Initially, xdp_frame::mem.id was used to search for the corresponding
&page_pool to return the page correctly.
However, after that struct page now contains a direct pointer to its PP,
further keeping of this field makes no sense. xdp_return_frame_bulk()
still uses it to do a lookup, but this is rather a leftover.
Remove xdp_frame::mem and replace it with ::mem_type, as only memory
type still matters and we need to know it to be able to free the frame
correctly.
As a cute side effect, we can now make every scalar field in &xdp_frame
of 4 byte width, speeding up accesses to them.

Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
 include/net/xdp.h                             | 14 +++++-----
 .../net/ethernet/freescale/dpaa/dpaa_eth.c    |  2 +-
 drivers/net/veth.c                            |  4 +--
 kernel/bpf/cpumap.c                           |  2 +-
 net/bpf/test_run.c                            |  2 +-
 net/core/filter.c                             | 12 ++++----
 net/core/xdp.c                                | 28 +++++++++----------
 7 files changed, 32 insertions(+), 32 deletions(-)

diff --git a/include/net/xdp.h b/include/net/xdp.h
index 49f596513435..c4b408d22669 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -169,13 +169,13 @@ xdp_get_buff_len(const struct xdp_buff *xdp)
 
 struct xdp_frame {
 	void *data;
-	u16 len;
-	u16 headroom;
+	u32 len;
+	u32 headroom;
 	u32 metasize; /* uses lower 8-bits */
 	/* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time,
-	 * while mem info is valid on remote CPU.
+	 * while mem_type is valid on remote CPU.
 	 */
-	struct xdp_mem_info mem;
+	enum xdp_mem_type mem_type:32;
 	struct net_device *dev_rx; /* used by cpumap */
 	u32 frame_sz;
 	u32 flags; /* supported values defined in xdp_buff_flags */
@@ -306,13 +306,13 @@ struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp)
 	if (unlikely(xdp_update_frame_from_buff(xdp, xdp_frame) < 0))
 		return NULL;
 
-	/* rxq only valid until napi_schedule ends, convert to xdp_mem_info */
-	xdp_frame->mem = xdp->rxq->mem;
+	/* rxq only valid until napi_schedule ends, convert to xdp_mem_type */
+	xdp_frame->mem_type = xdp->rxq->mem.type;
 
 	return xdp_frame;
 }
 
-void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct,
+void __xdp_return(void *data, enum xdp_mem_type mem_type, bool napi_direct,
 		  struct xdp_buff *xdp);
 void xdp_return_frame(struct xdp_frame *xdpf);
 void xdp_return_frame_rx_napi(struct xdp_frame *xdpf);
diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
index ac06b01fe934..da17ff573c81 100644
--- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
+++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
@@ -2275,7 +2275,7 @@ static int dpaa_a050385_wa_xdpf(struct dpaa_priv *priv,
 	new_xdpf->len = xdpf->len;
 	new_xdpf->headroom = priv->tx_headroom;
 	new_xdpf->frame_sz = DPAA_BP_RAW_SIZE;
-	new_xdpf->mem.type = MEM_TYPE_PAGE_ORDER0;
+	new_xdpf->mem_type = MEM_TYPE_PAGE_ORDER0;
 
 	/* Release the initial buffer */
 	xdp_return_frame_rx_napi(xdpf);
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 18148e068aa0..fd36d0529e51 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -634,7 +634,7 @@ static struct xdp_frame *veth_xdp_rcv_one(struct veth_rq *rq,
 			break;
 		case XDP_TX:
 			orig_frame = *frame;
-			xdp->rxq->mem = frame->mem;
+			xdp->rxq->mem.type = frame->mem_type;
 			if (unlikely(veth_xdp_tx(rq, xdp, bq) < 0)) {
 				trace_xdp_exception(rq->dev, xdp_prog, act);
 				frame = &orig_frame;
@@ -646,7 +646,7 @@ static struct xdp_frame *veth_xdp_rcv_one(struct veth_rq *rq,
 			goto xdp_xmit;
 		case XDP_REDIRECT:
 			orig_frame = *frame;
-			xdp->rxq->mem = frame->mem;
+			xdp->rxq->mem.type = frame->mem_type;
 			if (xdp_do_redirect(rq->dev, xdp, xdp_prog)) {
 				frame = &orig_frame;
 				stats->rx_drops++;
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
index a2f46785ac3b..774accbd4a22 100644
--- a/kernel/bpf/cpumap.c
+++ b/kernel/bpf/cpumap.c
@@ -190,7 +190,7 @@ static int cpu_map_bpf_prog_run_xdp(struct bpf_cpu_map_entry *rcpu,
 		int err;
 
 		rxq.dev = xdpf->dev_rx;
-		rxq.mem = xdpf->mem;
+		rxq.mem.type = xdpf->mem_type;
 		/* TODO: report queue_index to xdp_rxq_info */
 
