The goal is to register a memory region with the device, and later specify the desired packet buffer size. The code currently assumes a page size. Create the desired number of zctap buffers and DMA map them to the target device, recording the dma address for later use. Hold a page reference while the page is dma mapped. Change the freelist from an array of page pointers to an index into the device buffer list. Signed-off-by: Jonathan Lemon <jonathan.lemon@xxxxxxxxx> --- io_uring/zctap.c | 78 ++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 63 insertions(+), 15 deletions(-) diff --git a/io_uring/zctap.c b/io_uring/zctap.c index c088655ade22..9f892e9ed8f2 100644 --- a/io_uring/zctap.c +++ b/io_uring/zctap.c @@ -18,11 +18,14 @@ #define NR_ZCTAP_IFQS 1 struct ifq_region { + struct io_zctap_ifq *ifq; /* only for delayed_work */ struct io_mapped_ubuf *imu; int free_count; int nr_pages; u16 id; - struct page *freelist[]; + + struct io_zctap_buf *buf; + u16 freelist[]; }; typedef int (*bpf_op_t)(struct net_device *dev, struct netdev_bpf *bpf); @@ -60,49 +63,85 @@ bool io_zctap_put_page(struct io_zctap_ifq *ifq, struct page *page) } EXPORT_SYMBOL(io_zctap_put_page); +static inline struct device * +netdev2device(struct net_device *dev) +{ + return dev->dev.parent; /* from SET_NETDEV_DEV() */ +} + static void io_remove_ifq_region(struct ifq_region *ifr) { - struct io_mapped_ubuf *imu; - struct page *page; + struct device *device = netdev2device(ifr->ifq->dev); + struct io_zctap_buf *buf; int i; - imu = ifr->imu; for (i = 0; i < ifr->nr_pages; i++) { - page = imu->bvec[i].bv_page; - - ClearPagePrivate(page); - set_page_private(page, 0); + buf = &ifr->buf[i]; + set_page_private(buf->page, 0); + ClearPagePrivate(buf->page); + dma_unmap_page_attrs(device, buf->dma, PAGE_SIZE, + DMA_BIDIRECTIONAL, + DMA_ATTR_SKIP_CPU_SYNC); + put_page(buf->page); } + kvfree(ifr->buf); kvfree(ifr); } -static int io_zctap_map_region(struct ifq_region *ifr) +static int io_zctap_map_region(struct ifq_region *ifr, struct device *device) { struct io_mapped_ubuf *imu; + struct io_zctap_buf *buf; struct page *page; + dma_addr_t addr; + int i, err; u64 info; - int i; imu = ifr->imu; for (i = 0; i < ifr->nr_pages; i++) { page = imu->bvec[i].bv_page; - if (PagePrivate(page)) + + if (PagePrivate(page)) { + err = -EEXIST; goto out; + } + SetPagePrivate(page); info = zctap_mk_page_info(ifr->id, i); zctap_set_page_info(page, info); - ifr->freelist[i] = page; + + buf = &ifr->buf[i]; + addr = dma_map_page_attrs(device, page, 0, PAGE_SIZE, + DMA_BIDIRECTIONAL, + DMA_ATTR_SKIP_CPU_SYNC); + if (dma_mapping_error(device, addr)) { + set_page_private(page, 0); + ClearPagePrivate(page); + err = -ENOMEM; + goto out; + } + buf->dma = addr; + buf->page = page; + atomic_set(&buf->refcount, 0); + get_page(page); + + ifr->freelist[i] = i; } return 0; out: while (i--) { page = imu->bvec[i].bv_page; - ClearPagePrivate(page); set_page_private(page, 0); + ClearPagePrivate(page); + buf = &ifr->buf[i]; + dma_unmap_page_attrs(device, buf->dma, PAGE_SIZE, + DMA_BIDIRECTIONAL, + DMA_ATTR_SKIP_CPU_SYNC); + put_page(page); } - return -EEXIST; + return err; } int io_provide_ifq_region(struct io_zctap_ifq *ifq, u16 id) @@ -131,13 +170,22 @@ int io_provide_ifq_region(struct io_zctap_ifq *ifq, u16 id) if (!ifr) return -ENOMEM; + ifr->buf = kvmalloc_array(nr_pages, sizeof(*ifr->buf), GFP_KERNEL); + if (!ifr->buf) { + kvfree(ifr); + return -ENOMEM; + } + ifr->nr_pages = nr_pages; ifr->imu = imu; ifr->free_count = nr_pages; ifr->id = id; - err = io_zctap_map_region(ifr); + ifr->ifq = ifq; /* XXX */ + + err = io_zctap_map_region(ifr, netdev2device(ifq->dev)); if (err) { + kvfree(ifr->buf); kvfree(ifr); return err; } -- 2.30.2