Re: [PATCH 2/2] xfs: kill __xfs_buf_submit_common()

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Mon, Jun 18, 2018 at 10:52:44AM -0400, Brian Foster wrote:
> Now that there is only one caller, fold the common submission helper
> into __xfs_buf_submit().
> 
> Suggested-by: Christoph Hellwig <hch@infradead.org>
> Signed-off-by: Brian Foster <bfoster@redhat.com>

Looks ok enough to test,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
>  fs/xfs/xfs_buf.c | 83 ++++++++++++++++++++----------------------------
>  1 file changed, 34 insertions(+), 49 deletions(-)
> 
> diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
> index 64a9a09013e3..f747792038dc 100644
> --- a/fs/xfs/xfs_buf.c
> +++ b/fs/xfs/xfs_buf.c
> @@ -1449,15 +1449,34 @@ _xfs_buf_ioapply(
>  }
>  
>  /*
> - * Asynchronous IO submission path. This transfers the buffer lock ownership and
> - * the current reference to the IO. It is not safe to reference the buffer after
> - * a call to this function unless the caller holds an additional reference
> - * itself.
> + * Wait for I/O completion of a sync buffer and return the I/O error code.
>   */
>  static int
> -__xfs_buf_submit_common(
> +xfs_buf_iowait(
>  	struct xfs_buf	*bp)
>  {
> +	ASSERT(!(bp->b_flags & XBF_ASYNC));
> +
> +	trace_xfs_buf_iowait(bp, _RET_IP_);
> +	wait_for_completion(&bp->b_iowait);
> +	trace_xfs_buf_iowait_done(bp, _RET_IP_);
> +
> +	return bp->b_error;
> +}
> +
> +/*
> + * Buffer I/O submission path, read or write. Asynchronous submission transfers
> + * the buffer lock ownership and the current reference to the IO. It is not
> + * safe to reference the buffer after a call to this function unless the caller
> + * holds an additional reference itself.
> + */
> +int
> +__xfs_buf_submit(
> +	struct xfs_buf	*bp,
> +	bool		wait)
> +{
> +	int		error = 0;
> +
>  	trace_xfs_buf_submit(bp, _RET_IP_);
>  
>  	ASSERT(!(bp->b_flags & _XBF_DELWRI_Q));
> @@ -1467,9 +1486,18 @@ __xfs_buf_submit_common(
>  		xfs_buf_ioerror(bp, -EIO);
>  		bp->b_flags &= ~XBF_DONE;
>  		xfs_buf_stale(bp);
> +		if (bp->b_flags & XBF_ASYNC)
> +			xfs_buf_ioend(bp);
>  		return -EIO;
>  	}
>  
> +	/*
> +	 * Grab a reference so the buffer does not go away underneath us. For
> +	 * async buffers, I/O completion drops the callers reference, which
> +	 * could occur before submission returns.
> +	 */
> +	xfs_buf_hold(bp);
> +
>  	if (bp->b_flags & XBF_WRITE)
>  		xfs_buf_wait_unpin(bp);
>  
> @@ -1498,52 +1526,9 @@ __xfs_buf_submit_common(
>  			xfs_buf_ioend_async(bp);
>  	}
>  
> -	return 0;
> -}
> -
> -/*
> - * Wait for I/O completion of a sync buffer and return the I/O error code.
> - */
> -static int
> -xfs_buf_iowait(
> -	struct xfs_buf	*bp)
> -{
> -	ASSERT(!(bp->b_flags & XBF_ASYNC));
> -
> -	trace_xfs_buf_iowait(bp, _RET_IP_);
> -	wait_for_completion(&bp->b_iowait);
> -	trace_xfs_buf_iowait_done(bp, _RET_IP_);
> -
> -	return bp->b_error;
> -}
> -
> -/*
> - * Synchronous buffer IO submission path, read or write.
> - */
> -int
> -__xfs_buf_submit(
> -	struct xfs_buf	*bp,
> -	bool		wait)
> -{
> -	int		error;
> -
> -	/*
> -	 * Grab a reference so the buffer does not go away underneath us. For
> -	 * async buffers, I/O completion drops the callers reference, which
> -	 * could occur before submission returns.
> -	 */
> -	xfs_buf_hold(bp);
> -
> -	error = __xfs_buf_submit_common(bp);
> -	if (error) {
> -		if (bp->b_flags & XBF_ASYNC)
> -			xfs_buf_ioend(bp);
> -		goto out;
> -	}
> -
>  	if (wait)
>  		error = xfs_buf_iowait(bp);
> -out:
> +
>  	/*
>  	 * Release the hold that keeps the buffer referenced for the entire
>  	 * I/O. Note that if the buffer is async, it is not safe to reference
> -- 
> 2.17.1
> 
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