Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 688 insertions, 0 deletions

diff --git a/include/net/libeth/xsk.h b/include/net/libeth/xsk.h
new file mode 100644
index 000000000..a452b7828
--- /dev/null
+++ b/include/net/libeth/xsk.h
@@ -0,0 +1,688 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (C) 2025 Intel Corporation */
+
+#ifndef __LIBETH_XSK_H
+#define __LIBETH_XSK_H
+
+#include <net/libeth/xdp.h>
+#include <net/xdp_sock_drv.h>
+
+/* ``XDP_TXMD_FLAGS_VALID`` is defined only under ``CONFIG_XDP_SOCKETS`` */
+#ifdef XDP_TXMD_FLAGS_VALID
+static_assert(XDP_TXMD_FLAGS_VALID <= LIBETH_XDP_TX_XSKMD);
+#endif
+
+/* ``XDP_TX`` bulking */
+
+/**
+ * libeth_xsk_tx_queue_head - internal helper for queueing XSk ``XDP_TX`` head
+ * @bq: XDP Tx bulk to queue the head frag to
+ * @xdp: XSk buffer with the head to queue
+ *
+ * Return: false if it's the only frag of the frame, true if it's an S/G frame.
+ */
+static inline bool libeth_xsk_tx_queue_head(struct libeth_xdp_tx_bulk *bq,
+					    struct libeth_xdp_buff *xdp)
+{
+	bq->bulk[bq->count++] = (typeof(*bq->bulk)){
+		.xsk	= xdp,
+		__libeth_xdp_tx_len(xdp->base.data_end - xdp->data,
+				    LIBETH_XDP_TX_FIRST),
+	};
+
+	if (likely(!xdp_buff_has_frags(&xdp->base)))
+		return false;
+
+	bq->bulk[bq->count - 1].flags |= LIBETH_XDP_TX_MULTI;
+
+	return true;
+}
+
+/**
+ * libeth_xsk_tx_queue_frag - internal helper for queueing XSk ``XDP_TX`` frag
+ * @bq: XDP Tx bulk to queue the frag to
+ * @frag: XSk frag to queue
+ */
+static inline void libeth_xsk_tx_queue_frag(struct libeth_xdp_tx_bulk *bq,
+					    struct libeth_xdp_buff *frag)
+{
+	bq->bulk[bq->count++] = (typeof(*bq->bulk)){
+		.xsk	= frag,
+		__libeth_xdp_tx_len(frag->base.data_end - frag->data),
+	};
+}
+
+/**
+ * libeth_xsk_tx_queue_bulk - internal helper for queueing XSk ``XDP_TX`` frame
+ * @bq: XDP Tx bulk to queue the frame to
+ * @xdp: XSk buffer to queue
+ * @flush_bulk: driver callback to flush the bulk to the HW queue
+ *
+ * Return: true on success, false on flush error.
+ */
+static __always_inline bool
+libeth_xsk_tx_queue_bulk(struct libeth_xdp_tx_bulk *bq,
+			 struct libeth_xdp_buff *xdp,
+			 bool (*flush_bulk)(struct libeth_xdp_tx_bulk *bq,
+					    u32 flags))
+{
+	bool ret = true;
+
+	if (unlikely(bq->count == LIBETH_XDP_TX_BULK) &&
+	    unlikely(!flush_bulk(bq, LIBETH_XDP_TX_XSK))) {
+		libeth_xsk_buff_free_slow(xdp);
+		return false;
+	}
+
+	if (!libeth_xsk_tx_queue_head(bq, xdp))
+		goto out;
+
+	for (const struct libeth_xdp_buff *head = xdp; ; ) {
+		xdp = container_of(xsk_buff_get_frag(&head->base),
+				   typeof(*xdp), base);
+		if (!xdp)
+			break;
+
+		if (unlikely(bq->count == LIBETH_XDP_TX_BULK) &&
+		    unlikely(!flush_bulk(bq, LIBETH_XDP_TX_XSK))) {
+			ret = false;
+			break;
+		}
+
+		libeth_xsk_tx_queue_frag(bq, xdp);
+	}
+
+out:
+	bq->bulk[bq->count - 1].flags |= LIBETH_XDP_TX_LAST;
+
+	return ret;
+}
+
+/**
+ * libeth_xsk_tx_fill_buf - internal helper to fill XSk ``XDP_TX`` &libeth_sqe
+ * @frm: XDP Tx frame from the bulk
+ * @i: index on the HW queue
+ * @sq: XDPSQ abstraction for the queue
+ * @priv: private data
+ *
+ * Return: XDP Tx descriptor with the synced DMA and other info to pass to
+ * the driver callback.
