Re: [PATCH] Another dm and bio problem with 2.6.0

[Jens Axboe]

On Mon, Dec 22 2003, Mark Haverkamp wrote:
> This fixes a problem similar to the patch I submitted on 11/20
> 
> http://marc.theaimsgroup.com/?l=linux-kernel&m=106936439707962&w=2
> 
> In this case, though, the result is an:
> 
> "Incorrect number of segments after building list" message.
> 
> The macro __BVEC_START assumes a bi_idx of zero when the dm code can
> submit a bio with a non-zero bi_idx.  
> The code has been tested on an 8 way / 8gb OSDL STP machine with a 197G
> lvm volume running dbt2 test.
> 
> ===== include/linux/bio.h 1.34 vs edited =====
> --- 1.34/include/linux/bio.h	Sun Sep 21 14:50:33 2003
> +++ edited/include/linux/bio.h	Wed Dec 17 07:17:53 2003
> @@ -162,7 +162,7 @@
>   */
>  
>  #define __BVEC_END(bio)		bio_iovec_idx((bio), (bio)->bi_vcnt - 1)
> -#define __BVEC_START(bio)	bio_iovec_idx((bio), 0)
> +#define __BVEC_START(bio)	bio_iovec_idx((bio), (bio)->bi_idx)
>  #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)	\
>  	((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
>  #define BIOVEC_VIRT_MERGEABLE(vec1, vec2)	\

Must have been some nasty debugging, good job. The patch is correct.

-- 
Jens Axboe

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