 		xdp_convert_frame_to_buff(xdpf, &xdp);
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 6d7a442ceb89..eac959b04fa9 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -153,7 +153,7 @@ static void xdp_test_run_init_page(netmem_ref netmem, void *arg)
 	new_ctx->data = new_ctx->data_meta + meta_len;
 
 	xdp_update_frame_from_buff(new_ctx, frm);
-	frm->mem = new_ctx->rxq->mem;
+	frm->mem_type = new_ctx->rxq->mem.type;
 
 	memcpy(&head->orig_ctx, new_ctx, sizeof(head->orig_ctx));
 }
diff --git a/net/core/filter.c b/net/core/filter.c
index 7faee6c8f7d9..9b992dfd2e34 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4122,13 +4122,13 @@ static int bpf_xdp_frags_increase_tail(struct xdp_buff *xdp, int offset)
 }
 
 static void bpf_xdp_shrink_data_zc(struct xdp_buff *xdp, int shrink,
-				   struct xdp_mem_info *mem_info, bool release)
+				   enum xdp_mem_type mem_type, bool release)
 {
 	struct xdp_buff *zc_frag = xsk_buff_get_tail(xdp);
 
 	if (release) {
 		xsk_buff_del_tail(zc_frag);
-		__xdp_return(NULL, mem_info, false, zc_frag);
+		__xdp_return(NULL, mem_type, false, zc_frag);
 	} else {
 		zc_frag->data_end -= shrink;
 	}
@@ -4137,18 +4137,18 @@ static void bpf_xdp_shrink_data_zc(struct xdp_buff *xdp, int shrink,
 static bool bpf_xdp_shrink_data(struct xdp_buff *xdp, skb_frag_t *frag,
 				int shrink)
 {
-	struct xdp_mem_info *mem_info = &xdp->rxq->mem;
+	enum xdp_mem_type mem_type = xdp->rxq->mem.type;
 	bool release = skb_frag_size(frag) == shrink;
 
-	if (mem_info->type == MEM_TYPE_XSK_BUFF_POOL) {
-		bpf_xdp_shrink_data_zc(xdp, shrink, mem_info, release);
+	if (mem_type == MEM_TYPE_XSK_BUFF_POOL) {
+		bpf_xdp_shrink_data_zc(xdp, shrink, mem_type, release);
 		goto out;
 	}
 
 	if (release) {
 		struct page *page = skb_frag_page(frag);
 
-		__xdp_return(page_address(page), mem_info, false, NULL);
+		__xdp_return(page_address(page), mem_type, false, NULL);
 	}
 
 out:
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 0fde1bb54192..b1b426a9b146 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -427,12 +427,12 @@ EXPORT_SYMBOL_GPL(xdp_rxq_info_attach_page_pool);
  * is used for those calls sites.  Thus, allowing for faster recycling
  * of xdp_frames/pages in those cases.
  */
-void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct,
+void __xdp_return(void *data, enum xdp_mem_type mem_type, bool napi_direct,
 		  struct xdp_buff *xdp)
 {
 	struct page *page;
 
-	switch (mem->type) {
+	switch (mem_type) {
 	case MEM_TYPE_PAGE_POOL:
 		page = virt_to_head_page(data);
 		if (napi_direct && xdp_return_frame_no_direct())
@@ -455,7 +455,7 @@ void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct,
 		break;
 	default:
 		/* Not possible, checked in xdp_rxq_info_reg_mem_model() */
-		WARN(1, "Incorrect XDP memory type (%d) usage", mem->type);
+		WARN(1, "Incorrect XDP memory type (%d) usage", mem_type);
 		break;
 	}
 }
@@ -472,10 +472,10 @@ void xdp_return_frame(struct xdp_frame *xdpf)
 	for (i = 0; i < sinfo->nr_frags; i++) {
 		struct page *page = skb_frag_page(&sinfo->frags[i]);
 
-		__xdp_return(page_address(page), &xdpf->mem, false, NULL);
+		__xdp_return(page_address(page), xdpf->mem_type, false, NULL);
 	}
 out:
-	__xdp_return(xdpf->data, &xdpf->mem, false, NULL);
+	__xdp_return(xdpf->data, xdpf->mem_type, false, NULL);
 }
 EXPORT_SYMBOL_GPL(xdp_return_frame);
 
@@ -491,10 +491,10 @@ void xdp_return_frame_rx_napi(struct xdp_frame *xdpf)
 	for (i = 0; i < sinfo->nr_frags; i++) {
 		struct page *page = skb_frag_page(&sinfo->frags[i]);
 
-		__xdp_return(page_address(page), &xdpf->mem, true, NULL);
+		__xdp_return(page_address(page), xdpf->mem_type, true, NULL);
 	}
 out:
-	__xdp_return(xdpf->data, &xdpf->mem, true, NULL);
+	__xdp_return(xdpf->data, xdpf->mem_type, true, NULL);
 }
 EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);
 