+ */
+static inline struct libeth_xdp_tx_desc
+libeth_xsk_tx_fill_buf(struct libeth_xdp_tx_frame frm, u32 i,
+		       const struct libeth_xdpsq *sq, u64 priv)
+{
+	struct libeth_xdp_buff *xdp = frm.xsk;
+	struct libeth_xdp_tx_desc desc = {
+		.addr	= xsk_buff_xdp_get_dma(&xdp->base),
+		.opts	= frm.opts,
+	};
+	struct libeth_sqe *sqe;
+
+	xsk_buff_raw_dma_sync_for_device(sq->pool, desc.addr, desc.len);
+
+	sqe = &sq->sqes[i];
+	sqe->xsk = xdp;
+
+	if (!(desc.flags & LIBETH_XDP_TX_FIRST)) {
+		sqe->type = LIBETH_SQE_XSK_TX_FRAG;
+		return desc;
+	}
+
+	sqe->type = LIBETH_SQE_XSK_TX;
+	libeth_xdp_tx_fill_stats(sqe, &desc,
+				 xdp_get_shared_info_from_buff(&xdp->base));
+
+	return desc;
+}
+
+/**
+ * libeth_xsk_tx_flush_bulk - wrapper to define flush of XSk ``XDP_TX`` bulk
+ * @bq: bulk to flush
+ * @flags: Tx flags, see __libeth_xdp_tx_flush_bulk()
+ * @prep: driver callback to prepare the queue
+ * @xmit: driver callback to fill a HW descriptor
+ *
+ * Use via LIBETH_XSK_DEFINE_FLUSH_TX() to define an XSk ``XDP_TX`` driver
+ * callback.
+ */
+#define libeth_xsk_tx_flush_bulk(bq, flags, prep, xmit)			     \
+	__libeth_xdp_tx_flush_bulk(bq, (flags) | LIBETH_XDP_TX_XSK, prep,    \
+				   libeth_xsk_tx_fill_buf, xmit)
+
+/* XSk TMO */
+
+/**
+ * libeth_xsktmo_req_csum - XSk Tx metadata op to request checksum offload
+ * @csum_start: unused
+ * @csum_offset: unused
+ * @priv: &libeth_xdp_tx_desc from the filling helper
+ *
+ * Generic implementation of ::tmo_request_checksum. Works only when HW doesn't
+ * require filling checksum offsets and other parameters beside the checksum
+ * request bit.
+ * Consider using within @libeth_xsktmo unless the driver requires HW-specific
+ * callbacks.
+ */
+static inline void libeth_xsktmo_req_csum(u16 csum_start, u16 csum_offset,
+					  void *priv)
+{
+	((struct libeth_xdp_tx_desc *)priv)->flags |= LIBETH_XDP_TX_CSUM;
+}
+
+/* Only to inline the callbacks below, use @libeth_xsktmo in drivers instead */
+static const struct xsk_tx_metadata_ops __libeth_xsktmo = {
+	.tmo_request_checksum	= libeth_xsktmo_req_csum,
+};
+
+/**
+ * __libeth_xsk_xmit_fill_buf_md - internal helper to prepare XSk xmit w/meta
+ * @xdesc: &xdp_desc from the XSk buffer pool
+ * @sq: XDPSQ abstraction for the queue
+ * @priv: XSk Tx metadata ops
+ *
+ * Same as __libeth_xsk_xmit_fill_buf(), but requests metadata pointer and
+ * fills additional fields in &libeth_xdp_tx_desc to ask for metadata offload.
+ *
+ * Return: XDP Tx descriptor with the DMA, metadata request bits, and other
+ * info to pass to the driver callback.
