Re: [PATCH for-next v7 0/6] RDMA/rxe: Replace mr page map with an xarray

[Jason Gunthorpe <jgg@nvidia.com>]

On Thu, Jan 19, 2023 at 05:59:31PM -0600, Bob Pearson wrote:
> This patch series replaces the page map carried in each memory region
> with a struct xarray. It is based on a sketch developed by Jason
> Gunthorpe. The first five patches are preparation that tries to
> cleanly isolate all the mr specific code into rxe_mr.c. The sixth
> patch is the actual change.
> 
> v7:
>   Link: https://lore.kernel.org/linux-rdma/Y8f53jdDAN0B9qy7@nvidia.com/
>   Made changes requested by Jason to return RESPST_ERR_XXX from rxe_mr.c
>   to rxe_resp.c.

I took it to for-next, but I made these changes, please check:

diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index fe4049330c9f19..c80458634962c6 100644
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -114,7 +114,8 @@ static int rxe_mr_fill_pages_from_sgt(struct rxe_mr *mr, struct sg_table *sgt)
 
 			if (persistent && !is_pmem_page(page)) {
 				rxe_dbg_mr(mr, "Page can't be persistent\n");
-				return -EINVAL;
+				xas_set_err(&xas, -EINVAL);
+				break;
 			}
 
 			xas_store(&xas, page);
@@ -213,7 +214,6 @@ static int rxe_set_page(struct ib_mr *ibmr, u64 iova)
 {
 	struct rxe_mr *mr = to_rmr(ibmr);
 	struct page *page = virt_to_page(iova & mr->page_mask);
-	XA_STATE(xas, &mr->page_list, mr->nbuf);
 	bool persistent = !!(mr->access & IB_ACCESS_FLUSH_PERSISTENT);
 	int err;
 
@@ -225,13 +225,7 @@ static int rxe_set_page(struct ib_mr *ibmr, u64 iova)
 	if (unlikely(mr->nbuf == mr->num_buf))
 		return -ENOMEM;
 
-	do {
-		xas_lock(&xas);
-		xas_store(&xas, page);
-		xas_unlock(&xas);
-	} while (xas_nomem(&xas, GFP_KERNEL));
-
-	err = xas_error(&xas);
+	err = xa_err(xa_store(&mr->page_list, mr->nbuf, page, GFP_KERNEL));
 	if (err)
 		return err;
 
@@ -458,10 +452,8 @@ int rxe_flush_pmem_iova(struct rxe_mr *mr, u64 iova, unsigned int length)
 				mr_page_size(mr) - page_offset);
 
 		va = kmap_local_page(page);
-		if (!va)
-			return -EFAULT;
-
 		arch_wb_cache_pmem(va + page_offset, bytes);
+		kunmap_local(va);
 
 		length -= bytes;
 		iova += bytes;