Re: [PATCHv9 3/6] iomap: Add some uptodate state handling helpers for ifs state bitmap

[Andreas Gruenbacher <agruenba@xxxxxxxxxx>]

On Sat, Jun 10, 2023 at 1:39 PM Ritesh Harjani (IBM)
<ritesh.list@xxxxxxxxx> wrote:
> This patch adds two of the helper routines iomap_ifs_is_fully_uptodate()
> and iomap_ifs_is_block_uptodate() for managing uptodate state of
> ifs state bitmap.
>
> In later patches ifs state bitmap array will also handle dirty state of all
> blocks of a folio. Hence this patch adds some helper routines for handling
> uptodate state of the ifs state bitmap.
>
> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
> ---
>  fs/iomap/buffered-io.c | 28 ++++++++++++++++++++--------
>  1 file changed, 20 insertions(+), 8 deletions(-)
>
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index e237f2b786bc..206808f6e818 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -43,6 +43,20 @@ static inline struct iomap_folio_state *iomap_get_ifs(struct folio *folio)
>
>  static struct bio_set iomap_ioend_bioset;
>
> +static inline bool iomap_ifs_is_fully_uptodate(struct folio *folio,
> +                                              struct iomap_folio_state *ifs)
> +{
> +       struct inode *inode = folio->mapping->host;
> +
> +       return bitmap_full(ifs->state, i_blocks_per_folio(inode, folio));

This should be written as something like:

unsigned int blks_per_folio = i_blocks_per_folio(inode, folio);
return bitmap_full(ifs->state + IOMAP_ST_UPTODATE * blks_per_folio,
blks_per_folio);

> +}
> +
> +static inline bool iomap_ifs_is_block_uptodate(struct iomap_folio_state *ifs,
> +                                              unsigned int block)
> +{
> +       return test_bit(block, ifs->state);

This function should be called iomap_ifs_block_is_uptodate(), and
probably be written as follows, passing in the folio as well (this
will optimize out, anyway):

struct inode *inode = folio->mapping->host;
unsigned int blks_per_folio = i_blocks_per_folio(inode, folio);
return test_bit(block, ifs->state + IOMAP_ST_UPTODATE * blks_per_folio);

> +}
> +
>  static void iomap_ifs_set_range_uptodate(struct folio *folio,
>                 struct iomap_folio_state *ifs, size_t off, size_t len)
>  {
> @@ -54,7 +68,7 @@ static void iomap_ifs_set_range_uptodate(struct folio *folio,
>
>         spin_lock_irqsave(&ifs->state_lock, flags);
>         bitmap_set(ifs->state, first_blk, nr_blks);
> -       if (bitmap_full(ifs->state, i_blocks_per_folio(inode, folio)))
> +       if (iomap_ifs_is_fully_uptodate(folio, ifs))
>                 folio_mark_uptodate(folio);
>         spin_unlock_irqrestore(&ifs->state_lock, flags);
>  }
> @@ -99,14 +113,12 @@ static struct iomap_folio_state *iomap_ifs_alloc(struct inode *inode,
>  static void iomap_ifs_free(struct folio *folio)
>  {
>         struct iomap_folio_state *ifs = folio_detach_private(folio);
> -       struct inode *inode = folio->mapping->host;
> -       unsigned int nr_blocks = i_blocks_per_folio(inode, folio);
>
>         if (!ifs)
>                 return;
>         WARN_ON_ONCE(atomic_read(&ifs->read_bytes_pending));
>         WARN_ON_ONCE(atomic_read(&ifs->write_bytes_pending));
> -       WARN_ON_ONCE(bitmap_full(ifs->state, nr_blocks) !=
> +       WARN_ON_ONCE(iomap_ifs_is_fully_uptodate(folio, ifs) !=
>                         folio_test_uptodate(folio));
>         kfree(ifs);
>  }
> @@ -137,7 +149,7 @@ static void iomap_adjust_read_range(struct inode *inode, struct folio *folio,
>
>                 /* move forward for each leading block marked uptodate */
>                 for (i = first; i <= last; i++) {
> -                       if (!test_bit(i, ifs->state))
> +                       if (!iomap_ifs_is_block_uptodate(ifs, i))
>                                 break;
>                         *pos += block_size;
>                         poff += block_size;
> @@ -147,7 +159,7 @@ static void iomap_adjust_read_range(struct inode *inode, struct folio *folio,
>
>                 /* truncate len if we find any trailing uptodate block(s) */
>                 for ( ; i <= last; i++) {
> -                       if (test_bit(i, ifs->state)) {
> +                       if (iomap_ifs_is_block_uptodate(ifs, i)) {
>                                 plen -= (last - i + 1) * block_size;
>                                 last = i - 1;
>                                 break;
> @@ -451,7 +463,7 @@ bool iomap_is_partially_uptodate(struct folio *folio, size_t from, size_t count)
>         last = (from + count - 1) >> inode->i_blkbits;
>
>         for (i = first; i <= last; i++)
> -               if (!test_bit(i, ifs->state))
> +               if (!iomap_ifs_is_block_uptodate(ifs, i))
>                         return false;
>         return true;
>  }
> @@ -1627,7 +1639,7 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc,
>          * invalid, grab a new one.
>          */
>         for (i = 0; i < nblocks && pos < end_pos; i++, pos += len) {
> -               if (ifs && !test_bit(i, ifs->state))
> +               if (ifs && !iomap_ifs_is_block_uptodate(ifs, i))
>                         continue;
>
>                 error = wpc->ops->map_blocks(wpc, inode, pos);
> --
> 2.40.1
>

Thanks,
Andreas