@@ -513,7 +513,7 @@ EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);
 void xdp_return_frame_bulk(struct xdp_frame *xdpf,
 			   struct xdp_frame_bulk *bq)
 {
-	if (xdpf->mem.type != MEM_TYPE_PAGE_POOL) {
+	if (xdpf->mem_type != MEM_TYPE_PAGE_POOL) {
 		xdp_return_frame(xdpf);
 		return;
 	}
@@ -550,10 +550,11 @@ void xdp_return_buff(struct xdp_buff *xdp)
 	for (i = 0; i < sinfo->nr_frags; i++) {
 		struct page *page = skb_frag_page(&sinfo->frags[i]);
 
-		__xdp_return(page_address(page), &xdp->rxq->mem, true, xdp);
+		__xdp_return(page_address(page), xdp->rxq->mem.type, true,
+			     xdp);
 	}
 out:
-	__xdp_return(xdp->data, &xdp->rxq->mem, true, xdp);
+	__xdp_return(xdp->data, xdp->rxq->mem.type, true, xdp);
 }
 EXPORT_SYMBOL_GPL(xdp_return_buff);
 
@@ -599,7 +600,7 @@ struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp)
 	xdpf->headroom = 0;
 	xdpf->metasize = metasize;
 	xdpf->frame_sz = PAGE_SIZE;
-	xdpf->mem.type = MEM_TYPE_PAGE_ORDER0;
+	xdpf->mem_type = MEM_TYPE_PAGE_ORDER0;
 
 	xsk_buff_free(xdp);
 	return xdpf;
@@ -669,7 +670,7 @@ struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
 	 * - RX ring dev queue index	(skb_record_rx_queue)
 	 */
 
-	if (xdpf->mem.type == MEM_TYPE_PAGE_POOL)
+	if (xdpf->mem_type == MEM_TYPE_PAGE_POOL)
 		skb_mark_for_recycle(skb);
 
 	/* Allow SKB to reuse area used by xdp_frame */
@@ -716,8 +717,7 @@ struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf)
 	nxdpf = addr;
 	nxdpf->data = addr + headroom;
 	nxdpf->frame_sz = PAGE_SIZE;
-	nxdpf->mem.type = MEM_TYPE_PAGE_ORDER0;
-	nxdpf->mem.id = 0;
+	nxdpf->mem_type = MEM_TYPE_PAGE_ORDER0;
 
 	return nxdpf;
 }
-- 
2.47.0

Alexander Lobakin <aleksander.lobakin@intel.com> writes:

> Initially, xdp_frame::mem.id was used to search for the corresponding
> &page_pool to return the page correctly.
> However, after that struct page now contains a direct pointer to its PP,
> further keeping of this field makes no sense. xdp_return_frame_bulk()
> still uses it to do a lookup, but this is rather a leftover.
> Remove xdp_frame::mem and replace it with ::mem_type, as only memory
> type still matters and we need to know it to be able to free the frame
> correctly.
> As a cute side effect, we can now make every scalar field in &xdp_frame
> of 4 byte width, speeding up accesses to them.
>
> Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>

Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>

On Wed, 30 Oct 2024 17:51:53 +0100 Alexander Lobakin wrote:
> -	struct xdp_mem_info mem;
> +	enum xdp_mem_type mem_type:32;

There is a new use of this field coming in from c40dd8c4732
Can we wait for that to propagate to net-next ?
I don't have any great ideas on how we can conditionally apply
a fix up in the CI infra..
-- 
pw-bot: rfc

From: Jakub Kicinski <kuba@kernel.org>
Date: Thu, 31 Oct 2024 17:41:07 -0700

> On Wed, 30 Oct 2024 17:51:53 +0100 Alexander Lobakin wrote:
>> -	struct xdp_mem_info mem;
>> +	enum xdp_mem_type mem_type:32;
> 
> There is a new use of this field coming in from c40dd8c4732
> Can we wait for that to propagate to net-next ?
> I don't have any great ideas on how we can conditionally apply
> a fix up in the CI infra..

Good thing it happened already :D

Yeah I only need to assign mem_type instead of mem in that new place.
linux-next handles conflicts, but not our CI...

Thanks,
Olek

On Mon, 4 Nov 2024 15:36:34 +0100 Alexander Lobakin wrote:
> Yeah I only need to assign mem_type instead of mem in that new place.
> linux-next handles conflicts, but not our CI...

FWIW we do resolve (see the "(pull: resolved)" markings on the status
page) but this is a tricky case where the patch will likely apply but
build will fail. And if we add a local patch in the CI the build will
break if your series is _not_ pending.. So yeah I don't have any great
idea how to resolve such cases. It's first time it happened.