Used the paged attachment mappings support to create NET_TX pages. NET_TX pages can be used in the networking transmit path:
1. Create an iov_iter & bio_vec entries to represent this dmabuf.
2. Initialize the bio_vec with the backing dmabuf pages.
Signed-off-by: Mina Almasry almasrymina@google.com --- drivers/dma-buf/dma-buf.c | 47 ++++++++++++++++++++++++++++++++++++ include/linux/dma-buf.h | 7 ++++++ include/uapi/linux/dma-buf.h | 1 + 3 files changed, 55 insertions(+)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index acb86bf406f4..3ca71297b9b4 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -1683,6 +1683,7 @@ static void dma_buf_pages_destroy(struct percpu_ref *ref) }
const struct dma_buf_pages_type_ops net_rx_ops; +const struct dma_buf_pages_type_ops net_tx_ops;
static long dma_buf_create_pages(struct file *file, struct dma_buf_create_pages_info *create_info) @@ -1799,6 +1800,9 @@ static long dma_buf_create_pages(struct file *file, case DMA_BUF_PAGES_NET_RX: priv->type_ops = &net_rx_ops; break; + case DMA_BUF_PAGES_NET_TX: + priv->type_ops = &net_tx_ops; + break; default: err = -EINVAL; goto out_put_new_file; @@ -2140,3 +2144,46 @@ struct page *dma_buf_pages_net_rx_alloc(struct dma_buf_pages *priv) percpu_ref_get(&priv->pgmap.ref); return pg; } + +/******************************** + * dma_buf_pages_net_tx * + ********************************/ + +static void dma_buf_pages_net_tx_release(struct dma_buf_pages *priv, + struct file *file) +{ + int i; + for (i = 0; i < priv->num_pages; i++) + put_page(&priv->pages[i]); +} + +static int dma_buf_pages_net_tx_init(struct dma_buf_pages *priv, + struct file *file) +{ + int i; + priv->net_tx.tx_bv = kvmalloc_array(priv->num_pages, + sizeof(struct bio_vec), GFP_KERNEL); + if (!priv->net_tx.tx_bv) + return -ENOMEM; + + for (i = 0; i < priv->num_pages; i++) { + priv->net_tx.tx_bv[i].bv_page = &priv->pages[i]; + priv->net_tx.tx_bv[i].bv_offset = 0; + priv->net_tx.tx_bv[i].bv_len = PAGE_SIZE; + } + percpu_ref_get_many(&priv->pgmap.ref, priv->num_pages); + iov_iter_bvec(&priv->net_tx.iter, WRITE, priv->net_tx.tx_bv, + priv->num_pages, priv->dmabuf->size); + return 0; +} + +static void dma_buf_pages_net_tx_free(struct dma_buf_pages *priv) +{ + kvfree(priv->net_tx.tx_bv); +} + +const struct dma_buf_pages_type_ops net_tx_ops = { + .dma_buf_pages_init = dma_buf_pages_net_tx_init, + .dma_buf_pages_release = dma_buf_pages_net_tx_release, + .dma_buf_pages_destroy = dma_buf_pages_net_tx_free, +}; diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index e8e66d6407d0..93228a2fec47 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -22,6 +22,7 @@ #include <linux/fs.h> #include <linux/dma-fence.h> #include <linux/wait.h> +#include <linux/uio.h> #include <linux/genalloc.h> #include <linux/xarray.h> #include <net/page_pool.h> @@ -555,6 +556,11 @@ struct dma_buf_pages_type_ops { struct page *page); };
+struct dma_buf_pages_net_tx { + struct iov_iter iter; + struct bio_vec *tx_bv; +}; + struct dma_buf_pages_net_rx { struct gen_pool *page_pool; struct xarray bound_rxq_list; @@ -579,6 +585,7 @@ struct dma_buf_pages {
union { struct dma_buf_pages_net_rx net_rx; + struct dma_buf_pages_net_tx net_tx; }; };
diff --git a/include/uapi/linux/dma-buf.h b/include/uapi/linux/dma-buf.h index b392cef9d3c6..546f211a7556 100644 --- a/include/uapi/linux/dma-buf.h +++ b/include/uapi/linux/dma-buf.h @@ -187,6 +187,7 @@ struct dma_buf_create_pages_info { };
#define DMA_BUF_PAGES_NET_RX (1 << 0) +#define DMA_BUF_PAGES_NET_TX (2 << 0)
#define DMA_BUF_CREATE_PAGES _IOW(DMA_BUF_BASE, 4, struct dma_buf_create_pages_info)