Re: [PATCHv8 2/5] iomap: Renames and refactor iomap_folio state bitmap handling

["Darrick J. Wong" <djwong@kernel.org>]

On Tue, Jun 06, 2023 at 05:13:49PM +0530, Ritesh Harjani (IBM) wrote:
> This patch renames iomap_folio's uptodate bitmap to state bitmap.
> Also refactors and adds iof->state handling functions for uptodate
> state.
> 
> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>

Looks good to me,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/iomap/buffered-io.c | 107 +++++++++++++++++++++++------------------
>  1 file changed, 59 insertions(+), 48 deletions(-)
> 
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 741baa10c517..08f2a1cf0a66 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -24,14 +24,14 @@
>  #define IOEND_BATCH_SIZE	4096
>  
>  /*
> - * Structure allocated for each folio when block size < folio size
> - * to track sub-folio uptodate status and I/O completions.
> + * Structure allocated for each folio to track per-block uptodate state
> + * and I/O completions.
>   */
>  struct iomap_folio {
>  	atomic_t		read_bytes_pending;
>  	atomic_t		write_bytes_pending;
> -	spinlock_t		uptodate_lock;
> -	unsigned long		uptodate[];
> +	spinlock_t		state_lock;
> +	unsigned long		state[];
>  };
>  
>  static inline struct iomap_folio *iomap_get_iof(struct folio *folio)
> @@ -43,6 +43,47 @@ static inline struct iomap_folio *iomap_get_iof(struct folio *folio)
>  
>  static struct bio_set iomap_ioend_bioset;
>  
> +static inline bool iomap_iof_is_fully_uptodate(struct folio *folio,
> +					       struct iomap_folio *iof)
> +{
> +	struct inode *inode = folio->mapping->host;
> +
> +	return bitmap_full(iof->state, i_blocks_per_folio(inode, folio));
> +}
> +
> +static inline bool iomap_iof_is_block_uptodate(struct iomap_folio *iof,
> +					       unsigned int block)
> +{
> +	return test_bit(block, iof->state);
> +}
> +
> +static void iomap_iof_set_range_uptodate(struct folio *folio,
> +			struct iomap_folio *iof, size_t off, size_t len)
> +{
> +	struct inode *inode = folio->mapping->host;
> +	unsigned int first_blk = off >> inode->i_blkbits;
> +	unsigned int last_blk = (off + len - 1) >> inode->i_blkbits;
> +	unsigned int nr_blks = last_blk - first_blk + 1;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&iof->state_lock, flags);
> +	bitmap_set(iof->state, first_blk, nr_blks);
> +	if (iomap_iof_is_fully_uptodate(folio, iof))
> +		folio_mark_uptodate(folio);
> +	spin_unlock_irqrestore(&iof->state_lock, flags);
> +}
> +
> +static void iomap_set_range_uptodate(struct folio *folio, size_t off,
> +				     size_t len)
> +{
> +	struct iomap_folio *iof = iomap_get_iof(folio);
> +
> +	if (iof)
> +		iomap_iof_set_range_uptodate(folio, iof, off, len);
> +	else
> +		folio_mark_uptodate(folio);
> +}
> +
>  static struct iomap_folio *iomap_iof_alloc(struct inode *inode,
>  				struct folio *folio, unsigned int flags)
>  {
> @@ -58,12 +99,12 @@ static struct iomap_folio *iomap_iof_alloc(struct inode *inode,
>  	else
>  		gfp = GFP_NOFS | __GFP_NOFAIL;
>  
> -	iof = kzalloc(struct_size(iof, uptodate, BITS_TO_LONGS(nr_blocks)),
> +	iof = kzalloc(struct_size(iof, state, BITS_TO_LONGS(nr_blocks)),
>  		      gfp);
>  	if (iof) {
> -		spin_lock_init(&iof->uptodate_lock);
> +		spin_lock_init(&iof->state_lock);
>  		if (folio_test_uptodate(folio))
> -			bitmap_fill(iof->uptodate, nr_blocks);
> +			bitmap_fill(iof->state, nr_blocks);
>  		folio_attach_private(folio, iof);
>  	}
>  	return iof;
> @@ -72,14 +113,12 @@ static struct iomap_folio *iomap_iof_alloc(struct inode *inode,
>  static void iomap_iof_free(struct folio *folio)
>  {
>  	struct iomap_folio *iof = folio_detach_private(folio);
> -	struct inode *inode = folio->mapping->host;
> -	unsigned int nr_blocks = i_blocks_per_folio(inode, folio);
>  
>  	if (!iof)
>  		return;
>  	WARN_ON_ONCE(atomic_read(&iof->read_bytes_pending));
>  	WARN_ON_ONCE(atomic_read(&iof->write_bytes_pending));
> -	WARN_ON_ONCE(bitmap_full(iof->uptodate, nr_blocks) !=
> +	WARN_ON_ONCE(iomap_iof_is_fully_uptodate(folio, iof) !=
>  			folio_test_uptodate(folio));
>  	kfree(iof);
>  }
> @@ -110,7 +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, iof->uptodate))
> +			if (!iomap_iof_is_block_uptodate(iof, i))
>  				break;
