kernel/net/xdp/xsk_queue.c, branch linux-5.1.y

net: xsk: add a simple buffer reuse queue

2018-09-25T20:13:15Z

XSK UMEM is strongly single producer single consumer so reuse of frames is challenging. Add a simple "stash" of FILL packets to reuse for drivers to optionally make use of. This is useful when driver has to free (ndo_stop) or resize a ring with an active AF_XDP ZC socket. Signed-off-by: Jakub Kicinski Tested-by: Andrew Bowers Signed-off-by: Jeff Kirsher

xsk: i40e: get rid of useless struct xdp_umem_props

2018-08-31T23:38:16Z

This commit gets rid of the structure xdp_umem_props. It was there to be able to break a dependency at one point, but this is no longer needed. The values in the struct are instead stored directly in the xdp_umem structure. This simplifies the xsk code as well as af_xdp zero-copy drivers and as a bonus gets rid of one internal header file. The i40e driver is also adapted to the new interface in this commit. Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann

xsk: new descriptor addressing scheme

2018-06-04T15:21:02Z

Currently, AF_XDP only supports a fixed frame-size memory scheme where each frame is referenced via an index (idx). A user passes the frame index to the kernel, and the kernel acts upon the data. Some NICs, however, do not have a fixed frame-size model, instead they have a model where a memory window is passed to the hardware and multiple frames are filled into that window (referred to as the "type-writer" model). By changing the descriptor format from the current frame index addressing scheme, AF_XDP can in the future be extended to support these kinds of NICs. In the index-based model, an idx refers to a frame of size frame_size. Addressing a frame in the UMEM is done by offseting the UMEM starting address by a global offset, idx * frame_size + offset. Communicating via the fill- and completion-rings are done by means of idx. In this commit, the idx is removed in favor of an address (addr), which is a relative address ranging over the UMEM. To convert an idx-based address to the new addr is simply: addr = idx * frame_size + offset. We also stop referring to the UMEM "frame" as a frame. Instead it is simply called a chunk. To transfer ownership of a chunk to the kernel, the addr of the chunk is passed in the fill-ring. Note, that the kernel will mask addr to make it chunk aligned, so there is no need for userspace to do that. E.g., for a chunk size of 2k, passing an addr of 2048, 2050 or 3000 to the fill-ring will refer to the same chunk. On the completion-ring, the addr will match that of the Tx descriptor, passed to the kernel. Changing the descriptor format to use chunks/addr will allow for future changes to move to a type-writer based model, where multiple frames can reside in one chunk. In this model passing one single chunk into the fill-ring, would potentially result in multiple Rx descriptors. This commit changes the uapi of AF_XDP sockets, and updates the documentation. Signed-off-by: Björn Töpel Signed-off-by: Daniel Borkmann

xsk: fixed some cases of unnecessary parentheses

2018-05-18T14:07:03Z

Removed some cases of unnecessary parentheses. Signed-off-by: Björn Töpel Signed-off-by: Daniel Borkmann

xsk: clean up SPDX headers

2018-05-18T14:07:02Z

Clean up SPDX-License-Identifier and removing licensing leftovers. Signed-off-by: Björn Töpel Signed-off-by: Daniel Borkmann

xsk: add support for bind for Rx

2018-05-03T22:55:23Z

Here, the bind syscall is added. Binding an AF_XDP socket, means associating the socket to an umem, a netdev and a queue index. This can be done in two ways. The first way, creating a "socket from scratch". Create the umem using the XDP_UMEM_REG setsockopt and an associated fill queue with XDP_UMEM_FILL_QUEUE. Create the Rx queue using the XDP_RX_QUEUE setsockopt. Call bind passing ifindex and queue index ("channel" in ethtool speak). The second way to bind a socket, is simply skipping the umem/netdev/queue index, and passing another already setup AF_XDP socket. The new socket will then have the same umem/netdev/queue index as the parent so it will share the same umem. You must also set the flags field in the socket address to XDP_SHARED_UMEM. v2: Use PTR_ERR instead of passing error variable explicitly. Signed-off-by: Magnus Karlsson Signed-off-by: Alexei Starovoitov

xsk: add Rx queue setup and mmap support

2018-05-03T22:55:23Z

Another setsockopt (XDP_RX_QUEUE) is added to let the process allocate a queue, where the kernel can pass completed Rx frames from the kernel to user process. The mmapping of the queue is done using the XDP_PGOFF_RX_QUEUE offset. Signed-off-by: Björn Töpel Signed-off-by: Alexei Starovoitov

xsk: add umem fill queue support and mmap

2018-05-03T22:55:23Z

Here, we add another setsockopt for registered user memory (umem) called XDP_UMEM_FILL_QUEUE. Using this socket option, the process can ask the kernel to allocate a queue (ring buffer) and also mmap it (XDP_UMEM_PGOFF_FILL_QUEUE) into the process. The queue is used to explicitly pass ownership of umem frames from the user process to the kernel. These frames will in a later patch be filled in with Rx packet data by the kernel. v2: Fixed potential crash in xsk_mmap. Signed-off-by: Magnus Karlsson Signed-off-by: Alexei Starovoitov