+ */
+static __always_inline struct libeth_xdp_tx_desc
+__libeth_xsk_xmit_fill_buf_md(const struct xdp_desc *xdesc,
+			      const struct libeth_xdpsq *sq,
+			      u64 priv)
+{
+	const struct xsk_tx_metadata_ops *tmo = libeth_xdp_priv_to_ptr(priv);
+	struct libeth_xdp_tx_desc desc;
+	struct xdp_desc_ctx ctx;
+
+	ctx = xsk_buff_raw_get_ctx(sq->pool, xdesc->addr, xdesc->options);
+	desc = (typeof(desc)){
+		.addr	= ctx.dma,
+		__libeth_xdp_tx_len(xdesc->len),
+	};
+
+	BUILD_BUG_ON(!__builtin_constant_p(tmo == libeth_xsktmo));
+	tmo = tmo == libeth_xsktmo ? &__libeth_xsktmo : tmo;
+
+	xsk_tx_metadata_request(sq->pool, &ctx.meta, tmo, &desc);
+
+	return desc;
+}
+
+/* XSk xmit implementation */
+
+/**
+ * __libeth_xsk_xmit_fill_buf - internal helper to prepare XSk xmit w/o meta
+ * @xdesc: &xdp_desc from the XSk buffer pool
+ * @sq: XDPSQ abstraction for the queue
+ *
+ * Return: XDP Tx descriptor with the DMA and other info to pass to
+ * the driver callback.
+ */
+static inline struct libeth_xdp_tx_desc
+__libeth_xsk_xmit_fill_buf(const struct xdp_desc *xdesc,
+			   const struct libeth_xdpsq *sq)
+{
+	return (struct libeth_xdp_tx_desc){
+		.addr	= xsk_buff_raw_get_dma(sq->pool, xdesc->addr),
+		__libeth_xdp_tx_len(xdesc->len),
+	};
+}
+
+/**
+ * libeth_xsk_xmit_fill_buf - internal helper to prepare an XSk xmit
+ * @frm: &xdp_desc from the XSk buffer pool
+ * @i: index on the HW queue
+ * @sq: XDPSQ abstraction for the queue
+ * @priv: XSk Tx metadata ops
+ *
+ * Depending on the metadata ops presence (determined at compile time), calls
+ * the quickest helper to build a libeth XDP Tx descriptor.
+ *
+ * Return: XDP Tx descriptor with the synced DMA, metadata request bits,
+ * and other info to pass to the driver callback.
+ */
+static __always_inline struct libeth_xdp_tx_desc
+libeth_xsk_xmit_fill_buf(struct libeth_xdp_tx_frame frm, u32 i,
+			 const struct libeth_xdpsq *sq, u64 priv)
+{
+	struct libeth_xdp_tx_desc desc;
+
+	if (priv)
+		desc = __libeth_xsk_xmit_fill_buf_md(&frm.desc, sq, priv);
+	else
+		desc = __libeth_xsk_xmit_fill_buf(&frm.desc, sq);
+
+	desc.flags |= xsk_is_eop_desc(&frm.desc) ? LIBETH_XDP_TX_LAST : 0;
+
+	xsk_buff_raw_dma_sync_for_device(sq->pool, desc.addr, desc.len);
+
+	return desc;
+}
+
+/**
+ * libeth_xsk_xmit_do_bulk - send XSk xmit frames
+ * @pool: XSk buffer pool containing the frames to send
+ * @xdpsq: opaque pointer to driver's XDPSQ struct
+ * @budget: maximum number of frames can be sent
+ * @tmo: optional XSk Tx metadata ops
+ * @prep: driver callback to build a &libeth_xdpsq
+ * @xmit: driver callback to put frames to a HW queue
+ * @finalize: driver callback to start a transmission
+ *
+ * Implements generic XSk xmit. Always turns on XSk Tx wakeup as it's assumed
+ * lazy cleaning is used and interrupts are disabled for the queue.
+ * HW descriptor filling is unrolled by ``LIBETH_XDP_TX_BATCH`` to optimize
+ * writes.
+ * Note that unlike other XDP Tx ops, the queue must be locked and cleaned
+ * prior to calling this function to already know available @budget.
+ * @prepare must only build a &libeth_xdpsq and return ``U32_MAX``.
+ *
+ * Return: false if @budget was exhausted, true otherwise.
