On Wed, Aug 25, 2021 at 07:59:27AM +0300, Maor Gottlieb wrote:
On 8/24/2021 10:12 PM, Jason Gunthorpe wrote:
On Tue, Aug 24, 2021 at 05:25:30PM +0300, Maor Gottlieb wrote:
@@ -514,11 +531,13 @@ struct scatterlist *sg_alloc_append_table_from_pages(struct sg_table *sgt, offset = 0; cur_page = j; }
- sgt->nents += added_nents;
- sgt_append->sgt.nents += added_nents;
- sgt_append->sgt.orig_nents = sgt_append->sgt.nents;
- sgt_append->prv = s;
Why is nents being touched here?
Shouldn't it just be
sgt_append->sgt.orig_nents += added_nents; sgt_append->prv = s;?
In general yes, but all the sg_alloc_* functions update both orig_nents and nents (to same value). May be drivers that pass nents instead of orig_nents to dma_map_sg* (like umem did before this patch set). So I prefer to set it here as well, also not to break sg_alloc_table_from_pages_segment which use the same path. This kind of change could be done very carefully next cycle for all sg_alloc_*.
Ok, interesting
Jason