[RFC PATCH v3 06/15] io_uring: Provide driver API for zctap packet buffers.

Jonathan Lemon
2022-11-02T23:40:24Z

Introduce 'struct io_zctap_buf', representing a buffer used by
the network drivers, and the get/put functions which are used
by the network driver to obtain the buffers.

The code for these will be fleshed out in the next patch.

Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
---
include/linux/io_uring.h | 47 ++++++++++++++++++++++++++++++++++++++++
io_uring/zctap.c | 23 ++++++++++++++++++++
2 files changed, 70 insertions(+)

diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h
index 43bc8a2edccf..97c1a2e37077 100644
--- a/include/linux/io_uring.h
+++ b/include/linux/io_uring.h
@@ -32,6 +32,13 @@ struct io_uring_cmd {
u8 pdu[32]; /* available inline for free use */
};

+struct io_zctap_buf {
+ dma_addr_t dma;
+ struct page *page;
+ atomic_t refcount;
+ u8 _pad[4];
+};
+
#if defined(CONFIG_IO_URING)
int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
struct iov_iter *iter, void *ioucmd);
@@ -44,6 +51,21 @@ void __io_uring_free(struct task_struct *tsk);
void io_uring_unreg_ringfd(void);
const char *io_uring_get_opcode(u8 opcode);

+struct io_zctap_ifq;
+struct io_zctap_buf *io_zctap_get_buf(struct io_zctap_ifq *ifq, int refc);
+void io_zctap_put_buf(struct io_zctap_ifq *ifq, struct io_zctap_buf *buf);
+void io_zctap_put_buf_refs(struct io_zctap_ifq *ifq, struct io_zctap_buf *buf,
+ unsigned count);
+bool io_zctap_put_page(struct io_zctap_ifq *ifq, struct page *page);
+
+static inline dma_addr_t io_zctap_buf_dma(struct io_zctap_buf *buf)
+{
+ return buf->dma;
+}
+static inline struct page *io_zctap_buf_page(struct io_zctap_buf *buf)
+{
+ return buf->page;
+}
static inline void io_uring_files_cancel(void)
{
if (current->io_uring) {
@@ -92,6 +114,31 @@ static inline const char *io_uring_get_opcode(u8 opcode)
{
return "";
}
+static inline dma_addr_t io_zctap_buf_dma(struct io_zctap_buf *buf)
+{
+ return 0;
+}
+static inline struct page *io_zctap_buf_page(struct io_zctap_buf *buf)
+{
+ return NULL;
+}
+static inline struct io_zctap_buf *io_zctap_get_buf(struct io_zctap_ifq *ifq,
+ int refc)
+{
+ return NULL;
+}
+void io_zctap_put_buf(struct io_zctap_ifq *ifq, struct io_zctap_buf *buf)
+{
+}
+void io_zctap_put_buf_refs(struct io_zctap_ifq *ifq, struct io_zctap_buf *buf,
+ unsigned count)
+{
+}
+bool io_zctap_put_page(struct io_zctap_ifq *ifq, struct page *page)
+{
+ return false;
+}
+
#endif

#endif
diff --git a/io_uring/zctap.c b/io_uring/zctap.c
index f0d200f84ff5..c088655ade22 100644
--- a/io_uring/zctap.c
+++ b/io_uring/zctap.c
@@ -37,6 +37,29 @@ static u64 zctap_mk_page_info(u16 region_id, u16 pgid)
return (u64)0xface << 48 | (u64)region_id << 16 | (u64)pgid;
}

+struct io_zctap_buf *io_zctap_get_buf(struct io_zctap_ifq *ifq, int refc)
+{
+ return NULL;
+}
+EXPORT_SYMBOL(io_zctap_get_buf);
+
+void io_zctap_put_buf(struct io_zctap_ifq *ifq, struct io_zctap_buf *buf)
+{
+}
+EXPORT_SYMBOL(io_zctap_put_buf);
+
+void io_zctap_put_buf_refs(struct io_zctap_ifq *ifq, struct io_zctap_buf *buf,
+ unsigned count)
+{
+}
+EXPORT_SYMBOL(io_zctap_put_buf_refs);
+
+bool io_zctap_put_page(struct io_zctap_ifq *ifq, struct page *page)
+{
+ return false;
+}
+EXPORT_SYMBOL(io_zctap_put_page);
+
static void io_remove_ifq_region(struct ifq_region *ifr)
{
struct io_mapped_ubuf *imu;
--
2.30.2