+ */
+static __always_inline bool
+libeth_xsk_xmit_do_bulk(struct xsk_buff_pool *pool, void *xdpsq, u32 budget,
+			const struct xsk_tx_metadata_ops *tmo,
+			u32 (*prep)(void *xdpsq, struct libeth_xdpsq *sq),
+			void (*xmit)(struct libeth_xdp_tx_desc desc, u32 i,
+				     const struct libeth_xdpsq *sq, u64 priv),
+			void (*finalize)(void *xdpsq, bool sent, bool flush))
+{
+	const struct libeth_xdp_tx_frame *bulk;
+	bool wake;
+	u32 n;
+
+	wake = xsk_uses_need_wakeup(pool);
+	if (wake)
+		xsk_clear_tx_need_wakeup(pool);
+
+	n = xsk_tx_peek_release_desc_batch(pool, budget);
+	bulk = container_of(&pool->tx_descs[0], typeof(*bulk), desc);
+
+	libeth_xdp_tx_xmit_bulk(bulk, xdpsq, n, true,
+				libeth_xdp_ptr_to_priv(tmo), prep,
+				libeth_xsk_xmit_fill_buf, xmit);
+	finalize(xdpsq, n, true);
+
+	if (wake)
+		xsk_set_tx_need_wakeup(pool);
+
+	return n < budget;
+}
+
+/* Rx polling path */
+
+/**
+ * libeth_xsk_tx_init_bulk - initialize XDP Tx bulk for an XSk Rx NAPI poll
+ * @bq: bulk to initialize
+ * @prog: RCU pointer to the XDP program (never %NULL)
+ * @dev: target &net_device
+ * @xdpsqs: array of driver XDPSQ structs
+ * @num: number of active XDPSQs, the above array length
+ *
+ * Should be called on an onstack XDP Tx bulk before the XSk NAPI polling loop.
+ * Initializes all the needed fields to run libeth_xdp functions.
+ * Never checks if @prog is %NULL or @num == 0 as XDP must always be enabled
+ * when hitting this path.
+ */
+#define libeth_xsk_tx_init_bulk(bq, prog, dev, xdpsqs, num)		     \
+	__libeth_xdp_tx_init_bulk(bq, prog, dev, xdpsqs, num, true,	     \
+				  __UNIQUE_ID(bq_), __UNIQUE_ID(nqs_))
+
+struct libeth_xdp_buff *libeth_xsk_buff_add_frag(struct libeth_xdp_buff *head,
+						 struct libeth_xdp_buff *xdp);
+
+/**
+ * libeth_xsk_process_buff - attach XSk Rx buffer to &libeth_xdp_buff
+ * @head: head XSk buffer to attach the XSk buffer to (or %NULL)
+ * @xdp: XSk buffer to process
+ * @len: received data length from the descriptor
+ *
+ * If @head == %NULL, treats the XSk buffer as head and initializes
+ * the required fields. Otherwise, attaches the buffer as a frag.
+ * Already performs DMA sync-for-CPU and frame start prefetch
+ * (for head buffers only).
+ *
+ * Return: head XSk buffer on success or if the descriptor must be skipped
+ * (empty), %NULL if there is no space for a new frag.
+ */
+static inline struct libeth_xdp_buff *
+libeth_xsk_process_buff(struct libeth_xdp_buff *head,
+			struct libeth_xdp_buff *xdp, u32 len)
+{
+	if (unlikely(!len)) {
+		libeth_xsk_buff_free_slow(xdp);
+		return head;
+	}
+
+	xsk_buff_set_size(&xdp->base, len);
+	xsk_buff_dma_sync_for_cpu(&xdp->base);
+
+	if (head)
+		return libeth_xsk_buff_add_frag(head, xdp);
+
+	prefetch(xdp->data);
+
+	return xdp;
+}
+
+void libeth_xsk_buff_stats_frags(struct libeth_rq_napi_stats *rs,
+				 const struct libeth_xdp_buff *xdp);
+
+u32 __libeth_xsk_run_prog_slow(struct libeth_xdp_buff *xdp,
+			       const struct libeth_xdp_tx_bulk *bq,
+			       enum xdp_action act, int ret);
+
+/**
+ * __libeth_xsk_run_prog - run XDP program on XSk buffer
+ * @xdp: XSk buffer to run the prog on
+ * @bq: buffer bulk for ``XDP_TX`` queueing
+ *
+ * Internal inline abstraction to run XDP program on XSk Rx path. Handles
+ * only the most common ``XDP_REDIRECT`` inline, the rest is processed
+ * externally.
