(cc'ing Jens)
On Wed, Sep 26, 2012 at 11:49:00AM +0200, Maxim Levitsky wrote:
> Useful helper to know the number of entries in scatterlist.
>
> Signed-off-by: Maxim Levitsky <maximlevit...@gmail.com>
> ---
> include/linux/scatterlist.h | 1 +
> lib/scatterlist.c | 22 ++++++++++++++++++++++
> 2 files changed, 23 insertions(+)
>
> diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
> index 7b600da..4bd6c06 100644
> --- a/include/linux/scatterlist.h
> +++ b/include/linux/scatterlist.h
> @@ -201,6 +201,7 @@ static inline void *sg_virt(struct scatterlist *sg)
> return page_address(sg_page(sg)) + sg->offset;
> }
>
> +int sg_nents(struct scatterlist *sg);
> struct scatterlist *sg_next(struct scatterlist *);
> struct scatterlist *sg_last(struct scatterlist *s, unsigned int);
> void sg_init_table(struct scatterlist *, unsigned int);
> diff --git a/lib/scatterlist.c b/lib/scatterlist.c
> index e76d85c..5cd9cdc 100644
> --- a/lib/scatterlist.c
> +++ b/lib/scatterlist.c
> @@ -39,6 +39,28 @@ struct scatterlist *sg_next(struct scatterlist *sg)
> EXPORT_SYMBOL(sg_next);
>
> /**
> + * sg_nents - return total count of entries in scatterlist
> + * @sg: The scatterlist
> + *
> + * Description:
> + * Allows to know how many entries are in sg, taking into acount
> + * chaining as well
> + *
> + **/
> +int sg_nents(struct scatterlist *sg)
> +{
> + int nents = 0;
> + while (sg) {
> + nents++;
> + sg = sg_next(sg);
> + }
> +
> + return nents;
> +}
> +EXPORT_SYMBOL(sg_nents);
How about the following instead?
for (nents = 0; sg; sg = sg_next(sg))
nents++;
return nents;
Other than that,
Acked-by: Tejun Heo <t...@kernel.org>
Thanks.
--
tejun
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