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    Subject[PATCH v14 098/138] iomap: Use folio offsets instead of page offsets
    Date
    Pass a folio around instead of the page, and make sure the offset
    is relative to the start of the folio instead of the start of a page.
    Also use size_t for offset & length to make it clear that these are byte
    counts, and to support >2GB folios in the future.

    Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
    ---
    fs/iomap/buffered-io.c | 85 ++++++++++++++++++++++--------------------
    1 file changed, 44 insertions(+), 41 deletions(-)

    diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
    index fbe4ebc074ce..707a96e36651 100644
    --- a/fs/iomap/buffered-io.c
    +++ b/fs/iomap/buffered-io.c
    @@ -75,18 +75,18 @@ static void iomap_page_release(struct folio *folio)
    }

    /*
    - * Calculate the range inside the page that we actually need to read.
    + * Calculate the range inside the folio that we actually need to read.
    */
    -static void
    -iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
    - loff_t *pos, loff_t length, unsigned *offp, unsigned *lenp)
    +static void iomap_adjust_read_range(struct inode *inode, struct folio *folio,
    + loff_t *pos, loff_t length, size_t *offp, size_t *lenp)
    {
    + struct iomap_page *iop = to_iomap_page(folio);
    loff_t orig_pos = *pos;
    loff_t isize = i_size_read(inode);
    unsigned block_bits = inode->i_blkbits;
    unsigned block_size = (1 << block_bits);
    - unsigned poff = offset_in_page(*pos);
    - unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length);
    + size_t poff = offset_in_folio(folio, *pos);
    + size_t plen = min_t(loff_t, folio_size(folio) - poff, length);
    unsigned first = poff >> block_bits;
    unsigned last = (poff + plen - 1) >> block_bits;

    @@ -124,7 +124,7 @@ iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
    * page cache for blocks that are entirely outside of i_size.
    */
    if (orig_pos <= isize && orig_pos + length > isize) {
    - unsigned end = offset_in_page(isize - 1) >> block_bits;
    + unsigned end = offset_in_folio(folio, isize - 1) >> block_bits;

    if (first <= end && last > end)
    plen -= (last - end) * block_size;
    @@ -134,31 +134,31 @@ iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
    *lenp = plen;
    }

    -static void iomap_iop_set_range_uptodate(struct page *page,
    - struct iomap_page *iop, unsigned off, unsigned len)
    +static void iomap_iop_set_range_uptodate(struct folio *folio,
    + struct iomap_page *iop, size_t off, size_t len)
    {
    - struct inode *inode = page->mapping->host;
    + struct inode *inode = folio->mapping->host;
    unsigned first = off >> inode->i_blkbits;
    unsigned last = (off + len - 1) >> inode->i_blkbits;
    unsigned long flags;

    spin_lock_irqsave(&iop->uptodate_lock, flags);
    bitmap_set(iop->uptodate, first, last - first + 1);
    - if (bitmap_full(iop->uptodate, i_blocks_per_page(inode, page)))
    - SetPageUptodate(page);
    + if (bitmap_full(iop->uptodate, i_blocks_per_folio(inode, folio)))
    + folio_mark_uptodate(folio);
    spin_unlock_irqrestore(&iop->uptodate_lock, flags);
    }

    -static void iomap_set_range_uptodate(struct page *page,
    - struct iomap_page *iop, unsigned off, unsigned len)
    +static void iomap_set_range_uptodate(struct folio *folio,
    + struct iomap_page *iop, size_t off, size_t len)
    {
    - if (PageError(page))
    + if (folio_test_error(folio))
    return;

    if (iop)
    - iomap_iop_set_range_uptodate(page, iop, off, len);
    + iomap_iop_set_range_uptodate(folio, iop, off, len);
    else
    - SetPageUptodate(page);
    + folio_mark_uptodate(folio);
    }

    static void
    @@ -169,15 +169,17 @@ iomap_read_page_end_io(struct bio_vec *bvec, int error)
    struct iomap_page *iop = to_iomap_page(folio);

    if (unlikely(error)) {
    - ClearPageUptodate(page);
    - SetPageError(page);
    + folio_clear_uptodate(folio);
    + folio_set_error(folio);
    } else {
    - iomap_set_range_uptodate(page, iop, bvec->bv_offset,
    - bvec->bv_len);
    + size_t off = (page - &folio->page) * PAGE_SIZE +
    + bvec->bv_offset;
    +
    + iomap_set_range_uptodate(folio, iop, off, bvec->bv_len);
    }

    if (!iop || atomic_sub_and_test(bvec->bv_len, &iop->read_bytes_pending))
    - unlock_page(page);
    + folio_unlock(folio);
    }

    static void
    @@ -237,7 +239,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
    struct iomap_page *iop = iomap_page_create(inode, folio);
    bool same_page = false, is_contig = false;
    loff_t orig_pos = pos;
    - unsigned poff, plen;
    + size_t poff, plen;
    sector_t sector;

    if (iomap->type == IOMAP_INLINE) {
    @@ -246,14 +248,14 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
    return PAGE_SIZE;
    }