+ * Reports an XDP prog exception on errors.
+ *
+ * Return: libeth_xdp prog verdict depending on the prog's verdict.
+ */
+static __always_inline u32
+__libeth_xsk_run_prog(struct libeth_xdp_buff *xdp,
+		      const struct libeth_xdp_tx_bulk *bq)
+{
+	enum xdp_action act;
+	int ret = 0;
+
+	act = bpf_prog_run_xdp(bq->prog, &xdp->base);
+	if (unlikely(act != XDP_REDIRECT))
+rest:
+		return __libeth_xsk_run_prog_slow(xdp, bq, act, ret);
+
+	ret = xdp_do_redirect(bq->dev, &xdp->base, bq->prog);
+	if (unlikely(ret))
+		goto rest;
+
+	return LIBETH_XDP_REDIRECT;
+}
+
+/**
+ * libeth_xsk_run_prog - run XDP program on XSk path and handle all verdicts
+ * @xdp: XSk buffer to process
+ * @bq: XDP Tx bulk to queue ``XDP_TX`` buffers
+ * @fl: driver ``XDP_TX`` bulk flush callback
+ *
+ * Run the attached XDP program and handle all possible verdicts.
+ * Prefer using it via LIBETH_XSK_DEFINE_RUN{,_PASS,_PROG}().
+ *
+ * Return: libeth_xdp prog verdict depending on the prog's verdict.
+ */
+#define libeth_xsk_run_prog(xdp, bq, fl)				     \
+	__libeth_xdp_run_flush(xdp, bq, __libeth_xsk_run_prog,		     \
+			       libeth_xsk_tx_queue_bulk, fl)
+
+/**
+ * __libeth_xsk_run_pass - helper to run XDP program and handle the result
+ * @xdp: XSk buffer to process
+ * @bq: XDP Tx bulk to queue ``XDP_TX`` frames
+ * @napi: NAPI to build an skb and pass it up the stack
+ * @rs: onstack libeth RQ stats
+ * @md: metadata that should be filled to the XSk buffer
+ * @prep: callback for filling the metadata
+ * @run: driver wrapper to run XDP program
+ * @populate: driver callback to populate an skb with the HW descriptor data
+ *
+ * Inline abstraction, XSk's counterpart of __libeth_xdp_run_pass(), see its
+ * doc for details.
+ *
+ * Return: false if the polling loop must be exited due to lack of free
+ * buffers, true otherwise.
+ */
+static __always_inline bool
+__libeth_xsk_run_pass(struct libeth_xdp_buff *xdp,
+		      struct libeth_xdp_tx_bulk *bq, struct napi_struct *napi,
+		      struct libeth_rq_napi_stats *rs, const void *md,
+		      void (*prep)(struct libeth_xdp_buff *xdp,
+				   const void *md),
+		      u32 (*run)(struct libeth_xdp_buff *xdp,
+				 struct libeth_xdp_tx_bulk *bq),
+		      bool (*populate)(struct sk_buff *skb,
+				       const struct libeth_xdp_buff *xdp,
+				       struct libeth_rq_napi_stats *rs))
+{
+	struct sk_buff *skb;
+	u32 act;
+
+	rs->bytes += xdp->base.data_end - xdp->data;
+	rs->packets++;
+
+	if (unlikely(xdp_buff_has_frags(&xdp->base)))
+		libeth_xsk_buff_stats_frags(rs, xdp);
+
+	if (prep && (!__builtin_constant_p(!!md) || md))
+		prep(xdp, md);
+
+	act = run(xdp, bq);
+	if (likely(act == LIBETH_XDP_REDIRECT))
+		return true;
+
+	if (act != LIBETH_XDP_PASS)
+		return act != LIBETH_XDP_ABORTED;
+
+	skb = xdp_build_skb_from_zc(&xdp->base);
+	if (unlikely(!skb)) {
+		libeth_xsk_buff_free_slow(xdp);
+		return true;
+	}
+
+	if (unlikely(!populate(skb, xdp, rs))) {
+		napi_consume_skb(skb, true);
+		return true;
+	}
+
+	napi_gro_receive(napi, skb);
+
+	return true;
+}
+
+/**
+ * libeth_xsk_run_pass - helper to run XDP program and handle the result
+ * @xdp: XSk buffer to process
+ * @bq: XDP Tx bulk to queue ``XDP_TX`` frames
+ * @napi: NAPI to build an skb and pass it up the stack
+ * @rs: onstack libeth RQ stats
+ * @desc: pointer to the HW descriptor for that frame
+ * @run: driver wrapper to run XDP program
+ * @populate: driver callback to populate an skb with the HW descriptor data
+ *
+ * Wrapper around the underscored version when "fill the descriptor metadata"
+ * means just writing the pointer to the HW descriptor as @xdp->desc.
