Re: [RFD] blk_rq_map_pages new API

[Boaz Harrosh <bharrosh@panasas.com>]

Boaz Harrosh wrote:
> /**
>  * blk_rq_map_pages - Receives an array of pages and appends them to a request structure 
>  *
>  * @rq:  The request to map
>  * @pages_info: A structure that specifies the array of pages, offset and more that need to be
>  *              map to the request. the @pages_info->null_mapped is assumed to be 1 and is ignored.
>  * @length: Total bytes to map. Array of pages can be larger, stop mapping after @length bytes mapped.
>  * @max_pages: When allocating the internal bio use @max_pages as an hint that says the amount of anticipated
>  *             pages that will be mapped. This member is optional and can be zero.
>  * 
>  * blk_rq_map_pages can be called multiple times so the user does not need to allocate a contiguous array
>  * of struct page pointers but can call this routine multiple times. In that case max_pages can be set
>  * so no bio re-allocation occurs.
>  * There is no unmap function for this mapping, the request is completed in the regular way.
>  */
> 
> int blk_rq_map_pages(struct request rq, struct *rq_map_data pages_info, unsigned length, unsigned max_pages);
> 
> 
> Implementation comments:
> - Then when this member is available many places that call blk_rq_map_user() rq_map_data and null_mapped set,
>   and buff == NULL, can be converted to this member.
> 
> - Internal block implementation is refactored to not duplicate any code with blk_rq_map_user().
> 
> Thanks for any comments
> Boaz
> 
> --

FUJITA Tomonori wrote:
> Please send a patch to implement the proposal.
> 

Is the above API accepted by you? Is it accepted by Jens?
Should I also attempt first comment above.

If its OK I will implement it ASAP.

Thanks
Boaz