>  			*pos += block_size;
>  			poff += block_size;
> @@ -120,7 +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, iof->uptodate)) {
> +			if (iomap_iof_is_block_uptodate(iof, i)) {
>  				plen -= (last - i + 1) * block_size;
>  				last = i - 1;
>  				break;
> @@ -144,30 +183,6 @@ static void iomap_adjust_read_range(struct inode *inode, struct folio *folio,
>  	*lenp = plen;
>  }
>  
> -static void iomap_iof_set_range_uptodate(struct folio *folio,
> -		struct iomap_folio *iof, size_t off, size_t len)
> -{
> -	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(&iof->uptodate_lock, flags);
> -	bitmap_set(iof->uptodate, first, last - first + 1);
> -	if (bitmap_full(iof->uptodate, i_blocks_per_folio(inode, folio)))
> -		folio_mark_uptodate(folio);
> -	spin_unlock_irqrestore(&iof->uptodate_lock, flags);
> -}
> -
> -static void iomap_set_range_uptodate(struct folio *folio,
> -		struct iomap_folio *iof, size_t off, size_t len)
> -{
> -	if (iof)
> -		iomap_iof_set_range_uptodate(folio, iof, off, len);
> -	else
> -		folio_mark_uptodate(folio);
> -}
> -
>  static void iomap_finish_folio_read(struct folio *folio, size_t offset,
>  		size_t len, int error)
>  {
> @@ -177,7 +192,7 @@ static void iomap_finish_folio_read(struct folio *folio, size_t offset,
>  		folio_clear_uptodate(folio);
>  		folio_set_error(folio);
>  	} else {
> -		iomap_set_range_uptodate(folio, iof, offset, len);
> +		iomap_set_range_uptodate(folio, offset, len);
>  	}
>  
>  	if (!iof || atomic_sub_and_test(len, &iof->read_bytes_pending))
> @@ -213,7 +228,6 @@ struct iomap_readpage_ctx {
>  static int iomap_read_inline_data(const struct iomap_iter *iter,
>  		struct folio *folio)
>  {
> -	struct iomap_folio *iof;
>  	const struct iomap *iomap = iomap_iter_srcmap(iter);
>  	size_t size = i_size_read(iter->inode) - iomap->offset;
>  	size_t poff = offset_in_page(iomap->offset);
> @@ -231,15 +245,13 @@ static int iomap_read_inline_data(const struct iomap_iter *iter,
>  	if (WARN_ON_ONCE(size > iomap->length))
>  		return -EIO;
>  	if (offset > 0)
> -		iof = iomap_iof_alloc(iter->inode, folio, iter->flags);
> -	else
> -		iof = iomap_get_iof(folio);
> +		iomap_iof_alloc(iter->inode, folio, iter->flags);
>  
>  	addr = kmap_local_folio(folio, offset);
>  	memcpy(addr, iomap->inline_data, size);
>  	memset(addr + size, 0, PAGE_SIZE - poff - size);
>  	kunmap_local(addr);
> -	iomap_set_range_uptodate(folio, iof, offset, PAGE_SIZE - poff);
> +	iomap_set_range_uptodate(folio, offset, PAGE_SIZE - poff);
>  	return 0;
>  }
>  
> @@ -276,7 +288,7 @@ static loff_t iomap_readpage_iter(const struct iomap_iter *iter,
>  
>  	if (iomap_block_needs_zeroing(iter, pos)) {
>  		folio_zero_range(folio, poff, plen);
> -		iomap_set_range_uptodate(folio, iof, poff, plen);
> +		iomap_set_range_uptodate(folio, poff, plen);
>  		goto done;
>  	}
>  
> @@ -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, iof->uptodate))
> +		if (!iomap_iof_is_block_uptodate(iof, i))
>  			return false;
>  	return true;
>  }
> @@ -589,7 +601,7 @@ static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
>  			if (status)
>  				return status;
>  		}
> -		iomap_set_range_uptodate(folio, iof, poff, plen);
> +		iomap_set_range_uptodate(folio, poff, plen);
>  	} while ((block_start += plen) < block_end);
>  
>  	return 0;
> @@ -696,7 +708,6 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos,
>  static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len,
>  		size_t copied, struct folio *folio)
>  {
> -	struct iomap_folio *iof = iomap_get_iof(folio);
>  	flush_dcache_folio(folio);
>  
>  	/*
> @@ -712,7 +723,7 @@ static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len,
>  	 */
>  	if (unlikely(copied < len && !folio_test_uptodate(folio)))
>  		return 0;
> -	iomap_set_range_uptodate(folio, iof, offset_in_folio(folio, pos), len);
> +	iomap_set_range_uptodate(folio, offset_in_folio(folio, pos), len);
>  	filemap_dirty_folio(inode->i_mapping, folio);
>  	return copied;
>  }
> @@ -1628,7 +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 (iof && !test_bit(i, iof->uptodate))
> +		if (iof && !iomap_iof_is_block_uptodate(iof, i))
>  			continue;
>  
>  		error = wpc->ops->map_blocks(wpc, inode, pos);
> -- 
> 2.40.1
>