Baolin Wang <baolin.wang@xxxxxxxxxx> writes: > @@ -212,6 +212,37 @@ static inline void sg_unmark_end(struct scatterlist *sg) > } > > /** > + * sg_is_contiguous - Check if the scatterlists are contiguous > + * @sga: SG entry > + * @sgb: SG entry > + * > + * Description: > + * If the sga scatterlist is contiguous with the sgb scatterlist, > + * that means they can be merged together. > + * > + **/ > +static inline bool sg_is_contiguous(struct scatterlist *sga, > + struct scatterlist *sgb) > +{ > + return ((sga->page_link & ~0x3UL) + sga->offset + sga->length == > + (sgb->page_link & ~0x3UL)); > +} I don't understand that one. sga->page_link is a pointer to a "struct page *". How can it be added to an offset within a page ??? > @@ -370,6 +370,65 @@ int sg_alloc_table(struct sg_table *table, unsigned int > nents, gfp_t gfp_mask) ... > /** > + * sg_add_sg_to_table - Add one scatterlist into sg table > + * @sgt: The sg table header to use > + * @src: The sg need to be added into sg table > + * > + * Description: > + * The 'nents' member indicates how many scatterlists added in the sg table. > + * Copy the @src@ scatterlist into sg table and increase 'nents' member. > + * > + **/ > +int sg_add_sg_to_table(struct sg_table *sgt, struct scatterlist *src) > +{ > + unsigned int i = 0, orig_nents = sgt->orig_nents; > + struct scatterlist *sgl = sgt->sgl; > + struct scatterlist *sg; > + > + /* Check if there are enough space for the new sg to be added */ > + if (sgt->nents >= sgt->orig_nents) > + return -EINVAL; I must admit I don't understand that one either : how do comparing the number of "mapped" entries against the number of "allocated" entries determines if there is enough room ? > +/** > + * sg_alloc_empty_table - Allocate one empty sg table > + * @sgt: The sg table header to use > + * @nents: Number of entries in sg list > + * @gfp_mask: GFP allocation mask > + * > + * Description: > + * Allocate and initialize an sg table. The 'nents' member of sg_table > + * indicates how many scatterlists added in the sg table. It should set > + * 0 which means there are no scatterlists added in this sg table now. > + * > + **/ > +int sg_alloc_empty_table(struct sg_table *sgt, unsigned int nents, > + gfp_t gfp_mask) As for this one, there has to be a purpose for it I fail to see. From far away it looks exactly like sg_alloc_table(), excepting it "works around" the nents > 0 protection of __sg_alloc_table(). What is exactly the need for this one, and if it's usefull why not simply changing the __sg_alloc_table() "nents > 0" test and see what the outcome of the review will be ? Cheers. -- Robert -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html