Commit 7aeb7222 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Dave Chinner
Browse files

xfs: refactor xfs_buf_item_format_segment 



Add two helpers to make the code more readable.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent 9597df6b

fs/xfs/xfs_buf_item.c

+39 −33
Original line number Diff line number Diff line
@@ -182,6 +182,34 @@ xfs_buf_item_size( 
	trace_xfs_buf_item_size(bip);

}



static inline struct xfs_log_iovec *

xfs_buf_item_copy_iovec(

	struct xfs_log_iovec	*vecp,

	struct xfs_buf		*bp,

	uint			offset,

	int			first_bit,

	uint			nbits)

{

	offset += first_bit * XFS_BLF_CHUNK;



	vecp->i_type = XLOG_REG_TYPE_BCHUNK;

	vecp->i_addr = xfs_buf_offset(bp, offset);

	vecp->i_len = nbits * XFS_BLF_CHUNK;

	return vecp + 1;

}



static inline bool

xfs_buf_item_straddle(

	struct xfs_buf		*bp,

	uint			offset,

	int			next_bit,

	int			last_bit)

{

	return xfs_buf_offset(bp, offset + (next_bit << XFS_BLF_SHIFT)) !=

		(xfs_buf_offset(bp, offset + (last_bit << XFS_BLF_SHIFT)) +

		 XFS_BLF_CHUNK);

}



static struct xfs_log_iovec *

xfs_buf_item_format_segment(

	struct xfs_buf_log_item	*bip,
@@ -196,7 +224,6 @@ xfs_buf_item_format_segment( 
	int		last_bit;

	int		next_bit;

	uint		nbits;

	uint		buffer_offset;



	/* copy the flags across from the base format item */

	blfp->blf_flags = bip->__bli_format.blf_flags;
@@ -239,7 +266,6 @@ xfs_buf_item_format_segment( 
	/*

	 * Fill in an iovec for each set of contiguous chunks.

	 */



	last_bit = first_bit;

	nbits = 1;

	for (;;) {
@@ -252,42 +278,22 @@ xfs_buf_item_format_segment( 
		next_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,

					(uint)last_bit + 1);

		/*

		 * If we run out of bits fill in the last iovec and get

		 * out of the loop.

		 * Else if we start a new set of bits then fill in the

		 * iovec for the series we were looking at and start

		 * counting the bits in the new one.

		 * Else we're still in the same set of bits so just

		 * keep counting and scanning.

		 * If we run out of bits fill in the last iovec and get out of

		 * the loop.  Else if we start a new set of bits then fill in

		 * the iovec for the series we were looking at and start

		 * counting the bits in the new one.  Else we're still in the

		 * same set of bits so just keep counting and scanning.

		 */

		if (next_bit == -1) {

			buffer_offset = offset + first_bit * XFS_BLF_CHUNK;

			vecp->i_addr = xfs_buf_offset(bp, buffer_offset);

			vecp->i_len = nbits * XFS_BLF_CHUNK;

			vecp->i_type = XLOG_REG_TYPE_BCHUNK;

			xfs_buf_item_copy_iovec(vecp, bp, offset,

						first_bit, nbits);

			nvecs++;

			break;

		} else if (next_bit != last_bit + 1) {

			buffer_offset = offset + first_bit * XFS_BLF_CHUNK;

			vecp->i_addr = xfs_buf_offset(bp, buffer_offset);

			vecp->i_len = nbits * XFS_BLF_CHUNK;

			vecp->i_type = XLOG_REG_TYPE_BCHUNK;

		} else if (next_bit != last_bit + 1 ||

		           xfs_buf_item_straddle(bp, offset, next_bit, last_bit)) {

			vecp = xfs_buf_item_copy_iovec(vecp, bp, offset,

						       first_bit, nbits);

			nvecs++;

			vecp++;

			first_bit = next_bit;

			last_bit = next_bit;

			nbits = 1;

		} else if (xfs_buf_offset(bp, offset +

					      (next_bit << XFS_BLF_SHIFT)) !=

			   (xfs_buf_offset(bp, offset +

					       (last_bit << XFS_BLF_SHIFT)) +

			    XFS_BLF_CHUNK)) {

			buffer_offset = offset + first_bit * XFS_BLF_CHUNK;

			vecp->i_addr = xfs_buf_offset(bp, buffer_offset);

			vecp->i_len = nbits * XFS_BLF_CHUNK;

			vecp->i_type = XLOG_REG_TYPE_BCHUNK;

			nvecs++;

			vecp++;

			first_bit = next_bit;

			last_bit = next_bit;

			nbits = 1;