+ */
+#define libeth_xsk_run_pass(xdp, bq, napi, rs, desc, run, populate)	     \
+	__libeth_xsk_run_pass(xdp, bq, napi, rs, desc, libeth_xdp_prep_desc, \
+			      run, populate)
+
+/**
+ * libeth_xsk_finalize_rx - finalize XDPSQ after an XSk NAPI polling loop
+ * @bq: ``XDP_TX`` frame bulk
+ * @flush: driver callback to flush the bulk
+ * @finalize: driver callback to start sending the frames and run the timer
+ *
+ * Flush the bulk if there are frames left to send, kick the queue and flush
+ * the XDP maps.
+ */
+#define libeth_xsk_finalize_rx(bq, flush, finalize)			     \
+	__libeth_xdp_finalize_rx(bq, LIBETH_XDP_TX_XSK, flush, finalize)
+
+/*
+ * Helpers to reduce boilerplate code in drivers.
+ *
+ * Typical driver XSk Rx flow would be (excl. bulk and buff init, frag attach):
+ *
+ * LIBETH_XDP_DEFINE_START();
+ * LIBETH_XSK_DEFINE_FLUSH_TX(static driver_xsk_flush_tx, driver_xsk_tx_prep,
+ *			      driver_xdp_xmit);
+ * LIBETH_XSK_DEFINE_RUN(static driver_xsk_run, driver_xsk_run_prog,
+ *			 driver_xsk_flush_tx, driver_populate_skb);
+ * LIBETH_XSK_DEFINE_FINALIZE(static driver_xsk_finalize_rx,
+ *			      driver_xsk_flush_tx, driver_xdp_finalize_sq);
+ * LIBETH_XDP_DEFINE_END();
+ *
+ * This will build a set of 4 static functions. The compiler is free to decide
+ * whether to inline them.
+ * Then, in the NAPI polling function:
+ *
+ *	while (packets < budget) {
+ *		// ...
+ *		if (!driver_xsk_run(xdp, &bq, napi, &rs, desc))
+ *			break;
+ *	}
+ *	driver_xsk_finalize_rx(&bq);
+ */
+
+/**
+ * LIBETH_XSK_DEFINE_FLUSH_TX - define a driver XSk ``XDP_TX`` flush function
+ * @name: name of the function to define
+ * @prep: driver callback to clean an XDPSQ
+ * @xmit: driver callback to write a HW Tx descriptor
+ */
+#define LIBETH_XSK_DEFINE_FLUSH_TX(name, prep, xmit)			     \
+	__LIBETH_XDP_DEFINE_FLUSH_TX(name, prep, xmit, xsk)
+
+/**
+ * LIBETH_XSK_DEFINE_RUN_PROG - define a driver XDP program run function
+ * @name: name of the function to define
+ * @flush: driver callback to flush an XSk ``XDP_TX`` bulk
+ */
+#define LIBETH_XSK_DEFINE_RUN_PROG(name, flush)				     \
+	u32 __LIBETH_XDP_DEFINE_RUN_PROG(name, flush, xsk)
+
+/**
+ * LIBETH_XSK_DEFINE_RUN_PASS - define a driver buffer process + pass function
+ * @name: name of the function to define
+ * @run: driver callback to run XDP program (above)
+ * @populate: driver callback to fill an skb with HW descriptor info
+ */
+#define LIBETH_XSK_DEFINE_RUN_PASS(name, run, populate)			     \
+	bool __LIBETH_XDP_DEFINE_RUN_PASS(name, run, populate, xsk)
+
+/**
+ * LIBETH_XSK_DEFINE_RUN - define a driver buffer process, run + pass function
+ * @name: name of the function to define
+ * @run: name of the XDP prog run function to define
+ * @flush: driver callback to flush an XSk ``XDP_TX`` bulk
+ * @populate: driver callback to fill an skb with HW descriptor info
+ */
+#define LIBETH_XSK_DEFINE_RUN(name, run, flush, populate)		     \
+	__LIBETH_XDP_DEFINE_RUN(name, run, flush, populate, XSK)
