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Subject: Re: [PATCH v2] include: Remove pagemap.h from blkdev.h
To:     "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc:     linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
        linux-bcache@vger.kernel.org, linux-nvdimm@lists.01.org,
        linux-scsi@vger.kernel.org
References: <20210309195747.283796-1-willy@infradead.org>
From:   Coly Li <colyli@suse.de>
Message-ID: <4d6e3281-98e5-e161-3883-00ccc88e1682@suse.de>
Date:   Wed, 10 Mar 2021 18:29:06 +0800
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On 3/10/21 3:57 AM, Matthew Wilcox (Oracle) wrote:
> My UEK-derived config has 1030 files depending on pagemap.h before
> this change.  Afterwards, just 326 files need to be rebuilt when I
> touch pagemap.h.  I think blkdev.h is probably included too widely,
> but untangling that dependency is harder and this solves my problem.
> x86 allmodconfig builds, but there may be implicit include problems
> on other architectures.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
> v2: Fix CONFIG_SWAP=n implicit use of pagemap.h by swap.h.  Increases
>     the number of files from 240, but that's still a big win -- 68%
>     reduction instead of 77%.
> 
>  block/blk-settings.c      | 1 +
>  drivers/block/brd.c       | 1 +
>  drivers/block/loop.c      | 1 +
>  drivers/md/bcache/super.c | 1 +
>  drivers/nvdimm/btt.c      | 1 +
>  drivers/nvdimm/pmem.c     | 1 +
>  drivers/scsi/scsicam.c    | 1 +
>  include/linux/blkdev.h    | 1 -
>  include/linux/swap.h      | 1 +
>  9 files changed, 8 insertions(+), 1 deletion(-)
> 
[snipped]

> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index 71691f32959b..f154c89d1326 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -16,6 +16,7 @@
>  #include "features.h"
>  
>  #include <linux/blkdev.h>
> +#include <linux/pagemap.h>
>  #include <linux/debugfs.h>
>  #include <linux/genhd.h>
>  #include <linux/idr.h>[snipped]

For bcache part, Acked-by: Coly Li <colyli@suse.de>

Thanks.

Coly Li