[dm-devel] Re: [PATCH] add local bio pool support and modify dm

[Jens Axboe]

On Wed, Feb 02 2005, Andrew Morton wrote:
> Dave Olien <dmo at osdl.org> wrote:
> >
> >  +extern inline void zero_fill_bio(struct bio *bio)
> >  +{
> >  +	unsigned long flags;
> >  +	struct bio_vec *bv;
> >  +	int i;
> >  +
> >  +	bio_for_each_segment(bv, bio, i) {
> >  +		char *data = bvec_kmap_irq(bv, &flags);
> >  +		memset(data, 0, bv->bv_len);
> >  +		flush_dcache_page(bv->bv_page);
> >  +		bvec_kunmap_irq(data, &flags);
> >  +	}
> >  +}
> 
> heavens.  Why was this made inline?  And extern inline?
> 
> It's too big for inlining (and is super-slow anyway) and will cause all
> sorts of unpleasant header file dependencies for all architectures.  bio.h
> now needs to see the implementation of everyone's flush_dcache_page(), for
> example.
> 
> 
> Something like this?
> 
> --- 25/include/linux/bio.h~add-local-bio-pool-support-and-modify-dm-uninline-zero_fill_bio	2005-02-02 18:17:18.225901376 -0800
> +++ 25-akpm/include/linux/bio.h	2005-02-02 18:17:18.230900616 -0800
> @@ -286,6 +286,7 @@ extern void bio_set_pages_dirty(struct b
>  extern void bio_check_pages_dirty(struct bio *bio);
>  extern struct bio *bio_copy_user(struct request_queue *, unsigned long, unsigned int, int);
>  extern int bio_uncopy_user(struct bio *);
> +void zero_fill_bio(struct bio *bio);
>  
>  #ifdef CONFIG_HIGHMEM
>  /*
> @@ -335,18 +336,4 @@ extern inline char *__bio_kmap_irq(struc
>  	__bio_kmap_irq((bio), (bio)->bi_idx, (flags))
>  #define bio_kunmap_irq(buf,flags)	__bio_kunmap_irq(buf, flags)
>  
> -extern inline void zero_fill_bio(struct bio *bio)
> -{
> -	unsigned long flags;
> -	struct bio_vec *bv;
> -	int i;
> -
> -	bio_for_each_segment(bv, bio, i) {
> -		char *data = bvec_kmap_irq(bv, &flags);
> -		memset(data, 0, bv->bv_len);
> -		flush_dcache_page(bv->bv_page);
> -		bvec_kunmap_irq(data, &flags);
> -	}
> -}
> -
>  #endif /* __LINUX_BIO_H */
> diff -puN fs/bio.c~add-local-bio-pool-support-and-modify-dm-uninline-zero_fill_bio fs/bio.c
> --- 25/fs/bio.c~add-local-bio-pool-support-and-modify-dm-uninline-zero_fill_bio	2005-02-02 18:17:18.227901072 -0800
> +++ 25-akpm/fs/bio.c	2005-02-02 18:17:18.231900464 -0800
> @@ -182,6 +182,21 @@ struct bio *bio_alloc(int gfp_mask, int 
>  	return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
>  }
>  
> +void zero_fill_bio(struct bio *bio)
> +{
> +	unsigned long flags;
> +	struct bio_vec *bv;
> +	int i;
> +
> +	bio_for_each_segment(bv, bio, i) {
> +		char *data = bvec_kmap_irq(bv, &flags);
> +		memset(data, 0, bv->bv_len);
> +		flush_dcache_page(bv->bv_page);
> +		bvec_kunmap_irq(data, &flags);
> +	}
> +}
> +EXPORT_SYMBOL(zero_fill_bio);
> +
>  /**
>   * bio_put - release a reference to a bio
>   * @bio:   bio to release reference to
> _

Yep looks good, thanks Andrew.

-- 
Jens Axboe