RE: [PATCH 1/7] mpage: stop using bdev_{read,write}_page

From: Dan Williams <dan.j.williams@intel.com>
To: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	Minchan Kim <minchan@kernel.org>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	"Dan Williams" <dan.j.williams@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Ira Weiny <ira.weiny@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	<linux-block@vger.kernel.org>, <nvdimm@lists.linux.dev>,
	<linux-fsdevel@vger.kernel.org>, <linux-mm@kvack.org>
Subject: RE: [PATCH 1/7] mpage: stop using bdev_{read,write}_page
Date: Wed, 25 Jan 2023 09:58:56 -0800	[thread overview]
Message-ID: <63d16de08ab5e_3a36e52944e@dwillia2-xfh.jf.intel.com.notmuch> (raw)
In-Reply-To: <20230125133436.447864-2-hch@lst.de>

Christoph Hellwig wrote:
> These are micro-optimizations for synchronous I/O, which do not matter
> compared to all the other inefficiencies in the legacy buffer_head
> based mpage code.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/mpage.c | 10 ----------
>  1 file changed, 10 deletions(-)
> 
> diff --git a/fs/mpage.c b/fs/mpage.c
> index 0f8ae954a57903..124550cfac4a70 100644
> --- a/fs/mpage.c
> +++ b/fs/mpage.c
> @@ -269,11 +269,6 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
>  
>  alloc_new:
>  	if (args->bio == NULL) {
> -		if (first_hole == blocks_per_page) {
> -			if (!bdev_read_page(bdev, blocks[0] << (blkbits - 9),
> -								&folio->page))
> -				goto out;
> -		}
>  		args->bio = bio_alloc(bdev, bio_max_segs(args->nr_pages), opf,
>  				      gfp);
>  		if (args->bio == NULL)
> @@ -579,11 +574,6 @@ static int __mpage_writepage(struct page *page, struct writeback_control *wbc,
>  
>  alloc_new:
>  	if (bio == NULL) {
> -		if (first_unmapped == blocks_per_page) {
> -			if (!bdev_write_page(bdev, blocks[0] << (blkbits - 9),
> -								page, wbc))
> -				goto out;
> -		}
>  		bio = bio_alloc(bdev, BIO_MAX_VECS,
>  				REQ_OP_WRITE | wbc_to_write_flags(wbc),
>  				GFP_NOFS);
> -- 
> 2.39.0
> 

Makes sense,

Reviewed-by: Dan Williams <dan.j.williams@intel.com>