On 9/30/2020 2:58 PM, Jason Gunthorpe wrote:
On Wed, Sep 30, 2020 at 02:53:58PM +0300, Maor Gottlieb wrote:
On 9/30/2020 2:45 PM, Jason Gunthorpe wrote:
On Wed, Sep 30, 2020 at 12:53:21PM +0300, Leon Romanovsky wrote:
On Tue, Sep 29, 2020 at 04:59:29PM -0300, Jason Gunthorpe wrote:
On Sun, Sep 27, 2020 at 09:46:47AM +0300, Leon Romanovsky wrote:
@@ -296,11 +223,17 @@ static struct ib_umem *__ib_umem_get(struct ib_device *device,
goto umem_release;
cur_base += ret * PAGE_SIZE;
- npages -= ret;
-
- sg = ib_umem_add_sg_table(sg, page_list, ret,
- dma_get_max_seg_size(device->dma_device),
- &umem->sg_nents);
+ npages -= ret;
+ sg = __sg_alloc_table_from_pages(
+ &umem->sg_head, page_list, ret, 0, ret << PAGE_SHIFT,
+ dma_get_max_seg_size(device->dma_device), sg, npages,
+ GFP_KERNEL);
+ umem->sg_nents = umem->sg_head.nents;
+ if (IS_ERR(sg)) {
+ unpin_user_pages_dirty_lock(page_list, ret, 0);
+ ret = PTR_ERR(sg);
+ goto umem_release;
+ }
}
sg_mark_end(sg);
Does it still need the sg_mark_end?
It is preserved here for correctness, the release logic doesn't rely on
this marker, but it is better to leave it.
I mean, my read of __sg_alloc_table_from_pages() is that it already
placed it, the final __alloc_table() does it?
It marks the last allocated sge, but not the last populated sge (with page).
Why are those different?
It looks like the last iteration calls __alloc_table() with an exact
number of sges
+ if (!prv) {
+ /* Only the last allocation could be less than the maximum */
+ table_size = left_pages ? SG_MAX_SINGLE_ALLOC : chunks;
+ ret = sg_alloc_table(sgt, table_size, gfp_mask);
+ if (unlikely(ret))
+ return ERR_PTR(ret);
+ }
Jason
This is right only for the last iteration. E.g. in the first iteration
in case that there are more pages (left_pages), then we allocate
SG_MAX_SINGLE_ALLOC. We don't know how many pages from the second
iteration will be squashed to the SGE from the first iteration.
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