Re: [RFC PATCH 2/8] rqbased-dm: add block layer hook

[business1 <coreyu@bsgteamsite.com>]

Kiyoshi Ueda wrote:
> 
> This patch adds new "end_io_first" hook in __end_that_request_first()
> for request-based device-mapper.
> 
> 
> Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
> 
> diff -rupN 1-blk-get-request-irqrestore/block/ll_rw_blk.c
> 2-add-generic-hook/block/ll_rw_blk.c
> --- 1-blk-get-request-irqrestore/block/ll_rw_blk.c	2006-12-15
> 10:21:29.000000000 -0500
> +++ 2-add-generic-hook/block/ll_rw_blk.c	2006-12-15 10:23:30.000000000
> -0500
> @@ -260,6 +260,7 @@ static void rq_init(request_queue_t *q, 
>  	rq->data = NULL;
>  	rq->nr_phys_segments = 0;
>  	rq->sense = NULL;
> +	rq->end_io_first = NULL;
>  	rq->end_io = NULL;
>  	rq->end_io_data = NULL;
>  	rq->completion_data = NULL;
> @@ -3216,6 +3217,22 @@ static int __end_that_request_first(stru
>  
>  	blk_add_trace_rq(req->q, req, BLK_TA_COMPLETE);
>  
> +	if (!uptodate) {
> +		if (blk_fs_request(req) && !(req->cmd_flags & REQ_QUIET))
> +			printk("end_request: I/O error, dev %s, sector %llu\n",
> +				req->rq_disk ? req->rq_disk->disk_name : "?",
> +				(unsigned long long)req->sector);
> +	}
> +
> +	if (blk_fs_request(req) && req->rq_disk) {
> +		const int rw = rq_data_dir(req);
> +
> +		disk_stat_add(req->rq_disk, sectors[rw], nr_bytes >> 9);
> +	}
> +
> +	if (req->end_io_first)
> +		return req->end_io_first(req, uptodate, nr_bytes);
> +
>  	/*
>  	 * extend uptodate bool to allow < 0 value to be direct io error
>  	 */
> @@ -3230,19 +3247,6 @@ static int __end_that_request_first(stru
>  	if (!blk_pc_request(req))
>  		req->errors = 0;
>  
> -	if (!uptodate) {
> -		if (blk_fs_request(req) && !(req->cmd_flags & REQ_QUIET))
> -			printk("end_request: I/O error, dev %s, sector %llu\n",
> -				req->rq_disk ? req->rq_disk->disk_name : "?",
> -				(unsigned long long)req->sector);
> -	}
> -
> -	if (blk_fs_request(req) && req->rq_disk) {
> -		const int rw = rq_data_dir(req);
> -
> -		disk_stat_add(req->rq_disk, sectors[rw], nr_bytes >> 9);
> -	}
> -
>  	total_bytes = bio_nbytes = 0;
>  	while ((bio = req->bio) != NULL) {
>  		int nbytes;
> diff -rupN 1-blk-get-request-irqrestore/include/linux/blkdev.h
> 2-add-generic-hook/include/linux/blkdev.h
> --- 1-blk-get-request-irqrestore/include/linux/blkdev.h	2006-12-11
> 14:32:53.000000000 -0500
> +++ 2-add-generic-hook/include/linux/blkdev.h	2006-12-15
> 10:23:30.000000000 -0500
> @@ -126,6 +126,7 @@ void copy_io_context(struct io_context *
>  void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
>  
>  struct request;
> +typedef int (rq_end_first_fn)(struct request *, int, int);
>  typedef void (rq_end_io_fn)(struct request *, int);
>  
>  struct request_list {
> @@ -312,6 +313,7 @@ struct request {
>  	/*
>  	 * completion callback.
>  	 */
> +	rq_end_first_fn *end_io_first;
>  	rq_end_io_fn *end_io;
>  	void *end_io_data;
>  };
> 
> -
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> 

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