    - /* zero post-eof blocks as the page may be mapped */
    - iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen);
    + /* zero post-eof blocks as the folio may be mapped */
    + iomap_adjust_read_range(inode, folio, &pos, length, &poff, &plen);
    if (plen == 0)
    goto done;

    if (iomap_block_needs_zeroing(inode, iomap, pos)) {
    - zero_user(page, poff, plen);
    - iomap_set_range_uptodate(page, iop, poff, plen);
    + zero_user(&folio->page, poff, plen);
    + iomap_set_range_uptodate(folio, iop, poff, plen);
    goto done;
    }

    @@ -264,7 +266,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
    /* Try to merge into a previous segment if we can */
    sector = iomap_sector(iomap, pos);
    if (ctx->bio && bio_end_sector(ctx->bio) == sector) {
    - if (__bio_try_merge_page(ctx->bio, page, plen, poff,
    + if (__bio_try_merge_page(ctx->bio, &folio->page, plen, poff,
    &same_page))
    goto done;
    is_contig = true;
    @@ -296,7 +298,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
    ctx->bio->bi_end_io = iomap_read_end_io;
    }

    - bio_add_page(ctx->bio, page, plen, poff);
    + bio_add_folio(ctx->bio, folio, plen, poff);
    done:
    /*
    * Move the caller beyond our range so that it keeps making progress.
    @@ -531,9 +533,8 @@ iomap_write_failed(struct inode *inode, loff_t pos, unsigned len)
    truncate_pagecache_range(inode, max(pos, i_size), pos + len);
    }

    -static int
    -iomap_read_page_sync(loff_t block_start, struct page *page, unsigned poff,
    - unsigned plen, struct iomap *iomap)
    +static int iomap_read_folio_sync(loff_t block_start, struct folio *folio,
    + size_t poff, size_t plen, struct iomap *iomap)
    {
    struct bio_vec bvec;
    struct bio bio;
    @@ -542,7 +543,7 @@ iomap_read_page_sync(loff_t block_start, struct page *page, unsigned poff,
    bio.bi_opf = REQ_OP_READ;
    bio.bi_iter.bi_sector = iomap_sector(iomap, block_start);
    bio_set_dev(&bio, iomap->bdev);
    - __bio_add_page(&bio, page, plen, poff);
    + bio_add_folio(&bio, folio, plen, poff);
    return submit_bio_wait(&bio);
    }

    @@ -555,14 +556,15 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags,
    loff_t block_size = i_blocksize(inode);
    loff_t block_start = round_down(pos, block_size);
    loff_t block_end = round_up(pos + len, block_size);
    - unsigned from = offset_in_page(pos), to = from + len, poff, plen;
    + size_t from = offset_in_folio(folio, pos), to = from + len;
    + size_t poff, plen;

    - if (PageUptodate(page))
    + if (folio_test_uptodate(folio))
    return 0;
    - ClearPageError(page);
    + folio_clear_error(folio);

    do {
    - iomap_adjust_read_range(inode, iop, &block_start,
    + iomap_adjust_read_range(inode, folio, &block_start,
    block_end - block_start, &poff, &plen);
    if (plen == 0)
    break;
    @@ -575,14 +577,15 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags,
    if (iomap_block_needs_zeroing(inode, srcmap, block_start)) {
    if (WARN_ON_ONCE(flags & IOMAP_WRITE_F_UNSHARE))
    return -EIO;
    - zero_user_segments(page, poff, from, to, poff + plen);
    + zero_user_segments(&folio->page, poff, from, to,
    + poff + plen);
    } else {
    - int status = iomap_read_page_sync(block_start, page,
    + int status = iomap_read_folio_sync(block_start, folio,
    poff, plen, srcmap);
    if (status)
    return status;
    }
    - iomap_set_range_uptodate(page, iop, poff, plen);
    + iomap_set_range_uptodate(folio, iop, poff, plen);
    } while ((block_start += plen) < block_end);

    return 0;
    @@ -661,7 +664,7 @@ static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len,
    */
    if (unlikely(copied < len && !PageUptodate(page)))
    return 0;
    - iomap_set_range_uptodate(page, iop, offset_in_page(pos), len);
    + iomap_set_range_uptodate(folio, iop, offset_in_folio(folio, pos), len);
    __set_page_dirty_nobuffers(page);
    return copied;
    }
    --
    2.30.2
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