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From: Christoph Hellwig <hch@lst.de>
To: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	"Darrick J. Wong" <djwong@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Christian Brauner <christian@brauner.io>,
	linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-xfs@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 6/6] fs: add CONFIG_BUFFER_HEAD
Date: Fri, 21 Jul 2023 08:24:23 +0200	[thread overview]
Message-ID: <20230721062423.GA20845@lst.de> (raw)
In-Reply-To: <ZLlId9+kXl5Tb7wj@casper.infradead.org>

On Thu, Jul 20, 2023 at 03:45:11PM +0100, Matthew Wilcox wrote:
> On Thu, Jul 20, 2023 at 04:04:52PM +0200, Christoph Hellwig wrote:
> > @@ -400,7 +391,8 @@ static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> >  	iomap->type = IOMAP_MAPPED;
> >  	iomap->addr = iomap->offset;
> >  	iomap->length = isize - iomap->offset;
> > -	iomap->flags |= IOMAP_F_BUFFER_HEAD;
> > +	if (IS_ENABLED(CONFIG_BUFFER_HEAD))
> > +		iomap->flags |= IOMAP_F_BUFFER_HEAD;
> 
> Wouldn't it be simpler to do ...
> 
> +#ifdef CONFIG_BUFFER_HEAD
>  #define IOMAP_F_BUFFER_HEAD     (1U << 4)
> +#else
> +#define IOMAP_F_BUFFER_HEAD	0
> +#endif
> 
> in include/linux/iomap.h ?

> ... because this function then goes away.

I guess we could do that.  It is less intrusive, but I have to say I find
flags that get defined away to 0 fairly confusing for the reader.

  reply	other threads:[~2023-07-21  6:24 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-20 14:04 allow building a kernel without buffer_heads Christoph Hellwig
2023-07-20 14:04 ` [PATCH 1/6] fs: remove emergency_thaw_bdev Christoph Hellwig
2023-07-20 14:12   ` Johannes Thumshirn
2023-07-20 15:43   ` Hannes Reinecke
2023-07-24 19:54   ` Luis Chamberlain
2023-07-20 14:04 ` [PATCH 2/6] fs: rename and move block_page_mkwrite_return Christoph Hellwig
2023-07-20 14:13   ` Johannes Thumshirn
2023-07-20 15:45   ` Hannes Reinecke
2023-07-24 19:55   ` Luis Chamberlain
2023-07-20 14:04 ` [PATCH 3/6] block: open code __generic_file_write_iter for blkdev writes Christoph Hellwig
2023-07-20 14:14   ` Johannes Thumshirn
2023-07-20 15:46   ` Hannes Reinecke
2023-07-24 20:05   ` Luis Chamberlain
2023-07-20 14:04 ` [PATCH 4/6] block: stop setting ->direct_IO Christoph Hellwig
2023-07-20 14:15   ` Johannes Thumshirn
2023-07-20 15:46   ` Hannes Reinecke
2023-07-24 20:07   ` Luis Chamberlain
2023-07-20 14:04 ` [PATCH 5/6] block: use iomap for writes to block devices Christoph Hellwig
2023-07-20 15:48   ` Hannes Reinecke
2023-07-24 20:14   ` Luis Chamberlain
     [not found]   ` <CGME20230727091404eucas1p2cbc14ec51eb1442496b1a4c30cd04803@eucas1p2.samsung.com>
2023-07-27  9:14     ` Pankaj Raghav
2023-07-20 14:04 ` [PATCH 6/6] fs: add CONFIG_BUFFER_HEAD Christoph Hellwig
2023-07-20 14:45   ` Matthew Wilcox
2023-07-21  6:24     ` Christoph Hellwig [this message]
2023-07-20 15:53   ` Hannes Reinecke
2023-07-21  6:25     ` Christoph Hellwig
2023-07-24 20:16   ` Luis Chamberlain
2023-07-20 14:51 ` allow building a kernel without buffer_heads Bob Peterson
2023-07-21  6:26   ` Christoph Hellwig
  -- strict thread matches above, loose matches on Subject: below --
2023-08-01 17:21 allow building a kernel without buffer_heads v3 Christoph Hellwig
2023-08-01 17:22 ` [PATCH 6/6] fs: add CONFIG_BUFFER_HEAD Christoph Hellwig
2023-08-02 11:51   ` Johannes Thumshirn

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