include <linux/iomap.h>
struct iomap_ioend *iomap_init_ioend(struct inode *inode,
struct bio *bio, loff_t file_offset, u16 ioend_flags)
{
struct iomap_ioend *ioend = iomap_ioend_from_bio(bio);
atomic_set(&ioend->io_remaining, 1);
ioend->io_error = 0;
ioend->io_parent = NULL;
INIT_LIST_HEAD(&ioend->io_list);
ioend->io_flags = ioend_flags;
ioend->io_inode = inode;
ioend->io_offset = file_offset;
ioend->io_size = bio->bi_iter.bi_size;
ioend->io_sector = bio->bi_iter.bi_sector;
return ioend;
}
EXPORT_SYMBOL_GPL(iomap_init_ioend);
/*
* Split up to the first @max_len bytes from @ioend if the ioend covers more
* than @max_len bytes.
*
* If @is_append is set, the split will be based on the hardware limits for
* REQ_OP_ZONE_APPEND commands and can be less than @max_len if the hardware
* limits don't allow the entire @max_len length.
*
* The bio embedded into @ioend must be a REQ_OP_WRITE because the block layer
* does not allow splitting REQ_OP_ZONE_APPEND bios. The file systems has to
* switch the operation after this call, but before submitting the bio.
*/
struct iomap_ioend *iomap_split_ioend(struct iomap_ioend *ioend,
unsigned int max_len, bool is_append)
{
struct bio *bio = &ioend->io_bio;
struct iomap_ioend *split_ioend;
unsigned int nr_segs;
int sector_offset;
struct bio *split;
if (is_append) {
struct queue_limits *lim = bdev_limits(bio->bi_bdev);
max_len = min(max_len,
lim->max_zone_append_sectors << SECTOR_SHIFT);
sector_offset = bio_split_rw_at(bio, lim, &nr_segs, max_len);
if (unlikely(sector_offset < 0))
return ERR_PTR(sector_offset);
if (!sector_offset)
return NULL;
} else {
if (bio->bi_iter.bi_size <= max_len)
return NULL;
sector_offset = max_len >> SECTOR_SHIFT;
}
/* ensure the split ioend is still block size aligned */
sector_offset = ALIGN_DOWN(sector_offset << SECTOR_SHIFT,
i_blocksize(ioend->io_inode)) >> SECTOR_SHIFT;
split = bio_split(bio, sector_offset, GFP_NOFS, &iomap_ioend_bioset);
if (IS_ERR(split))
return ERR_CAST(split);
split->bi_private = bio->bi_private;
split->bi_end_io = bio->bi_end_io;
split_ioend = iomap_init_ioend(ioend->io_inode, split, ioend->io_offset,
ioend->io_flags);
split_ioend->io_parent = ioend;
atomic_inc(&ioend->io_remaining);
ioend->io_offset += split_ioend->io_size;
ioend->io_size -= split_ioend->io_size;
split_ioend->io_sector = ioend->io_sector;
if (!is_append)
ioend->io_sector += (split_ioend->io_size >> SECTOR_SHIFT);
return split_ioend;
}
EXPORT_SYMBOL_GPL(iomap_split_ioend);
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