+
+/**
+ * LIBETH_XSK_DEFINE_FINALIZE - define a driver XSk NAPI poll finalize function
+ * @name: name of the function to define
+ * @flush: driver callback to flush an XSk ``XDP_TX`` bulk
+ * @finalize: driver callback to finalize an XDPSQ and run the timer
+ */
+#define LIBETH_XSK_DEFINE_FINALIZE(name, flush, finalize)		     \
+	__LIBETH_XDP_DEFINE_FINALIZE(name, flush, finalize, xsk)
+
+/* Refilling */
+
+/**
+ * struct libeth_xskfq - structure representing an XSk buffer (fill) queue
+ * @fp: hotpath part of the structure
+ * @pool: &xsk_buff_pool for buffer management
+ * @fqes: array of XSk buffer pointers
+ * @descs: opaque pointer to the HW descriptor array
+ * @ntu: index of the next buffer to poll
+ * @count: number of descriptors/buffers the queue has
+ * @pending: current number of XSkFQEs to refill
+ * @thresh: threshold below which the queue is refilled
+ * @buf_len: HW-writeable length per each buffer
+ * @truesize: step between consecutive buffers, 0 if none exists
+ * @nid: ID of the closest NUMA node with memory
+ */
+struct libeth_xskfq {
+	struct_group_tagged(libeth_xskfq_fp, fp,
+		struct xsk_buff_pool	*pool;
+		struct libeth_xdp_buff	**fqes;
+		void			*descs;
+
+		u32			ntu;
+		u32			count;
+	);
+
+	/* Cold fields */
+	u32			pending;
+	u32			thresh;
+
+	u32			buf_len;
+	u32			truesize;
+
+	int			nid;
+};
+
+int libeth_xskfq_create(struct libeth_xskfq *fq);
+void libeth_xskfq_destroy(struct libeth_xskfq *fq);
+
+/**
+ * libeth_xsk_buff_xdp_get_dma - get DMA address of XSk &libeth_xdp_buff
+ * @xdp: buffer to get the DMA addr for
+ */
+#define libeth_xsk_buff_xdp_get_dma(xdp)				     \
+	xsk_buff_xdp_get_dma(&(xdp)->base)
+
+/**
+ * libeth_xskfqe_alloc - allocate @n XSk Rx buffers
+ * @fq: hotpath part of the XSkFQ, usually onstack
+ * @n: number of buffers to allocate
+ * @fill: driver callback to write DMA addresses to HW descriptors
+ *
+ * Note that @fq->ntu gets updated, but ::pending must be recalculated
+ * by the caller.
+ *
+ * Return: number of buffers refilled.
+ */
+static __always_inline u32
+libeth_xskfqe_alloc(struct libeth_xskfq_fp *fq, u32 n,
+		    void (*fill)(const struct libeth_xskfq_fp *fq, u32 i))
+{
+	u32 this, ret, done = 0;
+	struct xdp_buff **xskb;
+
+	this = fq->count - fq->ntu;
+	if (likely(this > n))
+		this = n;
+
+again:
+	xskb = (typeof(xskb))&fq->fqes[fq->ntu];
+	ret = xsk_buff_alloc_batch(fq->pool, xskb, this);
+
+	for (u32 i = 0, ntu = fq->ntu; likely(i < ret); i++)
+		fill(fq, ntu + i);
+
+	done += ret;
+	fq->ntu += ret;
+
+	if (likely(fq->ntu < fq->count) || unlikely(ret < this))
+		goto out;
+
+	fq->ntu = 0;
+
+	if (this < n) {
+		this = n - this;
+		goto again;
+	}
+
+out:
+	return done;
+}
+
+/* .ndo_xsk_wakeup */
+
+void libeth_xsk_init_wakeup(call_single_data_t *csd, struct napi_struct *napi);
+void libeth_xsk_wakeup(call_single_data_t *csd, u32 qid);
+
+/* Pool setup */
+
+int libeth_xsk_setup_pool(struct net_device *dev, u32 qid, bool enable);
+
+#endif /* __LIBETH_XSK_H */