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From: Christoph Hellwig <hch@infradead.org>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: linux-fsdevel@vger.kernel.org, linux-nvdimm@lists.01.org,
	hch@infradead.org, dm-devel@redhat.com
Subject: Re: [PATCH 5/5] dax,iomap: Add helper dax_iomap_zero() to zero a range
Date: Wed, 5 Feb 2020 10:36:09 -0800
Message-ID: <20200205183609.GE26711@infradead.org> (raw)
In-Reply-To: <20200203200029.4592-6-vgoyal@redhat.com>

> +int dax_iomap_zero(loff_t pos, unsigned offset, unsigned size,
> +			      struct iomap *iomap)
>  {
>  	pgoff_t pgoff;
>  	long rc, id;
> +	sector_t sector = iomap_sector(iomap, pos & PAGE_MASK);
>  
> -	rc = bdev_dax_pgoff(bdev, sector, PAGE_SIZE, &pgoff);
> +	rc = bdev_dax_pgoff(iomap->bdev, sector, PAGE_SIZE, &pgoff);
>  	if (rc)
>  		return rc;
>  
>  	id = dax_read_lock();
> -	rc = dax_zero_page_range(dax_dev, pgoff, offset, size);
> +	rc = dax_zero_page_range(iomap->dax_dev, pgoff, offset, size);
>  	dax_read_unlock(id);
>  	return rc;
>  }
> -EXPORT_SYMBOL_GPL(__dax_zero_page_range);
> +EXPORT_SYMBOL_GPL(dax_iomap_zero);

This function is only used by fs/iomap/buffered-io.c, so no need to
export it.

>  #ifdef CONFIG_FS_DAX
> -int __dax_zero_page_range(struct block_device *bdev,
> -		struct dax_device *dax_dev, sector_t sector,
> -		unsigned int offset, unsigned int length);
> +int dax_iomap_zero(loff_t pos, unsigned offset, unsigned size,
> +			      struct iomap *iomap);
>  #else
> -static inline int __dax_zero_page_range(struct block_device *bdev,
> -		struct dax_device *dax_dev, sector_t sector,
> -		unsigned int offset, unsigned int length)
> +static inline int dax_iomap_zero(loff_t pos, unsigned offset, unsigned size,
> +				 struct iomap *iomap)
>  {
>  	return -ENXIO;
>  }

Given that the only caller is under an IS_DAX() check you could just
declare the function unconditionally and let the compiler optimize
away the guaranteed dead call for the !CONFIG_FS_DAX case, like we
do with various other functions.
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  parent reply index

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-03 20:00 [RFC PATCH 0/5][V2] dax,pmem: Provide a dax operation to zero range of memory Vivek Goyal
2020-02-03 20:00 ` [PATCH 1/5] dax, pmem: Add a dax operation zero_page_range Vivek Goyal
2020-02-05 18:30   ` Christoph Hellwig
2020-02-05 20:02     ` Vivek Goyal
2020-02-06  0:40       ` Dan Williams
2020-02-06  7:41         ` Christoph Hellwig
2020-02-07 16:57           ` Dan Williams
2020-02-07 17:01             ` Vivek Goyal
2020-02-07 17:06               ` Dan Williams
2020-02-06 14:34         ` Vivek Goyal
2020-02-07 16:58           ` Dan Williams
2020-02-03 20:00 ` [PATCH 2/5] s390,dax: Add dax zero_page_range operation to dcssblk driver Vivek Goyal
2020-02-05 18:32   ` Christoph Hellwig
2020-02-05 20:04     ` Vivek Goyal
2020-02-03 20:00 ` [PATCH 3/5] dm,dax: Add dax zero_page_range operation Vivek Goyal
2020-02-05 18:33   ` Christoph Hellwig
2020-02-07 16:34     ` Vivek Goyal
2020-02-03 20:00 ` [PATCH 4/5] dax,iomap: Start using dax native zero_page_range() Vivek Goyal
2020-02-05 18:33   ` Christoph Hellwig
2020-02-05 20:10     ` Vivek Goyal
2020-02-07 15:31     ` Vivek Goyal
2020-02-03 20:00 ` [PATCH 5/5] dax,iomap: Add helper dax_iomap_zero() to zero a range Vivek Goyal
2020-02-04  5:17   ` kbuild test robot
2020-02-05 18:36   ` Christoph Hellwig [this message]
2020-02-05 20:15     ` Vivek Goyal

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