Am 13.01.2015 um 17:25 schrieb Christoph Hellwig:
>> + struct ubi_sgl usgl;
>
> Btw, what's in struct ubi_sgl? Can't find that in my tree.
"[PATCH 1/2] UBI: Add initial support for scatter gather" adds it.
/**
* struct ubi_sgl - UBI scatter gather list data structure.
* @list_pos: current position in @sg[]
* @page_pos: current position in @sg[@list_pos]
* @sg: the scatter gather list itself
*
* ubi_sgl is a wrapper around a scatter list which keeps track of the
* current position in the list and the current list item such that
* it can be used across multiple ubi_leb_read_sg() calls.
*/
struct ubi_sgl {
int list_pos;
int page_pos;
struct scatterlist sg[UBI_MAX_SG_COUNT];
};
>> +static void ubiblock_do_work(struct work_struct *work)
>> +{
>> + int ret;
>> + struct ubiblock_pdu *pdu = container_of(work, struct ubiblock_pdu,
>> work);
>> + struct request *req = blk_mq_rq_from_pdu(pdu);
>> +
>> + blk_mq_start_request(req);
>> + blk_rq_map_sg(req->q, req, pdu->usgl.sg);
>
> blk_rq_map_sg returns the number of entries actually mapped, which
> might be smaller than the number passed in due to merging.
Yep, but the ubi_sql has a fixed number of scatterlist entries,
UBI_MAX_SG_COUNT.
And I limit it also to that using: blk_queue_max_segments(dev->rq,
UBI_MAX_SG_COUNT);
Is there another reason why I should use the return value of blk_rq_map_sg()?
Please also note that the UBI block driver is read-only.
Thanks,
//richard
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
