io_uring/zcrx: always dma map in advance

zcrx was originally establisihing dma mappings at a late stage when it
was being bound to a page pool. Dma-buf couldn't work this way, so it's
initialised during area creation.

It's messy having them do it at different spots, just move everything to
the area creation time.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://patch.msgid.link/334092a2cbdd4aabd7c025050aa99f05ace89bb5.1774261953.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c
index 2f60193365ce87875c246206cb7863c58893e12c..a6a08ee48b34f1d9c630725349b7932ba0b7f5e1 100644 (file)
--- a/io_uring/zcrx.c
+++ b/io_uring/zcrx.c
@@ -194,6 +194,7 @@ static int io_import_umem(struct io_zcrx_ifq *ifq,
 {
        struct page **pages;
        int nr_pages, ret;
+       bool mapped = false;
 
        if (area_reg->dmabuf_fd)
                return -EINVAL;
@@ -210,6 +211,12 @@ static int io_import_umem(struct io_zcrx_ifq *ifq,
        if (ret)
                goto out_err;
 
+       ret = dma_map_sgtable(ifq->dev, &mem->page_sg_table,
+                             DMA_FROM_DEVICE, IO_DMA_ATTR);
+       if (ret < 0)
+               goto out_err;
+       mapped = true;
+
        mem->account_pages = io_count_account_pages(pages, nr_pages);
        ret = io_account_mem(ifq->user, ifq->mm_account, mem->account_pages);
        if (ret < 0) {
@@ -223,6 +230,9 @@ static int io_import_umem(struct io_zcrx_ifq *ifq,
        mem->size = area_reg->len;
        return ret;
 out_err:
+       if (mapped)
+               dma_unmap_sgtable(ifq->dev, &mem->page_sg_table,
+                                 DMA_FROM_DEVICE, IO_DMA_ATTR);
        sg_free_table(&mem->page_sg_table);
        unpin_user_pages(pages, nr_pages);
        kvfree(pages);
@@ -288,30 +298,6 @@ static void io_zcrx_unmap_area(struct io_zcrx_ifq *ifq,
        }
 }
 
-static int io_zcrx_map_area(struct io_zcrx_ifq *ifq, struct io_zcrx_area *area)
-{
-       int ret;
-
-       guard(mutex)(&ifq->pp_lock);
-       if (area->is_mapped)
-               return 0;
-
-       if (!area->mem.is_dmabuf) {
-               ret = dma_map_sgtable(ifq->dev, &area->mem.page_sg_table,
-                                     DMA_FROM_DEVICE, IO_DMA_ATTR);
-               if (ret < 0)
-                       return ret;
-       }
-
-       ret = io_populate_area_dma(ifq, area);
-       if (ret && !area->mem.is_dmabuf)
-               dma_unmap_sgtable(ifq->dev, &area->mem.page_sg_table,
-                                 DMA_FROM_DEVICE, IO_DMA_ATTR);
-       if (ret == 0)
-               area->is_mapped = true;
-       return ret;
-}
-
 static void io_zcrx_sync_for_device(struct page_pool *pool,
                                    struct net_iov *niov)
 {
@@ -464,6 +450,7 @@ static int io_zcrx_create_area(struct io_zcrx_ifq *ifq,
        ret = io_import_area(ifq, &area->mem, area_reg);
        if (ret)
                goto err;
+       area->is_mapped = true;
 
        if (buf_size_shift > io_area_max_shift(&area->mem)) {
                ret = -ERANGE;
@@ -499,6 +486,10 @@ static int io_zcrx_create_area(struct io_zcrx_ifq *ifq,
                niov->type = NET_IOV_IOURING;
        }
 
+       ret = io_populate_area_dma(ifq, area);
+       if (ret)
+               goto err;
+
        area->free_count = nr_iovs;
        /* we're only supporting one area per ifq for now */
        area->area_id = 0;
@@ -1082,7 +1073,6 @@ static bool io_pp_zc_release_netmem(struct page_pool *pp, netmem_ref netmem)
 static int io_pp_zc_init(struct page_pool *pp)
 {
        struct io_zcrx_ifq *ifq = io_pp_to_ifq(pp);
-       int ret;
 
        if (WARN_ON_ONCE(!ifq))
                return -EINVAL;
@@ -1095,10 +1085,6 @@ static int io_pp_zc_init(struct page_pool *pp)
        if (pp->p.dma_dir != DMA_FROM_DEVICE)
                return -EOPNOTSUPP;
 
-       ret = io_zcrx_map_area(ifq, ifq->area);
-       if (ret)
-               return ret;
-
        refcount_inc(&ifq->refs);
        return 0;
 }